Work machine control system, work machine, and work machine control method

Abstract

This work machine control system comprises a computer. The computer acquires a pre-correction command, and corrects the pre-correction command and outputs a post-correction command for operating the work machine, the correction being performed so as to satisfy a constraint for maintaining stability of the work machine while keeping the deviation between the pre-correction command and the post-correction command small.

Description

Work machine control system, work machine, and work machine control method

[0001] The present disclosure relates to a work machine control system, a work machine, and a work machine control method.

[0002] Known in the art of work machines are stabilization systems for articulated machines, such as that disclosed in U.S. Patent No. 6,275,623. In U.S. Patent No. 6,275,623, the stabilization system automatically adjusts brakes or other machine actions to slow machine motion in order to maintain an acceptable level of machine instability.

[0003] US Patent Application Publication No. 2023 / 0359203

[0004] If the operation of the work machine is slowed down excessively in order to maintain the stability of the work machine, the workability of the work machine may decrease.

[0005] An object of the present disclosure is to suppress a decrease in the workability of a work machine.

[0006] According to the present disclosure, there is provided a work machine control system including a computer, which acquires an uncorrected command, corrects the uncorrected command so as to satisfy constraints for maintaining the stability of the work machine and reduce deviation from the uncorrected command, and outputs a corrected command for operating the work machine.

[0007] According to the present disclosure, it is possible to suppress a decrease in the workability of a work machine.

[0008] FIG. 1 is a diagram showing a remote operation system for a work machine according to a first embodiment. FIG. 2 is a configuration diagram showing a work machine and an operation device according to the first embodiment. FIG. 3 is a hardware configuration diagram showing an on-board controller according to the first embodiment. FIG. 4 is a block diagram showing a control system for a work machine according to the first embodiment. FIG. 5 is a diagram explaining a constraint condition under which a work machine according to the first embodiment does not tip over. FIG. 6 is a diagram explaining a constraint condition under which a load held in a bucket of a work machine according to the first embodiment does not collapse. FIG. 7 is a diagram explaining a constraint condition under which a load held in a bucket of a work machine according to the first embodiment does not collapse. FIG. 8 is a flowchart showing a control method for a work machine according to the first embodiment. FIG. 9 is a block diagram showing a control system for a work machine according to a second embodiment. FIG. 10 is a diagram explaining the operation of a work machine according to the second embodiment. FIG. 11 is a flowchart showing a method for determining target operating conditions according to the second embodiment. FIG. 12 is a block diagram showing a control system for a work machine according to a third embodiment. FIG. 13 is a schematic diagram of a forklift according to another embodiment, viewed from above. FIG. 14 is a schematic diagram of a forklift according to another embodiment, viewed from above. FIG. 15 is a schematic diagram of a forklift according to another embodiment, as viewed from above.

[0009] Hereinafter, the present embodiment of the present disclosure will be described with reference to the drawings, but the present disclosure is not limited to the present embodiment. The components of the present embodiment described below can be combined as appropriate. In addition, some components may not be used.

[0010] First Embodiment A first embodiment will be described.

[0011] <Remote Control System> Figure 1 is a diagram showing a remote control system 200 for a work machine 1 according to this embodiment. The remote control system 200 remotely controls a work machine 1 that is located at a work site 201. At least a part of the remote control system 200 is disposed in a remote control room 202 provided outside the work machine 1. The remote control system 200 comprises an operation device 70, a display device 80, an input device 81, and a remote controller 82.

[0012] The operation device 70 is disposed in the remote control room 202. The operation device 70 is operated by an operator in the remote control room 202. The operator can operate the operation device 70 while seated in the operator seat 83. The operator may also operate a portable operation device 700. The operation device 700 may also be operated outside the remote control room 202.

[0013] The display device 80 is disposed in the remote control room 202. An example of the display device 80 is a flat panel display such as a liquid crystal display or an organic EL display. The display device 80 displays at least an image of the work site 201. The display device 80 may also output audio of the work site 201.

[0014] The operator operates the operation device 70 while checking an image of the work site 201 displayed on the display device 80. The work machine 1 is remotely controlled by the operation device 70.

[0015] The input device 81 is placed in the remote control room 202. The input device 81 is operated by an operator in the remote control room 202. Examples of the input device 81 include a computer keyboard, a touch panel, a mouse, and a voice input device.

[0016] The remote controller 82 is disposed in a remote operation room 202. The remote controller 82 and the work machine 1 communicate with each other via a communication system 203. Examples of the communication system 203 include the Internet, a local area network (LAN), a mobile phone communication network, and a satellite communication network.

[0017] <Working Machine> In this embodiment, the working machine 1 is a wheel loader. As shown in Figure 1, the working machine 1 is equipped with a vehicle body 2, a traveling device 5 including an articulated cylinder 7 and wheels 4, and a working implement 6. The working machine 1 travels on the traveling device 5 at a work site 201. The working machine 1 performs work using the working implement 6 at the work site 201. Examples of work performed by the working machine 1 include excavation work, loading work, and transporting work.

[0018] The vehicle body 2 supports a work implement 6. The vehicle body 2 includes a front frame 2F and a rear frame 2R. The front frame 2F is disposed forward of the rear frame 2R. The front frame 2F and the rear frame 2R are connected via an articulation mechanism 3.

[0019] The traveling device 5 supports the vehicle body 2. The traveling device 5 includes wheels 4 and an articulating cylinder 7. The wheels 4 include front wheels 4F attached to the front frame 2F and rear wheels 4R attached to the rear frame 2R. The wheels 4 include tires. The articulating cylinder 7 connects the front frame 2F and the rear frame 2R. The articulating cylinder 7 is a hydraulic cylinder. When the articulating cylinder 7 extends and retracts, the front frame 2F bends left and right relative to the rear frame 2R. When the front frame 2F bends relative to the rear frame 2R, the traveling direction of the work machine 1 is adjusted. The articulating cylinder 7 is an example of a steering device for the work machine 1.

[0020] The work implement 6 is supported by the vehicle body 2. The work implement 6 is connected to the front frame 2F. The work implement 6 has a boom 8, a bucket 9, a bell crank 10, a bucket link 11, a boom cylinder 12, and a bucket cylinder 13.

[0021] The base end of the boom 8 is rotatably connected to the front frame 2F. The base end of the bucket 9 is rotatably connected to the tip end of the boom 8. The middle portion of the bell crank 10 is rotatably connected to a bracket 14 of the boom 8. The lower end of the bell crank 10 is rotatably connected to the base end of a bucket link 11. The tip end of the bucket link 11 is rotatably connected to a bracket 15 of the bucket 9. The bell crank 10 is connected to the bucket 9 via the bucket link 11.

[0022] The bucket 9 is a working member that excavates an excavation target. The bucket 9 is replaceable with another working member. An example of the other working member is a fork that transports an object to be transported.

[0023] The boom 8 is operated by a boom cylinder 12. The boom cylinder 12 is a hydraulic cylinder. A base end of the boom cylinder 12 is connected to the front frame 2F. A tip end of the boom cylinder 12 is connected to the boom 8. The bucket 9 is operated by a bucket cylinder 13. The bucket cylinder 13 is a hydraulic cylinder. A base end of the bucket cylinder 13 is connected to the front frame 2F. A tip end of the bucket cylinder 13 is connected to the upper end of the bell crank 10.

[0024] In this embodiment, the work machine 6 is a front-loading type work machine in which the opening of the bucket 9 faces forward during excavation work. The boom cylinder 12 extends and retracts to raise or lower the boom 8. The bucket cylinder 13 extends and retracts to tilt or dump the bucket 9.

[0025] <Configuration of Work Machine and Operating Device> Figure 2 is a configuration diagram showing the work machine 1 and operating device 70 according to this embodiment. As shown in Figure 2, the work machine 1 includes a drive machine 16, a power take-off (PTO) 17, a power transmission device 18, wheels 4, a brake device 19, a steering pump 20, a steering control valve 21, an articulated cylinder 7, a work implement pump 22, a work implement control valve 23, a boom cylinder 12, a bucket cylinder 13, a position sensor 24, a direction sensor 25, a speed sensor 26, a steering sensor 27, a work implement attitude sensor 28, an external sensor 29, a load sensor 30, a camera 31, and an on-board controller 32. The traveling device 5 includes the power transmission device 18, the brake device 19, wheels 4, and the articulated cylinder 7.

[0026] The drive machine 16 is a drive source for the work machine 1. The drive machine 16 is supported by the vehicle body 2. Examples of the drive machine 16 include a diesel engine and an electric motor. The power take-off 17 distributes the driving force of the drive machine 16 to a power transmission device 18, a steering pump 20, and a work implement pump 22.

[0027] The power transmission device 18 transmits the driving force of the drive machine 16 to the wheels 4. The power transmission device 18 controls the traveling speed and direction of travel of the work machine 1. The traveling direction of the work machine 1 includes forward and reverse. The power transmission device 18 may be a transmission having a torque converter, or may be a transmission having a plurality of speed change gears. An input shaft 61 is connected to the power take-off 17. The power transmission device 18 changes the speed of rotation of the input shaft 61 and outputs it to an output shaft 62. The brake device 19 slows down or stops the working machine 1 while it is traveling.

[0028] The traveling device 5 has a front axle 51 that supports the front wheels 4F, a rear axle 52 that supports the rear wheels 4R, and a rear propeller shaft 53. The front axle 51 is supported by the front frame 2F. The front wheels 4F are attached to the left and right ends of the front axle 51. The front axle 51 is connected to an output shaft 62. The rear axle 52 is supported by the rear frame 2R. The rear wheels 4R are attached to the left and right ends of the rear axle 52. The rear propeller shaft 53 is connected to the output shaft 62. A coupling portion 54 is provided at the rear end of the rear propeller shaft 53. The rear axle 52 is connected to the coupling portion 54. The rear axle 52 is connected to the output shaft 62 via the rear propeller shaft 53. The driving force of the driving machine 16 is transmitted to the front axle 51 and the rear axle 52 via the input shaft 61 , the power transmission device 18 , and the output shaft 62 .

[0029] In this embodiment, the traveling device 5 has a rear axle oscillating mechanism 50 such as that disclosed in WO 2021 / 065404. The rear axle oscillating mechanism 50 is a mechanism for keeping the vehicle body 2 horizontal when the work machine 1 travels on uneven ground or ground that slopes in the vehicle width direction. The rear axle oscillating mechanism 50 tilts the rear wheels 4R of the work machine 1 to the left and right according to the shape of the ground at the work site 201. The rear axle oscillating mechanism 50 allows each of the two front wheels 4F and the two rear wheels 4R to always contact the ground, thereby transmitting driving force to the ground.

[0030] The rear axle oscillating mechanism 50 includes a connecting portion 54. The rear axle 52 is supported on the rear frame 2R by the rear axle oscillating mechanism 50 so that it can swing around the connecting portion 54. The rear axle oscillating mechanism 50 allows the rear axle 52 to tilt in an inclination direction centered on the rotation axis of the rear propeller shaft 53. The rear axle oscillating mechanism 50 prevents the work machine 1 from tipping over when the work machine 1 travels on uneven ground or ground that slopes in the vehicle width direction.

[0031] The steering pump 20 is a hydraulic pump that is operated by the driving force generated by the driving machine 16. The hydraulic oil discharged from the steering pump 20 is supplied to the articulate cylinder 7 via a steering control valve 21. The steering control valve 21 controls the flow rate and direction of the hydraulic oil supplied from the steering pump 20 to the articulate cylinder 7. The articulate cylinder 7 is operated by the hydraulic oil from the steering pump 20.

[0032] The work implement pump 22 is a hydraulic pump that operates using driving force generated by the driving machine 16. The hydraulic oil discharged from the work implement pump 22 is supplied to each of the boom cylinder 12 and the bucket cylinder 13 via a work implement control valve 23. The work implement control valve 23 controls the flow rate and direction of the hydraulic oil supplied from the work implement pump 22 to each of the boom cylinder 12 and the bucket cylinder 13. The work implement 6 operates using hydraulic oil from the work implement pump 22. The work implement 6 operates using hydraulic oil from the work implement pump 22.

[0033] The position sensor 24 detects the position of the work machine 1. The position of the work machine 1 is detected using a global navigation satellite system (GNSS). The global navigation satellite system includes a global positioning system (GPS). The global navigation satellite system detects the position of a global coordinate system defined by coordinate data of latitude, longitude, and altitude. The global coordinate system is a coordinate system fixed to the Earth. The position sensor 24 includes a GNSS receiver, and detects the absolute position of the work machine 1, which indicates the position of the work machine 1 in the global coordinate system.

[0034] The orientation sensor 25 detects the orientation of the work machine 1. The orientation of the work machine 1 includes an orientation angle relative to a reference orientation. An example of the orientation sensor 25 is an inertial sensor (IMU: Inertial Measurement Unit). The orientation sensor 25 may include a calculator that calculates the orientation from position data detected by two GNSS antennas provided on the work machine 1. The calculator can calculate the orientation from a vector connecting the two GNSS antennas.

[0035] The speed sensor 26 detects the traveling speed of the work machine 1. An example of the speed sensor 26 is a magnetic sensor that detects the rotation speed of a drive shaft connected to the wheels 4.

[0036] The steering sensor 27 detects one or both of the steering angle and the steering angular velocity of the work machine 1. Examples of the steering sensor 27 include a cylinder stroke sensor that detects the stroke length of the articulate cylinder 7, and an angle sensor that detects the angle of the front frame 2F relative to the rear frame 2R.

[0037] The work implement attitude sensor 28 detects the attitude of the work implement 6. The attitude of the work implement 6 includes the angle and height of the work implement 6. The work implement attitude sensor 28 includes a boom angle sensor 28A that detects the attitude of the boom 8, and a bucket angle sensor 28B that detects the attitude of the bucket 9.

[0038] The attitude of the boom 8 includes the angle and height of the boom 8. The boom angle sensor 28A detects the boom angle indicating the angle of the boom 8. The boom angle refers to the angle of the boom 8 with respect to the vehicle body 2 in the local coordinate system. The length of the boom 8 is known. By detecting the boom angle, the height of the tip of the boom 8 is calculated. An angle sensor arranged at the connection between the front frame 2F and the boom 8 is exemplified as the boom angle sensor 28A.

[0039] The attitude of the bucket 9 includes the angle and height of the bucket 9. The bucket angle sensor 28B detects a bucket angle that indicates the angle of the bucket 9. The bucket angle refers to the angle of the bucket 9 with respect to the boom 8 in the local coordinate system. In this embodiment, the bucket angle sensor 28B detects a bell crank angle that indicates the angle of the bell crank 10 with respect to the boom 8 in the local coordinate system. An example of the bucket angle sensor 28B is an angle sensor that is disposed at the connection between the boom 8 and the bell crank 10. The bucket angle and the bell crank angle correspond one-to-one. The bucket angle sensor 28B detects the bell crank angle. The bucket angle is calculated based on the detection data of the bell crank angle and the detection data of the boom angle. The dimensions of the bucket 9 are known. The height of the tip of the bucket 9 is calculated by detecting the bucket angle. The tip of the bucket 9 includes the cutting edge of the bucket 9.

[0040] The work implement attitude sensor 28 is not limited to an angle sensor. The work implement attitude sensor 28 may be a cylinder stroke sensor or an inclination sensor such as an inertial measurement unit (IMU). The boom angle sensor 28A may be a cylinder stroke sensor that detects the stroke length of the boom cylinder 12 or an inclination sensor attached to the boom 8. The bucket angle sensor 28B may be a cylinder stroke sensor that detects the stroke length of the bucket cylinder 13 or an inclination sensor attached to the bucket 9.

[0041] The external sensor 29 detects the three-dimensional shape of objects in the vicinity of the work machine 1. The external sensor 29 is disposed on at least a part of the vehicle body 2. An example of the external sensor 29 is a laser sensor (LiDAR: Light Detection and Ranging) that detects objects by emitting laser light. Note that the external sensor 29 may also be a radar sensor (RADAR: Radio Detection and Ranging) that detects objects by emitting radio waves, or a stereo camera. In this embodiment, the external sensor 29 detects the three-dimensional shape of the load held in the bucket 9.

[0042] The load sensor 30 detects the load state of the work implement 6. The load sensor 30 detects whether the bucket 9 is in a loaded state where it holds a load, or in an empty state where it does not hold a load. In this embodiment, the load sensor 30 includes a weight sensor that detects the weight of the work implement 6. The weight of the work implement 6 differs between a loaded state where the bucket 9 holds a load and an empty state where it does not hold a load. The load sensor 30 can detect whether the work implement 6 is in a loaded state or an empty state by detecting the weight of the work implement 6. An example of the load sensor 30 is a bottom pressure sensor that detects the bottom pressure of the boom cylinder 12.

[0043] The camera 31 captures an image of the work site 201. The camera 31 captures an image of at least the work site 201 in front of the work machine 1. The camera 31 captures an image of at least a portion of the work implement 6. The camera 31 is disposed, for example, in a cab provided on the rear frame 2R. Image data captured by the camera 31 is transmitted to the remote controller 82 via the on-board controller 32 and the communication system 203. The remote controller 82 displays the image data captured by the camera 31 on the display device 80.

[0044] The operation device 70 is operated by an operator. When operated by the operator, the operation device 70 generates operation commands for operating the work machine 1. The operation commands generated by the operation device 70 are transmitted to the on-board controller 32 via the remote controller 82 and the communication system 203. The on-board controller 32 outputs control commands for operating the work machine 1 based on the operation commands transmitted from the remote controller 82. The operation device 70 includes a traveling system operation device 70A and a work machine operation device 70B.

[0045] The traveling system operation device 70A is operated by an operator to operate at least one of the drive machine 16, the power transmission device 18, and the brake device 19. The traveling system operation device 70A generates operation commands to operate at least one of the drive machine 16, the power transmission device 18, and the brake device 19. The traveling system operation device 70A includes an accelerator pedal 71, a brake pedal 72, a steering wheel 73, and a forward / reverse switch lever 74.

[0046] The work implement operating device 70B is operated by an operator to operate the work implement 6. The work implement operating device 70B generates an operation command to operate the work implement 6. The work implement operating device 70B includes a boom lever 75 and a bucket lever 76. The boom lever 75 is operated to operate the boom 8. The bucket lever 76 is operated to operate the bucket 9.

[0047] When the boom lever 75 is operated, the boom spool of the work implement control valve 23 moves. When the boom lever 75 is operated to one side from the neutral position of the boom lever 75 and the boom spool is located in the bottom position, the boom cylinder 12 extends. When the boom lever 75 is operated to the other side from the neutral position of the boom lever 75 and the boom spool is located in the rod position, the boom cylinder 12 retracts. When the boom spool is located in the neutral position, the extension and contraction of the boom cylinder 12 stops.

[0048] When the bucket lever 76 is operated, the bucket spool of the work implement control valve 23 moves. When the bucket spool is located in the bottom position, the bucket cylinder 13 extends. When the bucket spool is located in the rod position, the bucket cylinder 13 retracts. When the bucket spool is located in the neutral position, the bucket cylinder 13 stops extending and retracting.

[0049] The input device 81 is operated by an operator. The input device 81 generates input data when operated by the operator. The input data generated by the input device 81 is transmitted to the in-vehicle controller 32 via the remote controller 82 and the communication system 203.

[0050] <On-Vehicle Controller> FIG. 3 is a hardware configuration diagram showing the on-vehicle controller 32 according to this embodiment. The on-vehicle controller 32 includes a computer 33. The computer 33 has a processor 34 such as a central processing unit (CPU), a main memory 35 including a nonvolatile memory such as a read-only memory (ROM) and a volatile memory such as a random access memory (RAM), a storage 36, an input / output interface 37 including an input / output circuit, and a communication interface 38 including a communication circuit. The functions of the on-vehicle controller 32 are stored in the storage 36 as a computer program 39. The processor 34 reads the computer program 39 from the storage 36, loads it into the main memory 35, and executes processing in accordance with the computer program 39. The computer program 39 may be distributed to the computer 33 via a network.

[0051] The remote controller 82 also includes a computer. Like the on-board controller 32, the remote controller 82 has a processor, a main memory, storage, an input / output interface, and a communication interface.

[0052] <Control System> Figure 4 is a block diagram showing a control system 100A of the work machine 1 according to this embodiment. The control system 100A includes a remote controller 82 and an on-vehicle controller 32. Detection data from the position sensor 24, direction sensor 25, speed sensor 26, steering sensor 27, work implement attitude sensor 28, external sensor 29, and load sensor 30 is transmitted to the on-vehicle controller 32. Operation commands from the operation device 70 are transmitted to the on-vehicle controller 32 via a communication system 203. Input data from the input device 81 is transmitted to the on-vehicle controller 32 via the communication system 203. The on-vehicle controller 32 transmits control commands to each of the traveling devices 5 and the work implement 6.

[0053] 4, the on-vehicle controller 32 includes a constraint condition calculation unit 41 and a command correction unit 42. The constraint condition calculation unit 41 and the command correction unit 42 are each realized by the computer 33 described above.

[0054] The constraint condition calculation unit 41 calculates the constraint condition B for maintaining the stability of the work machine 1. The constraint condition B for maintaining the stability of the work machine 1 is the constraint condition B for preventing the work machine 1 from tipping over when the traveling device 5 is traveling. １ and constraint condition B under which the load held in the bucket 9 of the work implement 6 does not collapse during the travel of the traveling device 5. ２ and constraint condition B under which the work machine 1 does not come into contact with an obstacle when the traveling device 5 is traveling. ３ In this embodiment, the load held in the bucket 9 includes earth and sand. When the load (earth and sand) held in the bucket 9 does not collapse, this means that the load does not spill out of the bucket 9 or the load does not fall from the bucket 9.

[0055] The constraint condition calculation unit 41 acquires the detection data of the position sensor 24, the detection data of the direction sensor 25, the detection data of the speed sensor 26, the detection data of the steering sensor 27, the detection data of the work implement attitude sensor 28, the detection data of the external sensor 29, and the detection data of the load sensor 30. In addition, the constraint condition calculation unit 41 acquires input data from the input device 81 via the communication system 203.

[0056] The constraint condition calculation unit 41 calculates the constraint condition B based on the vehicle state parameters and the cargo parameters. The constraint condition calculation unit 41 can acquire the vehicle state parameters and the cargo parameters by acquiring one or both of the detection data and the input data.

[0057] The vehicle state parameters include the position of the work machine 1, the attitude (tilt angle) of the work machine 1, the forward acceleration of the work machine 1, the lateral acceleration of the work machine 1, the position (height) of the work implement 6, the attitude (angle) of the work implement 6, the operating speed of the work implement 6, and the operating acceleration of the work implement 6. The constraint condition calculation unit 41 is able to obtain the position of the work machine 1 by acquiring detection data from the position sensor 24. If the orientation sensor 25 is an inertial sensor (IMU), the constraint condition calculation unit 41 is able to obtain the attitude and forward acceleration of the work machine 1 by acquiring detection data from the orientation sensor 25. The constraint condition calculation unit 41 is able to estimate the lateral acceleration of the work machine 1 based on detection data from the speed sensor 26 and detection data from the steering sensor 27. The constraint condition calculation unit 41 is able to calculate the position of the work machine 6, the attitude of the work implement 6, the operating speed of the work implement 6, and the operating acceleration of the work implement 6 based on detection data from the work implement orientation sensor 28.

[0058] The load parameters indicate the state of the load held by the bucket 9 of the work implement 6. The state of the load includes the mass of the load held by the bucket 9, the inertia tensor of the load, and the position of the center of gravity of the load. The constraint condition calculation unit 41 can obtain the mass of the load by acquiring detection data from the load sensor 30. The constraint condition calculation unit 41 can calculate the inertia tensor and the position of the center of gravity of the load based on detection data from the external sensor 29. The external sensor 29 can detect the three-dimensional shape of the load held by the bucket 9. Assuming that the density of the load is constant, the constraint condition calculation unit 41 can calculate the inertia tensor and the position of the center of gravity of the load based on the three-dimensional shape of the load detected by the external sensor 29.

[0059] The cargo parameters include soil parameters that indicate the properties of the soil that is the cargo. In this embodiment, the cargo parameters include the adhesion strength c [N / m ２], the internal friction angle of the soil φ [°], and the density of the soil ρ [kg / m ３ The cargo parameters may be input to the constraint condition calculation unit 41 from the input device 81.

[0060] The constraint condition calculation unit 41 may calculate the density ρ of the soil and sand based on the three-dimensional shape (volume) of the soil and sand held in the bucket 9 and the weight of the soil and sand held in the bucket 9. The external sensor 29 is capable of detecting the three-dimensional shape (volume) of the soil and sand held in the bucket 9. The load sensor 30 is capable of detecting the weight of the soil and sand held in the bucket 9.

[0061] The command correction unit 42 acquires an operation command from the operation device 70 via the communication system 203. In the following description, the operation command from the operation device 70 is appropriately referred to as a pre-correction command u ｒ In this embodiment, the pre-correction command u ｒ includes an operation command generated by operating the operation device 70.

[0062] The command correction unit 42 corrects the operation command and outputs a control command for operating the work machine 1. The traveling device 5 and the work implement 6 each operate based on the control command output from the command correction unit 42. In the following description, the control command output from the command correction unit 42 will be referred to as the corrected command u as appropriate. ｃ , called.

[0063] The command correction unit 42 determines the constraint B (B １ , B ２ , B ３ ) and the pre-correction command u ｒ The pre-correction command u ｒ Corrected command u for correcting and operating the work machine 1 ｃ The command correction unit 42 outputs the constraint condition B (B １ , B ２ , B ３ ) and the pre-correction command u ｒ and the corrected command u ｃ The pre-correction command u ｒCorrect the command u ｃ Calculate.

[0064] Constraint Conditions Constraint Condition B will now be described. As shown in equations (1) and (2), the corrected command u ｃ The value of is a predetermined lower limit value u ｍｉｎ is greater than the upper limit u ｍａｘ and is calculated so as to satisfy constraint condition B. In equation (2), x is a vehicle state parameter.

[0065]

[0066]

[0067] As shown in equation (3), the constraint condition calculation unit 41 calculates the constraint condition B that prevents the work machine 1 from tipping over. １ , constraint condition B that the load held in the bucket 9 of the work machine 6 does not collapse ２ , and a constraint B that the work machine 1 does not come into contact with an obstacle. ３ The corrected command u is set to satisfy each of the above. ｃ Calculate.

[0068]

[0069] (Constraint condition B １ 5 shows constraint condition B under which the work machine 1 according to this embodiment does not tip over. １ The constraint condition calculation unit 41 calculates the constraint condition B that prevents the work machine 1 from tipping over when the work machine 1 is traveling. １ Calculate.

[0070] As shown in [Form 1] of FIG. 5, constraint B under which the work machine 1 does not tip over is satisfied. １ includes a condition that the zero moment point of the work machine 1 does not deviate from a set range AP1 that is set based on a plurality of ground contact points of the traveling device 5. The zero moment point (ZMP) refers to the dynamic center of gravity position of the work machine 1 that takes into account the influence of inertial force (centrifugal force). The zero moment point is the point where the resultant force of gravity and inertial force intersects with the ground.

[0071] In [Configuration 1], the set range AP1 is a rectangular range connecting the ground contact points of the four wheels 4 of the traveling device 5. The ground contact points of the wheels 4 refer to the parts of the wheels 4 (tires) that come into contact with the ground at the work site.

[0072] The constraint condition calculation unit 41 calculates the zero moment point based on the vehicle state parameters and the cargo parameters. １ The vehicle state parameters used to calculate the constraint condition B include the tilt angle of the work machine 1, the forward acceleration of the work machine 1, the lateral acceleration of the work machine 1, the position of the work implement 6, the attitude of the work implement 6, the operating speed of the work implement 6, and the operating acceleration of the work implement 6. １ The load parameters for calculating (a) include the mass of the load held in the bucket 9, the inertia tensor of the load, and the position of the center of gravity of the load. The constraint condition calculation unit 41 may calculate the zero moment based on vehicle parameters including the mass of each link of the work machine 1, the inertia tensor of each link of the work machine 1, and the position of the center of gravity of each link of the work machine 1. The constraint condition calculation unit 41 may calculate the zero moment point based on vehicle state parameters, load parameters, and vehicle parameters.

[0073] As shown in [Mode 2] of FIG. 5, a set range AP2 smaller than the set range AP1 may be set. １ may be a condition under which the zero moment point of the work machine 1 does not deviate from the set range AP2. In [Configuration 2], the set range AP2 is a triangular range connecting the ground contact point of the left front wheel 4F, the ground contact point of the right front wheel 4F, and the center point of the two rear wheels 4R. The connecting portion 54 of the rear axle oscillating mechanism 50 is located at the center point of the two rear wheels 4R. The set range AP2 may be set to a triangular range with the rear axle oscillating mechanism 50 as its vertex.

[0074] As shown in [Configuration 3] of FIG. 5, a set range AP3 smaller than the set range AP1 may be set. １ may be a condition that the zero moment point of the work machine 1 does not deviate from the set range AP3. In [Configuration 3], the set range AP3 is a rectangular range similar to the set range AP1.

[0075] The constraint condition calculation unit 41 takes into consideration the topography of the work site 201 and determines the constraint condition B under which the work machine 1 does not tip over. １ That is, the constraint condition calculation unit 41 may calculate the constraint condition B by taking into account the inclination angle of the ground of the work site 201. １ If the ground at the work site 201 includes a slope, a work machine 1 traveling on a slope may be more likely to tip over than a work machine 1 traveling on a flat surface parallel to the horizontal plane. Therefore, the constraint condition calculation unit 41 determines the constraint condition B by taking into account the inclination angle of the ground at the work site 201. １ may be determined.

[0076] (Constraint condition B ２ 6 and 7 show constraint condition B, which prevents the load held in the bucket 9 of the work machine 6 according to this embodiment from collapsing. ２ The constraint condition calculation unit 41 calculates the constraint condition B that prevents the load held in the bucket 9 of the work implement 6 from collapsing when the work machine 1 travels. ２ Calculate.

[0077] The constraint condition calculation unit 41 calculates the constraint condition B based on the inertial force acting on the load held in the bucket 9, the shape of the load held in the bucket 9, and the load parameters related to the load held in the bucket 9. ２ In this embodiment, the constraint condition calculation unit 41 calculates the constraint condition B that prevents the load held in the bucket 9 from collapsing based on the mole's destruction criterion. ２ Calculate.

[0078] As shown in Figure 6, when the work machine 1 accelerates or decelerates while it is traveling, an inertial force Fa acts in the front-to-rear direction on the load held in the bucket 9. When the work machine 1 swings while it is traveling, an inertial force Fb (centrifugal force) acts in the left-to-right direction on the load held in the bucket 9. The inertial force F acting on the load held in the bucket 9 is the resultant force of the inertial forces Fa and Fb.

[0079] Constraint condition B ２ The cargo parameters for calculating the load include soil parameters that indicate the properties of the soil. In this embodiment, the cargo parameters include the adhesion strength c [N / m２ ], the internal friction angle of the soil φ [°], and the density of the soil ρ [kg / m ３ As described above, the load parameters may be input from the input device 81. The density ρ of the soil and sand may be calculated based on the three-dimensional shape (volume) of the soil and sand held in the bucket 9 and the weight of the soil and sand held in the bucket 9.

[0080] As shown in Figure 7, in Mohr's failure criterion, a slide surface is set in the soil held by the bucket 9. The angle θ between the slide surface and the minimum principal stress (horizontal plane) is set arbitrarily. The inertial force F is calculated by the angle θ, the traveling speed v [m / sec] of the work machine 1, and the acceleration a [m / sec] of the work machine 1. ２ ] and the steering angle δ [rad]. The inertial force F [θ, v, a, δ] is the inertial force acting on the soil above the slide surface.

[0081] The shape of the load held in bucket 9 includes an angle θmax formed by the opening of bucket 9 and a tangent to the surface of the soil and sand located outside the opening of bucket 9, which passes through the point of contact between the opening of bucket 9 and the opening of bucket 9. Angle θmax is detected by external sensor 29.

[0082] The gravity W acting on the soil above the slide surface is a function of the angle θ. The constraint condition calculation unit 41 can calculate the gravity W(θ) based on the three-dimensional shape of the soil (volume of the soil above the slide surface) detected by the external sensor 29 and the density ρ of the soil.

[0083] The area A of the slide surface is a function of the angle θ. The constraint condition calculation unit 41 can calculate the area A(θ) based on the three-dimensional shape of the soil detected by the external sensor 29.

[0084] Normal stress σ and shear stress τ act on the slip surface. The normal stress σ acting on the slip surface is expressed by the balance equation shown in the following equation (4).

[0085]

[0086] In this embodiment, the constraint B under which the load held by the bucket 9 does not collapse is ２is the condition under which no soil slide occurs on the slide surface. The condition under which no soil slide occurs on the slide surface is expressed by the following equation (5).

[0087]

[0088] The command correction unit 42 calculates the corrected command u so as to satisfy the condition of the above-mentioned equation (5) within the range of [0<θ<θmax]. ｃ Calculate.

[0089] The constraint condition calculation unit 41 determines the constraint condition B that prevents the load held by the bucket 9 from collapsing, taking into consideration the topography of the work site 201. ２ That is, the constraint condition calculation unit 41 may calculate the constraint condition B by taking into account the inclination angle of the ground of the work site 201. ２ If the ground at the work site 201 includes a slope, there is a possibility that the load held in the bucket 9 may easily collapse when the work machine 1 travels on the slope. Therefore, the constraint condition calculation unit 41 determines the constraint condition B by taking into account the inclination angle of the ground at the work site 201. ２ may be determined.

[0090] (Constraint condition B ３ The constraint condition calculation unit 41 calculates constraint condition B, which specifies that the work machine 1 does not come into contact with obstacles present around the work machine 1 while the work machine 1 is traveling. ３ The external sensor 29 can detect obstacles that exist around the work machine 1. The constraint condition calculation unit 41 calculates the constraint condition B based on the detection data of the external sensor 29. ３ can be calculated.

[0091] <Correction command u ｃ The command correction unit 42 calculates the constraint B (B １ , B ２ , B ３ ) and the pre-correction command u ｒ and the corrected command u ｃ The pre-correction command u ｒ Correct the command u ｃ The command correction unit 42 outputs the following when the operating conditions of the work machine 1 are the constraint condition B (B １, B ２ , B ３ ) and the pre-correction command u ｒ and the corrected command u ｃ The corrected command u that minimizes the deviation from the value of ｃ Calculate.

[0092] The command correction unit 42 calculates the pre-correction command u ｒ and the corrected command u ｃ Evaluation function E including evaluation items related to the value and deviation ａ is calculated, and the corrected command u ｃ Calculate the evaluation function E ａ is expressed by the following equation (6): ｒ and the corrected command u ｃ The smaller the deviation from the value of the evaluation function E ａ The command correction unit 42 improves the evaluation value of the pre-correction command u ｒ and corrected command u ｃ The smaller the deviation from the evaluation function E, the better the evaluation value. ａ is calculated, and the corrected command u ｃ Output.

[0093]

[0094] In this embodiment, the evaluation function E ａ The degree of evaluation value of the evaluation function E ａ As shown in equation (6), in this embodiment, the evaluation function E ａ is the pre-correction command u ｒ and the corrected command u ｃ , and a weighting matrix H.

[0095] As shown in the following equation (7), the pre-correction command u ｒ is a traction force source command u that defines the traction force of the traveling device 5 ｒｆ and a steering angle command u that defines the steering angle of the traveling device 5. ｒｓ and a work machine source command u that specifies the operating conditions of the work machine 6. ｒｗ Includes the tractive force command u ｒｆincludes an operation command for accelerating or decelerating the traveling device 5, and includes an operation command generated by operating at least one of the accelerator pedal 71 and the brake pedal 72. ｒｓ includes an operation command for turning the traveling device 5, and includes an operation command generated by operating the steering wheel 73. ｒｗ includes an operation command for operating the work implement 6, and includes an operation command generated by operating at least one of the boom lever 75 and the bucket lever 76.

[0096] As shown in the following equation (8), the corrected command u ｃ is a traction force command u that controls the traction force of the traveling device 5. ｃｆ and a steering angle command u that controls the steering angle of the traveling device 5. ｃｓ and a work machine command u for operating the work machine 6. ｃｗ and tractive force command u ｃｆ is a control command for accelerating or decelerating the traveling device 5. ｃｓ is a control command for turning the traveling device 5. ｃｗ is a control command for operating the work implement 6.

[0097] As shown in the following equation (9), the weighting matrix H is ｃｆ and tractive force command u ｒｆ Weight value w to multiply the deviation with １ and steering angle command u ｃｓ and steering angle command u ｒｓ Weight value w to multiply the deviation with ２ and work machine command u ｃｗ and work equipment command u ｒｗ Weight value w to multiply the deviation with ３ The command correction unit 42 calculates the tractive force command u ｃｆ and tractive force command u ｒｆ The deviation from the weight value w １ The command correction unit 42 multiplies the steering angle command u ｃｓ and steering angle command u ｒｓ The deviation from the weight value w ２ The command correction unit 42 multiplies the work machine command u ｃｗ and work equipment command uｒｗ The deviation from the weight value w ３ Multiply by.

[0098]

[0099]

[0100]

[0101] For example, [w １ = 0.1, w ２ = 100, w ３ = 100], the weight value w １ When is set to a small value, the tractive force source command u ｒｆ and tractive force command u ｃｆ In other words, even if the operator operates the operation device 70 so as to increase the tractive force (acceleration or deceleration) of the traveling device 5, the corrected command u ｃ On the other hand, the steering angle command u ｃｓ is the steering angle command u ｒｓ is maintained at a value close to the value of the work implement command u ｃｗ is the work equipment command u ｒｗ That is, the steering angle of the traveling device 5 and the operation of the work implement 6 are maintained at a value close to the value of the corrected command u that is close to the operation command from the operation device 70. ｃ Since the tractive force is reduced, the work machine 1 is prevented from tipping over, and the load held in the bucket 9 is prevented from collapsing.

[0102] For example, [w １ = 100, w ２ = 0.1, w ３ = 100], the weight value w ２ When is set to a small value, the steering angle original command u ｒｓ and steering angle command u ｃｓ In other words, even if the operator operates the control device 70 so as to reduce the turning radius of the work machine 1, the corrected command u ｃ On the other hand, the traction force command u ｃｆ is the tractive force command u ｒｆis maintained at a value close to the value of the work implement command u ｃｗ is the work equipment command u ｒｗ That is, the tractive force of the traveling device 5 and the operation of the work implement 6 are maintained at a value approximate to the value of the corrected command u that approximates the operation command from the operation device 70. ｃ Since the turning radius is increased, the work machine 1 is prevented from tipping over, and the load held in the bucket 9 is prevented from collapsing.

[0103] In addition, the evaluation function E ａ The degree of evaluation value of the evaluation function E ａ The evaluation value of the evaluation function E ａ By changing the sign of ａ The larger the evaluation value of the evaluation function E ａ This means that the degree of evaluation value of

[0104] <Control Method> Fig. 8 is a flowchart showing a control method for the work machine 1 according to this embodiment. The command corrector 42 receives an operation command (pre-correction command u ｒ ) is acquired (step SA1).

[0105] The constraint condition calculation unit 41 calculates constraint conditions B for maintaining the stability of the work machine 1 based on the vehicle state parameters and the load parameters (step SA2).

[0106] The command corrector 42 determines whether the operating conditions of the work machine 1 satisfy constraint condition B (step SA3).

[0107] In step SA3, if it is determined that the operating conditions of the work machine 1 satisfy the constraint condition B (step SA3: Yes), the command corrector 42 converts the operation command acquired in step SA1 into a control command (corrected command u ｃ ) (Step SA4).

[0108] In step SA3, if it is determined that the operating conditions of the work machine 1 do not satisfy the constraint condition B (step SA3: No), the command corrector 42 corrects the operation command (pre-correction command u ｒ) so that the deviation from the control command (corrected command u ｃ ) is calculated and output (step SA5).

[0109] <Effects> As described above, according to this embodiment, the pre-correction command u is generated by operating the operation device 70. ｒ If the operating conditions of the work machine 1 operating based on the operation command do not satisfy the constraint condition B for maintaining the stability of the work machine 1, the pre-correction command u is generated so as to satisfy the constraint condition B. ｒ is the corrected command u ｒｃ If the operation of the work machine 1 is slowed down excessively in order to maintain the stability of the work machine 1, the workability of the work machine 1 may be reduced. In this embodiment, the pre-correction command u is corrected to satisfy the constraint condition B for maintaining the stability of the work machine 1. ｒ and corrected command u ｒｃ The corrected command u is set so that the deviation from ｒｃ That is, the corrected command u is output, which satisfies the constraint condition B and is as close as possible to the value of the operation command. ｒｃ The corrected command u is output, which is close to the value of the operation command generated by operating the operation device 70. ｒｃ is output, the operation of the work machine 1 is prevented from becoming excessively slow. Therefore, a decrease in the workability of the work machine 1 can be prevented.

[0110] In this embodiment, the work machine 1 is remotely controlled. When the work machine 1 is remotely controlled, the operator in the remote control room 202 does not easily feel that the work machine 1 is moving violently, even if he or she operates the control device 70 violently. The operator in the remote control room 202 does not easily feel that the travelling device 5 is suddenly accelerating, decelerating or turning sharply, even if he or she operates the traveling system control device 70A violently. The operator in the remote control room 202 does not easily feel that the work machine 6 is moving violently, even if he or she operates the work implement control device 70B violently. For this reason, the operator in the remote control room 202 may unintentionally operate the control device 70 violently. If the control device 70 is operated violently and the work machine 1 moves violently, there is a high possibility that the work machine 1 will tip over while traveling, the load held in the bucket 9 will collapse, or the work machine 1 will come into contact with an obstacle. According to this embodiment, when the operating device 70 is operated violently, the pre-correction command u from the operating device 70 is adjusted so that the operation of the work machine 1 does not become violent, that is, so that the operating conditions of the work machine 1 satisfy the constraint condition B. ｒ (operation command) is the corrected command u ｃ This maintains the stability of the work machine 1. This prevents the work machine 1 from tipping over while traveling, the load held in the bucket 9 from collapsing, and the work machine 1 from coming into contact with an obstacle.

[0111] In this embodiment, the constraint condition B for maintaining the stability of the work machine 1 is the constraint condition B for preventing the work machine 1 from tipping over while the traveling device 5 is traveling. １ and constraint condition B under which the load held in the bucket 9 of the work implement 6 does not collapse during the travel of the traveling device 5. ２ and constraint condition B under which the work machine 1 does not come into contact with an obstacle when the traveling device 5 is traveling. ３ Constraint condition B includes multiple constraint conditions B １ , B ２ , B ３ Therefore, the stability of the work machine 1 is maintained. １If only constraint condition B is included, even though an obstacle exists around the work machine 1, if the brake device 19 is operated loosely to prevent the work machine 1 from tipping over, the work machine 1 may come into contact with the obstacle. ３ If only constraint B is included, there is a possibility that the working machine 1 may tip over if the brake device 19 is suddenly activated to avoid contact between the working machine 1 and an obstacle. １ and constraint B ３ By including both of the above, operation of the brake device 19 is initiated in a state where, for example, the work machine 1 is sufficiently far from an obstacle. Therefore, both the work machine 1 tipping over and contact between the work machine 1 and an obstacle are avoided.

[0112] Other Examples In the present embodiment, at least some of the functions of the in-vehicle controller 32 may be provided in the remote controller 82. At least one of the constraint condition calculation unit 41 and the command correction unit 42 may be provided in the remote controller 82.

[0113] In this embodiment, the work machine 1 is remotely operated. An operator sitting in the cab of the work machine 1 may operate the work machine 1. The operation device 70 may be arranged in the cab of the work machine 1.

[0114] Second Embodiment A second embodiment will be described below. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the description of those components will be simplified or omitted.

[0115] In the first embodiment described above, the pre-correction command u ｒ is an operation command generated by operating the operation device 70. In the second embodiment, the tracking command (control command) when the work machine 1 is automatically controlled is the pre-correction command u ｒ An example where

[0116] Fig. 9 is a block diagram showing a control system 100B according to this embodiment. Fig. 10 is a diagram illustrating the operation of the work machine 1 according to this embodiment. The control system 100B includes an on-vehicle controller 32. As in the first embodiment described above, the on-vehicle controller 32 has a constraint condition calculation unit 41 and a command correction unit 42. The on-vehicle controller 32 also has an operating condition determination unit 43, a control input value generation unit 44, a model constraint condition calculation unit 45, and a tracking control unit 46.

[0117] The operating condition determination unit 43 determines target operating conditions for the work machine 1. The operating condition determination unit 43 determines target operating conditions for the work machine 1 so that the work machine 1 moves from a first position Pi to a second position Pg. The target operating conditions include target traveling conditions for the travel device 5 from the first position Pi to the second position Pg and target working conditions for the work implement 6. The target traveling conditions for the travel device 5 from the first position Pi to the second position Pg include a target trajectory Tr for the travel device 5 from the first position Pi to the second position Pg. The target trajectory Tr is defined by a trajectory that passes through a plurality of points Pt. Each of the plurality of points Pt indicates a target position of the work machine 1. A target azimuth angle, a target traveling speed, and a target steering angle of the work machine 1 are set for each of the plurality of points Pt. The target position of the work machine 1 refers to the target position of the work machine 1 when passing through point Pt. The target azimuth angle of the work machine 1 refers to the target azimuth angle of the work machine 1 when passing through point Pt. The target traveling speed of the work machine 1 refers to the target traveling speed of the work machine 1 when passing through point Pt. The target steering angle of the work machine 1 refers to the target steering angle of the work machine 1 when passing through point Pt. The work machine 1 travels through the work site 201 according to the target trajectory Tr.

[0118] The target traveling conditions of the traveling device 5 from the first position Pi to the second position Pg include a target azimuth angle, a target traveling speed, and a target steering angle of the traveling device 5 at each of the multiple points Pt on the target trajectory Tr.

[0119] The target working conditions of the work implement 6 from the first position Pi to the second position Pg include a target attitude of the work implement 6 at each of the multiple points Pt on the target trajectory Tr. The target attitude of the work implement 6 includes a target attitude angle of the work implement 6 and a target height of the work implement 6.

[0120] As an example, the first position Pi is an excavation position where the work machine 1 excavates an excavation target. The work machine 1 excavates the excavation target with the bucket 9 of the work implement 6. When the excavation target is excavated with the bucket 9, a load, which is the excavated material, is held in the bucket 9. The second position Pg is a loading position where the work machine 1 loads the load into the dump body of the dump truck 90, which is the loading target.

[0121] The operating condition determination unit 43 uses a model of the work machine 1 to determine the target operating conditions of the work machine 1. In this embodiment, the model of the work machine 1 refers to a model for predicting the state at the next time from the state x[k] of the work machine 1 at a certain time and the control input value u[k].

[0122] If x[k] is the state of the model of the work machine 1 at the kth time and u[k] is the control input value at the kth time, the model of the work machine 1 is expressed by the following equation (10).

[0123]

[0124] As shown in equation (10), the state of the model at time k+1 is a function of the state of the model at time k and the control input value at time k. The state of the model at time 0 is the first state of the model.

[0125] When a plane parallel to the ground at the work site where the work machine 1 travels is taken as the xy plane, that is, when the target trajectory Tr is generated in the xy plane, the state xt of the model of the work machine 1 is represented by the following equation (11). The control input value ut can be arbitrarily adopted. As an example, the control input value ut is represented by the following equation (12). The state of the model includes the position of the model represented by the x coordinate and the y coordinate, the azimuth angle of the model, the traveling speed of the traveling device 5 of the model, the steering angle of the traveling device 5 of the model, the attitude angle of the working machine 6 of the model, and the height of the working machine 6 of the model. The azimuth angle of the model means the direction in which the vehicle body 2 of the model is facing. In the present embodiment, the work machine 1 is a wheel loader, and the steering angle corresponds to the articulation angle. The control command value includes the traveling acceleration of the traveling device 5, the steering angular velocity of the traveling device 5, the attitude angular velocity of the working machine 6, and the height velocity of the working machine 6. Note that when it is assumed that the working machine 6 does not operate during the traveling of the work machine 1, the attitude angular velocity and the height velocity of the working machine 6 may not be included in the control input value.

[0126]

[0127]

[0128] The change in the internal state of the model of the work machine 1 at every certain time interval Δt is represented by the state transition model equation shown in the following equation (13). In equation (13), Δt is the time step width between each time, which is a time interval, and W is the wheelbase of the model of the work machine 1. When the work machine 1 is a wheel loader, W corresponds to the distance from the articulation center to the front axle center.

[0129]

[0130] The operating condition determiner 43 acquires a first state of the work machine 1. The first state of the work machine 1 includes an initial state of the model of the work machine 1. The first state of the work machine 1 includes at least a first position Pi of the work machine 1. In the present embodiment, the first state of the work machine 1 includes the first position Pi, a first azimuth angle of the work machine 1 at the first position Pi, a first traveling speed of the traveling gear 5, a first steering angle, and a first attitude (first angle and first height) of the work implement 6. The operating condition determiner 43 may acquire the first state of the work machine 1 from the input device 84. In other words, the user of the control system 100B may operate the input device 84 to input the first state of the work machine 1 to the on-board controller 32. When the work machine 1 is present at the first position Pi, the operating condition determination unit 43 may acquire detection data from the position sensor 24 as the first position, acquire detection data from the orientation sensor 25 as the first orientation angle, acquire detection data from the speed sensor 26 as the first traveling speed, acquire detection data from the steering sensor 27 as the first steering angle, and acquire detection data from the work machine orientation sensor 28 as the first orientation.

[0131] The operating condition determiner 43 also acquires a second state of the work machine 1. The second state of the work machine 1 is a state that comes later than the first state of the work machine 1. The second state of the work machine 1 includes a target state of the model of the work machine 1. The second state of the work machine 1 includes at least a second position Pg of the work machine 1. In the present embodiment, the second state of the work machine 1 includes the second position Pg, a second azimuth angle of the work machine 1 at the second position Pg, a second traveling speed of the traveling device 5, a second steering angle, and a second attitude (second angle and second height) of the work implement 6. The operating condition determiner 43 may acquire the second state of the work machine 1 from the input device 84. In other words, a user of the control system 100B may operate the input device 84 to input the second state of the work machine 1 to the on-board controller 32. If a computer different from the on-board controller 32 generates the second state of the work machine 1, the operating condition determiner 43 may acquire the second state of the work machine 1 from a computer different from the on-board controller 32.

[0132] The control input value generation unit 44 generates control input values ​​including driving input values ​​that control the driving device 5 of the work machine 1 and work input values ​​that control the work implement 6 of the work machine 1 when the model of the work machine 1 moves from the first position Pi to the second position Pg. As described above, the control command values ​​include the driving acceleration of the driving device 5, the steering angular velocity of the driving device 5, the attitude angular velocity of the work implement 6, and the height velocity of the work implement 6. The driving input values ​​include the driving acceleration and steering angular velocity of the driving device 5. The work input values ​​include the attitude angular velocity and height velocity of the work implement 6.

[0133] The model constraint condition calculation unit 45 calculates the model constraint conditions Bm for maintaining the stability of the work machine 1 as the model of the work machine 1 moves from the first position Pi to the second position Pg. The model constraint condition calculation unit 45 calculates the model constraint conditions Bm based on the vehicle state parameters and the load parameters. As with the constraint conditions B described above, the model constraint conditions Bm are the constraint conditions Bm for preventing the model of the work machine 1 from tipping over as it travels. １ and the constraint Bm that the load held in the bucket 9 of the model does not collapse. ２ and the constraint Bm that the model of the work machine 1 does not come into contact with the obstacle. ３ The model constraint conditions Bm also include a condition that the state x[k] of the model of the work machine 1 does not exceed a predetermined upper limit value and a predetermined lower limit value, and that the control input value u[k] does not exceed a predetermined upper limit value and a predetermined lower limit value.

[0134] The operating condition determination unit 43 determines target operating conditions for the work machine 1 from the first position Pi to the second position Pg. The target operating conditions for the work machine 1 include target operating conditions for the model of the work machine 1. The target operating conditions for the work machine 1 include target traveling conditions for the traveling device 5 and target working conditions for the work implement 6 from the first position Pi to the second position Pg. The operating condition determination unit 43 inputs the first state of the work machine 1, the second state of the work machine 1, and the control input values ​​into the model of the work machine 1, and determines the target operating conditions for the work machine 1 from the first position Pi to the second position Pg so as to satisfy the model constraint conditions Bm in the movement of the model of the work machine 1 from the first position Pi to the second position Pg.

[0135] The operating condition determination unit 43 may input the topography of the work site from the first position Pi to the second position Pg into a model of the work machine 1, and determine target operating conditions for the work machine 1 so as to satisfy the model constraint conditions Bm during movement of the work machine 1 from the first position Pi to the second position Pg. In other words, the operating condition determination unit 43 may determine the target operating conditions for the work machine 1 by taking into account the inclination angle of the ground at the work site.

[0136] The target operating conditions include a target trajectory Tr from the first position Pi to the second position Pg. The operating condition determination unit 43 calculates candidates for the target trajectory Tr. The model constraint condition calculation unit 45 determines whether or not there is a possibility that the stability of the work machine 1 will not be maintained if the model of the work machine 1 travels according to the candidate target trajectory Tr calculated by the operating condition determination unit 43. The control input value generation unit 44 sequentially generates (changes) control input values ​​until the model of the work machine 1 satisfies the model constraint condition Bm. The operating condition determination unit 43 calculates candidates for the target trajectory Tr until the model of the work machine 1 satisfies the model constraint condition Bm. The operating condition determination unit 43 performs optimal control to calculate optimal control input values ​​and target trajectory Tr so that the operating conditions of the model of the work machine 1 satisfy the model constraint condition Bm.

[0137] The operating condition determiner 43 changes the internal state of the model of the work machine 1 based on the state transition model formula shown in equation (13) so that the model of the work machine 1 travels from the first position Pi towards the second position Pg. The operating condition determiner 43 sequentially changes the internal state of the model of the work machine 1 from the first state of the work machine 1 in accordance with the control input values ​​(input series) over a time interval Δt, to generate a final state of the work machine 1. The operating condition determiner 43 determines the target operating conditions so that the final state of the work machine 1 becomes the second state of the work machine 1. The first state of the work machine 1 refers to the internal state of the model at the first position Pi. The second state of the work machine 1 refers to the internal state of the model at the second position Pg. The final state of the work machine 1 refers to the internal state of the model at the final position Pf.

[0138] The operating condition determination unit 43 determines an evaluation function E based on the model constraint condition Bm, the evaluation function E including an evaluation item relating to the deviation between the second state and the final state of the work machine 1 at the final position Pf of the target trajectory Tr. ｂ The target operating conditions are determined so that the evaluation value of the evaluation function is improved. ｂ is expressed by the following equation (14).

[0139]

[0140] As shown in equation (14), in this embodiment, the evaluation function E ｂ includes an evaluation item related to the deviation between the second state and the final state, and an evaluation item related to the control input value. The deviation between the second state and the final state is the deviation between the element value of the second state and the element value of the final state. As shown in equation (11), the element values ​​of the state of the work machine 1 (second state and final state) include the position of the work machine 1 represented by the x-coordinate and y-coordinate of the work machine 1, the azimuth angle of the work machine 1, the traveling speed of the work machine 1, the steering angle of the work machine 1, the attitude angle of the work implement 6, and the height of the work implement 6.

[0141] The first term on the right side of equation (14) is a penalty term indicating an evaluation item whose evaluation value improves as the deviation between the second state and the final state decreases. The second term on the right side of equation (14) is a penalty term indicating an evaluation item whose evaluation value improves as the control input value decreases.

[0142] In this embodiment, the evaluation function E ｂ The degree of evaluation value of the evaluation function E ｂ This means that the evaluation value of the evaluation function E becomes smaller. ｂ In this embodiment, the evaluation function E ｂ The solution of the target operating conditions including the target trajectory Tr is optimized so that the evaluation value of is small.

[0143] In this embodiment, the evaluation function E ｂA first specified value relating to the improvement amount of the evaluation value of the second state and a second specified value relating to the deviation between the second state and the final state are determined. Each of the first specified value and the second specified value is a fixed value determined in advance. Each of the first specified value and the second specified value is determined for each type of work machine 1, for example. ｂ When the improvement in the evaluation value is equal to or less than a first specified value and the deviation between the second state and the final state is equal to or less than a second specified value, it is determined that the solution for the target operating conditions has reached the appropriate criterion.

[0144] Evaluation function E ｂ The evaluation value of the evaluation function E is optimized by repeated calculations, which will be described later. The first specified value is a specified value for terminating optimization by repeated calculations. When the first specified value is set to a small value, the evaluation function E ｂ The calculation is repeated until the evaluation value of becomes small, which lengthens the calculation time. If the first specified value is set to a large value, the calculation ends without fine-tuning the target trajectory Tr, which may result in the generation of an inappropriate target trajectory Tr. Therefore, the first specified value is determined by a trade-off between the optimality of the target trajectory Tr (task time and input size) and the calculation time. The first specified value is tuned to an appropriate value by planning the target trajectory Tr in advance using various patterns, and checking the optimality of the resulting target trajectory Tr while taking into account the allowable calculation time.

[0145] The second specified value is a value that specifies the allowable error between the second position Pg and the final position Pf of the target trajectory Tr. Therefore, the second specified value is set to a very small value, for example, 0.1 cm or less.

[0146] In addition, the evaluation function E ｂ The degree of evaluation value of the evaluation function E ｂ The evaluation value of the evaluation function E ｂ By changing the sign of ｂ The larger the evaluation value of the evaluation function E ｂ This means that the degree of evaluation value of

[0147] 11 is a flowchart showing a method for determining target operating conditions according to this embodiment. The operating condition determiner 43 acquires the first state and the second state of the work machine 1 (step SB1).

[0148] The control input value generating unit 44 generates an initial value of the control input value, which is input to the operating condition determining unit 43 (step SB2).

[0149] The operating condition determination unit 43 inputs the first state, the second state, and the control input value into the model of the work machine 1. The operating condition determination unit 43 sequentially inputs the control input value into the state transition model equation at each time interval Δt to generate the final state of the model (step SB3).

[0150] The operating condition determination unit 43 evaluates the final state of the work machine 1 with respect to the second state (step SB4). The operating condition determination unit 43 calculates the evaluation function E ｂ The element values ​​of the second state, the element values ​​of the final state, and the control input values ​​are input to the evaluation function E ｂ The operating condition determining unit 43 also calculates the deviation between the second state and the final state.

[0151] The operating condition determination unit 43 compares the evaluation value calculated in step SB4 with the evaluation value calculated in the previous step SB4, and determines whether the improvement in the evaluation value is less than or equal to a predetermined first specified value (step SB5).

[0152] If it is determined in step SB5 that the improvement in the evaluation value exceeds the first specified value (step SB5: No), the operating condition determination unit 43 returns to the processing of step SB3.

[0153] In step SB5, if it is determined that the improvement in the evaluation value is less than or equal to the first specified value (step SB5: Yes), the operating condition determination unit 43 determines whether the deviation between the second state calculated in step SB4 and the final state is less than or equal to a predetermined second specified value (step SB6).

[0154] If it is determined in step SB6 that the deviation between the second state and the final state exceeds the second specified value (step SB6: No), the operating condition determination unit 43 changes the initial value of the control input value (step SB7) and returns to the processing of step SB2.If it is determined in step SB6 that the deviation between the second state and the final state is the second specified value (step SB6: Yes), the operating condition determination unit 43 ends the processing for determining the target operating condition.

[0155] That is, the operating condition determiner 43 changes the control input value u[k] input to the state transition model equation until the final state of the model of the work machine 1 approximates the second state. The operating condition determiner 43 determines, as target operating conditions, operating conditions including the control input value and model trajectory when the improvement amount of the evaluation value becomes equal to or less than a first specified value and the deviation between the second state and the final state becomes equal to or less than a second specified value. The operating condition determiner 43 determines the target operating conditions based on the model constraint conditions Bm.

[0156] As shown in Fig. 9, the follow-up control unit 46 outputs a follow-up command (control command) so that the work machine 1 operates in accordance with the target operating conditions determined by the operating condition determination unit 43. The follow-up control unit 46 outputs a follow-up command to control each of the traveling device 5 and the work implement 6. The follow-up control unit 46 outputs a follow-up command to control the traveling device 5 including the articulated cylinder 7 so that the work machine 1 travels based on the target traveling conditions. The follow-up control unit 46 outputs a follow-up command to control the work implement 6 so that the work implement 6 operates based on the target working conditions. The follow-up control unit 46 functions as at least a part of an automatic driving system that automatically drives the work machine 1.

[0157] The follow-up control unit 46 controls the operation of the traveling device 5 and the operation of the work machine 6 from the first position Pi to the second position Pg based on the target operating conditions determined by the operating condition determination unit 43. The follow-up control unit 46 controls each of the traveling device 5 and the work machine 6 based on the deviation between the target operating conditions (target trajectory Tr) determined by the operating condition determination unit 43 and the current operating state (current trajectory). By moving the work machine 1 from the first position Pi to the second position Pg based on the target operating conditions, the working time of the work machine 1 is prevented from becoming longer and the work machine 1 is prevented from tipping over.

[0158] In this embodiment, the pre-correction command u ｒ includes a follow-up command output from the follow-up control unit 46. As in the first embodiment, the constraint condition calculation unit 41 calculates the constraint condition B based on the vehicle state parameters and the cargo parameters. The command correction unit 42 calculates the pre-correction command u ｒ If the operating conditions of the work machine 1 that operates based on the ｒ and corrected command u ｃ The corrected command u is set so that the deviation from ｃ Output.

[0159] Follow-up command (pre-correction command u ｒ ) is generated based on the model constraint condition Bm so as to maintain the stability of the model of the work machine 1. The operation command (pre-correction command u ｒ ) is output, there is a possibility that the stability of the work machine 1 will not be maintained due to, for example, the input of a disturbance to the work machine 1. According to this embodiment, when the operating conditions of the work machine 1 operating based on the follow-up command do not satisfy the constraint condition B, the work machine 1 satisfies the constraint condition B and the follow-up command (pre-correction command u ｒ ) and the control command (corrected command u ｃ ) so that the deviation from the control command (corrected command u ｃ ) is output, so that the stability of the work machine 1 is maintained even if a disturbance is input.

[0160] In this embodiment, at least some of the functions of the on-vehicle controller 32 may be provided in a computer located outside the work machine 1. For example, if the on-vehicle controller 32 communicates with a server including a computer located outside the work machine 1, at least some of the functions of the on-vehicle controller 32 may be provided in the server. At least one of the constraint condition calculation unit 41 and the command correction unit 42 may be provided in the server.

[0161] Third Embodiment A third embodiment will be described below. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the description of those components will be simplified or omitted.

[0162] Fig. 12 is a block diagram showing a control system 100C according to this embodiment. As shown in Fig. 12, the control system 100C includes an on-vehicle controller 32. The on-vehicle controller 32 has an artificial intelligence command unit 47. The artificial intelligence command unit 47 outputs operation commands for operating the work machine 1 based on an artificial intelligence (AI) algorithm. The artificial intelligence command unit 47 may use a model that has been trained using a technique such as reinforcement learning so as to output operation commands for moving the work machine 1 from a first position Pi to a second position Pg.

[0163] In this embodiment, the pre-correction command u ｒ includes the operation command output from the artificial intelligence command unit 47. As in the first embodiment, the constraint condition calculation unit 41 calculates the constraint condition B based on the vehicle state parameters and the cargo parameters. The command correction unit 42 calculates the pre-correction command u ｒ If the operating conditions of the work machine 1 that operates based on the ｒ and corrected command u ｃ The corrected command u is set so that the deviation from ｃ Output.

[0164] The artificial intelligence command unit 47 issues an operation command (pre-correction command u) so that the stability of the work machine 1 is maintained. ｒ) is output, an unexpected operation command may be output when the work machine 1 is placed in a situation that is not included in the learning data, and as a result, the stability of the work machine 1 may not be maintained. According to this embodiment, when the operating conditions of the work machine 1 that operates based on the operation command do not satisfy the constraint condition B, the work machine 1 satisfies the constraint condition B and the operation command (pre-correction command u ｒ ) and the control command (corrected command u ｃ ) so that the deviation from the control command (corrected command u ｃ ) is output, so that the stability of the work machine 1 is maintained.

[0165] [Other Embodiments] In the above-described embodiment, the constraint condition B for maintaining the stability of the work machine 1 is the constraint condition B for preventing the work machine 1 from tipping over while traveling. １ and constraint condition B under which the load held in the bucket 9 of the work implement 6 does not collapse when the work machine 1 travels. ２ and constraint B under which the work machine 1 does not come into contact with an obstacle while traveling. ３ Constraint B is １ , constraint B ２ , and constraint B ３ Constraint condition B may be at least one of: １ , constraint B ２ , and constraint B ３ The constraints may be different from those.

[0166] In the above-described embodiment, the articulate cylinder 7, the boom cylinder 12, and the bucket cylinder 13 are each a hydraulic cylinder. However, at least one of the articulate cylinder 7, the boom cylinder 12, and the bucket cylinder 13 may be an electric cylinder that is operated by electricity.

[0167] In the above-described embodiment, the load sensor 30 that detects the load state of the work machine 6 includes a weight sensor that detects the weight of the work machine 6. The load sensor 30 may include, for example, a camera that captures an image of the bucket 9. The camera can capture an image of the load held in the bucket 9. Image data of the load acquired by the camera is transmitted to the on-board controller 32. Density data indicating the density of the load is pre-stored in the constraint condition calculation unit 41. The constraint condition calculation unit 41 estimates the volume of the load held in the bucket 9 based on the image data of the load. The constraint condition calculation unit 41 can calculate the weight of the load held in the bucket 9 based on the estimated volume of the load and the load density data. Note that the three-dimensional shape of the load may be detected by a three-dimensional sensor such as a laser scanner or a stereo camera. The constraint condition calculation unit 41 may estimate the volume of the load held in the bucket 9 based on the three-dimensional shape of the load.

[0168] In the above-described embodiment, the work machine 1 is a wheel loader. However, the work machine 1 may be any work machine that has a work implement that holds a load. The work machine 1 may also be, for example, a forklift.

[0169] 13 is a schematic diagram showing a forklift 301 according to another embodiment as viewed from above. The forklift 301 has a vehicle body 302 and a work implement 306 disposed at the front of the vehicle body 302.

[0170] The work implement 306 has a mast 307, a bracket 308, and a fork 309. The mast 307 is supported at the front of the vehicle body 302 so as to be able to tilt. The mast 307 is long in the vertical direction. The bracket 308 supports the fork 309. The bracket 308 is supported by the mast 307. The bracket 308 is able to move in the vertical direction along the mast 307. The fork 309 supports a load 400. The fork 309 has a support surface (upper surface) that supports the load 400. The load 400 is placed on the support surface of the fork 309.

[0171] The forks 309 are supported on the mast 307 via brackets 308. A pair of forks 309 are provided. The forks 309 include a first fork 309L and a second fork 309R located to the right of the first fork 309L. The brackets 308 support the first fork 309L and the second fork 309R.

[0172] The constraint condition calculation unit 41 calculates a constraint condition B under which the forklift 301 maintains stability during the movement of the forklift 301. For example, the constraint condition calculation unit 41 calculates a constraint condition B under which the load 400 held by the forks 309 does not collapse during the movement of the forklift 301 from the first position Pi to the second position Pg. ２ The load 400 held by the forks 309 includes a container. The load 400 (container) held by the forks 309 not collapsing means that the load 400 does not fall off the forks 309.

[0173] The constraint condition calculation unit 41 calculates a constraint condition B that prevents the load 400 held by the forks 309 from collapsing based on the load parameters related to the load 400. ２ Constraint B ２ includes a condition that the zero moment point Z0 of the load 400 does not deviate from the set range AP that is set based on the shape of the fork 309.

[0174] The set range AP corresponds to the support polygon of the load 400 placed on the forks 309. The set range AP is a rectangular range connecting the front end of the left end of the support surface of the first fork 309L, the rear end of the left end of the support surface of the first fork 309L, the front end of the right end of the support surface of the second fork 309R, and the rear end of the right end of the support surface of the second fork 309R.

[0175] The constraint condition calculation unit 41 calculates the zero moment point ZMP based on the load parameters related to the load 400 held by the forks 309. The load parameters include the mass of the load 400 held by the forks 309, the inertia tensor of the load 400, and the center of gravity position of the load 400.

[0176] The forklift 301 has a load sensor that detects the weight of the load 400 and an external sensor that detects the three-dimensional shape of the load 400. The constraint condition calculation unit 41 can obtain the mass of the load 400 by acquiring detection data from the load sensor. The constraint condition calculation unit 41 can calculate the inertia tensor and center of gravity position of the load 400 based on the detection data from the external sensor. Assuming that the density of the load 400 is constant, the constraint condition calculation unit 41 can calculate the inertia tensor and center of gravity position of the load 400 based on the three-dimensional shape of the load 400 detected by the external sensor.

[0177] 14 and 15 are schematic diagrams of a forklift 301 according to another embodiment, viewed from above. As shown in FIGS. 14 and 15 , the forks 309 may support a load 400 via a pallet 410. That is, the forklift 301 may move from a first position Pi to a second position Pg with the pallet 410 placed on the support surface of the forks 309 and the load 400 (container) placed on the pallet 410. When the forks 309 hold the load 400 via the pallet 410, the constraint conditions include a condition that the zero moment point Z0 of the load 400 does not deviate from a set range AP set based on the shape of the forks 309 and a set range BP set based on the shape of the load 400.

[0178] The set range AP corresponds to the support polygon of the pallet 410 placed on the forks 309. The support polygon of the pallet 410 is a rectangular range connecting the front end of the left end of the support surface of the first fork 309L, the rear end of the left end of the support surface of the first fork 309L, the front end of the right end of the support surface of the second fork 309R, and the rear end of the right end of the support surface of the second fork 309R.

[0179] The set range BP corresponds to the support polygon of the load 400 placed on the pallet 410. The support polygon of the load 400 is the outline of the contact surface of the top surface of the pallet 410 with which the load 400 comes into contact.

[0180] That is, when the cargo 400 is supported by the forks 309 via the pallet 410, the constraint conditions include a condition that the zero moment point Z0 of the cargo 400 does not deviate outside the support polygon of the pallet 410, and does not deviate outside the support polygon of the cargo 400.

[0181] FIG. 14 shows an example in which the set range BP is inside the set range AP. FIG. 15 shows an example in which part of the set range BP is inside the set range AP and part of the set range BP is outside the set range AP. In the examples shown in FIGS. 14 and 15, the zero moment point Z0 is located inside the set range AP and inside the set range BP. In the examples shown in FIGS. 14 and 15, the pallet 410 is stably supported by the forks 309, and the load 400 is stably supported by the pallet 410. For example, if the zero moment point Z0 of the load 400 deviates outside the set range AP, the pallet 410 may tilt. If the zero moment point Z0 of the load 400 deviates outside the set range BP, the load 400 may tip over.

[0182] When the forks 309 hold the load 400 via a pallet 410, the constraints may include a condition that the load 400 does not slip on the pallet 410. That is, the constraints may include a condition that the sliding surface component of the force acting on the load 400 does not exceed the static friction force. This constraint is calculated as a condition that the component of the force acting on the load 400 on the pallet surface is smaller than the static friction force between the load 400 and the pallet 410. The static friction force is calculated from the static friction coefficient μ and the normal force N acting on the load 400. The normal force N is calculated from the angle of the work machine 306 and the mass of the load 400. The static friction coefficient μ may be input to the constraint calculation unit 41 from the input device 81. The constraint calculation unit 41 can calculate the constraints based on the mass of the load 400 and the static friction coefficient.

[0183] The command correction unit 42 satisfies the constraint condition B and calculates the pre-correction command u ｒ and corrected command u ｃ The corrected command u for operating the forklift 301 is calculated so that the deviation from ｃ Output.

[0184] [Supplementary Notes] The present disclosure may also adopt the following configurations. (Supplementary Note 1) A work machine control system including a computer, wherein the computer acquires a pre-correction command and outputs a corrected command for operating the work machine by correcting the pre-correction command so as to satisfy constraints for maintaining the stability of the work machine and to reduce deviation from the pre-correction command. (Supplementary Note 2) The work machine control system described in (Supplementary Note 1), wherein the computer calculates an evaluation function such that the smaller the deviation between the pre-correction command and the corrected command, the better the degree of evaluation value, and outputs the corrected command. (Supplementary Note 3) The work machine control system described in (Supplementary Note 1) or (Supplementary Note 2), wherein the work machine has a traveling device, and the constraint condition includes a condition that the work machine does not tip over when the traveling device is traveling. (Supplementary Note 4) The work machine control system described in (Supplementary Note 3), wherein the constraint condition includes a condition that the zero moment point of the work machine does not deviate from a set range that is set based on a plurality of ground contact points of the traveling device. (Supplementary Note 5) The work machine control system described in any one of (Supplementary Note 1) to (Supplementary Note 4), wherein the work machine has a traveling device including a steering device and a work implement, and the constraint conditions include a condition that a load held by the work implement does not collapse when the traveling device travels. (Supplementary Note 6) The work machine control system described in (Supplementary Note 5), wherein the computer calculates the constraint conditions based on an inertial force acting on the load and load parameters related to the load. (Supplementary Note 7) The work machine control system described in (Supplementary Note 6), wherein the load includes soil and sand, and the load parameters include the adhesion of the soil, the internal friction force of the soil, and the density of the soil. (Supplementary Note 8) A work machine control system according to any one of (Supplementary Note 5) to (Supplementary Note 7), wherein the computer calculates the constraint conditions based on load parameters including the mass of the load, the inertia tensor of the load, and the position of the center of gravity of the load, and the constraint conditions include a condition that the zero moment point of the load does not deviate outside the support polygon of the load.(Supplementary Note 9) A work machine control system according to any one of (Supplementary Note 5) to (Supplementary Note 7), wherein the computer calculates the constraint conditions based on the mass and coefficient of static friction of the load, and the constraint conditions include a condition that a slide surface component of the force acting on the load does not become larger than the static friction force. (Supplementary Note 10) A work machine control system according to any one of (Supplementary Note 1) to (Supplementary Note 9), wherein the work machine has a traveling device, and the constraint conditions include a condition that the work machine does not come into contact with an obstacle when the traveling device is traveling. (Supplementary Note 11) A work machine control system according to any one of (Supplementary Note 1) to (Supplementary Note 10), wherein the work machine has a traveling device, and the constraint conditions include a condition that the work machine does not come into contact with an obstacle when the traveling device is traveling. (Supplementary Note 12) A work machine control system as set forth in any one of (Supplementary Note 1) to (Supplementary Note 11), wherein the computer: acquires a first state including a first position of the work machine; acquires a second state subsequent to the first state including a second position of the work machine; generates control input values ​​including travel input values ​​that control a travel device of the work machine and a work input value that controls a work implement of the work machine in movement of the work machine from the first position to the second position; inputs the first state, the second state and the control input values ​​into a model of the work machine to determine target operating conditions of the work machine including target travel conditions of the travel device from the first position to the second position and target work conditions of the work implement; and outputs a follow-up command so that the work machine operates in accordance with the target operating conditions, and the pre-correction command includes the follow-up command.(Supplementary Note 13) The work machine has a traveling device and a work implement that holds a load, and the pre-correction command includes a traction force source command that defines the traction force of the traveling device, a steering angle source command that defines the steering angle of the traveling device, and a work implement source command that defines the operation of the work implement 6, and the corrected command includes a traction force command that controls the traction force of the traveling device, a steering angle command that controls the steering angle of the traveling device, and a work implement command that operates the work implement, and the computer multiplies by weight values ​​each of the deviation between the traction force command and the traction force source command, the deviation between the steering angle command and the steering angle source command, and the deviation between the work implement command and the work implement source command. (Supplementary Note 14) A work machine comprising the work machine control system of any one of (Supplementary Note 1) to (Supplementary Note 13). (Supplementary Note 15) A control method for a work machine, comprising: a computer acquiring a pre-correction command; and correcting the pre-correction command so as to satisfy constraints for maintaining the stability of the work machine and to reduce deviation from the pre-correction command, and outputting a corrected command for operating the work machine.

[0185] 1...working machine, 2...body, 2F...front frame, 2R...rear frame, 3...articulating mechanism, 4...wheel, 4F...front wheel, 4R...rear wheel, 5...traveling device, 6...working machine, 7...articulating cylinder, 8...boom, 9...bucket, 10...bell crank, 11...bucket link, 12...boom cylinder, 13...bucket cylinder, 14...bracket, 15...bracket, 16...driving machine, 17...power take-off, 18...power transmission device, 19...brake device, 20...steering pump, 21...steering control valve, 22...working machine pump, 23...working Work machine control valve, 24...position sensor, 25...orientation sensor, 26...speed sensor, 27...steering sensor, 28...work machine attitude sensor, 28A...boom angle sensor, 28B...bucket angle sensor, 29...external sensor, 30...load sensor, 31...camera, 32...on-vehicle controller, 33...computer, 34...processor, 35...main memory, 36...storage, 37...input / output interface, 38...communication interface, 39...computer program, 41...constraint condition calculation unit, 42...command correction unit, 43...operating condition determination unit, 44...control input value generation unit, 45 ...Model constraint condition calculation unit, 46...Follow-up control unit, 47...Artificial intelligence command unit, 50...Rear axle oscillation mechanism, 51...Front axle, 52...Rear axle, 53...Rear propeller shaft, 54...Coupling unit, 61...Input shaft, 62...Output shaft, 70...Operation device, 70A...Travel system operation device, 70B...Work machine operation device, 71...Accelerator pedal, 72...Brake pedal, 73...Steering wheel, 74...Forward / reverse switch lever, 75...Boom lever, 76...Bucket lever, 80...Display device, 81...Input device, 82...Remote controller, 83...Operator seat , 84...input device, 90...dump truck, 100A...control system, 100B...control system, 100C...control system, 200...remote operation system, 201...work site, 202...remote operation room, 203...communication system, 301...forklift, 302...vehicle body, 306...work equipment, 307...mast, 308...bracket, 309...fork, 309L...fork, 309R...fork, 400...load, 410...pallet, 700...operation device, AP1...setting range, AP2...setting range, AP3...setting range, BP...setting range, Pf...final position, Pg...second position,Pi...first position, Pt...point, Tr...target trajectory.

Claims

1. A control system for a work machine, comprising a computer that acquires a pre-correction command, corrects the pre-correction command so as to satisfy constraints for maintaining the stability of the work machine and to reduce deviation from the pre-correction command, and outputs a corrected command for operating the work machine.

2. A work machine control system according to claim 1, wherein the computer calculates an evaluation function that improves the degree of evaluation value as the deviation between the pre-correction command and the corrected command decreases, and outputs the corrected command.

3. A control system for a work machine according to claim 1, wherein the work machine has a traveling device, and the constraint condition includes a condition that the work machine does not tip over when the traveling device is traveling.

4. A work machine control system according to claim 3, wherein the constraint conditions include a condition that the zero moment point of the work machine does not deviate from a set range that is set based on a plurality of ground contact points of the traveling device.

5. A control system for a work machine as described in claim 1, wherein the work machine has a traveling device including a steering device and a work implement, and the constraint conditions include a condition that a load held by the work implement does not collapse when the traveling device travels.

6. A work machine control system according to claim 5, wherein the computer calculates the constraint conditions based on an inertial force acting on the load and load parameters related to the load.

7. The work machine control system according to claim 6, wherein the load includes soil and sand, and the load parameters include the adhesion of the soil, the internal friction of the soil, and the density of the soil.

8. A work machine control system according to claim 5, wherein the computer calculates the constraint conditions based on load parameters including the mass of the load, the inertia tensor of the load, and the position of the center of gravity of the load, and the constraint conditions include a condition that the zero moment point of the load does not deviate outside the support polygon of the load.

9. A control system for a work machine according to claim 5, wherein the computer calculates the constraint conditions based on the mass and static friction coefficient of the load, and the constraint conditions include a condition that the slide surface component of the force acting on the load does not become larger than the static friction force.

10. A work machine control system according to claim 1, wherein the work machine has a traveling device, and the constraint condition includes a condition that the work machine does not come into contact with an obstacle while the traveling device is traveling.

11. A work machine control system according to claim 1, wherein the pre-correction command includes an operation command generated by operating an operation device.

12. A work machine control system as described in claim 1, wherein the computer: acquires a first state including a first position of the work machine; acquires a second state subsequent to the first state including a second position of the work machine; generates control input values ​​including travel input values ​​that control a travel device of the work machine and work input values ​​that control a work implement of the work machine in movement of the work machine from the first position to the second position; inputs the first state, the second state and the control input values ​​into a model of the work machine to determine target operating conditions of the work machine including target travel conditions of the travel device from the first position to the second position and target working conditions of the work implement; and outputs a follow-up command so that the work machine operates in accordance with the target operating conditions, and the pre-correction command includes the follow-up command.

13. A control system for a work machine as described in claim 1, wherein the work machine has a traveling device and a work implement that holds a load, the pre-correction command includes a traction force source command that defines the traction force of the traveling device, a steering angle source command that defines the steering angle of the traveling device, and a work implement source command that defines the operation of the work implement, the corrected command includes a traction force command that controls the traction force of the traveling device, a steering angle command that controls the steering angle of the traveling device, and a work implement command that operates the work implement, and the computer multiplies by a weight value each of the deviation between the traction force command and the traction force source command, the deviation between the steering angle command and the steering angle source command, and the deviation between the work implement command and the work implement source command.

14. A work machine comprising the work machine control system according to claim 1.

15. A method for controlling a work machine, comprising: a computer acquiring a pre-correction command; and correcting the pre-correction command so as to satisfy constraints for maintaining the stability of the work machine and to reduce deviation from the pre-correction command, and outputting a corrected command for operating the work machine.

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