Reconfigurable autonomous docking control system for unmanned vehicleTechnical Field
The invention relates to a docking system, in particular to an autonomous docking control method and system for a reconfigurable unmanned vehicle, and belongs to the technical field of unmanned vehicles.
Background
The unmanned vehicle can independently execute functional tasks such as logistics, transportation, distribution, patrol, public transportation, retail, cleaning, connection, rescue and the like, and is a core element for future intelligent transportation and smart city construction. It is expected that most tasks will be completed by unmanned vehicles instead of human beings in future transportation and travel and human life, and vehicles will be evolved from traditional vehicles into intelligent carriers for performing functional tasks, and have great influence on the development of human society. Compared with the traditional intelligent networked automobile, the unmanned automobile aims at executing functional tasks, does not have a human driving mechanism, subverts the basic design concept of the traditional automobile centering on human, and is innovative in configuration, flexible and changeable. Therefore, the fundamental theory and key technology of the unmanned vehicle must realize original breakthrough, is a brand new challenge brought by the era of intelligent vehicles, and is a research hotspot in the international and domestic fields.
With the continuous expansion of the connotation of intelligent transportation and smart cities in the future, the development of unmanned vehicles faces major challenges of complex and variable execution tasks, three-dimensional and multidimensional running environments, continuous expansion of functional requirements, single limitation of carrier configuration and the like. Obviously, the traditional unmanned vehicle with a fixed configuration has difficulty in meeting the challenges and cannot meet the requirements of the intelligent transportation and the smart city for a novel intelligent vehicle in the future. The reconfigurable unmanned vehicle technology thoroughly breaks through the form constraint of the traditional fixed configuration unmanned vehicle, can independently realize complex functions such as function reconfiguration, topology reconfiguration and the like, realizes independent combination, butt joint and disintegration among multiple unmanned vehicle units, comprehensively expands the function task execution boundary of the unmanned vehicle, and is expected to become a subversive innovation technology in the future. How to realize the butt joint and the disintegration between the minimum reconstruction units of the reconfigurable unmanned vehicle is a key technology which needs to be solved firstly by the reconfigurable unmanned vehicle; in the butt joint process, the position and the posture of the butt joint end are controlled to directly influence the butt joint efficiency.
Disclosure of Invention
In view of the above, the invention provides a reconfigurable unmanned vehicle autonomous docking control method, which is used for realizing autonomous dynamic docking between unmanned vehicle units (i.e., unmanned vehicle minimum reconfiguration units), so as to quickly realize topology reconfiguration of unmanned vehicles, widen task execution boundaries of unmanned vehicles, and meet complex environment and task requirements in future intelligent transportation and smart cities.
The reconfigurable unmanned vehicle autonomous docking control method comprises the following steps: in the butt joint process of two unmanned vehicle units, one unmanned vehicle unit serves as an active butt joint vehicle to provide a butt joint active end, and the other unmanned vehicle unit serves as a passive butt joint vehicle to provide a butt joint passive end; the butt joint of the two unmanned vehicle units is realized through the coaxial butt joint of the butt joint active end and the butt joint passive end;
after two unmanned vehicle units receive a docking command, the active docking vehicle preliminarily adjusts the position of the docking active end according to the position information of the image recognition positioning plate on the docking passive end of the passive docking vehicle, which is obtained by the vision sensor on the docking active end, so that the relative position of the docking active end and the docking passive end meets the set docking position requirement;
then the active docking vehicle obtains an included angle between the axis of the active docking end and the axis of the passive docking end according to distance information between the detection plates of the laser sensors on the passive docking end and the distance information detected by more than two laser ranging sensors distributed on the active docking end; then the active docking car further adjusts the posture of the docking active end to eliminate the included angle, so that the axis of the docking active end is overlapped with the axis of the docking passive end;
and finally, the active docking car controls the docking active end to be in coaxial docking with the docking passive end on the passive docking car, so that the docking of the two unmanned car units is completed.
As a preferred mode of the present invention, in the process of docking two unmanned vehicle units, the active docking end monitors the stress of the docking surface in real time through two or more force sensors.
In addition, the present invention provides a reconfigurable autonomous docking control system for an unmanned vehicle, comprising: the device comprises an active capture module, a locking module, a sensing module and a control module; the reconfigurable unmanned vehicle comprises more than one unmanned vehicle unit; each unmanned vehicle unit is provided with an autonomous docking system; when two unmanned vehicle units need to be butted, an active capturing module on one unmanned vehicle unit is butted with a locking module on the other unmanned vehicle unit;
the active capture module adopts a six-degree-of-freedom platform, the fixed end of the six-degree-of-freedom platform is fixedly connected with the unmanned vehicle unit, and the movable end of the six-degree-of-freedom platform is provided with a locking core; the six-degree-of-freedom platform can drive the locking core to move along the transverse direction, the longitudinal direction, the vertical direction, the yaw direction, the rolling direction and the pitching direction so as to adjust the position and the posture of the locking core;
the locking module includes: a locking mechanism and a docking guide block; the butt joint guide block is fixedly connected with the unmanned vehicle unit; the butt joint guide block is provided with a butt joint guide hole matched with the locking core and used for accommodating the locking core; the locking mechanism is used for locking the position of the butted guide block and the locking core after being butted;
the sensing module is used for sensing the position and the posture of the locking core on the active capture module relative to the butt joint guide block on the locking module and sending the position and the posture to the control module; the control module controls the active capture module to adjust the position and the posture of the locking core relative to the butt joint guide block according to the sensing information of the sensing module, so that the locking core is inserted into the butt joint guide hole of the butt joint guide block when two unmanned vehicle units are in butt joint.
As a preferred mode of the present invention, the sensing module comprises a vision sensor mounted at the fixed end of the six-degree-of-freedom platform and more than two laser ranging sensors mounted at the end face of the movable end of the six-degree-of-freedom platform; the vision sensor and the more than two laser ranging sensors are respectively connected with the control module and used for sending detected signals to the control module;
an image recognition positioning plate matched with the vision sensor is arranged on the butt joint guide block, and the vision sensor obtains the position of the butt joint guide block relative to the locking core through recognition of the image recognition positioning plate; the control module adjusts the position of the locking core on the six-degree-of-freedom platform according to the position, so that the locking core and the butt joint guide block reach the expected relative position;
the butt joint guide block is provided with a laser sensor detection board used for being matched with the laser ranging sensors, more than two laser ranging sensors are distributed at intervals along the circumferential direction, the control module obtains an included angle between the axis of the locking core and the axis of the butt joint guide block according to distance information between the detection board of the laser sensor and the distance information detected by the more than two laser ranging sensors respectively, and the control module adjusts the posture of the locking core so that the butt joint guide block is coaxial with the locking core.
As a preferable mode of the present invention, the sensing module further includes two or more force sensors; more than two force sensors are arranged on the end face of the movable end of the six-degree-of-freedom platform and are distributed at intervals along the circumferential direction; the force sensor is connected with the control module;
when two unmanned vehicle units are in butt joint, the force sensor is in contact with the butt joint surface of the butt joint guide block, and the stress of the butt joint surface of the butt joint guide block and the butt joint surface of the locking core is fed back to the control module.
As a preferred mode of the present invention, a stress threshold of the force sensor is preset in the control module, and is used to indicate that the locking core and the docking guide block are docked in place, and when the stress magnitude fed back by the force sensor reaches the preset threshold, it indicates that the locking core is inserted to reach a specified position; when the stress fed back by the force sensor changes suddenly, the control module controls the locking core of the six-freedom-degree platform to adjust.
As a preferred aspect of the present invention, the six-degree-of-freedom platform includes: the device comprises a base and six electrically-driven linear actuators; the base is used as a fixed end of the six-degree-of-freedom platform and is fixedly connected with the unmanned vehicle unit; the locking core is fixed on the locking core connecting plate; the fixed ends of the six electric-driven linear actuators are hinged with the base, and the actuating ends of the six electric-driven linear actuators are respectively hinged with the locking core connecting plate; and the six electric-driven linear actuators are controlled to move so as to drive the locking core to move in the transverse, longitudinal, vertical, yaw, roll and pitch directions.
In a preferred aspect of the present invention, the lock mechanism includes a lock pin and a lock pin actuator;
more than one locking pin actuators are distributed at intervals along the circumferential direction on the outer circumference of the butt joint guide block, pin hole groups which correspond to the locking pin actuators one by one are distributed at intervals along the circumferential direction on the outer circular surface of the locking core, and each pin hole group comprises more than one pin hole; the actuating end of each locking pin actuator is provided with locking pins which are in one-to-one correspondence with the pin holes in the pin hole group; a spring is arranged inside the locking pin; initially, the locking pin actuator pulls on the locking pin compression spring;
when the locking core enters the butt joint guide hole in the butt joint guide block, the locking pin actuator releases force, and when the locking core rotates to the pin hole and corresponds to the locking pin in position, the locking pin automatically extends out under the action of the spring and enters the pin hole corresponding to the locking pin.
As a preferred mode of the present invention, the control module adopts a full digital servo control system, which comprises a microcontroller, a programmable logic controller, a servo driver and a motor;
the microcontroller calculates the relative position and posture of two unmanned vehicle units to be butted according to the sensing information of the sensing module; the programmable logic controller reversely calculates the stretching amount of six electric-drive linear actuators in the active capture module through relative positions and postures, transmits the stretching amount to the servo driver, and the servo driver drives the servo motor to rotate so as to change the positions of the electric-drive linear actuators.
As a preferred aspect of the present invention, an encoder mounted on the servo motor detects the speed and position information of the servo motor in real time and transmits the information to the servo driver, so as to form a closed-loop control, so as to precisely control the expansion and contraction amount of the electrically driven linear actuator in real time.
Has the advantages that:
(1) the reconfigurable autonomous docking control method for the unmanned vehicle can accurately sense the relative position and posture change of two unmanned vehicle units to be docked, and provides a basis for dynamic docking; therefore, autonomous dynamic docking between the unmanned vehicle units can be realized, topology reconstruction of the unmanned vehicle is rapidly realized, and complex environment and task requirements in future intelligent transportation and smart cities are met.
(2) The reconfigurable autonomous docking control system for the unmanned vehicles is provided with a sensing module, an active capturing module, a locking module and a control module, and can meet the requirements of dynamic docking and disassembly among unmanned vehicle units. The sensing module consists of a plurality of physical quantity sensors and can accurately sense the motion state, relative position and posture change of the butted and butted unmanned vehicle units; the active capture module can dynamically adjust according to the position and posture change of the docking unmanned vehicle unit, so as to realize dynamic docking and active capture between the docking unmanned vehicle units; the locking module realizes the locking between the butted unmanned vehicle units after the butting process is finished, and ensures the driving stability of the unmanned vehicle units after the butting is finished.
(3) The active capture module adopts a six-degree-of-freedom platform, and the postures of the active capture module in the transverse, longitudinal, vertical, yaw, roll, pitch and other directions can be adjusted through telescopic control of an electric cylinder of the six-degree-of-freedom platform, so that the flexible docking requirement is met; the multi-sensor sensing module based on the vision sensor, the laser ranging sensor and the force sensor can guarantee accuracy and stability of a butt joint process, and high-precision flexible butt joint is achieved.
Drawings
FIG. 1 is a schematic structural diagram of an active capture module of an autonomous docking control system of a reconfigurable unmanned vehicle according to the present invention;
FIG. 2 is a schematic structural diagram of a locking module of the reconfigurable autonomous docking control system for the unmanned vehicle;
fig. 3 is a working schematic diagram of a control module of the autonomous docking control system of the reconfigurable unmanned vehicle.
Wherein: the device comprises avision sensor 1, an electrically drivenlinear actuator 2, abase 3, alaser ranging sensor 4, aforce sensor 5, alocking core 6, alocking pin actuator 7, a buttjoint guide block 8, an imagerecognition positioning plate 9, a lasersensor detection plate 10 and a lockingcore connecting plate 11.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings.
The embodiment provides an autonomous docking control system for a reconfigurable unmanned vehicle, which is used for realizing autonomous dynamic docking and disassembly between unmanned vehicle units.
This autonomic butt joint control system includes: the device comprises an active capture module, a locking module, a sensing module and a control module; each unmanned vehicle unit is provided with the autonomous docking control system; when two unmanned vehicle units need to be in butt joint, an active capture module on one unmanned vehicle unit is in butt joint with a locking module on the other unmanned vehicle unit, and for convenience of description, an unmanned vehicle unit for providing the active capture module in the two unmanned vehicle units is in active butt joint, and an unmanned vehicle unit for providing the locking module is in passive butt joint.
As shown in fig. 1, the active capture module includes: an electrically drivenlinear actuator 2, abase 3 and alock core 6; the active capture module is arranged at the front end of the unmanned vehicle unit; the active capture module adopts a six-degree-of-freedom platform, thebase 3 is used as a fixed end of the six-degree-of-freedom platform, and thebase 3 is fixedly connected with a vehicle body of the unmanned vehicle unit; thelocking core 6 is fixed in the middle of the lockingcore connecting plate 11, and three groups of pin holes are uniformly distributed on the outer circumferential surface of thelocking core 6 at intervals along the circumferential direction.
Every two six electric-drivenlinear actuators 2 form a group, three groups of electric-drivenlinear actuators 2 are uniformly distributed on thebase 3 at intervals along the circumferential direction, and the other ends of the two electric-drivenlinear actuators 2 in each group are respectively hinged with the lockingcore connecting plate 11; namely, the fixed end of the electric drivelinear actuator 2 is hinged with thebase 3, and the actuating end is hinged with the lockingcore connecting plate 11. And a lockingcore connecting plate 11 connected with a lockingcore 6 is used as a movable end of the six-degree-of-freedom platform. By controlling the extension and retraction of the six electric-drivenlinear actuators 2, the postures of the active capture module in the transverse, longitudinal, vertical, yaw, roll and pitch directions can be adjusted.
When the autonomous docking control systems of the two unmanned vehicle units are docked, the control module on the active docking vehicle controls the six electrically-drivenlinear actuators 2 to move according to expected positions and postures, so that the motion of the movable end of the platform in six freedom directions (transverse, longitudinal, vertical, yaw, roll and pitch) in a Cartesian coordinate system is realized, and finally the lockingcore 6 on the movable end of the platform is dynamically controlled to be aligned with thedocking guide block 8 on the locking module of the passive docking vehicle in a high-precision mode, and the docking action is completed.
The sensing module is installed on the initiative capture module, and the sensing module includes: the device comprises avision sensor 1 arranged on abase 3, and threelaser ranging sensors 4 and threeforce sensors 5 arranged on a lockingcore connecting plate 11; wherein thevision sensor 1 is positioned right above thebase 3, and the image acquisition direction of thevision sensor 1 faces to the movable end of the six-degree-of-freedom platform; the threelaser ranging sensors 4 are uniformly distributed at intervals along the circumferential direction of the lockingcore connecting plate 11; the threeforce sensors 5 are arranged on the end face of the end of the lockingcore connecting plate 11 where thelocking core 6 is located and are uniformly distributed at intervals along the circumferential direction; preferably, the threeforce sensors 5 and the three laserdistance measuring sensors 4 are offset in position from one another. And each sensor in the sensing module is respectively connected with the control module and used for sending the detected signal to the control module.
As shown in fig. 2, the locking module arrangement includes: the device comprises a locking mechanism, an imagerecognition positioning plate 9, a buttjoint guide block 8 and a lasersensor detection plate 10; the locking module is arranged at the rear end of the vehicle body of the unmanned vehicle unit; wherein the buttjoint guide block 8 is fixedly connected with the vehicle body of the unmanned vehicle unit through a bracket; thedocking guide block 8 is centrally provided with a docking guide hole for cooperating with the lockingcore 6 for accommodating thelocking core 6. The lasersensor detection plate 10 is arranged on the outer circumference of the middle part of the buttjoint guide block 8, and divides the buttjoint guide block 8 into two parts along the axial direction, wherein one part is used for butt joint with the active capture module, and the other part is used for installing a locking mechanism.
The locking mechanism is used for realizing the position locking after the butt joint of the buttjoint guide block 8 and thelocking core 6, and adopts a locking pin and alocking pin actuator 7. Specifically, threelocking pin actuators 7 are uniformly distributed on the outer circumference of the buttjoint guide block 8 at intervals along the circumferential direction, the actuating end of eachlocking pin actuator 7 is provided with locking pins which are in one-to-one correspondence with pin holes on thelocking core 6, and in order to ensure that the locking pins can be smoothly inserted into the corresponding pin holes, a spring is arranged inside each locking pin; initially, thelocking pin actuator 7 pulls the locking pin to compress the spring, so that the spring is in a compressed state and the locking pin is not pushed out; after the lockingcore 6 enters the butt joint guide hole in the buttjoint guide block 8, thelocking pin actuator 7 releases force, the lockingcore 6 is rotated through the six-degree-of-freedom platform, when the lockingcore 6 rotates to the pin hole and corresponds to the locking pin in position, the locking pin automatically extends out under the action of the restoring force of the spring and enters the pin hole, and therefore locking between the buttjoint guide block 8 and thelocking core 6 is achieved. An imagerecognition positioning plate 9 is connected to one of thelocking pin actuators 7; preferably, the imagerecognition positioning plate 9 is located at a position right above thedocking guide block 8, and corresponds to the position of thevision sensor 1 on thebase 3.
The imagerecognition positioning plate 9 on the passive docking car is used for being matched with thevision sensor 1 on the active docking car, and thevision sensor 1 can obtain the relative position information of the imagerecognition positioning plate 9 on the passive docking car locking module based on a position area recognition algorithm and an edge line recognition algorithm and send the relative position information to the control module; the control module adjusts the position of thelocking core 6 on the six-degree-of-freedom platform according to the position, so that the lockingcore 6 and the buttjoint guide block 8 reach an expected relative position, and the accurate butt joint requirement is met.
The lasersensor detection board 10 on the passive docking car is used for being matched with the threelaser ranging sensors 4 on the active docking car; when an active capture module on an active butt joint vehicle is in butt joint with a locking module on a passive butt joint vehicle, a control module on the active butt joint vehicle establishes a two-plane parallel mathematical model according to distance information between a lasersensor detection plate 10 on the locking module of the passive butt joint vehicle and the distance information respectively detected by threelaser ranging sensors 4, an included angle between the axis of alocking core 6 on the active butt joint vehicle and the axis of aguide block 8 on the passive butt joint vehicle is calculated, then thelocking core 6 on a six-degree-of-freedom platform is controlled to move to eliminate the included angle, so that the buttjoint guide block 8 is coaxial with thelocking core 6, and thelocking core 6 can be accurately inserted into the buttjoint guide block 8 during butt joint.
In addition, during butt joint, theforce sensor 5 on the active butt joint vehicle is in contact with the plane where theguide block 8 in the locking module of the passive butt joint vehicle is located, and the control module judges whether the plane where theguide block 8 is located is parallel to the plane where the lockingcore connecting plate 11 is located or not according to the stress fed back by the three force sensors 5 (if the two planes are parallel, the stress of the positions where the threeforce sensors 5 are located are the same). Meanwhile, a threshold value of the stress detected by the force sensors is preset in the control module, and the threshold value indicates that the lockingcore 6 and the buttjoint guide block 8 are in butt joint in place, namely when the stress fed back by the three force sensors reaches the preset threshold value, the lockingcore 6 is inserted to reach a specified position. In addition,force sensor 5 still is used for detecting the stress sudden change that leads to because the unequally disturbance of ground when the butt joint, and when the sudden change appears in stress, control module in time controls thelocking core 6 of six degrees of freedom platforms and adjusts, and the rocking that the unequally disturbance of ground arouses when avoiding the butt joint leads to the mechanism to damage.
The multi-sensor sensing module based on the vision sensor, the laser ranging sensor and the force sensor can ensure the accuracy and stability of the butt joint process. When the butt joint is started, thevision sensor 1 acquires the position information of the imagerecognition positioning plate 9 and feeds the position information back to the control module, and the relative position of the butt joint system of the two unmanned vehicle units to be butt jointed is adjusted to initially meet the requirement required by flexible butt joint; then, thelaser ranging sensor 4 acquires distance information of the active capture module and the locking module of the two unmanned vehicle units to be butted, so that the movable end (the active capture module) and the fixed end (the locking module) of the butt joint system of the two unmanned vehicle units are kept parallel; when the movable end and the fixed end are aligned, the lockingcore 6 on the active capture module is slowly inserted into the buttjoint guide block 8 of the locking module, and in the process, theforce sensor 5 acquires stress information between the active capture module and the locking module during butt joint, so that butt joint of two unmanned vehicle units is ensured to be in place, and deviation and collision caused by road jolt are avoided during flexible butt joint.
As shown in FIG. 3, the docking action between the active capture module and the locking module operates under the control of the control module. The control module realizes the control of the six electrically-drivenlinear actuators 2 according to the information detected by the sensing module. The control module adopts a full-digital servo control system and comprises a microcontroller, a programmable logic controller, a servo driver and a motor. The microcontroller carries out the attitude calculation of the active capture module according to the information transmitted by the sensing module, the programmable logic controller calculates the elongation of six electric-drivenlinear actuators 2 in the active capture module through position inverse solution, transmits the elongation to the servo driver, and drives the servo motor to rotate by the servo driver, so that the positions of the electric-drivenlinear actuators 2 are changed, namely the electric-drivenlinear actuators 2 are controlled to stretch out and draw back, and the motion of the motion platform in six degrees of freedom in a Cartesian coordinate system is realized. The encoder installed on the servo motor detects the speed and the position information of the servo motor in real time and sends the speed and the position information to the servo driver to form a closed-loop control system, so that the elongation of each electrically-drivenlinear actuator 2 is accurately controlled in real time, meanwhile, the servo driver transmits the speed and the position information to the microcontroller, and the microcontroller ensures the coordinated action and the control accuracy of the six actuators.
The working principle of the butt joint system is as follows:
after the control modules of the two unmanned vehicle units receive the docking command, the relative positions of the two unmanned vehicle units are close to meet the docking requirement through the intersection of trajectory planning and trajectory tracking.
Then, thevision sensor 1 on the active capture module of the active butt joint vehicle detects the imagerecognition positioning plate 9 on the locking module of the passive butt joint vehicle, and controls thelocking core 6 on the active capture module to perform initial position adjustment according to the position information transmitted by thevision sensor 1. After preliminary adjustment, the control module on the active butt joint vehicle controls the active capture module to eliminate the included angle between the axis of thelocking core 6 and the axis of the buttjoint guide block 8, which are calculated by the threelaser sensors 1, so that the axes of the locking core and the axis of the butt joint guide block coincide to meet the requirement of accurate butt joint. After thelocking core 6 on the active docking vehicle aligns to thedocking guide block 8 on the passive docking vehicle, the control module on the active docking vehicle controls the active capture module to insert thelocking core 6 into thedocking guide block 8; meanwhile, theforce sensor 5 is in contact with the plane where the buttjoint guide block 8 on the locking module is located, and the control module on the active butt joint vehicle adjusts the position relation between the buttjoint guide block 8 and thelocking core 6 according to the feedback stress so as to enable the butt joint guide block and the locking core to be in place. And finally, the locking pin on the buttjoint guide block 8 on the passive butt joint vehicle is pushed into the pin hole on thelocking core 6 under the action of thelocking pin actuator 7, so that the locking of the active capture module and the locking module is completed, and the butt joint of the two unmanned vehicle units is completed.
When the control modules of two butted unmanned vehicle units receive a disassembly command, the control module on the passive butted vehicle firstly controls thelocking pin actuator 7 to act, and the locking pin is pulled back to separate the locking pin from the pin hole on thelocking core 6 of the active butted vehicle, so that the active capture module on the active butted vehicle and the locking module on the passive butted vehicle are unlocked; then the active butt joint vehicle and/or the passive butt joint vehicle move backwards to separate thelocking core 6 from the buttjoint guide block 8, and the disassembly of the two unmanned vehicle units is completed.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.