CN113585389A - Work vehicle magnetorheological fluid joystick system providing implement command guidance - Google Patents

Abstract

Translated fromChinese

本公开涉及提供机具命令引导的作业车辆磁流变流体操纵杆系统。具体地，作业车辆磁流变流体(MRF)操纵杆系统包括：操纵杆装置、MRF操纵杆阻力机构、控制器架构以及机具跟踪数据源，该机具跟踪数据源被配置成在作业车辆的操作期间跟踪机具的移动。该操纵杆装置又包括：基壳、操纵杆以及操纵杆位置传感器。该MRF操纵杆阻力机构能够被控制以改变阻碍相对于基壳的操纵杆移动的MRF阻力。该控制器架构被配置成：(i)利用由机具跟踪数据源提供的数据来跟踪机具相对于虚拟边界的移动；以及(ii)至少部分地基于相对于虚拟边界的机具移动，命令MRF操纵杆阻力机构改变MRF阻力。

The present disclosure relates to a work vehicle magnetorheological fluid joystick system that provides implement command guidance. Specifically, a work vehicle magnetorheological fluid (MRF) joystick system includes a joystick device, an MRF joystick resistance mechanism, a controller architecture, and a source of implement tracking data configured to during operation of the work vehicle Track the movement of implements. The joystick device further comprises: a base shell, a joystick and a joystick position sensor. The MRF joystick resistance mechanism can be controlled to vary the MRF resistance against movement of the joystick relative to the base housing. The controller architecture is configured to: (i) track movement of the implement relative to the virtual boundary using data provided by the implement tracking data source; and (ii) command the MRF joystick based at least in part on the movement of the implement relative to the virtual boundary The resistance mechanism changes the MRF resistance.

Description

Work vehicle magnetorheological fluid joystick system providing implement command guidance

Cross reference to related applicationsFork lift

This application claims priority from U.S. provisional application No.63/019,083 filed on united states patent and trademark office on day 1, month 5, 2020.

Technical Field

The present disclosure relates to work vehicle (work vehicle) magnetorheological fluid (MRF) joystick (joystick) systems that direct joystick-controlled positioning of a work vehicle implement (implementation) by variations in force applied through the MRF against (restraining) joystick movement.

Background

Joystick devices are commonly used to control various operational aspects of work vehicles employed within the construction, agricultural, forestry, and mining industries. For example, in the case of a work vehicle equipped with a boom (boom) assembly, an operator may utilize one or more joystick devices to control boom assembly movement, and thus, movement of a tool or implement mounted to an external terminal of the boom assembly. Common examples of work vehicles having such boom assemblies controlled via a joystick include: excavators (excavator), feller bunkers (feeder), skidders (skid), tractors (on which modular front end loader (loader) and backhoe (backhoe) attachments may be mounted), tractor loaders, wheel loaders, and various compact loaders. Similarly, in the case of bulldozers (dozers), motor graders (motor graders), and other work vehicles equipped with earth-moving blades, an operator may interface with one or more joysticks to control the movement and positioning of the blade. As in the case of motor graders, dozers, and certain loaders such as skid steer loaders, joystick devices are also commonly used to steer or otherwise control the directional movement of the work vehicle chassis itself. In view of the popularity of joystick devices within work vehicles, coupled with the relatively challenging dynamic environment in which work vehicles often operate, there is a continuing need to improve the design and functionality of work vehicle joystick systems, particularly to the extent that such advances may improve the safety and efficiency of work vehicle operations.

Disclosure of Invention

A work vehicle magnetorheological fluid (MRF) joystick system for use on a work vehicle is disclosed. In an embodiment, the work vehicle MRF joystick system comprises: a joystick device, an implement tracking data source, an MRF joystick resistance mechanism, and a controller architecture. The joystick device further includes: a base shell; a lever mounted to the base housing and movable relative to the base housing; and a joystick position sensor configured to monitor joystick movement relative to the base housing. The implement tracking data source is configured to track movement of the implement during operation of the work vehicle while the MRF joystick resistance mechanism can be controlled to vary the MRF resistance resisting (impedance) joystick movement relative to the base housing. The controller architecture is coupled to the MRF joystick resistance mechanism, the joystick position sensor, and the implement tracking data source. The controller architecture is configured to: (i) tracking movement of the implement relative to the virtual boundary using data provided by the implement tracking data source; and (ii) command the MRF joystick resistance mechanism to change the MRF resistance based at least in part on the implement movement relative to the virtual boundary.

In other embodiments, the work vehicle MRF joystick system includes: a joystick device, an MRF joystick resistance mechanism, and a controller architecture. The joystick device includes: a base shell; a lever mounted to the base housing and movable relative to the base housing; and a joystick position sensor configured to monitor joystick movement relative to the base housing. The MRF joystick resistance mechanism is at least partially integrated into the base housing and is controllable to selectively resist movement of the joystick relative to the base housing. A controller architecture coupled to the MRF joystick resistance mechanism and the joystick position sensor is configured to: (i) determining, when operator movement of the joystick in the operator input direction is detected, whether continued joystick movement in the operator input direction would cause the implement to be endangered violating the first virtual boundary; and (ii) upon determining that continued joystick movement in the operator input direction would cause the implement to be imminent in violation of the first virtual boundary, issue a command to the MRF joystick resistance mechanism to generate a first MRF resistance that resists continued joystick movement in the operator input direction.

In yet further implementations, the MRF joystick system includes a joystick device comprising: a lever rotatable relative to the base housing; an MRF joystick resistance mechanism controllable to selectively resist rotation of the joystick about at least one axis relative to the base housing; and an implement tracking data source configured to track movement of the implement during operation of the work vehicle. A controller architecture is coupled to the joystick device, the MRF joystick resistance mechanism, and the implement tracking data source. The controller architecture is configured to: (i) tracking movement of the implement relative to at least the first virtual boundary when the operator commands movement of the implement using the joystick device; and (ii) issuing a command to the MRF joystick resistance mechanism to change the MRF resistance resisting movement of the joystick in the at least one degree of freedom to provide tactile feedback to the operator indicating proximity of the implement to the first virtual boundary.

The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.

Drawings

At least one example of the disclosure will be described hereinafter in connection with the following figures:

FIG. 1 is a schematic illustration of an example magnetorheological fluid (MRF) joystick system on a work vehicle (here, an excavator) as exemplified in accordance with an example embodiment of the present disclosure;

FIG. 2 is a perspective view from within the excavator cab shown in FIG. 1 illustrating two joystick devices that may be included in the example MRF joystick system and used by an operator to control movement of an excavator motor arm assembly;

FIGS. 3 and 4 are cross-sectional schematic views, as partially shown and taken along a vertical section through the joystick, of an example MRF joystick system illustrating one possible configuration of the MRF joystick system;

FIG. 5 is a flow chart of an example process suitably performed by a controller architecture of the MRF joystick system to vary the MRF resistance that selectively inhibits joystick movement as a function of implement movement relative to one or more virtual boundaries;

FIG. 6 is a schematic diagram of one manner in which the excavator shown in FIG. 1 may be used to mine an excavation feature, while the controller architecture of the MRF joystick system performs the process set forth in FIG. 5 in an exemplary use case; and

fig. 7 is a diagram illustrating, in a non-exhaustive manner, additional example work vehicles in which embodiments of MRF joystick systems may be advantageously integrated.

Like reference symbols in the various drawings indicate like elements. For simplicity and clarity of illustration, descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the illustrative and non-limiting embodiments of the invention described in the following detailed description. It should also be understood that the features or elements shown in the figures are not necessarily drawn to scale unless otherwise indicated.

Detailed Description

Embodiments of the present disclosure are illustrated in the figures that are briefly described above. Various modifications to the example embodiments may be devised by those skilled in the art without departing from the scope of the present invention as set forth in the appended claims. As presented herein, the term "work vehicle" includes all portions of a work vehicle. Thus, in implementations where the boom-assembly terminating in an implement is attached to the chassis of a work vehicle, the term "work vehicle" encompasses both the chassis and the boom-assembly, as well as implements mounted to the end of the boom-assembly.

SUMMARY

Disclosed below is a work vehicle magnetorheological fluid (MRF) joystick system that provides implement command guidance (implement command guidance) through controlled variation of resistance applied through the MRF that resists joystick movement in one or more degrees of freedom (DOF). Embodiments of the MRF joystick system include a processing subsystem or "controller architecture" operatively coupled to the MRF joystick drag mechanism; that is, mechanisms, devices or dampers that contain magnetorheological fluids and are capable of modifying the rheology (viscosity) of the fluid through changes in Electromagnetic (EM) field strength to provide controlled adjustment of the resistance to joystick movement along at least one DOF. This resistance is referred to hereinafter as the "MRF resistance," and the degree to which the MRF resistance opposes joystick motion in a particular direction or combination of directions is referred to as the "joystick stiffness" in the relevant direction.

During operation of the MRF joystick system, the controller architecture provides the desired implement command guidance by inhibiting a change in MRF resistance to joystick movement. Specifically, in embodiments of the MRF joystick system, the controller architecture may command the MRF joystick resistance mechanism to change the MRF resistance in accordance with the joystick-controlled implement movement relative to one or more virtual boundaries. When joystick movement occurs in a particular direction (referred to herein as the "operator input direction"), the controller architecture determines whether continued joystick movement in the operator input direction will bring the implement into a predetermined proximity (proximity) to one or more virtual boundaries established by the controller in a three-dimensional (3D) volume of space. If it is determined that continued joystick movement in the operator input direction will bring the implement into a predetermined proximity to the virtual boundary, the controller architecture issues a command to the MRF joystick resistance mechanism to generate an MRF resistance that inhibits (deterring) continued joystick movement in the operator input direction. In doing so, the MRF joystick system passes through the associated joystick and provides tactile cues to the operator to slow (if not stop) the movement of the joystick in the direction of the operator input.

If the operator continues to turn (or otherwise move) the joystick in the direction of operator input, the controller architecture may repeat the above process to progressively increase the joystick resistance. For example, in one approach, the controller architecture issues a command to the MRF joystick resistance mechanism to increase the MRF resistance against joystick movement in the operator input direction as the joystick-controlled implement approaches proximity to the virtual boundary, where the MRF resistance increases approximately in proportion to a decrease in the distance or separation between the implement and the virtual boundary. Additionally or alternatively, the controller architecture may determine when a joystick-controlled implement is imminent violation of a virtual boundary; for example, the prediction occurs within a relatively short time frame (e.g., about one second or less). When it is determined that the implement is imminent violating a virtual boundary, the controller architecture may issue a command to the MRF joystick resistance mechanism to generate a maximum MRF resistance that resists further joystick movement in the operator input direction. In an embodiment, the maximum MRF resistance can be sufficient to completely resist (arrest) joystick movement in the direction of operator input, or at least make such joystick movement relatively difficult, to further block (if not prevent) the implement from violating the virtual boundary. In still other cases, when the implement violates such a virtual boundary, the controller architecture may generate a haptic cue, such as a brief resistance pulse or a sensory stop (tent).

In various operational scenarios, the MRF-based joystick guidance scheme described above and the corresponding virtual boundaries are usefully established. Such virtual boundaries may be advantageously utilized, for example, in connection with the operation of a bulldozer, motor grader, excavator, backhoe, or similar work vehicle equipped with (e.g., integrated) grade control systems, wherein the MRF joystick system provides MRF-generated haptic feedback (MRF-generated grade feedback) to assist the operator in positioning the implement in a manner that imparts a desired grade or topology to the surface. In particular, in such embodiments, the altitude coordinates defined by the design data loaded into the on-board computer of the work vehicle may be used to establish such a virtual boundary and generate a varying MRF resistance effect based on the proximity of an implement (e.g., a cutting edge of the implement) relative to the virtual boundary. Similarly, in other excavation operations, virtual boundaries may be established corresponding to surfaces of trenches or other excavation features created as desired with an excavation tool or excavation implement used as a work vehicle. For example, in at least some embodiments, the virtual boundary may be established in the form of a two-dimensional (2D) or 3D excavation floor (excavation floor), which may represent a lower threshold, desirably avoiding further excavation below the excavation floor. In still other cases, the controller of the MRF joystick system may establish a virtual boundary around or adjacent obstacles (e.g., buried conduits or electrical conduits) to prevent or at least inhibit operator joystick commands that might otherwise cause the implement to undesirably approach or contact such obstacles during performance of an excavation task. Likewise, the virtual boundaries described below may also be used to help guide movement of a joystick-controlled implement during non-excavation work tasks. For example, at this latter point, a virtual boundary in the form of a virtual ceiling may be established to limit the above-ground height to which a bucket or other implement may be raised; for example, it may be useful as when a work vehicle, such as a tractor equipped with a front end loader (FEL:) attachment, is operating in an enclosed structure (e.g., a grain silo), a mine, or a work area where elevated obstacles exist.

In the manner described above, embodiments of the MRF joystick system provide intuitive tactile guidance during joystick-controlled movement of the implement to enhance the operator's awareness of implement movement relative to one or more virtual boundaries. This, in turn, may assist or guide the operator in commanding implement movement with a greater degree of accuracy, increased efficiency, and with a reduced likelihood of accidental or problematic implement movement. Furthermore, the use of MRF techniques to direct joystick input motion provides several benefits over the use of other mechanisms (e.g., brake mechanisms and manual force feedback (AFF) motors) that can potentially selectively limit joystick motion. As one such benefit, the rheological properties (e.g., viscosity) of a given magnetorheological fluid can generally be adjusted in a relatively precise, apparent, and rapid manner by varying the strength of the EM field immersed in the magnetorheological fluid. Since the strength of the EM field may likewise be varied in a controlled and responsive manner, the MRF joystick resistance mechanism may provide a highly simplified, low-hysteresis response time, e.g., on the order of a few milliseconds (ms) or less. Furthermore, the MRF joystick resistance mechanism is able to accurately vary the strength of the MRF resistance over a substantially continuous range. These characteristics may enable the MRF joystick device to generate a variety of different haptic resistance effects that may be felt by the work vehicle operator, including selectively applying stops, and suppressing continuous changes in MRF resistance to joystick movement in a particular direction. As a further benefit, MRF joystick systems may provide reliable low noise operation in combination with the use of non-toxic (e.g., carbonyl iron containing) magnetorheological fluids.

An example embodiment of a work vehicle MRF joystick system will now be described in conjunction with fig. 1-6. In the examples described below, the MRF joystick system is discussed primarily in the context of a particular type of work vehicle (i.e., excavator). Additionally, in the following example, the MRF joystick system includes two joystick devices having joysticks that are rotatable about two perpendicular axes and used to control movement of an excavator boom assembly and an implement (e.g., a bucket) attached to the boom assembly. In further implementations, the MRF joystick system may include a greater or lesser number of joysticks, and each joystick device may be moved in any number of DOF and along any suitable motion pattern (motion pattern), notwithstanding the following examples; for example, in alternative embodiments, a given joystick may rotate about a single axis, or may also be constrained to move along a predetermined trajectory (e.g., an H-shaped trajectory) or motion pattern. Further, the MRF joystick system described below may be deployed on a wide range of work vehicles including joystick-controlled functions, additional examples of which are discussed below in connection with fig. 7.

Example MRF joystick System providing implement Command guidance

Referring initially to fig. 1, an example work vehicle (here, excavator 20) equipped with a work vehicle MRF joystick system 22 is presented. In addition to the MRF joystick system 22, theexcavator 20 includes aboom assembly 24 that terminates in an implement or tool (such as a bucket 26). Various other implements may be interchanged withbucket 26 and attached to the terminal end of boom-set 24, including other buckets, grapples, and hammers, for example. Theexcavator 20 has a body orchassis 28, a trackedundercarriage 30 supporting thechassis 28, and acab 32 located at the front of thechassis 28 and surrounding an operator's station. Theexcavator boom assembly 24 extends from thechassis 28 and includes, as major structural components, an inboard or proximal boom 34 (hereinafter referred to as "boom 34"), an outboard or distal boom 36 (hereinafter referred to as "dipper stick (dipper) 36"), and a plurality ofhydraulic cylinders 38, 40, 42.Hydraulic cylinders 38, 40, 42 in turn comprise: twolift cylinders 38, adipper handle cylinder 40, and adipper cylinder 42. Extension and retraction of thelift cylinder 38 rotates thelift arm 34 about a first pivot joint where thelift arm 34 is coupled to the excavator chassis 28 (here, a position adjacent (to the right of) the cab 32). Extension and retraction of thedipper handle cylinder 40 rotates thedipper 36 about a second pivot joint where the dipper handle 36 is coupled to theboom 34. Finally, extension and retraction of thebucket cylinder 42 rotates or "curls" theexcavator bucket 26 about a third pivot joint where thebucket 26 is engaged to thedipper handle 36.

Thehydraulic cylinders 38, 40, 42 are included in an electro-hydraulic (EH)actuation system 44, which EHactuation system 44 is surrounded in FIG. 1 by aframe 46 entitled "actuators for joystick controlled functions". Movement of the excavatorouter assembly 24 is controlled with at least one joystick located within theexcavator cab 32 and included in the MRF joystick system 22. Specifically, an operator may control extension and retraction ofhydraulic cylinders 38, 40, 42 using one or more joysticks included in MRF joystick system 22, and control the swing action ofboom assembly 24 via rotation ofexcavator chassis 28 relative to trackedundercarriage 30. The depicted EHactuation system 44 also includes various other hydraulic components not illustrated, which may include flow lines (e.g., flexible hoses), check valves or relief valves, pumps, fittings, filters, and the like. Additionally, the EHactuation system 44 includes an electronic valve actuator and a flow control valve (such as a spool-type multiplex valve) that may be modulated to regulate the flow of pressurized hydraulic fluid into and out of thehydraulic cylinders 38, 40, 42. Given that thecontroller architecture 50 described below is capable of controlling movement of the boom-assembly 24 via commands sent to selected ones of theactuators 46 that implement the joystick-controlled functions of theexcavator 20, the particular configuration or architecture of the EHactuation system 44 set forth herein is largely immaterial to the embodiments of the present disclosure.

As schematically illustrated in the upper left portion of fig. 1, work vehicle MRF joystick system 22 includes one or moreMRF joystick devices 52, 54. As presented herein, the term "MRF joystick device" refers to an operator input device that includes at least one joystick or control lever whose movement may be selectively resisted by utilizing an MRF joystick resistance mechanism of the type described herein. While one suchMRF joystick device 52 is schematically illustrated in fig. 1 for clarity, the MRF joystick system 22 may include any practical number of joystick devices, as indicated by thesymbol 58. In the case of theexample excavator 20, the MRF joystick system 22 will typically include two joystick devices; such as thejoystick devices 52, 54 described below in connection with fig. 2. The manner in which twosuch joystick devices 52, 54 may be used to control the movement of theexcavator arm assembly 24 is discussed further below. However, a general discussion of thejoystick device 52 as schematically illustrated in fig. 1 is first provided to set up a general framework that may better understand embodiments of the present disclosure.

As schematically illustrated in fig. 1, theMRF joystick device 52 includes ajoystick 60 mounted to a lower support structure orbase housing 62. Thejoystick 60 is movable relative to thebase housing 62 in at least one DOF and is rotatable relative to thebase housing 62 about one or more axes. In the depicted embodiment, and as indicated byarrow 64, thelever 60 of theMRF lever device 52 is rotatable about two perpendicular axes relative to thebase housing 62, and as such will be described below. TheMRF joystick device 52 includes one or morejoystick position sensors 66 for monitoring the current position and movement of thejoystick 60 relative to thebase housing 62. Variousother components 68 may also be included in theMRF joystick device 52, including: buttons, dials, switches, or other manual input features, which may be located on thejoystick 60 itself, on thebase housing 62, or a combination of the two. Spring members (gas or mechanical springs), magnets or fluid dampers may be incorporated into thejoystick device 52 to provide a desired return rate for the home position of the joystick, as well as to fine tune the desired feel or "stiffness" of thejoystick 60 as perceived by the operator when interacting with theMRF joystick device 52. In more complex assemblies, various other assemblies (e.g., potentially including one or more AFF motors) may also be incorporated into theMRF joystick device 52. In other implementations, such components may be omitted from theMRF joystick device 52.

The MRFjoystick resistance mechanism 56 is at least partially integrated into thebase housing 62 of theMRF joystick device 52. MRF joystick resistance mechanism 56 (as well as the other MRF joystick resistance mechanisms mentioned herein) may alternatively be referred to as an "MRF damper", an "MRF brake device", or simply an "MRF device". The MRFjoystick resistance mechanism 56 can be controlled to adjust the MRF resistance, and thus the joystick stiffness, to resist movement of the joystick relative to thebase housing 62 in at least one DOF. During operation of the MRF joystick system 22, thecontroller architecture 50 may selectively issue commands to the MRFjoystick resistance mechanism 56 to increase the joystick stiffness to resist joystick rotation about a particular axis or combination of axes. As discussed more fully below, thecontroller architecture 50 may issue commands to the MRFjoystick resistance mechanism 56 to apply such MRF resistance by increasing the strength of the EM field at least partially immersed in the magnetorheological fluid contained in themechanism 56. A generalized example of one manner in which the MRFjoystick resistance mechanism 56 may be implemented is described below in conjunction with fig. 3 and 4. When it is determined that continued rotation of thejoystick 60 in a particular direction (referred to herein as the "operator input direction") would result in the implement moving to a defined proximity of a virtual boundary or a virtual boundary violation, thecontroller architecture 50 may issue a command to the MRFmotion resistance mechanism 56 to generate such MRF resistance. In the case ofexcavator 20, in particular,controller architecture 50 determines that continued rotation ofjoystick 60 included in MRF joystick device 52 (and/or continued rotation of another joystick included in a second, similar MRF joystick device) will result in bucket 26 (or another portion of boom assembly 24) moving to a defined proximity of a virtual boundary and/or will result inbucket 26 moving past the virtual boundary.

In terms of the manner in which rotation of the joystick 60 (and/or a second joystick included in the MRF joystick system 22) results in the projection of movement of theexcavator boom assembly 24 relative to the virtual boundary or boundaries in question, thecontroller architecture 50 takes into account inputs from a plurality of data sources, including a plurality ofnon-joystick sensors 70 on theexcavator 20. Suchnon-stick sensors 70 may include sensors included in an implement tracking data source, and implement trackingdata source 72 may include any sensor or data source that provides information related to a change in position, speed, heading, or orientation ofexcavator 20. A sensor system adapted to monitor the position and movement of theexcavator chassis 28 includes: a GPS module; a sensor from which the rotation rate of the undercarriage tracks can be calculated; an electronic compass; and MEMS devices (such as accelerometers and gyroscopes) that may be packaged as one or more IMUs. Similarly, in an embodiment, the orientation of theexcavator chassis 28 relative to gravity (or another reference direction) may be monitored with one or more MEMS devices or tilt sensors (inclinometers) secured to thechassis 28.

Implement trackingdata source 72 may also include any number and type of boom-set tracking sensors adapted to track the position and movement of excavator boom-set 24. In an embodiment, such a sensor may comprise: a rotary or linear variable displacement transducer integrated intoexcavator boom assembly 24. For example, in one possible implementation, a rotational position sensor may be integrated into the pivot joint of boom-assembly 24; and the angular displacement readings captured by the rotational position sensor, in combination with the known dimensions of boom-assembly 24 (as recalled from memory 48), may be used to track the attitude and position of boom-assembly 24 (including bucket 26) in three-dimensional space. In other cases, the extension and retraction ofhydraulic cylinders 38, 40, 42 may be measured (e.g., using linear variable displacement sensors) and used to calculate the current pose and position of theexcavator arm assembly 24. In addition to or in lieu of the foregoing sensor readings, thecontroller architecture 50 may also consider other sensor inputs, such as inertia-based sensor readings (e.g., sensor readings captured by an IMU incorporated into the boom-assembly 24) and/or vision system tracking of the excavator implement, to name a few examples.

In an embodiment,excavator 20 may also be equipped withgrade control system 74. Suchgrade control system 74 may be integrated into an excavator; or instead added to the excavator via after-market equipment modification; for example, the retrofitting of external masts (external masts) and cables.Grade control system 74 may be a two-dimensional or three-dimensional system that utilizes design data to calculate the position of the edge of a work vehicle implement (e.g., bucket 26) based on the current position of the implement and, more generally, the work vehicle in a realistic context. Typically, this is achieved by: loading a data file containing a desired terrain layout onto a work vehicle computing system; and correlate the desired topographical layout to the machine location as monitored, for example, using a GPS module on the work vehicle. A visual guide (e.g., ondisplay device 82 described below) may then be generated, which the operator may rely on when controlling the work vehicle to position the cutting edge of the implement in a manner suitable for achieving the desired grade. Such systems are now deployed on excavators, bulldozers, motor graders, and similar work vehicles commonly used for excavation purposes.

Thenon-joystick sensor input 70 may also include one or more sensors that provide data indicative of local ground level or altitude. For example, in an embodiment,excavator 20 may be equipped with a relatively comprehensive (e.g., 360 degree) obstacle detection system that provides highly accurate, wide-range detection of obstacles near the work vehicle, for example, using lidar (radar), radar (radar), or ultrasonic sensor arrays. When present, thecontroller architecture 50 may utilize such an obstacle detection system to estimate the excavated ground height to thechassis 28 of theexcavator 20. In other cases, thecontroller architecture 50 may estimate the terrain differently; for example, the excavated ground height is estimated by using a calibration process in which the operator places thebucket 26 on the ground and then estimates the position of thebucket 26. Such data may be useful, for example, for: the operator is allowed to specify a desired vertical position of a virtual ceiling or a virtual base defining an operational envelope (operational envelope) by inputting data indicating an above-ground height or an below-ground height of an upper boundary or a lower boundary, respectively, of such boundaries.

In various implementations, thenon-joystick sensor input 70 may also include sensors related to obstacle detection. Such sensors may be included in an obstacle detection system that provides relatively wide range detection (e.g., 360 degree detection) of obstacles near the work vehicle, for example, using lidar, radar, or ultrasonic sensor arrays. In an embodiment, such an obstacle detection system may also detect obstacles near theexcavator 20 through visual analysis or image processing of live camera feeds provided by one or more cameras located around theexcavator 20. Such obstacle detection data (as collected by an obstacle detection system on the excavator 20) may then be placed on a vehicle bus (e.g.,CAN bus 84 described below), or may otherwise be provided to thecontroller architecture 50, for consideration in embodiments where theexcavator 20 establishes one or more virtual boundaries with respect to such obstacles, as discussed further below. Similarly, in an embodiment, thecontroller architecture 50 may recall from thememory 48 data mapping the location of obstacles near theshovel 20, which may be associated with the shovel location using GPS or another tracking method. Such obstacles, which it may be desirable to avoid during an excavation task performed withexcavator 20, may include, for example, buried conduits, electrical conduits, or other such structures. With such obstacle mapping data recalled from thememory 48, as a geographic reference for the current shovel position, thecontroller architecture 50 may establish a virtual wall that defines or borders an operational envelope (bording) within which it is desirable to maintain thedipper 26, such as when digging a trench or other digging feature at a location adjacent the shovel.

Embodiments of the MRF joystick system 22 may also include any number of additionalnon-joystick components 78, such as anoperator interface 80, adisplay device 82 located in theexcavator cab 32, and various other non-illustrated component types typically included in work vehicles. In particular, theoperator interface 80 may include any number and type of non-joystick input devices for receiving operator inputs, such as buttons, switches, knobs, and similar manual inputs external to theMRF joystick device 52. Such input devices included inoperator interface 80 may also include a cursor-type input device, such as a trackball or joystick, for interacting with a Graphical User Interface (GUI) generated ondisplay device 82.Display device 82 may be disposed withincab 32 and may take the form of any image-generating device on which visual alerts and other information may be visually presented. Thedisplay device 82 may also generate a GUI that receives operator inputs, which may be related to thecontroller architecture 50 when performing the processes described below, or may include other inputs (e.g., buttons or switches) that receive operator inputs. In some cases, thedisplay device 82 may also have touch input capabilities.

As further schematically depicted in fig. 1, acontroller architecture 50 is associated with thememory 48 and may communicate with the various illustrated components through any number of wired data connections, wireless data connections, or any combination thereof; for example, as generally illustrated, thecontroller architecture 50 may receive data from the various components over a centralized vehicle bus, such as a Controller Area Network (CAN)bus 84. As presented herein, the term "controller architecture" is utilized in a non-limiting sense to generally refer to the processing subsystems of a work vehicle MRF joystick system, such as the exemplary MRF joystick system 22. Thus, thecontroller architecture 50 may encompass or may be associated with any practical number of processors, individual controllers, computer-readable memory, power supplies, storage devices, interface cards, and other standardized components. In many cases, thecontroller architecture 50 may include a local controller directly associated with the joystick interface, as well as other controllers disposed within the operator station enclosed by thecab 32, and the local controller communicates with other controllers on theexcavator 20 as needed. Thecontroller architecture 50 may also include or cooperate with any number of firmware and software programs or computer-readable instructions designed to perform various processing tasks, calculations, and control functions described herein. Such computer readable instructions may be stored in a non-volatile sector ofmemory 48 associated with (accessible to)controller architecture 50. Although illustrated generally as a single block in fig. 1,memory 48 may encompass any number and type of storage media suitable for storing computer-readable code or instructions, as well as other data for supporting the operation of MRF joystick system 22. In an embodiment, thememory 48 may be integrated into thecontroller architecture 50, such as a system-in-package, a system-on-chip, or another type of microelectronic package or module, for example.

Discussing the joystick configuration or layout ofexcavator 20 in more detail, the number of joystick devices included in MRF joystick system 22, as well as the structural aspects and functionality of such joysticks, will vary from one implementation to another. As previously mentioned, although only asingle joystick device 52 is schematically illustrated in fig. 1, MRF joystick systems 22 typically have twojoystick devices 52, 54 that support control of the excavator arm assembly. Further illustrating this, fig. 2 provides a perspective view from within theexcavator cab 32 and depicts twoMRF joystick devices 52, 54 suitably included in an embodiment of the MRF joystick system 22. As can be seen, theMRF joystick devices 52, 54 are disposed on opposite sides of the operator'sseat 86 so that the operator can simultaneously manipulate both the leftMRF joystick device 52 and theright joystick device 54 with relative ease using both hands. Continuing with the reference numerals introduced above in connection with fig. 1, eachlever device 52, 54 includes alever 60, thelever 60 being mounted to a lower support structure orbase housing 62 for rotation relative to thebase housing 62 about two perpendicular axes. Thejoystick devices 52, 54 also each include a flexible cover or boot (boot)88, the flexible cover or boot 88 being engaged between the lower portion of thejoysticks 60 and theirrespective base housings 62. Additional joystick inputs are also provided on eachjoystick 60 in the form of thumb-accessible buttons, and may also be provided on thebase housing 62 as other manual inputs (e.g., buttons, dials, and/or switches) not illustrated. Other salient features of theexcavator 20 shown in fig. 2 include theaforementioned display device 82 and pedal/lever mechanisms 90, 92, which pedal/lever mechanisms 90, 92 control the respective movement of the left and right tracks of the trackedundercarriage 30.

Different control schemes may be utilized to translate movement of thejoystick 60 included in thejoystick devices 51, 54 into corresponding movement of the excavatormotor arm assembly 24. In many cases,excavator 20 will support boom-assembly control in either of a "backhoe control" or "SAE control" mode and an "international standards organization" or "ISO" control mode (and typically allow switching between these modes). For the case of the backhoe control mode, movement of theleft joystick 60 to the left of the operator (arrow 94) causes the excavatormotor arm assembly 24 to swing in a left direction (corresponding to counterclockwise rotation of thechassis 28 relative to the tracked undercarriage 30), movement of theleft joystick 60 to the right of the operator (arrow 96) causes the excavatormotor arm assembly 24 to swing in a right direction corresponding to clockwise rotation of thechassis 28 relative to the tracked undercarriage 30), movement of theleft joystick 60 in a forward direction (arrow 98) lowers thelift arm 34, and movement of theleft joystick 60 in a rearward (aft or return) direction (arrow 100) raises thelift arm 34. Also, for the case of the backhoe control mode, movement of theright joystick 60 to the left (arrow 102) causes thebucket 26 to roll inward, movement of theright joystick 60 to the right (arrow 104) causes thebucket 26 to spread (uncurl) or "open", movement of theright joystick 60 in a forward direction (arrow 106) causes the dipper handle 36 to rotate outward, and movement of theright joystick 60 in a rearward direction (arrow 108) causes the dipper handle 36 to rotate inward. In comparison, for the case of the ISO control mode, the stick motions for the swing command and the bucket roll command remain unchanged, while the stick maps of the boom and the dipper stick are reversed (reversed). Thus, in the ISO control mode, forward and rearward movement of theleft operating lever 60 controls dipper stick rotation in the manner described above, while forward and rearward movement of theright operating lever 60 controls movement (raising and lowering) of theboom 34 in the manner described above.

Referring now to fig. 3 and 4, an exemplary configuration of theMRF joystick device 52 and MRFjoystick resistance mechanism 56 is shown in two simplified cross-sectional schematic views. Although these figures illustrate a single MRF joystick device (i.e., MRF joystick device 52), the following description applies equally to anotherMRF joystick device 54 included in the example MRF joystick system 22. The following description is provided by way of non-limiting example only, noting that a number of different joystick designs incorporating or functionally cooperating with an MRF joystick resistance mechanism are possible. Given that meaningful changes in the rheological properties (viscosity) of a magnetorheological fluid occur in conjunction with controlled changes in the EM field strength (as described below), the particular composition of the magnetorheological fluid is also largely immaterial to embodiments of the present disclosure. For the sake of completeness, however, it is noted that a magnetorheological fluid composition well suited for use in embodiments of the present disclosure includes magnetically permeable (e.g., carbonyl iron) particles dispersed in a carrier fluid consisting primarily by weight of an oil or alcohol (e.g., ethylene glycol). Such magnetically permeable particles may have an average diameter in the micrometer range (or other maximum cross-sectional dimension if the particles have a non-spherical (e.g., oblong) shape); for example, in one embodiment, spherical magnetically permeable particles having an average diameter between 1 micron and 10 microns are used. Various other additives, such as dispersants or diluents, may also be included in the magnetorheological fluid to fine tune its properties.

Referring now to the example joystick configuration shown in fig. 3 and 4, and again as appropriate continuing with the previously introduced reference numbers, theMRF joystick device 52 includes ajoystick 60 having at least two distinct portions or structural regions: an upper handle 110 (only a simplified lower portion of which is shown in this figure), and a generally spherical lower base 112 (hereinafter, referred to as "generallyspherical base 112"). The generallyspherical base 112 of thejoystick 60 is captured between twowalls 114, 116 of thebase housing 62, which may extend generally parallel to each other to form an upper portion of thebase housing 62. A vertically aligned central opening is provided through thehousing walls 114, 116 and the respective diameter of the central opening is sized to be smaller than the diameter of the generallyspherical base 112. The spacing or vertical offset between thewalls 114, 116 is also selected such that the generallyspherical base 112 is captured entirely between the vertically spacedhousing walls 114, 116 to form a ball and socket joint. This allows thejoystick 60 to rotate relative to thebase housing 62 about two perpendicular axes corresponding to the X-axis and Y-axis of the coordinatelegend 118 appearing in fig. 3 and 4; while generally preventing translational movement ofjoystick 60 along the X-axis, Y-axis, and Z-axis of coordinatelegend 118. In other embodiments, various other mechanical arrangements may be employed to mount the joystick to the base housing while allowing the joystick to rotate about two perpendicular axes (such as a gimbal arrangement). In a less complex embodiment, a pivot (pivot) or pin joint (pin joint) may be provided to allowjoystick 60 to rotate about a single axis relative tobase housing 62.

Thejoystick 60 of theMRF joystick device 52 also includes a stab (stinger) orlower joystick extension 120 that projects from the generallyspherical base 112 in a direction opposite thejoystick handle 110. In the illustrated schematic, thelower lever extension 120 is coupled to the stationary attachment point of thebase housing 62 by asingle return spring 124; note here that this arrangement is simplified for illustrative purposes, and a more complex spring return arrangement (or other lever biasing mechanism, if any) would typically be employed in a practical implementation of theMRF lever apparatus 52. When thelever 60 is displaced from the neutral position or home position shown in fig. 3, thereturn spring 124 is biased to urge thelever 60 back toward the home position (fig. 3), as shown in fig. 4. Thus, by way of example, if the work vehicle operator subsequently releases the lever handle 110 after rotating to the position shown in FIG. 4, thelever 60 will return to the neutral or home position shown in FIG. 3 under the influence of thereturn spring 124.

The example MRFjoystick resistance mechanism 56 includes afirst MRF cylinder 126 and a second MRF cylinder 128 as shown in fig. 3 and 4, respectively. A first MRF cylinder 126 (fig. 3) is mechanically engaged between thelower lever extension 120 and a partially illustrated static attachment point or basestructural feature 130 of thebase housing 62. Similarly, a second MRF cylinder 128 (fig. 4) is mechanically engaged between thelower joystick extension 120 and thestationary attachment point 132 of thebase housing 62, and the MRF cylinder 128 is rotated approximately 90 degrees about the Z-axis of the coordinatelegend 118 for theMRF cylinder 126. Due to this structural configuration, the MRF cylinder 126 (FIG. 3) may be controlled to selectively resist rotation of thejoystick 60 about the X-axis of the coordinatelegend 118, while the MRF cylinder 128 (FIG. 4) may be controlled to selectively resist rotation of thejoystick 60 about the Y-axis of the coordinatelegend 118. Additionally, bothMRF cylinders 126, 128 may be commonly controlled to selectively resist rotation of thejoystick 60 about any axis falling between the X and Y axes and extending within the X-Y plane. In other embodiments, different configurations of MRF cylinders may be utilized and include a greater or lesser number of MRF cylinders; for example, in implementations where it is desired to selectively resist rotation of thejoystick 60 about only the X-axis or only the Y-axis, or in implementations where thejoystick 60 can only rotate about a single axis, a single MRF cylinder or a pair of antagonistic (antagonistic) cylinders may be employed. Finally, although not shown in the simplified schematic, in further implementations, any number of additional groups may be included in or associated with theMRF cylinders 126, 128. Such additional components may include sensors that monitor the travel of thecylinders 126, 128 (if desired) to track, for example, the position of the joystick, in place of thejoystick sensors 182, 184 described below.

TheMRF cylinders 126, 128 each include acylinder block 134, withpistons 138, 140 slidably mounted to thecylinder block 134. Eachcylinder 134 contains a cylindrical cavity or bore 136 in which is mounted ahead 138 of one of thepistons 138, 140 for translational movement along a longitudinal axis or centerline of thecylinder 134. Around the periphery of the cavity or bore, eachpiston head 138 is fitted with one or more dynamic seals (e.g., O-rings) to sealingly engage the inner surface of thecylinder 134, thereby dividing thebore 136 into two opposing variable volume hydraulic chambers. Thepistons 138, 140 also each include anelongated piston rod 140, with thepiston rod 140 projecting from thepiston head 138 toward thelower lever extension 120 of thelever 60. Thepiston rod 140 extends through an end cap 142 fixed over the open end of the cylinder 134 (again, engaging any number of seals) to attach to thelower lever extension 120 at alever attachment point 144. In the illustrated example, thejoystick attachment point 144 takes the form of a pin or pivot joint; however, in other embodiments, more complex joints (e.g., ball joints) may be employed to form such mechanical couplings. Opposite thejoystick attachment point 144, opposite ends of theMRF cylinders 126, 128 are mounted to the respective stationary attachment points 130, 132 via ball joints 145. Finally,hydraulic ports 146, 148 are also provided in opposite ends of eachMRF cylinder 126, 128 to allow for the inflow and outflow of magnetorheological fluid in combination with the translational movement or stroke change of thepistons 138, 140 along the respective longitudinal axes of theMRF cylinders 126, 128.

TheMRF cylinders 126, 128 are fluidly interconnected with corresponding MRF valves (valve)150, 152 viaflow line connections 178, 180, respectively. As with theMRF cylinders 126, 128, theMRF valves 150, 152 are shown as identical in the illustrated example, but may be varied in further implementations. Although referred to as a "valve" in general terms (particularly in view of theMRF valves 150, 152 function to control the flow of magnetorheological fluid), it will be observed that in the present example, theMRF valves 150, 152 lack valve components and other moving mechanical parts. As a beneficial corollary, theMRF valves 150, 152 provide fail-safe operation, as magnetorheological fluid is still allowed to pass through theMRF valves 150, 152 with relatively little resistance in the unlikely event of failure of the MRF valves. Thus, if either or both of theMRF valves 150, 152 fail for any reason, the ability of the MRFjoystick resistance mechanism 56 to apply a resistance that limits or inhibits joystick movement may be compromised; however, thejoystick 60 will be free to rotate about the X and Y axes in a manner similar to conventional non-MRF joystick systems, and theMRF joystick device 52 will still generally be able to control theexcavator boom assembly 24.

In the depicted embodiment,MRF valves 150, 152 each include avalve housing 154, thevalve housing 154 includingend caps 156 secured to opposite ends of anelongated core 158. A generally annular ortubular flow passage 160 extends around thecore 158 and between twofluid ports 162, 164, which are provided through the opposingend caps 156. Theannular flow channel 160 is surrounded by (extending through) a plurality of EM induction coils 166 (hereinafter referred to as "EM coils 166") that are wound around aparamagnetic holder 168 and interspersed with a plurality of axially or longitudinally spaced ferrite rings 170. Atubular housing 172 surrounds the assembly while a number of leads are provided through thetubular housing 172 to facilitate electrical interconnection with the housed EM coil 166. Two such leads, and corresponding electrical connections to the power and controlsource 177, are schematically represented in fig. 3 and 4 bylines 174, 176. As indicated byarrow 179, thecontroller architecture 50 is operatively coupled to the power and controlsource 177 in the following manner:controller architecture 50 is enabled to controlsource 177 to vary the current supplied to or the voltage applied across EM coil 166 during operation of MRF joystick system 22. Thus, this structural arrangement may enable thecontroller architecture 50 to command or control the MRFjoystick resistance mechanism 56 to vary the strength of the EM field generated by the EM coils 166. Theannular flow passage 160 extends through the EM coil 166 (and may be substantially coaxial with the EM coil) such that the magnetorheological fluid passes through the center of the EM field as the magnetorheological fluid is directed through theMRF valves 150, 152.

Thefluid ports 162, 164 of theMRF valves 150, 152 are fluidly connected to theports 146, 148 of thecorresponding MRF cylinders 126, 128, respectively, by theconduits 178, 180 mentioned above. The length of theconduits 178, 180 may, for example, be sufficient to provide a flexible tube with sufficient slack to accommodate any movement of theMRF cylinders 126, 128 that occurs in conjunction with rotation of thejoystick 60. In this regard, consider the example scenario of FIG. 4. In this example, the operator has moved thejoystick handle 110 in the operator input direction (indicated by arrow 185) such that thejoystick 60 rotates in a clockwise direction about the Y-axis of the coordinatelegend 118. In conjunction with this joystick movement, the MRF cylinder 128 rotates about the ball joint 145 as shown to tilt slightly upward. Also, in conjunction with this operator controlled joystick movement, thepistons 138, 140 contained in the MRF cylinder 128, when retracted, cause thepiston tip 138 to move to the left in fig. 4 (toward the attachment point 132). The translational movement of thepistons 138, 140 urges the magnetorheological fluid to flow through theMRF valve 152 to accommodate a decrease in volume of the chamber to the left of thepiston head 138 and a corresponding increase in volume of the chamber to the right of thepiston head 138. Thus, at any time during such operator-controlled joystick rotation, thecontroller architecture 50 may vary the current supplied to the EM coil 166 or the voltage applied across the EM coil 166 to vary the force against the magnetorheological fluid flowing through theMRF valve 152 to achieve the desired MRF resistance against further stroke changes of thepistons 138, 140.

Given the responsiveness of the MRFjoystick resistance mechanism 56, thecontroller architecture 50 may control theresistance mechanism 56 to apply such MRF resistance only briefly, thereby increasing the strength of the MRF resistance in a predetermined manner (e.g., in a gradual or stepwise manner), while increasing the displacement of the piston, or providing various other resistance effects (e.g., tactile detent (detent) or pulsing (pulsing) effects), as discussed in detail below. Thecontroller architecture 50 may also control the MRFjoystick resistance mechanism 56 to selectively provide a resistive effect such as: thepistons 138, 140 included in theMRF valve 150 perform stroke changes in conjunction with rotation of thejoystick 60 about the X-axis of the coordinatelegend 118. Further, the MRFjoystick resistance mechanism 56 is capable of independently varying the EM field strength generated by the EM coils 166 within theMRF valves 150, 152 to allow independent control of the MRF resistance that inhibits rotation of the joystick about the X and Y axes of the coordinatelegend 118.

TheMRF joystick device 52 may also include one or morejoystick position sensors 182, 184 (e.g., optical or non-optical sensors or transformers) that monitor the position or movement of thejoystick 60 relative to thebase housing 62. In the example shown, in particular, theMRF joystick device 52 comprises: a first joystick position sensor 182 (FIG. 3) that monitors rotation of thejoystick 60 about the X-axis of the coordinatelegend 118; and a second joystick position sensor 184 (fig. 4) that monitors rotation of thejoystick 60 about the Y-axis of the coordinatelegend 118. The data connections between thejoystick position sensors 182, 184 and thecontroller architecture 50 are represented bylines 186, 188, respectively. In further implementations, theMRF joystick device 52 may include various other non-illustrated components, such as may include an MRFjoystick resistance mechanism 56. Such components may include operator inputs and corresponding electrical connections provided on thejoystick 60 orbase housing 62, AFF motors, and pressure and/or flow rate sensors included in the flow circuit of the MRFjoystick resistance mechanism 56, as appropriate, to best suit a particular application or use.

As previously emphasized, the above-described embodiment of theMRF joystick device 52 is provided by way of non-limiting example only. In alternative implementations, the configuration of thejoystick 60 may differ in various respects. Provided that the MRFjoystick resistance mechanism 56 is controllable by thecontroller architecture 50 to selectively apply a resistance (through a change in rheology of the magnetorheological fluid) to inhibit movement of the joystick relative to the base housing in at least one DOF, in further embodiments, the MRFjoystick resistance mechanism 56 also differs for the examples shown in fig. 3 and 4. In further implementation, an EM induction coil similar or identical to EM coil 166 may be integrated directly intoMRF cylinders 126, 128 to provide the desired controllable MRF resistance effect. In this implementation, magnetorheological fluid flow between the variable volume chambers within a givenMRF cylinder 126, 128 may be permitted via one or more orifices provided through thepiston head 138 by providing an annulus (annular) or slightly smaller annular gap around thepiston head 138 and the inner surface of thecylinder 134, or by providing a flow passage through thecylinder 134 or the sleeve itself. Advantageously, this configuration may give the MRF joystick resistance mechanism a relatively compact integrated design. In comparison, in at least some instances, the use of one or more external MRF valves, such asMRF valves 150, 152 (fig. 3 and 4), can facilitate cost-effective manufacturing and allow the use of commercially available modular components.

In still other implementations, the MRF joystick device design may allow the magnetorheological fluid to wrap around (envelop) and act directly on the lower portion of thejoystick 60 itself (such as thespherical base 112 in the case of the joystick 60), and the EM coil is placed around the lower portion of the joystick and surrounds the body of magnetorheological fluid. In such embodiments, thespherical base 112 may be provided with ribs, grooves or similar topological features to facilitate displacement of the magnetorheological fluid in conjunction with the lever rotation, wherein energizing the EM coil increases the viscosity of the magnetorheological fluid, thereby impeding fluid flow through the restricted flow passages provided around thespherical base 112, or may also be due to the magnetorheological fluid turning in conjunction with the lever rotation. In further embodiments of the MRF joystick system 22, various other designs are also possible.

Regardless of the particular design of the MRFjoystick resistance mechanism 56, the use of MRF techniques that selectively produce a variable MRF resistance that dampens (resists or prevents) problematic joystick movement provides a number of advantages. As a major advantage, in terms of the rheology of the magnetorheological fluid, and ultimately in terms of the MRF resistance to damping of the joystick motion over a highly shortened period (e.g., in some cases, a period of about 1 ms); the MRF joystick resistance mechanism 56 (and typically the MRF joystick resistance mechanism) has a high responsivity and can achieve the desired variation in EM field strength. Accordingly, the MRFjoystick resistance mechanism 56 may enable MRF resistance to be removed (or at least greatly reduced) with equal rapidity by rapidly reducing the current flowing through the EM coil and allowing the rheology (e.g., fluid viscosity) of the magnetorheological fluid to return to its normal, non-irritating state. Thecontroller architecture 50 may also control the MRFjoystick resistance mechanism 56 to generate MRF resistance to have a continuous range of intensities or intensity (intensity) within limits by utilizing corresponding changes in the intensity of the EM field generated by the EM coil 166. Advantageously, the MRFjoystick resistance mechanism 56 may provide reliable, substantially noise-free operation over extended periods of time. Additionally, the magnetorheological fluid may be formulated to be non-toxic in nature, such as when the magnetorheological fluid comprises iron carbonyl particles dispersed in an alcohol-based or oil-based carrier fluid, as previously described. Finally, as a further advantage, the above-described configuration of the MRFjoystick resistance mechanism 56 may enable the MRF joystick system 22 to selectively generate a first resistance force to inhibit rotation of the joystick about a first axis (e.g., the X-axis of the coordinatelegend 118 in fig. 3 and 4), while also selectively generating a second resistance force independent of the first resistance force to inhibit rotation of the joystick about a second axis (e.g., the Y-axis of the coordinate legend 118); that is, the first resistance and the second resistance are made to have different magnitudes as needed.

Referring now to fig. 5, anexample process 190 suitably performed by thecontroller architecture 50 of the MRF joystick system 22 is shown, theexample process 190 selectively varying the MRF resistance that inhibits joystick movement as a function of implement movement relative to one or more virtual boundaries. Process 190 (hereinafter referred to as "implementcommand guidance process 190") includes a plurality of process steps 192, 194, 196, 198, 200, 202, 204, 206, 208, 210, each of which is described in turn below.Steps 204, 206, 208, 210 are further grouped into a hierarchical (graded) MRFforce generation sub-process 212. The various steps illustrated generally in fig. 5 may require a single process or multiple sub-processes depending on the particular manner in which implement toolcommand guidance process 190 is implemented. Furthermore, the steps illustrated in fig. 5 and described below are provided by way of non-limiting example only. In alternative embodiments of the implementcommand guide process 190, additional process steps may be performed, certain steps may be omitted, and/or the illustrated process steps may be performed in an alternative order.

In response to the occurrence of a predetermined triggering event, implementcommand guidance process 190 begins atstep 192. The triggering event may be, for example, the activation of a work vehicle (e.g.,excavator 20 shown in fig. 1 and 2), or alternatively, the input of an operator input requesting that implementcommand guidance process 190 be enabled; for example, in one embodiment, an operator may interact with a GUI generated ondisplay device 82 to initiate implementcommand guidance process 190. In other cases,controller architecture 50 may automatically (i.e., without operator input) begin implementcommand guidance process 190 when it is determined that the work vehicle is engaged in a particular type of work task, such as a digging or grading task. For example, in the case of an excavator (e.g.,excavator 20 shown in fig. 1 and 2), a backhoe, a dozer, a motor grader, or similar work vehicle,controller architecture 50 may automatically initiate implementcommand guidance process 190 when a bucket, blade, or similar excavation implement attached to the work vehicle is lowered to a ground-penetrating position, when a stabilizer arm of the work vehicle is lowered (in the case of a backhoe), or when an operator provides input indicating an impending excavation operation. As a further possibility, thecontroller architecture 50 may initiate the implementcommand guidance process 190 in response to detecting a different predetermined condition or event. As another example, in implementations where a virtual boundary is established around or adjacent to a detected obstacle,controller architecture 50 may begin implementcommand guidance process 190 when a sensor on the work vehicle (e.g., included innon-joystick sensor 76 shown in fig. 1) detects a nearby obstacle near the work vehicle.

After initiating the implementcommand guidance process 190, thecontroller architecture 50 proceeds to step 194 and collects pertinent non-stick data inputs utilized in executing the remainder of theprocess 190. Such data entry will typically include receiving current implement tracking data that is used to monitor the position of the implement or tool controlled via the joystick relative to the body or chassis of the work vehicle. Thus, for the case ofexcavator 20, data from boom-assembly tracking sensor 72 may be received atcontroller architecture 50 duringstep 194 of implementcommand guidance process 190. Thecontroller architecture 50 then uses this data to estimate the position of the bucket 26 (or other implement) coupled to the external terminal end of theboom assembly 24 in the 3D volume of space or "tool space" adjacent theexcavator chassis 28. As described above, such machine tracking data may include data captured by an accelerometer, gyroscope, magnetometer, or other such MEMS device (e.g., packaged as an IMU), data from an inclinometer, or data from similar sensors disposed onboom assembly 24. Additionally or alternatively, the angular displacement of the pivot joints about theboom assembly 24 and/or the linear displacement of thehydraulic cylinders 38, 40, 42 may be considered in conjunction with known kinematics (regarding assembly dimensions) to estimate the positional movement of thebucket 26 in 3D tool space. As a further possibility, in embodiments, image analysis from one or more video feeds captured by the vision system may also be utilized for implement movement. Generally, any type of data suitable for tracking positioning may then be collected by thecontroller architecture 50 duringstep 194 of the implementcommand guidance process 190, and the orientation of the movable implement in 3D space may also be collected.

Other data may also be collected duringstep 194 and considered by thecontroller architecture 50 in establishing the location, orientation, and/or geometry of one or more virtual boundaries within the 3D tool space, as further considered during the hierarchical MRF force generation sub-process 212 (described below). This may include data related to local ground height, ground slope (slope), and/or other terrain characteristics provided by on-board sensors (e.g.,non-stick sensors 70 ofexcavator 20 shown in fig. 1), as may be determined using ranging equipment or other sensors integrated into the work vehicle. Such data may be useful when establishing the location of at least one virtual boundary (e.g., the excavation base described below), for example, using the local ground height as a reference point. Operator input data relating to the virtual boundary may also be input via theoperator interface 80 and further considered by thecontroller architecture 50 duringstep 194 in executing theprocess 190. Such operator input may, for example, specify a desired position and/or orientation of one or more virtual boundaries, such as a subsurface depth (and possibly a slope) of a virtual excavation base, an above-ground height of a virtual ceiling, or other data indicative of a desired location (and possibly orientation) or one or more virtual boundaries.

In embodiments in which the work vehicle is equipped with a grade control system, such asgrade control system 74 of example excavator 20 (fig. 1), data from the grade control system may be provided tocontroller architecture 50; such as via placement on thevehicle bus 84. Thecontroller architecture 50 may then utilize this data (referred to herein as "grade target data") to establish the position and orientation of the virtual excavation base (and geometry when the virtual excavation base is three-dimensional or non-planar) using data provided by thegrade control system 74. Thus, in such implementations, the work vehicle in question (e.g., a bulldozer or motor grader) may be moved relative to the virtual excavation base while an operator repeatedly positions a work vehicle implement (e.g., a blade) using the associated joystick device or devices to displace the underlying earth (or other material) in a controlled manner to create a desired surface topology that generally conforms to the virtual excavation base. As a further possibility, when such data is used to generate a virtual boundary as described below, data indicative of the location of any nearby obstacles may be collected duringstep 194, such as, for example, a keep-out zone (keep out zone) or a virtual barrier that blocks accidental contact between the implement and nearby obstacles. Again, such obstacle detection data may be provided by a suitable sensor array (e.g., a sensor array included in theadditional sensors 76 as shown in fig. 1) that measures energy signals (e.g., laser pulses, acoustic pulses, or radar pulses) reflected from obstacles in the vicinity of the work vehicle.

Proceeding to step 198 of the implementcommand guidance process 190, thecontroller architecture 50 receives data indicative of the current joystick movement and position of the MRF joystick device or devices under consideration. In the case of theexample excavator 20, thecontroller architecture 50 receives data from thejoystick position sensors 182, 184 that describes the movement of therespective joysticks 60 included in thedevices 52, 54. Thecontroller architecture 50 utilizes this data to determine whether an operationally significant (apparent-significant) movement of one or more joysticks has occurred during the current iteration of the implementcommand guidance process 190. If such joystick movement is detected, thecontroller architecture 50 proceeds to a hierarchical MRFforce generation sub-process 212, described below. Otherwise, thecontroller architecture 50 proceeds to step 200 and determines whether the current iteration of the implementcommand guidance process 190 should terminate; for example, due to a work vehicle shutdown, due to continued inactivity of a function controlled via the joystick for a predetermined period of time, or due to removal of a condition or triggering event initially initiated atstep 192 in response toprocess 190. If it is determined that the implementcommand guidance process 190 should terminate atstep 200, thecontroller architecture 50 proceeds to step 202, whereupon theprocess 190 terminates. If instead it is determined that the implementcommand guidance process 190 should continue, thecontroller architecture 50 returns to step 194 and the above process steps repeat.

In response to detecting an operationally significant joystick rotation (or other joystick movement) atstep 202, thecontroller architecture 50 advances to a hierarchical MRFforce generation sub-process 212 of the implementcommand guidance process 190. As indicated in fig. 5, thecontroller architecture 50 may issue commands to the MRFjoystick resistance mechanism 56 during thesub-processing module 212 to generate a range of resistance or stiffness responses, for example, based on the proximity of an implement (e.g., thebucket 26 of the excavator 20) to one or more virtual boundaries established by thecontroller architecture 50 in the real 3D volume of space. In this regard, and as discussed more fully below, the hierarchical MRFforce generation sub-process 212 may be performed to provide a range of MRF resistance responses to implement movement relative to one or more virtual boundaries, which may define or interface (loader) an operational envelope within which an implement controlled via a joystick is desirably constrained. In other, less complex implementations, thecontroller architecture 50 may control theMRF resistance mechanism 56 to provide a single haptic feedback effect that, for example, indicates implement movement relative to one or more virtual boundaries. For example, in a simplified approach, thecontroller architecture 50 may issue a command to the MRF resistance mechanism to generate a sensory stop, a brief pulsing resistance effect, or the like upon detecting an implement violating a virtual boundary. Similarly, in other embodiments, thecontroller architecture 50 may control the MRFjoystick resistance mechanism 56 to provide a single MRF applied effect (rather than a graded or gradually changing MRF resistance response of the type described below) to block virtual boundary violations in other ways; for example, thecontroller architecture 50 may issue a command to the MRFjoystick resistance mechanism 56 to generate a maximum MRF resistance that prevents or impedes further joystick-controlled implement movement corresponding to the current operator input direction when, or just before, the implement violates the virtual boundary.

In performing the hierarchical MRFforce generation sub-process 212, thecontroller architecture 50 may determine the location of the virtual boundary in any suitable manner. In some cases, and as discussed above, thecontroller architecture 50 may utilize operator input data received via theoperator interface 80 to establish the location of the virtual boundary. Such operator input may, for example, specify a vertical (e.g., underground) depth of the excavation base, which is a vertical depth at which the implement controlled by the joystick is desirably maintained above the excavation base during the work task. Thecontroller architecture 50 may measure such subsurface depths along a vertical axis (parallel to gravity) from any suitable spatial reference point, such as local ground height. Similarly, the operator input may specify a vertical (e.g., above-ground) height at which the implement is desirably maintained below the virtual ceiling. In some cases, the MRF joystick system 22 may also allow the operator to adjust the slope or orientation of such virtual boundaries via interaction with theoperator interface 80; for example, by interacting with a GUI generated on thedisplay device 82 to set a grade or slope of the virtual excavation base, as described below in connection with fig. 6. In still other cases, the positioning of such virtual boundaries or excavation bases may be determined using data provided by a grade control system, such as thegrade control system 74 on theexample excavator 20 shown in fig. 1, where the virtual excavation base has a 2D (planar) or 3D (non-planar) geometry that generally conforms to the target grade data provided by the grade control system.

In further implementations, and as also discussed above, the location of one or more virtual boundaries may be determined using data provided by the obstacle detection system on the work vehicle under consideration. For example, in the case of theexample excavator 20, thecontroller architecture 50 may utilize data received from the (e.g., obstacle detection)sensors 76 to establish one or more virtual boundaries that are spatially positioned to reduce the likelihood of accidental contact between a joystick-controlled implement and a detected obstacle (such as a sidewall of a structure, another work vehicle, or another physical object in the vicinity of the work vehicle). This is useful, for example, whenexcavator 20 or another work vehicle is utilized to dig a trench or other adjacent excavation feature for the adjacent obstacle. In other cases, thecontroller architecture 50 may recall from thememory 48 the obstacle location or map data when establishing the spatial location of one or more virtual boundaries to be utilized in executing the sub-process 212. Thecontroller architecture 50 may then utilize such stored map data to establish a virtual boundary between the implement and any mapped obstacles (e.g., buried pipes, buried electrical conduits, power lines, etc.) to help maintain a desired spatial offset for a forbidden zone between the implement and the obstacle, or to otherwise reduce the likelihood of accidental contact with such obstacles while performing a work task (such as digging a trench or other excavation feature) with theexample excavator 20 described in fig. 1.

Atstep 204 of the hierarchical MRFforce generation sub-process 212, thecontroller architecture 50 determines whether continued joystick rotation in the direction of the operator input would cause the joystick-controlled implement to be imminent in violation of a virtual boundary. In an embodiment,controller architecture 50 may determine duringstep 204 whether any portion of an implement (which may be boom-set 24 in the case of exemplary excavator 20) would violate a virtual boundary. In other implementations, thecontroller architecture 50 may only consider whether a particular portion of the implement being controlled via the joystick (such as the edge of the implement) is currently violating the virtual boundary under consideration or is at risk of being violating the virtual boundary under consideration. In making this determination, thecontroller architecture 50 may utilize any suitable processing or spatial modeling technique (a few of which have been outlined above) to track the movement of the implement in 3D space relative to one or more virtual boundaries. If duringstep 204 ofsub-process 212, it is determined that continued joystick rotation (or other movement) in the operator input direction would result in an imminent stick violation of a virtual boundary by the implement being controlled by the joystick, thecontroller architecture 50 issues a command to theMRF resistance mechanism 56 to generate an MRF resistance that inhibits continued joystick rotation in the operator input direction. In an implementation, thecontroller architecture 50 may issue a command to the MRFjoystick resistance mechanism 56 to generate a maximum MRF resistance that attempts to prevent further joystick rotation in the operator input direction; or at least make continuous rotation of the joystick in the direction of operator input relatively difficult. Thus, violation of the virtual boundary by the implement can be avoided, whether by physically preventing joystick movement in the problematic direction or by communicating a very noticeable tactile signal to the operator to terminate continued joystick rotation in the problematic direction. After the desired MRF resistance effect is applied (step 200), thecontroller architecture 50 then proceeds to step 200 to determine whether the implementcommand guidance process 190 should continue or terminate.

Conversely, if duringstep 204, it is determined that continued joystick rotation in the operator input direction does not result in an imminent virtual boundary violation of the implement controlled by the joystick, thecontroller architecture 50 proceeds to step 206 of the hierarchical MRFforce generation sub-process 212. Duringstep 206, thecontroller architecture 50 evaluates whether continued joystick rotation in the operator input direction will bring the implement into a predetermined proximity to the virtual boundary. If it is determined that this is not the case, thecontroller architecture 50 proceeds to step 200 and again considers whether the current iteration of theprocess 190 should terminate. Otherwise, the controller architecture proceeds to step 210 and issues a command to the MRFjoystick resistance mechanism 56 to generate an increasing MRF resistance that opposes joystick movement in the operator input direction. In doing so, the MRF joystick system 22 generates an intuitive tactile cue (e.g., communicated to the operator by the associated joystick device) that indicates that the implement controlled by the joystick is approaching a virtual boundary. If such MRF resistance has not been applied, thecontroller architecture 50 may issue a command to the MRFjoystick resistance mechanism 56 to initially generate MRF resistance that inhibits further rotation of the joystick in the direction of the operator input. Conversely, if such MRF resistance has been previously applied, thecontroller architecture 50 may issue a command to the MRFjoystick resistance mechanism 56 to increase the magnitude of the MRF resistance. In the latter case, the MRF resistance may be increased in a gradual (step-wise or continuous) manner to the extent that joystick rotation in the direction of operator input continues and the joystick-controlled implement is incrementally moved toward the virtual boundary under consideration. Through multiple iterations ofstep 210, thecontroller architecture 50 may issue commands to the MRFjoystick resistance mechanism 56 to change the MRF resistance such that the MRF resistance increases approximately in proportion to the separation distance between the implement and the virtual boundary as the implement approaches or approaches the virtual boundary. Afterstep 210, thecontroller architecture 50 proceeds to step 200 and again determines whether the current iteration of theprocess 190 should terminate or continue.

As implementcommand guidance process 190 is repeatedly executed in the manner just described,controller architecture 50 of MRF joystick system 22 selectively commands MRFjoystick resistance mechanism 56 to change the MRF resistance against joystick movement based at least in part on implement movement relative to one or more virtual boundaries. In doing so, MRF joystick system 22 provides implement command guidance (e.g., such as intuitive tactile cues) to the work vehicle operator to slow (if not stop) the movement of the joystick in the direction of operator input at the appropriate time to violate the prevention virtual boundary. Furthermore, where the controller architecture commands the MRF joystick resistance mechanism to generate the maximum MRF resistance, the MRF resistance can be sufficient to make joystick movement in the direction of operator input very difficult, or can also physically prevent continued joystick movement in the problematic direction. In this manner, MRF joystick system 22 may assist an operator in controlling the implement via one or more joystick devices, such as imparting a desired grade or topology to the terrain, excavating excavation features to a desired size (e.g., a desired depth or slope), reducing the likelihood of an undesirable impact between the implement and a nearby obstacle, and/or providing various other functions for guiding a joystick-controlled implement mounted to a work vehicle. For completeness, an example use case scenario in which implementcommand guidance process 190 may be advantageously performed during operation ofexample excavator 20 is further described below in conjunction with fig. 6.

Fig. 6 illustrates an example scenario in which theexcavator 20 described above is used to perform a mining or excavation task to create anexcavation feature 216 within the ground 214 of a work area. In this example, thecontroller architecture 50 of the MRF joystick system 22 has established a lower virtual boundary or excavation base in the 3D tool space as represented byhorizontal line 220. The MRF joystick system 22 can be operated in a cut depth limiting mode to prevent (or at least inhibit) the operator from controlling the implement attached via the boom assembly (here, thebucket 26 attached to the digging boom assembly 24) to cut thedigging feature 216 to an excessive depth. The location and possibly orientation of theexcavation base 220 can be established from data recalled from thememory 48 and with reference to the current location of the excavation machine 20 (e.g., as determined from a GPS module on the excavation machine 20). Alternatively, the position of theexcavation base 220 may be established from operator input data entered into the MRF joystick system 22 via the operator interface 80 (fig. 1). For example, in an embodiment, the operator may input a ground level or "set excavation depth" at which thevirtual excavation base 220 is desirably positioned. As indicated above, such underground depths; for example, a depth measured in a downward direction along thevertical axis 224 from the local groundheight reference point 218 that is substantially parallel to the direction of gravity. To establish this reference point, thecontroller architecture 50 may measure the local ground height with an appropriate sensor (e.g., a laser-based sensor or ranging device included in the sensor 76); determining a local ground height using a calibration process in which the operator controls boom-assembly 24 to restbucket 26 on the ground, whereincontroller architecture 50 then calculates the local ground height using data from boom-assembly tracking sensor 72 and known kinematics of boom-assembly 24; or the local ground level is estimated as a default setting relative to the work vehicle chassis.

In addition to or instead of establishing thevirtual digging base 220, thecontroller architecture 50 of the MRF joystick system 22 may establish any number of additional virtual boundaries that are referenced during subsequent digging tasks. For example, in an embodiment, thecontroller architecture 50 may also establish an upper boundary or virtual ceiling 226 below which the implement 26 (and perhaps all portions of the boom-assembly 24) is desirably maintained. Thecontroller architecture 50 may establish the position of the virtual ceiling in any suitable manner, including based on operator input or data provided by an obstacle detection system on theexcavator 20. In one approach, for example, the MRF joystick system 22 may receive an operator input specifying a desired above-ground height of the virtual ceiling 226 (as measured along avertical axis 228 extending parallel to the direction of gravity). The above-described process of changing the MRF joystick stiffness or resistance based on implement proximity to the virtual ceiling 226 may then be performed in a manner similar to that described above. The provision of a virtual ceiling 226 may be useful in the following embodiments: where excavator 20 (or another work vehicle) is operated in an enclosed environment, such as a grain silo or mine, or whenexcavator 20 is operated in an outdoor environment where elevated obstructions (e.g., branches or overhanging structural features) are present.

In various implementations, thecontroller architecture 50 of the MRF joystick system 22 utilizes data provided by the boomassembly tracking sensor 72 to track the position of the excavation implement (here, the excavator bucket 26) relative to these virtual boundaries or thresholds in generating either or both of thevirtual excavation base 220 and the virtual ceiling 226. As previously discussed above in connection withstep 194 ofprocess 190, boom-assembly tracking sensor 74 may include any type and number of sensors that monitor the movement of the excavation implement relative to the undercarriage or other fixed reference point ofexcavator 20. For example, in one approach, a rotational position sensor is integrated into the pivot joint of boom-assembly 24; and angular displacement readings captured by the rotational position sensor in conjunction with the known dimensions of boom-set 24 are used to track the position of the excavation implement (bucket 26), and may also track exclusively the position of the edge ofbucket 26 in 3D tool space. In addition to or in lieu of such rotational position readings, other sensor inputs may be considered, such as linear displacements ofhydraulic cylinders 38, 40, 42 integrated intoboom assembly 24, inertial-based sensor readings (as captured by MEMS devices (such as MEMS accelerometers or gyroscopes) incorporated into boom assembly 24), measurements captured by the sensors indicative of the current orientation ofexcavator chassis 28.

Regardless of the particular manner in which thebucket 26 is tracked, thecontroller architecture 50 repeatedly predicts when operator-commanded movement of the digging implementassembly 24 will cause thebucket 26 to violate the virtual digging base 220 (or virtual ceiling 226). When it is determined that operator-commanded movement of the excavation implementassembly 24 would result in a violation of thevirtual excavation base 220, thecontroller architecture 50 issues a command to the MRFjoystick resistance mechanism 56 to generate an MRF resistance that inhibits (or may be an attempt to inhibit) continued joystick movement in the operator input direction. This provides an intuitive tactile cue to the work vehicle operator to slow (if not stop) the movement of the joystick in the direction of the operator input. Further, where thecontroller architecture 50 commands the MRFjoystick resistance mechanism 56 to generate the maximum MRF resistance, the MRF resistance can be sufficient to completely prevent joystick movement in the direction of operator input (or at least make such joystick movement relatively difficult). Additionally or alternatively, assuming thebucket 26 is within a predetermined distance of thebase 220, thecontroller architecture 50 may also issue commands to the MRFstick resistance mechanism 56 to progressively increase the MRF resistance as the proximity of thebucket 26 to thevirtual digging base 220 increases. Similar processing may likewise be applied with respect to movement ofbucket 26 relative to virtual ceiling 226 to help maintain bucket 26 (and possibly other portions of boom assembly 24) below virtual ceiling 226.

In other embodiments, the MRF joystick system 22 may enable an operator to establish a dig in addition to or in lieu of thevirtual dig base 220 described aboveOther virtual (e.g., 2D planar or 3D non-planar) boundaries of features. For example, in some cases, thecontroller architecture 50 may prevent violation of a virtual sidewall of a digging feature, such as the back of a trench, during a given digging operation. This possibility is further indicated in fig. 6. The digging feature or trench illustrated therein is imparted with a back 222, the back 222 forming a desired angle (θ) with respect to avertical line 224 extending parallel to the direction of gravity_BF). During operation of theexcavator 20, as the operator drives the excavatormining excavation feature 216, the MRF joystick system may selectively increase the MRF resistance applied to the joystick 60 (fig. 1 and 2) for controlling boom assembly movement, preventing or at least inhibiting theback face 222 from being penetrated. Accordingly, tactile cues may be generated and communicated by a suitable joystick device to assist the operator in forming the surface of thedigging feature 216 to have a desired angle. For the case of trench backs 222, this may be particularly useful given that the operator cannot directly view the back 222 from thecab 32 of theexcavator 20. Similarly, in an embodiment, the desired grade may be defined via avirtual mining base 220, or may also be a non-planar 3D geometry, wherein the MRF joystick system then applies a change in MRF resistance to assist the operator in controlling theboom assembly 24 to mine theexcavation feature 216 to conform to the desired mining base. In the case of other work vehicles equipped with an Integrated Grade Control (IGC) system, such as a bulldozer or motor grader, a similar approach may be utilized to provide tactile cues to assist the operator in creating a desired gradient, as discussed further below in connection with fig. 7.

Additional examples of work vehicles advantageously equipped with an MRF joystick system

Thus, the foregoing has described an example of an MRF joystick system that provides implement command guidance through critical changes in MRF resistance that impede joystick movement along one or more DOF. While the foregoing description has focused primarily on a particular type of work vehicle (excavator) that includes a particular type of implement controlled via a joystick, the embodiments of the MRF joystick system described herein are suitable for integration into a wide range of work vehicles that include a joystick device for controlling movement of an implement, such as movement of a bucket (or other implement) attached to a terminal end of an articulated boom assembly, movement of a bucket attached to a terminal end of an FEL assembly, or movement of a blade movably coupled to a chassis of a motor grader, bulldozer, or another work vehicle, to name a few examples. The left part of fig. 7 illustrates an example work vehicle and the right part illustrates an example MRF joystick device. Three additional examples of such work vehicles are set forth specifically in the left portion of fig. 7, and include acrawler excavator 230, amotor grader 232, and abackhoe loader 234.

First with respect to thetrack dozer 230, thetrack excavator 230 may be equipped with an exampleMRF joystick device 236 disposed within thecab 238 of theexcavator 230. Operator movement of ajoystick 240 included inMRF joystick device 236 may position ablade 242 ofbulldozer 230,blade 242 being pivotally coupled to a bulldozer chassis 244 and a trackedundercarriage 246 via apush frame 248 and a plurality ofhydraulic cylinders 250, 252. Specifically, during operation of thetrack dozer 230, rotation of thejoystick 240 relative to the base housing of theMRF joystick device 236 may position theblade 242 via extension and retraction of thepitch cylinder 250 andlift cylinder 252. Analogs of the various components described above in connection with fig. 1 may be integrated into thetrack dozer 230 to provide MRF-applied guidance to the joystick input used to control the movement and positioning of the dozer blade 242 (more generally, an "excavator" or "implement") in the manner described above. For example, in one implementation where thetrack dozer 230 is equipped with a grade control system, the MRF joystick system including theMRF joystick device 236 may vary the joystick stiffness to assist the operator in positioning theblade 242 to achieve a desired grade as thetrack dozer 230 moves within the work area.

Turning next to theexample motor grader 232, twoMRF joystick devices 254 are disposed within acab 256 of themotor grader 232. Rotation of thejoystick 258 included in theMRF joystick device 254 positions ablade 260 suspended below a circular ring (circle)262, whichcircular ring 262 is mounted below afront frame 264 of themotor grader 232. Collectively, theshovel 260 and thetorus 262 form shovel-torus assemblies (blade-circle assembly)260, 262. In this case, rotation of thejoysticks 258 relative to their respective base housings can control theshovel position 260 via rotation of the circular ringrotary motor 266 in conjunction with stroke changes (extension and retraction) of thehydraulic cylinder 268. During operation of themotor grader 232, the MRF joystick system selectively varies the MRF resistance against rotation of thejoystick 258 to guide implement movement, and in particular, joystick movement, to control rotation of the blade-ring assemblies 260, 262, angular adjustment of the blade-ring assemblies 260, 262, and adjustment of the side-shift angle of theblade 260. In a manner similar to thetrack dozer 230, themotor grader 232 may be equipped with an IGC system (or a retread grade control system) that provides the controller architecture of the MRF joystick system with data indicative of the desired grade as themotor grader 232 is driven over the work area. The MRF joystick system then utilizes the target grade data provided by the grade control system to establish a virtual boundary corresponding to the desired grade, and changes the MRF resistance applied to thejoystick 258 based at least in part on implement movement relative to the virtual boundary. In this manner, intuitive tactile feedback is provided to the operator when positioning theshovel 260 at the appropriate time to achieve the desired target grade.

Referring finally to thebackhoe loader 234 depicted at the bottom-most portion of fig. 7, one or moreMRF joystick devices 270 may be positioned in acockpit 272 of thebackhoe loader 234. In this example, rotation of one ormore levers 274 included in the one or moreMRF lever devices 270 may be used to: controlling movement of aFEL assembly 276, theFEL assembly 276 terminating in aFEL bucket 278 and coupled to a front end of aloader chassis 280; controlling movement of abackhoe assembly 282, thebackhoe assembly 282 terminating in anFEL bucket 284 and being coupled to a rear end of theloader chassis 280; or both. TheMRF joystick device 270 may be controlled by the MRF joystick system described above to assist an operator in controlling theFEL assembly 276, thebackhoe assembly 282, or both, to excavate excavation features to a desired size (e.g., a desired depth), to avoid inadvertent contact with nearby obstacles, or to perform other functions. Specifically, in the case of thebackhoe assembly 282, the MRF joystick system on thebackhoe loader 234 may vary the MRF resistance of theMRF joystick device 270 to guide implement movement in a manner similar to that discussed above in connection with the example excavator shown in fig. 1 and 2. In comparison, in the case of theFEL assembly 276, the MRF joystick system may also increase the MRF resistance of theMRF joystick device 270 when thebackhoe loader 234 is operating inside a grain barn or another enclosed structure, for example, to prevent (or at least block) an operator joystick command from bringing theFEL bucket 278 to a raised position above a virtual ceiling.

Enumerated examples of work vehicle MRF joystick systems

For ease of reference, the following examples of work vehicle MRF joystick systems are also provided and numbered.

1. In an embodiment, a work vehicle MRF joystick system, comprising: a joystick device, an implement tracking data source, an MRF joystick resistance mechanism, and a controller architecture. The joystick device further includes: a base shell; a joystick mounted to the base housing and movable relative to the base housing; and a joystick position sensor configured to be able to monitor joystick movement relative to the base housing. The implement tracking data source is configured to track movement of the implement during operation of the work vehicle while the MRF joystick resistance mechanism is controllable to vary the MRF resistance resisting joystick movement relative to the base housing. The controller architecture coupled to the MRF joystick resistance mechanism, the joystick position sensor, and the implement tracking data source is configured to: (i) tracking movement of the implement relative to a virtual boundary using data provided by the implement tracking data source; and (ii) command the MRF joystick resistance mechanism to change the MRF resistance based at least in part on implement movement relative to the virtual boundary.

2. The work vehicle MRF joystick system of example 1, wherein the work vehicle is equipped with a grade control system. The controller architecture is coupled to the grade control subsystem and is configured to define the virtual boundary using grade target data provided by the grade control system.

3. The work vehicle MRF joystick system of example 2, wherein the work vehicle comprises a bulldozer or a motor grader, the implement takes the form of a blade, and the virtual boundary defines a virtual digging base.

4. The work vehicle MRF joystick system of example 1, wherein the virtual boundary takes the form of a virtual digging base. Further, the controller architecture is further configured to establish a position and orientation of the virtual excavation base in a 3D tool space through which the implement moves.

5. The work vehicle MRF joystick system of example 4, wherein the controller architecture establishes the position of the virtual excavation base based at least in part on a set excavation depth and a ground height reference point.

6. The work vehicle MRF joystick system of example 4, wherein the controller architecture establishes the orientation of the virtual excavation base based at least in part on operator input indicative of a target grade of an excavation feature desirably created with the implement.

7. The work vehicle MRF joystick system of example 1, wherein the controller architecture is configured to gradually increase the MRF resistance as the proximity of the implement to the virtual boundary increases.

8. The work vehicle MRF joystick system of example 1, wherein the controller architecture is configured to: (i) detecting joystick movement in an operator input direction; (ii) determining, when joystick movement in the operator input direction is detected, whether continued joystick movement in the operator input direction would cause the implement to immediately violate the virtual boundary; and (iii) upon determining that continued joystick movement in the operator input direction would result in imminent or immediate violation of the virtual boundary, issue a command to the MRF joystick resistance mechanism to generate a maximum MRF resistance to substantially stop continued joystick movement in the operator input direction.

9. The work vehicle MRF joystick system of example 8, wherein the controller architecture is further configured to: (i) upon determining that continued joystick movement in the operator input direction does not result in immediate violation of the virtual boundary, further determining whether continued joystick movement in the operator input direction would bring the implement into a predetermined proximity to the virtual boundary; and (ii) upon determining that continued joystick movement in the operator input direction would bring the implement into a predetermined proximity to the virtual boundary, issue a command to the MRF joystick resistance mechanism to generate an MRF resistance force less than the maximum MRF resistance force that resists continued joystick movement in the operator input direction.

10. The work vehicle MRF joystick system of example 1, wherein the controller architecture is configured to: (i) detecting joystick movement in an operator input direction; (ii) determining, when joystick movement in the operator input direction is detected, whether continued joystick movement in the operator input direction would cause the implement to immediately violate the virtual boundary; and (ii) upon determining that continued joystick movement in the operator input direction would result in immediate violation of the virtual boundary, issue a command to the MRF joystick resistance mechanism to generate a stopping or pulsing effect as the implement crosses the virtual boundary.

11. The work vehicle MRF joystick system of example 1, wherein the work vehicle includes a boom assembly having a terminal end to which the implement is attached. The controller architecture is configured to: (i) monitoring the joystick-commanded movement of the boom-assembly; and (ii) determine, based at least in part on the joystick-commanded movement of the boom-assembly, whether continued movement of the joystick in the operator-input direction would result in a virtual boundary violation.

12. The work vehicle MRF joystick system of example 11, wherein the virtual boundary includes a virtual ceiling under which the implement is desirably held.

13. The work vehicle MRF joystick system of example 12, further comprising an operator interface coupled to the controller architecture. The controller architecture is configured to position the virtual ceiling based at least in part on operator data specifying a ceiling height input by an operator via the operator interface.

14. The work vehicle MRF joystick system of example 1, wherein the controller architecture is further configured to: (i) estimating a spatial position of an obstacle relative to the work vehicle; and (ii) establishing a position of the virtual boundary based at least in part on the estimated spatial position of the obstacle such that the virtual boundary is located between the implement and the work vehicle.

15. The work vehicle MRF joystick system of example 1, wherein the controller architecture is configured to issue commands to the MRF joystick resistance mechanism to change the MRF resistance such that the MRF resistance increases substantially in proportion to a separation distance between the implement and the virtual boundary as the implement approaches the virtual boundary.

Conclusion

Thus, embodiments of MRF joystick systems have been described that guide joystick-controlled positioning of a work vehicle implement through intelligently applied changes in force applied through the MRF. In various implementations, the MRF joystick system may selectively impede or inhibit joystick movement based on implement movement relative to one or more virtual boundaries. This, in turn, may help or guide an operator in commanding movement of the implement when maneuvering with one or more joysticks with greater accuracy, increased efficiency, and, in some cases, reduced likelihood of undesirable impact between the implement and any nearby obstacles. In an embodiment, the virtual boundary may partially define or border an operational envelope to desirably maintain the implement within the operational envelope during a particular work task, such as a digging task. In other implementations, the virtual boundaries may be generated to conform to, or substantially conform to, the final grade topology or profile that is desired to be imparted to the surface of the earth over which a work vehicle (e.g., a dozer or motor grader) is traveling, in which case one or more of the virtual boundaries may be defined using a grade control system on the work vehicle, if present. In still other cases, the virtual boundaries may be used to set other thresholds that define a forbidden range or zone within which the implement controlled by the joystick desirably does not intrude; for example, such as when one or more virtual boundaries are established around an embedment, above-ground structure, or other obstacle, the virtual boundaries desirably prevent an implement attached to the work vehicle from inadvertently operating near such an obstacle.

As used herein, a description in the singular is intended to include the plural unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. The embodiments specifically referenced herein were chosen and described in order to best explain the principles of the disclosure and its practical application, and to enable others of ordinary skill in the art to understand the disclosure and recognize numerous alternatives, modifications, and variations to the described examples. Accordingly, various embodiments and implementations other than the ones explicitly described are within the scope of the following claims.

Claims (15)

Translated fromChinese

1.一种供在配备有机具(26)的作业车辆(20)上使用的作业车辆磁流变流体操纵杆系统(22)即作业车辆MRF操纵杆系统(22)，所述作业车辆MRF操纵杆系统(22)包括：1. A work vehicle magnetorheological fluid joystick system (22) for use on a work vehicle (20) equipped with an implement (26), namely a work vehicle MRF joystick system (22), the work vehicle MRF manipulation The rod system (22) includes:操纵杆装置(52、54)，所述操纵杆装置(52、54)包括：A joystick device (52, 54), the joystick device (52, 54) comprising:基壳(62)；base shell (62);操纵杆(60)，所述操纵杆(60)被安装至所述基壳(62)并且能够相对于所述基壳(62)移动；以及a joystick (60) mounted to the base housing (62) and movable relative to the base housing (62); and操纵杆位置传感器(66)，所述操纵杆位置传感器(66)被配置成，对相对于所述基壳(62)的操纵杆移动进行监测；a joystick position sensor (66) configured to monitor joystick movement relative to the base housing (62);机具跟踪数据源(72)，所述机具跟踪数据源(72)被配置成在所述作业车辆(20)的操做期间跟踪所述机具(26)的移动；an implement tracking data source (72) configured to track movement of the implement (26) during operation of the work vehicle (20);MRF操纵杆阻力机构(56)，所述MRF操纵杆阻力机构(56)能够被控制以改变阻碍相对于所述基壳(62)的操纵杆移动的MRF阻力；以及MRF joystick resistance mechanism (56), the MRF joystick resistance mechanism (56) being controllable to vary the MRF resistance against joystick movement relative to the base housing (62); and控制器架构(50)，所述控制器架构(50)联接至所述MRF操纵杆阻力机构(56)、所述操纵杆位置传感器(66)以及所述机具跟踪数据源(72)，所述控制器架构(50)被配置成：a controller architecture (50) coupled to the MRF joystick resistance mechanism (56), the joystick position sensor (66), and the implement tracking data source (72), the The controller architecture (50) is configured to:利用由所述机具跟踪数据源(72)提供的数据来跟踪所述机具(26)相对于虚拟边界(220、226)的移动；以及tracking the movement of the implement (26) relative to virtual boundaries (220, 226) using data provided by the implement tracking data source (72); and至少部分地基于相对于所述虚拟边界(220、226)的机具移动，来命令所述MRF操纵杆阻力机构(56)改变所述MRF阻力。The MRF joystick resistance mechanism (56) is commanded to vary the MRF resistance based at least in part on implement movement relative to the virtual boundaries (220, 226).2.根据权利要求1所述的作业车辆MRF操纵杆系统(22)，其中，所述作业车辆(20)配备有坡度控制系统(74)；并且2. The work vehicle MRF joystick system (22) of claim 1, wherein the work vehicle (20) is equipped with a grade control system (74); and其中，所述控制器架构(50)联接至所述坡度控制系统(74)，并且所述控制器架构(50)被配置成，利用由所述坡度控制系统(74)所提供的坡度目标数据来限定所述虚拟边界(220、226)。wherein the controller architecture (50) is coupled to the grade control system (74), and the controller architecture (50) is configured to utilize grade target data provided by the grade control system (74) to define the virtual boundaries (220, 226).3.根据权利要求2所述的作业车辆MRF操纵杆系统(22)，其中，所述作业车辆(20)包括推土机(230)或机动平地机(232)，所述机具(26)包括铲(242、260)，并且所述虚拟边界(220、226)限定了虚拟挖掘基底。3. The work vehicle MRF joystick system (22) of claim 2, wherein the work vehicle (20) comprises a bulldozer (230) or a motor grader (232) and the implement (26) comprises a shovel ( 242, 260), and the virtual boundaries (220, 226) define a virtual excavation base.4.根据权利要求1所述的作业车辆MRF操纵杆系统(22)，其中，所述虚拟边界(220、226)包括虚拟挖掘基底(220)；并且4. The work vehicle MRF joystick system (22) of claim 1, wherein the virtual boundary (220, 226) comprises a virtual excavation base (220); and其中，所述控制器架构(50)还被配置成，在所述机具(26)移动通过的三维3D工具空间中建立所述虚拟挖掘基底(220)的位置和取向。Wherein the controller architecture (50) is further configured to establish the position and orientation of the virtual excavation base (220) in the three-dimensional 3D tool space through which the implement (26) moves.5.根据权利要求4所述的作业车辆MRF操纵杆系统(22)，其中，所述控制器架构(50)至少部分地基于设定的挖掘深度以及地面高度基准点，来建立所述虚拟挖掘基底(220)的位置。5. The work vehicle MRF joystick system (22) of claim 4, wherein the controller architecture (50) establishes the virtual excavation based at least in part on a set excavation depth and ground level reference point The location of the substrate (220).6.根据权利要求4所述的作业车辆MRF操纵杆系统(22)，其中，所述控制器架构(50)至少部分地基于操作员输入来建立所述虚拟挖掘基底(220)的取向，所述操作员输入指示利用所述机具(26)如所希望地创建的挖掘特征的目标坡度。6. The work vehicle MRF joystick system (22) of claim 4, wherein the controller architecture (50) establishes the orientation of the virtual excavation base (220) based at least in part on operator input, whereby The operator input indicates a target grade for the excavation feature to be created as desired with the implement (26).7.根据权利要求1所述的作业车辆MRF操纵杆系统(22)，其中，所述控制器架构(50)被配置成，随着所述机具(26)到所述虚拟边界(220、226)的接近度的增加而逐渐地增加所述MRF阻力。7. The work vehicle MRF joystick system (22) of claim 1, wherein the controller architecture (50) is configured to follow the implement (26) to the virtual boundary (220, 226) ) gradually increases the MRF resistance.8.根据权利要求1所述的作业车辆MRF操纵杆系统(22)，其中，所述控制器架构(50)被配置成：8. The work vehicle MRF joystick system (22) of claim 1, wherein the controller architecture (50) is configured to:检测在操作员输入方向上的操纵杆移动；Detect joystick movement in the direction of operator input;当检测到在所述操作员输入方向上的操纵杆移动时，确定沿所述操作员输入方向的持续操纵杆移动是否会导致所述机具(26)濒临违反所述虚拟边界(220、226)；并且When joystick movement in the operator input direction is detected, it is determined whether continued joystick movement in the operator input direction would cause the implement (26) to verge on violating the virtual boundary (220, 226) ;and在确定沿所述操作员输入方向的持续操纵杆移动会导致立即违反所述虚拟边界(220、226)时，向所述MRF操纵杆阻力机构(56)发出命令，以生成最大MRF阻力，以在实质上停止沿所述操作员输入方向的持续操纵杆移动。Upon determining that continued joystick movement in the direction of the operator input would result in an immediate violation of the virtual boundary (220, 226), the MRF joystick resistance mechanism (56) is commanded to generate a maximum MRF resistance to Sustained joystick movement in the direction of the operator input is substantially stopped.9.根据权利要求8所述的作业车辆MRF操纵杆系统(22)，其中，所述控制器架构(50)还被配置成：9. The work vehicle MRF joystick system (22) of claim 8, wherein the controller architecture (50) is further configured to:在确定沿所述操作员输入方向的持续操纵杆移动不会导致立即违反所述虚拟边界(220、226)时，进一步确定沿所述操作员输入方向的持续操纵杆移动是否会使所述机具(26)达到与所述虚拟边界(220、226)的预定接近度；并且Upon determining that continued joystick movement in the operator input direction does not result in an immediate violation of the virtual boundary (220, 226), it is further determined whether continued joystick movement in the operator input direction will cause the implement (26) reaching a predetermined proximity to the virtual boundary (220, 226); and在确定沿所述操作员输入方向的持续操纵杆移动会使所述机具(26)达到与所述虚拟边界(220、226)的预定接近度时，向所述MRF操纵杆阻力机构(56)发出命令，以生成阻碍沿所述操作员输入方向的持续操纵杆移动的、比所述最大MRF阻力小的MRF阻力。Upon determining that continued joystick movement in the direction of the operator input will bring the implement (26) to a predetermined proximity to the virtual boundary (220, 226), the MRF joystick resistance mechanism (56) A command is issued to generate an MRF resistance less than the maximum MRF resistance that resists continued joystick movement in the direction of the operator input.10.根据权利要求1所述的作业车辆MRF操纵杆系统(22)，其中，所述控制器架构(50)被配置成：10. The work vehicle MRF joystick system (22) of claim 1, wherein the controller architecture (50) is configured to:检测在操作员输入方向上的操纵杆移动；Detect joystick movement in the direction of operator input;当检测到在所述操作员输入方向上的操纵杆移动时，确定沿所述操作员输入方向的持续操纵杆移动是否会导致所述机具(26)立即违反所述虚拟边界(220、226)；并且When joystick movement in the operator input direction is detected, determine whether continued joystick movement in the operator input direction would cause the implement (26) to immediately violate the virtual boundary (220, 226) ;and在确定沿所述操作员输入方向的持续操纵杆移动会导致立即违反所述虚拟边界(220、226)时，向所述MRF操纵杆阻力机构(56)发出命令，以随着所述机具(26)越过所述虚拟边界(220、226)而生成止动效果或脉动效果。Upon determining that continued joystick movement in the direction of the operator input would result in an immediate violation of the virtual boundary (220, 226), the MRF joystick resistance mechanism (56) is commanded to follow the implement (220, 226). 26) Crossing the virtual boundaries (220, 226) to generate a stop or pulsation effect.11.根据权利要求1所述的作业车辆MRF操纵杆系统(22)，其中，所述作业车辆(20)包括动臂组件(24)，所述动臂组件(24)具有所述机具(26)附接至的终端；并且11. The work vehicle MRF joystick system (22) of claim 1, wherein the work vehicle (20) includes a boom assembly (24) having the implement (26) ) is attached to the terminal; and其中，所述控制器架构(50)被配置成：wherein the controller architecture (50) is configured to:监测所述动臂组件(24)的经操纵杆命令的移动；以及monitoring joystick-commanded movement of the boom assembly (24); and至少部分地基于所述动臂组件(24)的所述经操纵杆命令的移动，来确定所述操纵杆沿操作员输入方向的持续移动是否会导致所述机具(26)违反虚拟边界(220、226)。Determining whether continued movement of the joystick in a direction of operator input would cause the implement (26) to violate a virtual boundary (220) based at least in part on the joystick-commanded movement of the boom assembly (24). , 226).12.根据权利要求11所述的作业车辆MRF操纵杆系统(22)，其中，所述虚拟边界(220、226)包括虚拟天花板(226)，所述机具(26)被如所希望地保持在所述天花板(226)下。12. The work vehicle MRF joystick system (22) of claim 11, wherein the virtual boundary (220, 226) includes a virtual ceiling (226), the implement (26) being held as desired in the under the ceiling (226).13.根据权利要求12所述的作业车辆MRF操纵杆系统(22)，所述作业车辆MRF操纵杆系统(22)还包括操作员界面(80)，所述操作员界面(80)联接至所述控制器架构(50)；并且13. The work vehicle MRF joystick system (22) of claim 12, further comprising an operator interface (80) coupled to the the described controller architecture (50); and其中，所述控制器架构(50)被配置成，至少部分地基于操作员数据来定位所述虚拟天花板，所述操作员数据指定由操作员经由所述操作员界面(80)输入的天花板高度。wherein the controller architecture (50) is configured to locate the virtual ceiling based at least in part on operator data specifying a ceiling height entered by an operator via the operator interface (80) .14.根据权利要求1所述的作业车辆MRF操纵杆系统(22)，其中，所述控制器架构(50)还被配置成：14. The work vehicle MRF joystick system (22) of claim 1, wherein the controller architecture (50) is further configured to:估计障碍物的相对于所述作业车辆(20)的空间位置；以及estimating the spatial location of the obstacle relative to the work vehicle (20); and至少部分地基于所述障碍物的所估计的空间位置来建立所述虚拟边界(220、226)的位置，使得所述虚拟边界(220、226)位于所述机具(26)与所述作业车辆(20)之间。establishing the position of the virtual boundary (220, 226) based at least in part on the estimated spatial position of the obstacle such that the virtual boundary (220, 226) is located between the implement (26) and the work vehicle (20) between.15.根据权利要求1所述的作业车辆MRF操纵杆系统(22)，其中，所述控制器架构(50)被配置成，向所述MRF操纵杆阻力机构(56)发出命令，以改变所述MRF阻力，使得随着所述机具(26)接近所述虚拟边界(220、226)，所述MRF阻力与所述机具(26)和所述虚拟边界(220、226)之间的间隔距离大致成比例地增加。15. The work vehicle MRF joystick system (22) of claim 1, wherein the controller architecture (50) is configured to issue commands to the MRF joystick resistance mechanism (56) to change all the MRF resistance, such that as the implement (26) approaches the virtual boundaries (220, 226), the MRF resistance and the separation distance between the implement (26) and the virtual boundaries (220, 226) increased roughly proportionally.

Images