US20100152980A1 - Machine Employing Cab Mounts and Method for Controlling Cab Mounts to Based on Machine Location - Google Patents

Abstract

A machine employing controllable mounts and a method for controlling such mounts based on machine location are disclosed. The controllable mount may include a housing, a pin, rheological fluid within the housing and coils provided proximate to the rheological fluid. As current is applied to the coils, the apparent viscosity of the rheological fluid is increased, and in so doing so is the stiffness of the controllable mount. Depending on machine location, however, the operator may want differing levels of stiffness in one or more of the controllable mounts. For example, when roading on rocky terrain, the operator may want relatively loose mounts so as to absorb the large vibration inputs and make for a more comfortable ride. The present disclosure therefore identifies the machine location through global positioning satellite information, topography maps, inclinometers, altimeters, operator input, and the like and controls the current to the coils, and thus the relative stiffness and damping of the controllable mounts, accordingly.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This is a non-provisional application claiming priority under 35 USC 119(e) to U.S. Provisional Patent Application Ser. No. 61/122,490 filed on Dec. 15, 2008.
TECHNICAL FIELD
• The present disclosure generally relates to cab mounts and, more particularly, relates to machines employing cab mounts and methods for controlling cab mounts.
BACKGROUND
• In many different heavy equipment machines, an operator cab is supported by a frame of the machine with cab mounts. Cab mounts are available in many different forms and configurations and generally try to isolate the cab from the undercarriage of the machine so as to limit the vibrational impact experienced by the operator when the machine moves or performs work. For example, with a loader traveling over rocky terrain, the chassis, undercarriage, and wheels/track of the loader may be jostled and bounced around considerably, but as the cab is not fixedly mounted to the frame, the play afforded by the cab mounts lessens the effect of that motion on the operator.
• Such mounts can be as simple as a mechanical spring or an elastomeric shock absorber offering a fixed level of vibration damping. Other types of mounts are fluid or electro-chemical in nature. Magneto-Rheological (MR) and Electro-Rheological (ER) mounts are two examples of such mounts. Taking a MR mount as an example, generally it includes a housing containing MR fluid, a structure that moves through the MR fluid, and a coil for providing a magnetic field across the MR fluid. By directing current to the coils, not only is the magnetic field created through the MR fluid, but the apparent viscosity of the MR fluid is increased as well. As the structure moves through the MR fluid, increasing the apparent viscosity of the MR fluid makes the mount more rigid.
• One example of a MR mount is disclosed in U.S. Pat. No. 7,063,191. The '191 patent discloses a hydraulic mount that includes a decoupler sub-assembly, a body filled with MR fluid, a pumping chamber and a diaphragm chamber. The body may be formed from a flexible, molded elastomer, such that vibrational inputs from the engine elastically deform the pumping chamber to cause fluid transfer between the pumping chamber and the diaphragm chamber through the decoupler sub-assembly for viscous damping. While somewhat effective, such a mount provides no feedback
• Another example of a MR mount is disclosed in US Patent Application Publication No. 2007/0257408, published Nov. 8, 207 to Kenneth Alan St. Clair. et al. The '408 publication discloses a strut with a magneto-rheological fluid damper that includes a tubular housing filled with magneto-rheological fluid and a piston head movable within the tubular housing along its longitudinal length.
SUMMARY OF THE DISCLOSURE
• In accordance with one aspect of the disclosure, a machine is therefore disclosed which comprises a frame, an operator cab supported by the frame, a controllable mount operatively connecting the operator cab to the frame and including a housing, a pin mounted within the housing, a rheological fluid within the housing, and coils positioned relative to the housing to generate a field through the rheological fluid, and an electronic control unit operatively associated with the coils and adapted to change a level of current applied to the coils to adjust an apparent viscosity of the rheological fluid based on machine location.
• In accordance with another aspect of the disclosure a method of controlling a cab mount is disclosed wherein the method comprises connecting a cab to a machine using a cab mount, the cab mount having a housing and a pin movable relative to the housing, receiving information relating to a location of the machine, and adjusting current flow to the coils based on the machine location.
• In accordance with yet another aspect of the disclosure a control system for controlling a mount operatively connecting an operator cab to a machine frame is disclosed, wherein the control system comprises a controllable mount including a housing, a pin movable within the housing, a volume of rheological fluid within the housing, and coils mounted proximate to the rheological fluid, a global positioning transceiver, and an electronic control unit adapted to receive the location of the machine via the global positioning transceiver and adjust a level of current directed to the coils based on the location of the machine.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a perspective view of a machine constructed in accordance with the teachings of this disclosure;
• FIG. 2 is a sectional view of a controllable mount constructed in accordance with the teachings of this disclosure;
• FIG. 3 a chart depicting creep in an elastomeric member of the controllable mount during initial use, over time, and as corrected;
• FIG. 4 is a schematic representation of a control system constructed in accordance with the teachings of this disclosure;
• FIGS. 5a-dare schematic representations of alternative embodiments for sensing mount displacement;
• FIG. 6 is a block diagram of an operator interface constructed in accordance with the teachings of this disclosure;
• FIG. 7 is a graph plotting frequency vs. spectral density, depicting historical data associated with a controllable mount, and identifying when a mount should be replaced or repaired;
• FIG. 8 is a graph plotting frequency vs. amplitude, and depicting stacked algorithms controlling same in accordance with the teachings of this disclosure;
• FIGS. 9a-eare schematic representations of different mount location embodiments.
DETAILED DESCRIPTION
• Referring now to the drawings, and with specific reference toFIG. 1, a machine constructed in accordance with the teachings of this disclosure is generally referred to byreference numeral100. Themachine100 includes aframe102 supporting anoperator cab104. As shown, themachine100 is depicted as a track-type tractor, but is to be understood that the teachings of this disclosure can be employed with equal efficacy with other heavy industry and construction machines such as, but not limited to, backhoe loaders, wheel loaders, tracked loaders, articulated trucks, off-highway trucks, excavators, motor graders, fork-lifts, skid steers, or any other machine known in the art that includes a cab mounted to a frame.
• Referring now toFIG. 2, a cross-sectional view illustrates an example of one embodiment of acontrollable mount106 for use with themachine100 and method disclosed herein. As shown, thecontrollable mount106 may include ahousing108 that may be mounted to the frame102 (seeFIG. 1) via amounting flange110. Thehousing108 may include afirst chamber112 and asecond chamber114. As will be described in further detail herein, thefirst chamber112 may be filled with arheological fluid116 such as a magneto-rheological (MR) fluid or an electro-rheological (ER) fluid. Thesecond chamber114 may be filled with acompressed fluid118 such as compressed gas including compressed air.
• Thecontrollable mount106 may also include apin120 that is partially disposed with the housing108 and may be attached to thecab104 at amounting end122. Thepin120 may be attached to thehousing108 by anelastomeric member124 that permits thepin120 limited axial movement alongaxis126 and radial movement perpendicular to theaxis126. Theelastomeric member124 may dampen axial as well as radial motion between thepin120 and thehousing108.
• As shown, adamping plate128 may be attached to thepin120 and be disposed within therheological fluid116 of thefirst chamber112. Thedamping plate128 may include a plurality ofapertures130 to permit therheological fluid116 to pass through thedamping plate128. As thedamping plate128 is moved through therheological fluid116, the relative motion between thehousing108 and thepin120 is damped. The level of damping may be adjusted by applying a magnetic or electric field to therheological fluid116. Moreover, by changing the strength of the magnetic or electric field, the apparent viscosity of therheological fluid116 is proportionally changed thereby providing a mechanism by which the degree of damping afforded by thecontrollable mount106 can be tailored to the needs of the operator.
• In order to generate the magnetic or electric field,coils131 are provided proximate therheological fluid116. More specifically, thecoils131 may be mounted on thehousing108 laterally adjacent thefirst chamber112.Leads132 may extend from thecoils131 for connection to acontrollable power supply134. Alternatively, or additionally, thecoils131 may be mounted on thepin120 and/or thedamping plate128.
• Thepin120 may also include aplunger136 that separates thefirst chamber112 from thesecond chamber114. Theplunger136 may include aseal138 that seals against ashaft140 of thehousing108. In such a configuration, theplunger136 and thesecond chamber114 act as agas spring142 for positioning thepin120 at anideal snubbing height144, the importance of which will be described in further detail herein. The pressure of thecompressed fluid118 within thegas spring142 may be adjusted by way of avalve146. By adjusting the pressure of the compressedfluid118, the biasing force of thegas spring142 applied to theplunger136 is adjusted as well. A first hose ortube148 may be connected to thevalve146 to supplypressurized fluid118 to thesecond chamber114. Thevalve146 may also include a second hose ortube150 to return the pressurizedfluid118 within thesecond chamber114 to astorage tank152, or to be vented to atmosphere.
• To assist in biasing theplunger136 toward theideal snubbing height144, amechanical spring154 may also be used. Thespring154 may be disposed about aguide extension156 of thepin120 and extend between theguide extension156 and abase158 of thehousing108. Theguide extension156 may be positioned to contact thehousing108 and act as a first end stop for thecontrollable mount106.
• Thecontrollable mount106 may also include asensor160 for generating a signal indicative of the relative displacement between thecab104 and theframe102. In the current embodiment, it does so by determining the relative displacement between thehousing108 and thepin120. Thesensor160 may include a strain gauge (not shown) disposed in achannel162 provided in theelastomeric member124. Alternatively, thechannel162 may be filled with aconductive elastomer164 having an electrical conductivity and resistance that changes with elongation and contraction. More specifically, the strain placed on theconductive elastomer164 may be correlated to the resistance exhibited by theconductive elastomer164. Thus, as the resistance is measured, the relative displacement between thehousing108 and thepin120 may be calculated.Leads166 may be used to communicate data from thesensor160 to an electronic control unit168 (seeFIG. 4).
• Thecontrollable mount106 may also include asensor170 to monitor the pressure offluid118 within thesecond chamber114. Thepressure sensor170 may be connected to theelectronic control unit168 as well with leads172. In general, thepressure sensor170 may be used to measure pressure spikes and thus wear on theelastomeric member124. In so doing, the remaining life and serviceability of thecontrollable mount106 can be calculated. In addition, failure of eithersensor160 or170 may indicate that thecontrollable mount106 needs replacement or repair.
• As an alternative or addition to thesensor160 within theelastomeric member124, thepressure sensor170 may also be used to determine the displacement of thepin120 relative to thehousing108. More specifically, the displacement may be determined using the formula:
• 
  V_n=P_i*V_I/P_n
• • wherein:
    • V_nis the new volume;
    • P_iis the initial pressure;
    • V_iis the initial volume; and
    • P_nis the new pressure.
      Initial pressure and initial volume could be initially calibrated from a known position of thepin120 and could correspond to the volume and pressure of thesecond chamber114. New pressure and new volume could correspond to the displacement from the initial position. The new position may be determined from the new volume using the formula:
• 
  D=(V_n−V_i)/(π*R²)
• wherein:
• • D is the change in displacement;
  • R is the radius of theshaft140;
  • V_iis again the initial volume; and
  • V_nis again the new volume.
    Temperature compensation may also be used to increase the accuracy of the displacement measurement. Alternatively, the displacement may be determined through stored tables where these calculations have already been determined.
• This calculated displacement may then be used to provide feedback in a control algorithm executed by theelectronic control unit168 controlling themount106. More specifically, the calculated displacement data may be used to adjust the current applied to thecoils130 of thecontrollable mount106 and hence adjust the apparent viscosity of thecontrollable mount106 to provide improved performance.
• In one embodiment, the apparent viscosity of therheological fluid116 is changed in direct relation to the displacement of themount106. Thus, as thepin120 moves away from theideal snubbing height144, more current is applied to the coil and the apparent viscosity of therheological fluid116 increases to bias thepin120 away from engagement with thehousing108. In so doing, thepin120 and dampingplate128 encounter greater resistance to movement and thus this feedback control may be used to minimize occurrences where thepin120 reaches an endstop, also known as bottoming or topping out.
• In another embodiment, statistical analysis of the data from one ormore sensors160,170 may be used to interpret the displacement of thecontrollable mount106 over time and adapt the control of thecontrollable mount106 to changes in weight in the cab, i.e., the weight of different operators, their tools and accessories, and the like. Initial pressure and initial volume may be determined and calibrated at the factory and during machine servicing.
• This displacement data may also be statistically analyzed and kept for long term storage. The historical data may include average displacements, frequency domain, and power spectral density data. The historical statistical displacement data may be used to determine when to replace a specific mount. For example, if the controllable mount is operating outside of its historical average, the controllable mount would be deemed to need replacement. Additionally, the history may be taken over the life of the controllable mount to develop a long historical average. The long historical average may be compared to a medium history and a short history to provide a total error or a point by point error to look for problems in performance.
• By tracking and maintaining a historical statistical average of displacement, the set and creep of theelastomeric member124 may also be determined. As used herein, the “set” and “creep” of theelastomeric member124 refers to changes in the elasticity of the elastomer. Initially, the elastomer will deform predictability and return to the same shape and strength. Over time and repetitive motion, however, the elastomer may begin to change at the molecular level so as not to exhibit the same elasticity. In the present application this can cause theelastomeric member124 to begin to sag over time.
• In graphical form, this means that as theelastomeric member124 sags, sets, and begins to creep, theelastomeric member124 may begin to behave nonlinearly as shown inFIG. 3. As shown, theelastomeric member124 may initially behave in a generally linear fashion as indicated byline174 between the end stops176. However, over time, theelastomeric member124 may take on a set and begin to creep as shown byline178.
• Theelectronic control unit168 may be used to compensate for this change in the material properties, as well as, minimize the effects of creep. For example, theelectronic control unit168 may be used to adjust the current applied to thecoils130 and thereby correct for the change in the material properties of theelastomeric member124, which is shown as dottedline180. Thus more current may be applied to thecoils130 when negative displacement is determined and less where positive displacement is determined. In configurations where a pneumatic system is available to increase the gas pressure within thegas spring142, the increased gas pressure may be used to compensate further and bias thepin120 toward theideal snubbing height144.
• Referring now toFIG. 4, a schematic diagram illustrates acontrol system182 for amachine100 on which thecontrollable mounts106 may be used. As shown, thesystem182 includes theelectronic control unit168 that is in electrical communication withmachine sensors186, anoperator interface188, and apower source190. Theelectronic control unit168 may include aprocessor192 and a computer readable media ormemory194 for storing instructions.Machine sensors186 may include a wide variety of sensors including accelerometers, inclinometers, temperature sensors, pressure transducers, and other sensors known in the art for use on themachine100. The operator interfaces188 may include joysticks, pedals, switches, buttons, touch screens, keypads, and other devices known in the art for receiving operator input.
• Theelectronic control unit168 may also be in electrical communication with a plurality ofcontrollable mounts106 used to mount thecab104 to amachine frame102.Such mounts106 may include a right frontcontrollable mount198, a right rearcontrollable mount200, a left rearcontrollable mount202, and a left frontcontrollable mount204. The right frontcontrollable mount198, right rearcontrollable mount200, left rearcontrollable mount202, and left frontcontrollable mount204 may each include the features ofcontrollable mount106 described above, as well as other features of controllable mounts known in the art.
• In one embodiment, thecontrollable mounts106 may be identical. However, their physical positions on themachine frame102 andcab104 may be different and known via awiring harness206 provided between thecontrollable mounts106 and theelectronic control unit168. For example, a series ofswitches208 may be coded to indicate the position of eachcontrollable mount106 on themachine frame102. If four mounts106 are used, for example, the following codes of TABLE 1 may be used:

• 	TABLE 1
  	Position	Switch	1	Switch 2
  	Cab, forward, right	0	0
  	Cab, forward, left	0	1
  	Cab, rear, right	1	0
  	Cab, rear, left	1	1

• The harness codes may provide the switch functionality through two wires and a ground line (not shown) being run to each mount location as part of thewiring harness206. Theswitches208 of the above table are then provided for in each connector by connecting a respective wire to ground to provide a 1 and left open for a 0. This may be routed through the connector to thecontrollable mount106 so that thecontrollable mount106 can identify its position on themachine frame102. This positional information may be used to tune and more precisely control thecontrollable mounts106 on themachine frame102.
• In another embodiment, thecontrollable mounts106 may be distinct and be configured to receive a specific connector from thewiring harness206. Alternatively, ageneric wiring harness206 may be used and eachcontrollable mount106 may be given its address by a technician to communicate its position to theelectronic control unit168.
• Optionally and as shown, thecontrollable mounts106 may each include thegas spring142 as discussed above in relation toFIG. 2. Eachgas spring142 may be pneumatically connected to a source of pressurized gas, such as apump210, and a source of low pressure gas, such as thetank152. In the depicted embodiment, theelectronic control unit168 is shown as being in communication with thepump210, but the control need not be electronic. For example a mechanical valve arrangement can be used. With the electronic embodiment, however, if the pressure of gas within thegas spring142 of the right frontcontrollable mount198 is determined to be too low, for example, theelectronic control unit168 may command thepump210 to provide pressurized gas and command a pneumatic valve (not shown) of the right frontcontrollable mount198 to open and receive the pressurized gas to increase the gas pressure within thegas spring142. When the pressure of thegas spring142 is sufficient, theelectronic control unit168 may close the valve and shut down thepump210. Alternatively, in situations where the pressure is too high in thegas spring142, theelectronic control unit168 may open the valve to thetank152 and close the valve when the pressure has been sufficiently reduced.
• Accurate mount displacement measurement permits thecontrollable mounts106 to be maintained at or near theideal snubbing height144 for maximum effectiveness of the controllable mounts106. By maintaining each mount at theirideal snubbing height144 throughout their useful life, excessive loading and bottoming out/topping out of themount106 during machine operation may be minimized or prevented. Consequently, fewer replacement parts of thecab104 and mounts106 may be needed over the life of themachine100. The present disclosure and its accommodating of different static loads of thecab104 may permit different systems and options to be installed at different times without having to replace themounts106, thus providing a high degree of modularity and tailoring of themachine100 to specific applications over the entire machine life while retaining the same mount package.
• Referring now toFIGS. 5a-d, in addition to the methods and systems discussed above, controllable mount displacement measurement can be achieved with other sensors including through the use of a Hall-effect sensor214. For example, as shown inFIG. 5a, apermanent magnet216 may be positioned on thehousing108 of thecontrollable mount106. Asensor chip218 may be connected to thecab104 and positioned to sense the relative position of themagnet216. In another embodiment (FIG. 5b), anexpandable chamber220 may house alaser222 in one end and areceiver224 in the other end. Each end may be attached to one of thecab104 and themachine frame102. As thechamber220 expands and contracts with the relative movement of thecab104 andframe102, accurate mount displacement measurement may be achieved. In another embodiment, abar code reader226 may be positioned to read a stainless steel or other corrosion-resistant materialbar code display228, as depicted inFIG. 5c. Thedisplay228 may be attached to theframe102 and thebar code reader226 attached to thecab104. In yet another embodiment, arotary sensor230 with agear232 disposed to move up and down a rack234 (seeFIG. 5d) may also be used to determine the displacement.
• In addition to diagnosing and correcting for creep or set in theelastomeric member124, thecontrollable mounts106 of the present disclosure also provide a mechanism by which machine feedback may be provided to the operator. For example, thecontrollable mounts106 can be hardened and thereby selectively lower damping so as to pass more of the vibration and impact loads to thecab104 from themachine frame102. As indicated above, hardening thecontrollable mounts106 occurs when an electrical current is provided tocoils131 and the apparent viscosity of therheological fluid116 is increased. Conversely, when machine feedback is not as desirable as comfort of the operator, thecontrollable mount106 may be softened by removing or reducing the current to thereby decrease damping. The level of damping may be manually selected by the operator, programmed to change during specific intervals of machine operation, and/or based on sensor inputs as described in greater detail below.
• Another feature of the present disclosure is that theoperator interface188 may permit the operator significant control over the controllable mounts106. For example, as shown schematically inFIG. 6, theoperator interface188 may include an on/offswitch236 to enable an operator to turn thecontrollable mounts106 off and thereby provide the softest ride at all times. In such a situation, thecontrollable mounts106 would function simply as a viscous mount. Alternatively, an operator may adjust the control algorithm via an incrementedswitch238, atouch screen240, or akeypad242 to scale the current flow provided by a control algorithm through thecontrollable mount106. For example, the operator may scale the control algorithm to fifty percent (or other) in order to obtain a softer ride, which may result in a different dynamic rate and damping characteristics of thecontrol system182.
• In another embodiment, theoperator interface188 may permit the operator to have to direct control over the current being applied to eachcontrollable mount106. For example, four slider bars244 (or a different number if a different number of controllable mounts are used) may respectively represent the fourrespective mounts106 and allow the operator to move theslider244 on theoperator interface188 to fit his or her personal preferences. Theoperator interface188 may be thetouch screen240 to allow direct control, or amouse246 orjoystick248 may be used to move a cursor over thescreen240 to make the desired changes to the controllable mount settings.
• Further, the control of thecontrollable mounts106 may be accessible through the menu oroperating system250 of themachine100. In some embodiments, control of thecontrollable mounts106 may be accessible only to a service technician via password protection or may be preprogrammed as part of anoperator identification device252 that would adjust settings to the specific operator. This may be achieved through the use of anRFID identification card254, or operator information stored on such items as acell phone256,flash drive258, personaldigital assistant260, or other computer readable media or device.
• Theoperator interface188 may also permit the operator to input or automatically input the geographical location of themachine100 as well as road and worksite material conditions. Consequently, theelectronic control unit168 may adjust or implement a control algorithm to best compensate for the individual terrain characteristics of the worksite and thereby provide for the best ride. For example, if a rocky worksite is being traversed, theelectronic control unit168 may increase the current flow to thecoils131 to a higher level in eachcontrollable mount106 in order to provide the more damping to thecab104 and operator. In one example, themachine100 may operate at fifty percent of maximum current while traveling over the rocky terrain, and zero percent over a smooth worksite.
• In a different configuration, and operator may also specify the type of machine task being performed, in which casedifferent control algorithms262 programmed to best damp vibrations when appropriate and allow feedback at other times may take over. For example, if the selected task is loading trucks from a pile of material, a loading algorithm264 may be selected. The loading algorithm264 may provide thecontrollable mounts106 with fifty percent (or other) maximum current while moving between the truck and the pile, but during bucket loading and when the bucket is raised above a predetermined height, theelectronic control unit168 may increase the current flow to one hundred percent in order to provide machine feedback and thus provide better operator control.
• In another example, an operator may indicate that themachine100 is a motor grader and the task to be performed is fine grading. Theelectronic control unit168 may then cause thecontrollable mounts106 to be hard while the transmission of themachine100 is in a forward gear, and soft while in a reverse gear. During fine grading, operators desire as much feedback as possible in order to more quickly complete the job within specified tolerances. Additionally, or alternatively, thecontrollable mounts106 may be tuned to the desire of the operator for selected operational settings. For example, the operator may direct theelectronic control unit168 to pass one hundred percent current during fine grading, zero percent doing roading, and fifty percent during snow removal.
• In other example, a wheel loader may keep thecontrollable mounts106 soft during roading and moving around a worksite, but harden thecontrollable mounts106 when the bucket is raised so that the operator can better feel the operation of the machine. In yet another example, the controllable mounts of a track-type tractor may be kept as soft as possible with zero current being passed through thecoils131 while themachine100 is being moved with the bucket and ripper up. Thesame machine100 may be programmed to pass the maximum current when either of those implements is performing a task.
• Similarly, if themachine100 is an excavator, when a large load is being placed, thecontrollable mounts106 may be hardened so as to provide the operator with valuable feedback. In contrast, when the excavator is being moved, zero current can be passed through thecontrollable mounts106 to provide a softer, more comfortable ride to the operator. Commonly with excavators, thecontrollable mounts106 may always be soft, except when transients occur during dumping, digging or other events.
• The teachings of the present disclosure can also be employed for detecting track slippage in a track-type tractor. By setting thecontrollable mounts106 to a high current setting, the operator is provided with increased feedback. This feedback may indicate to the operator that track slippage is occurring. In such an event, the operator may choose to cease operations so that maintenance can be performed and thus minimize undercarriage wear.
• Thecontrol system182 of the present disclosure may also employ any of thecontrol algorithms262 to most effectively and expeditiously balance feedback and comfort. In addition to the loading algorithm264 mentioned above, apredictive algorithm266 may be used by theelectronic control unit168 to control the controllable mounts106. The controllable mounts106 may be tuned to the specific machine use and task being performed, such as dozing, ripping, grading, or excavating, or to the desired setting such as improved ride, noise reduction or operator comfort. Specific machine use and task may be entered by the operator as indicated above, or may be determined from the position of a blade, ripper, bucket orother implements268 of themachine100 as sensed by an implementposition sensor269. Alternatively, they may be inferred from theoperator interface188, hydraulic pressures gauges270, worksite maps272, globalpositioning system information274,laser grading inputs276,topographical maps278,inclinometers280,determined pitch rates282, steering signals284,altimeters285, articulationjoint position286, andthermometers287. For example, shock loads may be anticipated from the position of a truck in a loading zone and thus thecontrollable mount106 may be adjusted accordingly to absorb as much of the impact from loading as possible.
• Alternatively, when the bucket of a wheel loader, tracked loader, excavator or other machine using buckets is lowered and positioned for engagement with a pile, thecontrollable mounts106 may be initially softened and then hardened when the hydraulic cylinder pressures exceed a predetermined threshold to provide feedback to the operator while minimizing the impact of the bucket engaging the pile. In addition, speed of themachine100 can be used to predict the desired settings for the controllable mounts106. For example, at higher speeds, as sensed by aspeedometer288, thecontrollable mounts106 may be softer and then hardened when the machine slows100. This hardening and softening may also be dependent on atransmission289 of the machine (100), specifically a gear in which themachine100 is operating. In first gear a fifty percent (or other) current may be passed through thecoils131 and in a second gear forty percent may be passed. In third gear, twenty five percent current may be passed and in fourth gear zero percent may be passed. Harder mounts at lower speeds would provide the operator with a better feedback, while higher speeds would provide greater comfort.
• Thepredictive algorithm266 may also use the sensed speed of the implement to control the controllable mounts106. For example, when a blade is lowered the initial contact with the ground can jar the operator. Thus, when the blade is being dropped, thecontrollable mounts106 may be softened in anticipation of the impact and hardened after contact has been made to improve feedback and control. Generally, thecontrol algorithm262 may also be set up to control the vibrational, heave, pitch, roll and yaw modes as well. Thepredictive algorithm266 may also be used to predict that when an implement268 is not in use and themachine100 is moving at a relatively high rate of speed, this may mean that roading is taking place and thecontrollable mounts106 should be adjusted for maximum comfort.
• Ahistorical algorithm290 may also be used. More specifically, a histogram of the performance of eachcontrollable mount106 may be obtained from the sensors associated with eachcontrollable mount106. The histogram may be used to continuously tune each individualcontrollable mount106 to current conditions. In other words, theelectronic control unit168 uses the sensor histories to adapt thecontrollable mount106 to current performance, thus providing improved performance over time and use. For example, peak pressure and frequency may be kept to develop a history of performance to identify when to harden and soften with decay rate. If thecontrollable mount106 undergoes very little movement over a past history, it can soften itself up to avoid unnecessary harshness and wasting of energy. As more motion is seen, thecontrollable mount106 can then increase damping. For example, if while the machine is roading, high frequency small displacement vibration is sensed, thecontrollable mounts106 can soften up to minimize noise, increase comfort, and save energy. When themachine100 begins encountering rough terrain, theelectronic control unit168 may increase current to change the damping of thecontrollable mount106 to compensate for the larger low frequency displacement.
• In order to prevent failure of one of thecontrollable mounts106 from causing damage to the othercontrollable mounts106 and/or other machine systems through continued use, the sensor data collected from sensors associated with thecontrollable mount106 may be collected and used by thehistorical algorithm290 to provide a history of operation which may then be used to determine operating tolerances. The current sensor data may be used to provide the power spectral density of thecontrollable mount106 and determine if thecontrollable mount106 should be replaced. For example, and referring toFIG. 7, the dottedlines292 may represent the tolerances for acceptable operation for thecontrollable mount106 and thesolid line294 may represent the actual running power spectral density. Aspike296 outside of atolerance zone298 or an average error which exceeds thetolerance zone298 may indicate that thecontrollable mount106 should be replaced. In an alternative, the displacement and acceleration of thecab104 relative to themount106 or the exact displacement of the mount components could be used to follow the life of thecontrollable mount106 and feed thehistorical algorithm290 to control the stiffness of thecontrollable mount106.
• Thesecontrol algorithms262 and the others discussed herein may be implemented as stackedalgorithms300 as well. For example, theelectronic control unit168 may use adefault algorithm302, anend stop algorithm304, and aresonant control algorithm306. Thedefault algorithm302 may use the controllable mount history to adjust the current to performance needs. All three algorithms may be calculated together and priority may be given to the algorithm that provides the highest force control over thecontrollable mount106 under the current circumstances. For example, and referring toFIG. 8, themachine100 may be roading during which thedefault algorithm302 may be used to control thecontrollable mount106. If themachine100 moves over a pothole, that will provide an impulse to thecontrol system182 which if undamped is represented byline308.Line310 represents the effect produced by the stackedalgorithms300 in response to the impulse. Thedefault algorithm302 may control until theendstop algorithm304 may then be given priority to control thecontrollable mount106. After theendstop algorithm304 has acted, theresonant control algorithm306 may be given priority to dampen out a resonance caused by the impact with the pothole. Thedefault algorithm302 may resume control of thecontrollable mount106 once the resonance has been controlled.
• In addition to operator selected control and the control to provide operator feedback, theelectronic control unit168 may be used to providecab104 leveling and adjustment. Specifically, static load adjustment and ride height adjustment may be attained by adjusting thegas spring142 to bias thepin120 of eachmount106 away from engagement with thehousing108 and toward itsideal snubbing height144. This therefore avoids having thepin120 engage thehousing108 in “topping out” or “bottoming out” fashion. Theelectronic control unit168 may monitor the relative displacement and adjust thegas spring142 by adding or releasing gas. If thesensors160,170 indicates that themount106 is at or near theideal snubbing height144, no action is taken by theelectronic control unit168 to adjust the pressure within thegas spring142.
• This adjustment of thecontrollable mount106 may be beneficial to compensate for different sized operators who may or may not be carrying tools, food and other equipment in thecab104. The different loads may move thecontrollable mounts106 away from theideal snubbing height144. In some applications, themachine100 may be operating on a slope and thus the downside controllable mounts may bear a larger portion of the load. Thus, the downside controllable mounts may not be located at theirideal snubbing heights144. Thepneumatic chamber114 of eachmount106 may thus be individually adjusted to return eachmount106 to theideal snubbing height144.
• Changes in altitude and ambient temperature may also move thecontrollable mounts106 from theirideal snubbing heights144. For example, amachine100 that has been operating in zero degree temperatures at sea level and then taken into the mountains and used at six thousand feet above sea level in fifty degree temperatures may have mounts that are no longer disposed at theirideal snubbing heights144. The present disclosure may therefore adjust for this change in altitude and ambient temperature to return themounts106 to theirideal snubbing heights144.
• A mixed mount arrangement may also be used to provide reduced cost and complexity while providing many of the benefits associated with controllable mounts. For example, as shown inFIGS. 9a-e,controllable mounts106 may be used at some locations to provide controllability to the cab response while using lower cost mounts to help support/attach thecab104 at other locations. In one embodiment (seeFIG. 9a), where pitching of thecab104 is desired to be controlled, twopassive mounts312 may be positioned at afront314 of thecab104 and twocontrollable mounts106 may be positioned atrear locations316. Thus, through selective hardening of thecontrollable mounts106, the pitch and roll motion may be controlled. The configuration may also be reversed as inFIG. 9bwith twopassive mounts312 positioned at the rear316 of thecab104 and twocontrollable mounts106 positioned at thefront314 of thecab104. As used herein, passive mounts have dampening characteristics that cannot be altered during operation and include, for example, viscous and rubber mounts.
• Alternatively, a three-point system may also be possible with a singlepassive mount312 infront314 and twocontrollable mounts106 positioned at the rear316 of thecab104, as shown inFIG. 9c, so that the structure is less expensive and easier to manufacture for plane and positional alignment. In yet another embodiment (seeFIG. 9d), twopassive mounts312 may be mounted near aninertial pitch axis318 with a thirdcontrollable mount106 being mounted away from theaxis318.
• Another cab mounting arrangement may be used withmachines100 that include an external roll-over protection structure320. For example, as shown inFIG. 9e),passive mounts312 may be mounted between thecab104 and theframe102 of themachine100. One or morecontrollable mounts106 may be disposed above thecab104 and mounted between thecab104 and the external roll-over protection structure320. In this configuration, the passive mounts312 provide noise reduction and the overheadcontrollable mounts106 may provide ride control.
INDUSTRIAL APPLICABILITY
• From the foregoing, it can be seen that the teachings of this disclosure have applicability in a variety of industrial situations, particularly with machines to which operator cabs are mounted. Such machines may include, but are not limited to, track-type tractors, wheel loaders, track loaders, excavators, motor graders, articulated trucks, off-highway trucks, skid steers, skidders, and the like. The machines may employ a controllable mount so as to isolate the vibrations generated by the undercarriage and engine of the machine from the cab and thus the operator within the cab.
• In addition, by providing a mount such as that disclosed herein, the ideal snubbing height of the pin within the housing can be maintained. In so doing, excessive loading and bottoming out or topping out of the mount during machine operation can be minimized or eliminated. This in turn can help to extend the serviceable life of the mount. Moreover, by monitoring the relative displacement of the pin with regard to the housing, a diagnostic can be generated indicating when an elastomeric member of the mount, or the mount itself, should be replaced.
• The teachings of the present disclosure may also be used to construct a machine that provides increased feedback to the operator. By stiffening the mounts, the operator will more acutely feel vibrations which can prove valuable in performing tasks, such as fine grading, plowing, or excavating, or sensing conditions such as track slippage. Conversely, when roading the mounts can be relaxed to decrease feedback and thus provide better operator comfort.
• The present disclosure also has applicability in providing a machine mount control system wherein an operator can select a desired hardness or feedback level through an appropriate operator interface. Such an operator interface can also allow the operator to select the type of task being performed and the control system can then set the mount accordingly.
• Sensors can also monitor the positions or speeds of the machine or implements to then predict the type of task being performed. Once predicted, the appropriate mount settings can be used. Such a predictive algorithm approach can not only use machine sensed parameters, but utilize global positioning satellite and other mapping technology as well to predict the task and desired mount settings.

Claims (20)

1. A machine, comprising:

a frame;

an operator cab supported by the frame;

a controllable mount operatively connecting the operator cab to the frame, the controllable mount including:

a housing;

a pin mounted within the housing;

a rheological fluid within the housing; and

coils positioned relative to the housing to generate a

field through the rheological fluid; and

an electronic control unit operatively associated with the coils and adapted to change a level of current applied to the coils to adjust an apparent viscosity of the rheological fluid based on machine location.

2. The machine ofclaim 1, wherein the operator cab includes an operator interface through which an operator can input a machine location.

3. The machine ofclaim 1, wherein the electronic control unit is in communication with a global positioning satellite and changes the level of current applied to the coils based on a location provided by the global positioning satellite.

4. The machine ofclaim 1, wherein the electronic control unit is in communication with a memory storing a topographical map, and changes the level of current applied to the coils based on the position of the machine relative to the topographical map.

5. The machine ofclaim 1, wherein the electronic control unit is in communication with a memory storing a worksite map identifying types of ground material over which the machine must traverse, and the electronic control unit changes the level of current applied to the coils based on the type of ground material.

6. The machine ofclaim 1, wherein the electronic control unit increases the current applied to the coils when the machine is on uneven ground, and decreases the current applied to the coils when the machine is on even ground.

7. The machine ofclaim 1, further including an altitude sensor, the electronic control unit being adapted to adjust the current applied to the coils based on sensed altitude.

8. The machine ofclaim 1, further including a temperature sensor, the electronic control unit being adapted to adjust the current applied to the coils based on sensed temperature.

9. The machine ofclaim 1, further including an incline sensor, the electronic control unit being adapted to adjust the current applied to the coils based on sensed incline.

10. The machine ofclaim 9, wherein the operator cab is supported by the frame with a plurality of controllable mounts, each of the controllable mounts being individually adjustable.

11. The machine ofclaim 10, wherein the plurality of controllable mounts include at least one forward mount and one rearward mount, and the controllable mount further includes a pressurized fluid chamber, the rearward mount being more pressurized than the forward mount when the vehicle is ascending an incline in a forward direction, and less pressurized than the forward mount when the machine is descending an incline in a forward direction as sensed by a sensor.

12. The machine ofclaim 10, wherein the plurality of controllable mounts include at least one left mount and at least one right mount, and the controllable mount further includes a pressurized fluid chamber, the left and right mounts being differently pressurized when ground topography causes the machine100 to lean to one side or the other as sensed by a sensor.

13. A method of controlling a cab mount, comprising:

connecting a cab to a machine using a cab mount, the cab mount having a housing, a pin movable relative to the housing, a volume of rheological fluid within the housing and coils mounted proximate to the volume of rheological fluid;

receiving information regarding the location of the machine; and

adjusting current flow to the coils based on the location of the machine.

14. The method ofclaim 13, wherein the information regarding the location of the machine is received from a global positioning satellite.

15. The method ofclaim 13, wherein the information regarding the location of the machine is received from a topographical map.

16. The method ofclaim 13, wherein the information regarding the location of the machine is received from a worksite map depicting types of ground material on the worksite.

17. The method ofclaim 13, wherein the information regarding the location of the machine is received from a operator manually entering the information into an operator interface.

18. The method ofclaim 13, wherein the controllable mount further includes a gas spring provided in a pressurized fluid chamber having a mechanical spring surrounded by pressured fluid, the pressure of the pressurized fluid being adjusted based on the location of the machine.

19. A control system for controlling a mount operatively connecting an operator cab to a frame of a machine, comprising:

a controllable mount including a housing, a pin movable within the housing, a volume of rheological fluid within the housing, and coils mounted proximate to the rheological fluid;

a global positioning transceiver; and

an electronic control unit adapted to receive the location of the machine via the global positioning transceiver and adjust a level of current directed to the coils based on the location of the machine.

20. The control system ofclaim 19, wherein the controllable mount further includes a pressurized fluid within a second chamber of the housing and the electronic control unit changes the pressure of the pressurized fluid based on the location of the machine.

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