Work vehicle measurement system and work vehicle measurement method

Abstract

A detection unit detects slipping of a traveling body of a work vehicle on the basis of vehicle body data including at least a value relating to the motive power of the traveling body and a value relating to the rotation speed of the traveling body.

Description

Work vehicle measurement system and work vehicle measurement method

[0001] This application claims priority to Japanese Patent Application No. 2023-141797, filed on August 31, 2023, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses a work vehicle that causes the cutting edge of a blade to follow a design surface. According to the technology disclosed in Patent Document 1, a control device identifies the position of the work vehicle using a Global Navigation Satellite System (GNSS), and determines a target height for the blade based on the identified position.

[0003] International Publication No. 2015 / 083469

[0004] A work vehicle may travel forward while performing work. The work vehicle travels while receiving a reaction force from the work object. The effect of this reaction force may cause the work vehicle to slip, reducing work efficiency. Meanwhile, the operator may not notice that the work vehicle is slipping. An example of an object of the present disclosure is to provide a measurement system for a work vehicle and a measurement method for a work vehicle that can detect slippage of a traveling object.

[0005] According to one aspect of the present disclosure, a detection system for a work vehicle includes a detection unit that detects slippage of the running body based on vehicle body data including at least a value related to the power of the running body of the work vehicle and a value related to the rotation speed of the running body.

[0006] According to the above aspect, as one example, the measurement system of the work vehicle can detect slippage of the traveling body.

[0007] FIG. 1 is a side view of a work vehicle according to a first embodiment. FIG. 2 is a diagram showing the internal configuration of a driver's cab according to the first embodiment. FIG. 3 is a schematic diagram showing a power system of a work vehicle according to the first embodiment. FIG. 4 is a diagram showing the configuration of a measurement system and a control device of a work vehicle according to the first embodiment. FIG. 5 is a flowchart showing a position output method according to the first embodiment. FIG. 6 is a diagram showing the configuration of a measurement system and a control device of a work vehicle according to a third embodiment. FIG. 7 is a diagram showing the configuration of a measurement system and a control device of a work vehicle according to a fourth embodiment. FIG. 8 is a diagram showing the configuration of a measurement system and a control device of a work vehicle according to a fifth embodiment.

[0008] <First embodiment> Hereinafter, an embodiment will be described in detail with reference to the drawings. Fig. 1 is a side view of a work vehicle according to a first embodiment. A work vehicle 100 according to the first embodiment is, for example, a bulldozer. The work vehicle 100 includes a vehicle body 110, a traveling device 120, a work implement 130, and a driver's cab 140.

[0009] The traveling device 120 is provided on the lower part of the vehicle body 110. The traveling device 120 has a pair of crawlers 121 and sprockets 122. The pair of crawlers 121 is provided on the left and right sides of the vehicle body 110. The crawlers 121 are rotated by the drive of the sprockets 122, causing the work vehicle 100 to travel.

[0010] The work machine 130 is used to excavate and transport excavation targets such as earth and sand. The work machine 130 includes a lift frame 131, a blade 132, a blade lift cylinder 133, a ripper 134, and a ripper lift cylinder 135. The blade 132 is disposed in front of the vehicle body 110. The ripper 134 is disposed in the rear of the vehicle body 110.

[0011] The base end of the lift frame 131 is attached to the side of the vehicle body 110 via a pin extending in the vehicle width direction. The tip end of the lift frame 131 is attached to the back surface of the blade 132 via a ball joint. This supports the blade 132 so that it can move up and down relative to the vehicle body 110. A cutting edge is provided at the lower end of the blade 132. The blade lift cylinder 133 is a hydraulic cylinder. The base end of the blade lift cylinder 133 is attached to the side of the vehicle body 110. The tip end of the blade lift cylinder 133 is attached to the lift frame 131. The blade lift cylinder 133 extends and contracts using hydraulic oil, thereby driving the lift frame 131 and the blade 132 in the raising and lowering directions.

[0012] A base end of the ripper lift cylinder 135 is attached to the vehicle body 110. A tip end of the ripper lift cylinder 135 is rotatably attached to the ripper 134. The ripper lift cylinder 135 is extended and contracted by hydraulic oil, thereby driving the ripper 134 in a raising or lowering direction.

[0013] The operator's cab 140 is a space where an operator sits and operates the work vehicle 100. The operator's cab 140 is provided on top of the vehicle body 110. Figure 2 is a diagram showing the internal configuration of the operator's cab 140 according to the first embodiment. Inside the operator's cab 140, there are provided a seat 141, a console 142, a blade operation lever 143, a ripper operation lever 144, a travel operation lever 145, a brake pedal 146, and a deceleration pedal 147. The brake pedal 146 and the deceleration pedal 147 may be configured as a single pedal.

[0014] An operation panel, instruments, and switches are attached to the console 142. The operator can visually check the status of the work vehicle 100 by checking the console 142. The blade operation lever 143 is operated to set the amount of movement for raising or lowering the blade 132. The blade operation lever 143 receives a lowering operation by tilting it forward, and a raising operation by tilting it backward. The blade operation lever 143 may also receive a tilt operation to rotate the blade 132 about an axis in the front-to-rear direction, and an angle operation to rotate the blade 132 about an axis in the up-to-down direction. The ripper operation lever 144 is operated to set the amount of movement for raising or lowering the ripper 134. The ripper operation lever 144 receives a lowering operation by tilting it forward, and a raising operation by tilting it backward. The travel operation lever 145 is operated to set the traveling direction of the travel device 120. The travel control lever 145 is tilted forward to accept a forward movement operation, and tilted backward to accept a reverse movement operation. The travel control lever 145 is also tilted left to accept a left turn operation, and tilted right to accept a right turn operation. The travel control lever 145 is also provided with a gear change button for inputting a speed range. The brake pedal 146 is operated to brake the travel device 120. The deceleration pedal 147 is operated to reduce the rotation speed of the travel device 120.

[0015] 3 is a schematic diagram showing the power system of the work vehicle according to Embodiment 1. The work vehicle 100 is equipped with an engine 210, a PTO (Power Take Off) 220, a pair of HSTs (Hydro Static Transmissions) 230, a hydraulic pump 250, and a proportional control valve 260.

[0016] The engine 210 is, for example, a diesel engine. The PTO 220 transmits a portion of the driving force of the engine 210 to the hydraulic pump 250. In other words, the PTO 220 distributes the driving force of the engine 210 to the HST 230 and the hydraulic pump 250. The HST 230 changes the speed of the driving force input to its input shaft and outputs it from its output shaft. The HST 230 includes a hydraulic pump driven by the rotation of the input shaft and a hydraulic motor that rotates the output shaft. The HST 230 controls the rotation speed of the output shaft by controlling the discharge flow rate of the hydraulic pump. The input shaft of the HST 230 is connected to the PTO 220, and the output shaft is connected to the sprocket 122. In other words, the HST 230 transmits the driving force of the engine 210 distributed by the PTO 220 to the sprocket 122. The output shafts of the pair of HSTs 230 are connected to the left sprocket 122 and the right sprocket 122, respectively. The hydraulic pump 250 is driven by driving force from the engine 210. The hydraulic oil discharged from the hydraulic pump 250 is supplied to the blade lift cylinder 133 via a proportional control valve 260. The proportional control valve 260 controls the flow rate of the hydraulic oil discharged from the hydraulic pump 250. In addition to the proportional control valve 260, the hydraulic pump 250 may supply hydraulic oil to other destinations such as a steering clutch (not shown).

[0017] <<Measurement System>> Figure 4 is a diagram showing the configuration of the measurement system and control device of work vehicle 100 according to the first embodiment. The measurement system of work vehicle 100 acquires vehicle body data that indicates the state of work vehicle 100. Work vehicle 100 is equipped with a rotation sensor 310, a dynamometer 320, an oil pressure sensor 330, an IMU (Inertial Measurement Unit) 340, a blade stroke sensor 350, a ripper stroke sensor 360, and a GNSS sensor 370.

[0018] A rotation sensor 310 is provided on each of the left and right sprockets 122. The rotation sensor 310 calculates the number of rotations of the sprocket 122.

[0019] The dynamometer 320 is provided on the engine 210. The dynamometer 320 measures the power generated by the engine 210.

[0020] An oil pressure sensor 330 is provided on each of the hydraulic motors of the left and right HSTs 230. The oil pressure sensor 330 measures the oil pressure on the outlet side of the hydraulic motor.

[0021] The IMU 340 is provided on the vehicle body 110. The IMU 340 measures the tilt angles of the vehicle body 110 in the roll and pitch directions, and the angular displacement in the yaw direction. The vehicle body coordinate system is, for example, an orthogonal coordinate system whose origin is the center of the traveling device 120 and is represented by an X axis extending in the longitudinal direction of the vehicle body, a Y axis extending in the lateral direction of the vehicle body, and a Z axis extending in the vertical direction of the vehicle body. The direction of rotation of the vehicle body 110 about the X axis is defined as the roll direction, the direction of rotation of the vehicle body 110 about the Y axis is defined as the pitch direction, and the direction of rotation of the vehicle body 110 about the Z axis is defined as the yaw direction.

[0022] The blade stroke sensor 350 is provided on the blade lift cylinder 133. The blade stroke sensor 350 measures the stroke amount of the blade lift cylinder 133. The stroke amount measured by the blade stroke sensor 350 can be converted into the position of the cutting edge of the blade 132 in the vehicle body coordinate system. Specifically, the rotation angle of the lift frame 131 is calculated based on the stroke amount of the blade lift cylinder 133. Because the shapes of the lift frame 131 and the blade 132 are known, the position of the cutting edge of the blade 132 can be identified from the rotation angle of the lift frame 131. Note that work vehicles 100 according to other embodiments may detect the rotation angle of the lift frame 131 using other sensors, such as an encoder.

[0023] The ripper stroke sensor 360 is provided on the ripper lift cylinder 135. The ripper stroke sensor 360 measures the stroke amount of the ripper lift cylinder 135. The stroke amount measured by the ripper stroke sensor 360 can be converted into the position of the ripper cutting edge in the vehicle body coordinate system. Note that work vehicles 100 according to other embodiments may detect the rotation angle of the ripper 134 using another sensor such as an encoder. Note that work vehicles 100 according to other embodiments do not need to be equipped with a sensor that detects the state of the ripper 134. In this case, for example, the control device 400 may determine whether the ripper 134 is raised or lowered based on the amount of operation of the ripper operating lever 144.

[0024] The GNSS sensor 370 is provided on the vehicle body 110. The GNSS sensor 370 measures the position and orientation of the vehicle body 110 in a global coordinate system based on signals from GNSS satellites. The GNSS sensor 370 may perform real-time kinematic (RTK) positioning. In this case, the GNSS sensor 370 communicates with a fixed station provided at the work site and corrects the measurement data. The GNSS sensor 370 outputs accuracy information indicating the positioning accuracy in addition to the position and orientation as measurement data. The accuracy information may indicate, for example, whether correction by the fixed station was successful or the number of satellites that were able to measure. The accuracy information may also be a numerical value indicating the positioning accuracy. The GNSS sensor 370 is an example of a position estimation unit that estimates the position and attitude of the work vehicle 100 based on measurement data.

[0025] <<Control Device>> The work vehicle 100 is equipped with a control device 400 for controlling the work vehicle 100. The control device 400 outputs control signals to the fuel injection device of the engine 210, the HST 230, and the proportional control valve 260 in accordance with the amount of operation of each operation device in the driver's cab 140 (console 142, blade operation lever 143, ripper operation lever 144, travel operation lever 145, brake pedal 146, and deceleration pedal 147). The control device 400 also measures the position of the work vehicle 100 based on measurement data from the measurement system, and displays the position on the console 142.

[0026] The control device 400 is a computer that includes a processor 410 , a main memory 430 , a storage 450 , and an interface 470 .

[0027] Storage 450 is a non-transitory tangible storage medium. Examples of storage 450 include a magnetic disk, a magneto-optical disk, and a semiconductor memory. Storage 450 may be an internal medium directly connected to the bus of control device 400, or an external medium connected to control device 400 via interface 470 or a communication line. Storage 450 stores a program for controlling work vehicle 100. Storage 450 also stores a motion state model 451, which is a machine learning model for calculating the velocity and angular velocity, as well as the tilt angle, of vehicle body 110 that have been learned in advance. The motion state model 451 will be described later.

[0028] In another embodiment, the control device 400 may include a custom large-scale integrated circuit (LSI) such as a programmable logic device (PLD) in addition to or instead of the above configuration. Examples of PLDs include programmable array logic (PAL), generic array logic (GAL), complex programmable logic device (CPLD), and field programmable gate array (FPGA). In this case, some or all of the functions implemented by the processor 410 may be implemented by the integrated circuit.

[0029] By executing a program, the processor 410 is provided with an operation amount acquisition unit 411, a measurement data acquisition unit 412, a work implement height calculation unit 413, a first movement amount estimation unit 414, a slip determination unit 416, and an output unit 417. Measurement data from the measurement system is input to the processor 410 via an interface 470.

[0030] The operation amount acquisition unit 411 acquires operation amounts from the blade operation lever 143 , the ripper operation lever 144 , the travel operation lever 145 , the brake pedal 146 , and the deceleration pedal 147 .

[0031] The measurement data acquisition unit 412 acquires measurement data from the rotation sensor 310, the dynamometer 320, the oil pressure sensor 330, the IMU 340, the blade stroke sensor 350, the ripper stroke sensor 360, and the GNSS sensor 370. That is, the measurement data acquisition unit 412 acquires measurement data on the yaw angle of the vehicle body 110, the roll angle of the vehicle body 110, the pitch angle of the vehicle body 110, the rotation speeds of the left and right sprockets 122, the stroke amount of the blade lift cylinder 133, and the stroke amount of the ripper lift cylinder 135.

[0032] The work implement height calculation unit 413 calculates the height of the cutting edge of the blade 132 relative to the vehicle body, based on the measurement data of the stroke amount of the blade lift cylinder 133 acquired by the measurement data acquisition unit 412. In other words, the work implement height calculation unit 413 calculates the height of the cutting edge of the blade 132 in the vehicle body coordinate system from pre-stored dimensional information of the vehicle body 110 and the measurement data of the stroke amount of the blade lift cylinder 133. The work implement height calculation unit 413 also calculates the height of the cutting edge of the ripper 134 relative to the vehicle body, based on the measurement data of the stroke amount of the ripper lift cylinder 135 acquired by the measurement data acquisition unit 412.

[0033] The first movement amount estimation unit 414 estimates the speed, angular velocity, and tilt angle of the work vehicle 100 by inputting the operation amount acquired by the measurement data acquisition unit 412 and the measurement data acquired by the measurement data acquisition unit 412 into the motion state model 451.

[0034] The second movement amount estimating unit 415 estimates the X-axis direction velocity, Y-axis direction velocity, Z-axis direction velocity, angular velocity around the X-axis, angular velocity around the Y-axis, angular velocity around the Z-axis, and tilt angle of the traveling device 120 based on the rotation speeds of the left and right sprockets 122 acquired by the measurement data acquiring unit 412 and the measurement data of the IMU 340. Specifically, the second movement amount estimating unit 415 calculates the angular velocity of the traveling device 120 by dividing the difference in the rotation speeds of the left and right sprockets 122 by the distance between the sprockets 122. The direction of rotation can be determined by whether the angular velocity is positive or negative. The second movement amount estimating unit 415 calculates the average value of the rotation speeds of the left and right sprockets 122 as a scalar value of the velocity of the traveling device 120. Based on the tilt angle indicated by the measurement data of the IMU 340 and the calculated angular velocity, the second movement amount estimating unit 415 breaks down the velocity scalar value into components in the X-axis direction, the Y-axis direction, and the Z-axis direction.

[0035] The slip determination unit 416 determines whether or not the traveling device 120 is slipping by comparing the speed, angular velocity, and tilt angle estimated by the first movement amount estimation unit 414 with the speed, angular velocity, and tilt angle estimated by the second movement amount estimation unit 415. The speed, angular velocity, and tilt angle estimated by the first movement amount estimation unit 414 are values ​​that take into account the possibility of slipping, while the speed, angular velocity, and tilt angle estimated by the second movement amount estimation unit 415 are values ​​that assume that slipping will not occur. Therefore, the difference between the speed, angular velocity, and tilt angle estimated by the first movement amount estimation unit 414 and the speed, angular velocity, and tilt angle estimated by the second movement amount estimation unit 415 indicates the amount of movement related to slipping. For example, if none of the differences between the speed, angular velocity, and tilt angle estimated by the first movement amount estimating unit 414 and the speed, angular velocity, and tilt angle estimated by the second movement amount estimating unit 415 exceed a predetermined threshold, the slip determination unit 416 determines that slippage has not occurred in the traveling device 120. On the other hand, if at least one of the differences exceeds a predetermined threshold, the slip determination unit 416 determines that slippage has occurred in the traveling device 120.

[0036] The output unit 417 outputs the determination result of the slip determination unit 416 as to whether or not there is a slip to the console 142 .

[0037] <Motion State Model> The motion state model 451 according to the first embodiment receives input of the operation amount of the travel control lever 145, the rotation speeds of the left and right sprockets 122, measurement data from the IMU 340, measurement data of the pressure of the HST 230 (hydraulic motor), measurement data from the dynamometer 320, the speed gear, the height of the blade 132, and the height of the ripper 134, and outputs the velocity in the X-axis direction, the Y-axis direction, the Z-axis direction, the angular velocity around the X-axis (roll angular velocity), the angular velocity around the Y-axis (pitch angular velocity), the angular velocity around the Z-axis (swing angular velocity), the roll angle, and the pitch angle in the vehicle body coordinate system. The motion state model 451 is a machine learning model such as a neural network. The motion state model 451 may be configured using a CNN or an RNN. In particular, when the motion state model 451 is configured using a recurrent neural network such as a long short-term memory (LSTM) or a transformer, the motion state of the work vehicle 100 can be appropriately estimated in accordance with changes in the state over time. Note that the motion state model 451 according to other embodiments does not necessarily need to use all of the operation amount of the travel operation lever 145, the rotation speeds of the left and right sprockets 122, the measurement data of the IMU 340, the measurement data of the pressure of the HST 230 (hydraulic motor), the measurement data of the dynamometer 320, the speed gear, the height of the blade 132, and the height of the ripper 134 to estimate the motion state. As will be described later, the motion state model 451 may calculate the movement amount of the work vehicle 100 using at least one of the height of the blade 132, the height of the ripper 134, the operation amount of the travel operation lever 145, the speed gear, the output of the engine 210, and the pressure of the hydraulic motor of the HST 230.

[0038] The motion state model 451 has been trained using a training data set consisting of a combination of the following input samples and output samples. The input samples are the operation amount of the travel control lever 145, the rotation speeds of the left and right sprockets 122, the measurement data of the IMU 340, the pressure of the HST 230, the power of the engine 210, the speed gear, the height of the blade 132, and the height of the ripper 134. The output samples are the velocity in the X-axis direction, the Y-axis direction, the Z-axis direction, the angular velocity around the X-axis, the angular velocity around the Y-axis, the angular velocity around the Z-axis, the roll angle, and the pitch angle of the vehicle body coordinate system. The velocity of the work vehicle 100 related to the output sample may be a value calculated from the measurement data of the GNSS sensor 370. The angular velocity and attitude angle of the work vehicle 100 related to the output sample may be values ​​identified from the measurement data of the IMU 340.

[0039] The rotation speed of the sprocket 122 has a strong correlation with the movement distance of the work vehicle 100. In typical autonomous navigation, the movement distance is often calculated from the rotation speed. However, when slippage occurs in the crawler 121, the movement distance calculated from the rotation speed of the sprocket 122 may differ from the actual movement distance.

[0040] The measurement data of IMU 340 has a strong correlation with the angular velocity and tilt angle of work vehicle 100. In typical autonomous navigation, the vehicle body's traveling direction is often calculated from the angular velocity and tilt angle of IMU 340. However, when work vehicle 100 is traveling while working, vehicle body 110 vibrates, and there is a possibility that noise due to the vibrations may be added to the measurement data of IMU 340.

[0041] The height of the blade 132 and the height of the ripper 134 relate to the reaction force that the work vehicle 100 receives from the work object. The lower the blade 132 and the ripper 134 are, the more likely it is that the blade 132 and the ripper 134 will be in contact with the work object and performing work. When the work vehicle 100 is performing work, the work vehicle 100 will receive a reaction force from the work object. The height of the blade 132 and the height of the ripper 134 are examples of values ​​related to the state of the work implement 130.

[0042] The combination of the amount of operation of the travel control lever 145 and the rotation speed of the sprocket 122 relates to the reaction force that the work vehicle 100 receives from the work object. Furthermore, measurement data related to the power of the travel device 120, such as the output of the engine 210 and the pressure of the hydraulic motor of the HST 230, relates to the reaction force that the work vehicle 100 receives from the work object and the resulting slippage.

[0043] The speed gear is related to slippage that occurs due to a reaction force that the work vehicle 100 receives from a work object. The speed gear determines the maximum speed and torque of the work vehicle 100. Therefore, the lower the speed gear, the less likely slippage occurs, and the higher the speed gear, the more likely slippage occurs.

[0044] When work vehicle 100 receives a strong reaction force from the work object, the rotation speed of sprocket 122 decreases due to static friction force acting on traveling device 120. As the rotation speed of sprocket 122 decreases, the rotation speed of the hydraulic motor of HST 230, which rotates sprocket 122, decreases. As the rotation speed of the hydraulic motor of HST 230 decreases, the pressure between the hydraulic pump and hydraulic motor of HST 230 increases. As the pressure of HST 230 increases, the rotation speed of the input shaft of HST 230 decreases, and the rotation speed of engine 210 decreases.

[0045] Subsequently, when slippage occurs due to a reaction force from the work object, the frictional force acting on the traveling device 120 changes from static frictional force to kinetic frictional force, and the rotation speed of the hydraulic motor of the HST 230 and the sprocket 122 increases. As the rotation speed of the hydraulic motor of the HST 230 increases, the pressure between the hydraulic pump and hydraulic motor of the HST 230 decreases. The decrease in pressure of the HST 230 increases the rotation speed of the input shaft of the HST 230, and the rotation speed of the engine 210 increases. For this reason, if the movement amount of the work vehicle 100 were calculated directly from the rotation speed of the sprocket 122, an error in the movement amount would be large. On the other hand, the motion state model 451 calculates the movement amount of the work vehicle 100 using at least one of the height of the blade 132, the height of the ripper 134, the operation amount of the travel operation lever 145, the speed gear, the output of the engine 210, and the pressure of the hydraulic motor of the HST 230, thereby making it possible to calculate the movement amount while suppressing the effects of slippage.

[0046] Furthermore, when the work vehicle 100 receives a reaction force from the work object, the traveling gear 120 may lift due to the reaction force. For example, if the traveling gear 120 moves forward while the blade 132 receives a reaction force, the vehicle body 110 may move forward while the front of the traveling gear 120 lifts. In this case, the traveling direction of the work vehicle 100 does not match the inclination angle of the vehicle body 110 measured by the IMU 340, and therefore a deviation occurs in the direction of movement in typical autonomous navigation. On the other hand, the motion state model 451 calculates the amount of movement of the work vehicle 100 using at least one of the height of the blade 132, the height of the ripper 134, the operation amount of the travel operation lever 145, the output of the engine 210, and the pressure of the hydraulic motor of the HST 230, thereby making it possible to estimate the traveling direction of the work vehicle 100 even if the traveling gear 120 lifts. Note that the inclination angle output by the motion state model 451 may be the inclination angle of the traveling direction of the work vehicle 100, rather than the inclination angle of the vehicle body 110.

[0047] <<Position Output Method>> Next, a position output method for work vehicle 100 according to the first embodiment will be described. Fig. 5 is a flowchart showing the position output method according to the first embodiment. While work vehicle 100 is operating, control device 400 repeatedly executes the flowchart shown in Fig. 4.

[0048] The operation amount acquisition unit 411 acquires the operation amount and the speed gear of the travel operation lever 145 (step S1). The measurement data acquisition unit 412 acquires measurement data from the rotation sensor 310, the dynamometer 320, the oil pressure sensor 330, the IMU 340, the blade stroke sensor 350, the ripper stroke sensor 360, and the GNSS sensor 370 (step S2).

[0049] The work machine height calculation unit 413 calculates the height of the cutting edges of the blade 132 and the ripper 134 based on the measurement data of the stroke amount of the blade lift cylinder 133 and the stroke amount of the ripper lift cylinder 135 acquired by the measurement data acquisition unit 412 (step S3).

[0050] The first movement amount estimator 414 inputs the operation amount and speed gear of the travel operation lever 145 acquired in step S1, the rotation speeds of the left and right sprockets 122 acquired in step S2, the measurement data of the IMU 340, the pressure measurement data of the HST 230, and the measurement data of the dynamometer 320, as well as the height of the blade 132 and the height of the ripper 134 calculated in step S3, into the motion state model 451. As a result, the first movement amount estimator 414 estimates the speed in the X-axis direction, the Y-axis direction, the Z-axis direction, the angular velocity about the X-axis, the angular velocity about the Y-axis, the angular velocity about the Z-axis, and the tilt angle (roll angle and pitch angle) of the work vehicle 100 (step S4).

[0051] Next, the second movement amount estimation unit 415 estimates the speed of the traveling device 120 in the X-axis direction, the Y-axis direction, the Z-axis direction, the angular velocity around the X-axis, the Y-axis direction, the angular velocity around the Z-axis, and the tilt angle based on the rotation speeds of the left and right sprockets 122 acquired in step S2 and the measurement data of the IMU 340 (step S5).

[0052] The slip determination unit 416 determines whether or not slip has occurred based on the difference between the estimation results of step S4 and step S5. That is, the slip determination unit 416 determines whether the difference in velocity in the X-axis direction, the difference in velocity in the Y-axis direction, the difference in velocity in the Z-axis direction, the difference in angular velocity around the X-axis, the difference in angular velocity around the Y-axis, the difference in angular velocity around the Z-axis, the difference in roll angle, and the difference in pitch angle are all smaller than thresholds (step S6). If all differences are smaller than thresholds (step S6: YES), the slip determination unit 416 determines that slip has not occurred. On the other hand, if at least one difference is equal to or greater than a threshold (step S6: NO), the slip determination unit 416 determines that slip has occurred. The output unit 417 displays a warning indicating the occurrence of slip on the console 142 (step S7).

[0053] <<Actions and Effects>> In this way, the control device 400 according to the first embodiment detects slippage of the work vehicle 100 based on vehicle body data including at least a value related to the power of the running body of the work vehicle 100 and a value related to the rotation speed of the running body. Because the reaction force acting on the work vehicle 100 is reflected in the value related to the power of the running body of the work vehicle 100, the control device 400 can detect slippage caused by the reaction force from the work object. Note that although the first movement amount estimating unit 414 of the control device 400 according to the first embodiment estimates the tilt angle in addition to the movement amount of the work vehicle 100, the first movement amount estimating unit 414 according to other embodiments does not need to estimate the tilt angle. For example, the control device 400 according to other embodiments may estimate a scalar value of the speed of the running device 120 and determine whether or not slippage is occurring based on the difference in speed.

[0054] Second Embodiment A control device 400 according to a second embodiment further inputs measurement data from a GNSS sensor 370 to a motion state model 451 to detect slippage of the traveling device 120. That is, in addition to the operation amount of the traveling operation lever 145, the rotation speeds of the left and right sprockets 122, measurement data from the IMU 340, measurement data of the pressure of the HST 230 (hydraulic motor), measurement data from the dynamometer 320, the speed gear, the height of the blade 132, and the height of the ripper 134, the position and orientation of the work vehicle 100, which are measurement data from the GNSS sensor 370, and accuracy information, are also input to the motion state model 451 according to the second embodiment.

[0055] The measurement data of the GNSS sensor 370 correlates with the movement amount and angular velocity of the work vehicle 100. In particular, when the motion state model 451 is configured as a regression neural network, the change over time in the measurement data of the GNSS sensor 370 represents the movement amount and angular velocity of the work vehicle 100.

[0056] Note that if the GNSS sensor 370 cannot capture a signal from a GNSS satellite, it cannot measure the position and orientation of the GNSS sensor 370. In this case, the GNSS sensor 370 outputs accuracy information indicating that the accuracy is significantly low, and therefore the motion state model 451 is trained so that the weights of the position and orientation of the GNSS sensor 370 are determined by the accuracy information, thereby preventing a decrease in the calculation accuracy of the motion state model 451 even when the GNSS sensor 370 cannot capture a signal from a GNSS satellite.

[0057] Third Embodiment Fig. 6 is a diagram showing the configuration of a measurement system and control device of a work vehicle 100 according to a third embodiment. The work vehicle 100 according to the third embodiment further includes, as a measurement system, an imaging device 380 that captures an image of a work target of the work vehicle 100. Examples of the imaging device 380 include a camera, LiDAR (Light Detection and Ranging), and a laser scanner. The measurement data of the imaging device 380 is a two-dimensional image or a range image.

[0058] The first movement amount estimator 414 according to the third embodiment inputs measurement data from the imaging device 380 into a motion state model 451 to estimate the position and orientation of the work vehicle 100. The motion state model 451 according to the third embodiment receives the measurement data from the imaging device 380 as input, in addition to the operation amount of the travel control lever 145, the rotation speeds of the left and right sprockets 122, measurement data from the IMU 340, measurement data of the pressure of the HST 230 (hydraulic motor), measurement data from the dynamometer 320, the speed gear, the height of the blade 132, and the height of the ripper 134. Instead of the measurement data itself from the imaging device 380, feature amount data extracted from the measurement data may be input to the motion state model 451. The feature amount of the measurement data from the imaging device 380 may be obtained, for example, from the intermediate layer of a convolutional autoencoder.

[0059] The measurement data of the imaging device 380 relates to slippage that occurs due to the reaction force that the work vehicle 100 receives from the work object. For example, the likelihood of the work vehicle 100 slipping varies depending on the work object and the properties of the ground. If the ground is muddy, the work vehicle 100 is more likely to slip. Therefore, the images and their feature quantities, which are the measurement data of the imaging device 380, may reflect the properties of the work object and the ground.

[0060] Furthermore, when the motion state model 451 is configured as a regression neural network, the measurement data of the image capture device 380 correlates with the movement amount and angular velocity of the work vehicle 100. As the work vehicle 100 travels, the scenery captured in the image, which is the measurement data of the image capture device 380, changes. The magnitude of the change in scenery over time differs depending on the movement amount and angular velocity of the work vehicle 100. Furthermore, when the image capture device 380 is a LiDAR, the measurement data indicates distance. The change in distance correlates with the movement amount of the work vehicle 100.

[0061] Therefore, the first movement amount estimating unit 414 according to the third embodiment can improve the accuracy of detecting slip by estimating the movement amount of the work vehicle 100 using the measurement data of the imaging device 380 .

[0062] 7 is a diagram showing the configuration of a measurement system and control device of a work vehicle 100 according to a fourth embodiment. A control device 400 according to the fourth embodiment further includes a control unit 418 in addition to the configuration of the first embodiment. The control unit 418 controls the work implement 130 in accordance with the determination result of the slip determination unit 416.

[0063] Specifically, when slip determination unit 416 detects that slip is occurring, control unit 418 generates a control signal for raising the height of blade 132 and ripper 134 by a predetermined amount and outputs the control signal to proportional control valve 260. Control unit 418 repeats the automatic control for raising blade 132 and ripper 134 until slip no longer occurs, and ends the automatic control of blade 132 and ripper 134 when slip no longer occurs. In this way, control device 400 can perform work while preventing slip from occurring.

[0064] Note that the control device 400 according to other embodiments may perform control to raise the blade 132 or the ripper 134 that is lower than a predetermined height, for example, based on the blade height and ripper height calculated by the work implement height calculation unit 413. Furthermore, the control device 400 according to other embodiments may output a control signal to the HST 230 to reduce the speed of the traveling device 120 when it is detected that slippage is occurring.

[0065] Fifth Embodiment Figure 8 is a diagram showing the configuration of a measurement system and control device of a work vehicle 100 according to a fifth embodiment. The control device 400 according to the embodiments described above estimates the amount of movement of the work vehicle 100 and determines whether or not slippage is occurring based on that amount of movement. In contrast, the control device 400 according to the fifth embodiment determines whether or not slippage is occurring without estimating the amount of movement. Therefore, as shown in Figure 8, the control device 400 according to the fifth embodiment does not need to be equipped with a first movement amount estimator 414 and a second movement amount estimator 415.

[0066] In the fifth embodiment, a storage 450 stores a slip detection model 452 instead of the motion state model 451. The slip detection model 452 receives the operation amount of the travel control lever 145, the rotation speeds of the left and right sprockets 122, measurement data from the IMU 340, measurement data of the pressure of the HST 230 (hydraulic motor), measurement data from the dynamometer 320, the speed gear, the height of the blade 132, and the height of the ripper 134, and outputs a label indicating whether or not slip is occurring in the travel device 120. The slip detection model 452 is a machine learning model such as a neural network. The slip detection model 452 may be configured as a CNN or an RNN. In particular, when the slip detection model 452 is configured as a recurrent neural network such as a long short-term memory (LSTM) or a transformer, it can appropriately estimate the presence or absence of slippage in accordance with changes in the state over time.

[0067] The slip detection model 452 is trained using a training dataset consisting of a combination of the following input samples and output samples. The input samples are the operation amount of the travel control lever 145, the rotation speeds of the left and right sprockets 122, the measurement data of the IMU 340, the pressure of the HST 230, the power of the engine 210, the speed gear, the height of the blade 132, and the height of the ripper 134. The output samples are labels indicating the presence or absence of slip. The labels associated with the output samples may be values ​​calculated from the rotation speed of the sprocket 122 and the measurement data of the GNSS sensor 370. For example, a flag indicating the occurrence of slip can be set when the difference between the speed calculated from the rotation speed of the sprocket 122 and the speed calculated from the measurement data of the GNSS sensor 370 exceeds a predetermined amount, and a flag indicating the absence of slip can be set when the speed difference does not exceed the predetermined amount.

[0068] <Other Embodiments> Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to that described above, and various design modifications and the like are possible. That is, in other embodiments, the order of the above-described processes may be changed as appropriate. Furthermore, some processes may be executed in parallel. The control device 400 according to the above-described embodiment may be configured by a single computer, or the configuration of the control device 400 may be divided into multiple computers, and the multiple computers may function as the control device 400 by cooperating with each other. In this case, some of the computers configuring the control device 400 may be mounted inside the work vehicle 100, and other computers may be provided outside the work vehicle 100.

[0069] Although the work vehicle 100 according to the above-described embodiment includes the HST 230 as the power transmission device, this is not limited thereto. For example, the power transmission device of the work vehicle 100 according to another embodiment may be a hydromechanical continuously variable transmission (HMT) (which performs gear shift control by combining the HST 230 and a planetary gear mechanism). Furthermore, the power transmission device of the work vehicle 100 according to another embodiment may be a clutch. Even when the power transmission device is an HMT or a clutch, the output of the engine 210 is related to the reaction force that the work vehicle 100 receives from the work object and the resulting slippage. This is because, when the engine 210 and the power transmission device are connected, the reaction force affects the engine 210. Therefore, by inputting the measurement data of the dynamometer 320 into the motion state model 451, the control device 400 can estimate the movement amount of the work vehicle 100 while suppressing the influence of the reaction force from the work object. Furthermore, for example, the power transmission device of the work vehicle 100 according to another embodiment may be an electric mechanical transmission (EMT) having a generator and an electric motor instead of a hydraulic pump and a hydraulic motor. In this case, the control device 400 may estimate the amount of movement of the work vehicle 100 by inputting measurement data of the electric motor current value into the motion state model 451. The measurement data of the electric motor current value is an example of a value related to the power of the traveling body.

[0070] Furthermore, while the work vehicle 100 according to the embodiment described above is a bulldozer, the work vehicle 100 according to other embodiments is not limited to this. For example, the work vehicle 100 according to other embodiments may be a wheel loader, a motor grader, or the like. In other words, the running body of the work vehicle 100 according to other embodiments does not necessarily have to be a crawler, and may be, for example, tires or legs. Furthermore, the work vehicle 100 according to other embodiments may be an electric vehicle equipped with a battery and an electric motor instead of the engine 210.

[0071] According to the present disclosure, as an example, a measurement system of a work vehicle can detect slippage of a moving object.

[0072] 100...Work vehicle 110...Vehicle body 120...Traveling device 121...Crawler 122...Sprocket 123...Travel motor 130...Work machine 131...Lift frame 132...Blade 133...Blade lift cylinder 134...Ripper 135...Ripper lift cylinder 140...Operator's cab 141...Seat 142...Console 143...Blade operation lever 144...Ripper operation lever 145...Travel operation lever 146...Brake pedal 147...Deceleration pedal 210...Engine 220...PTO 230...HST 250...Hydraulic pump 260...Proportional control valve 310...Rotation sensor 320...Dynamometer 330...Hydraulic pressure sensor 340...IMU 350...Blade stroke sensor 360...Ripper stroke sensor 370...GNSS sensor 380...Imaging device 400: Control device 410: Processor 411: Operation amount acquisition unit 412: Measurement data acquisition unit 413: Work implement height calculation unit 414: First movement amount estimation unit 416: Slip determination unit 417: Output unit 418: Control unit 430: Main memory 450: Storage 451: Motion state model 470: Interface 415: Second movement amount estimation unit 452: Slip detection model

Claims

1. A detection system for a work vehicle comprising: a detection unit that detects slippage of a running body of the work vehicle based on vehicle body data including at least a value related to the power of the running body of the work vehicle and a value related to the rotation speed of the running body.

2. A detection system for a work vehicle as described in claim 1, comprising: a first movement amount estimation unit that outputs a first value related to the movement amount of the moving body by inputting vehicle body data into a trained model that has been trained to output a value related to the movement amount from the vehicle body data; and a second movement amount estimation unit that estimates a second value related to the movement amount of the moving body based on a value related to the rotation speed of the moving body, wherein the detection unit detects slippage of the moving body based on the deviation between the first value and the second value.

3. The work vehicle detection system of claim 1, wherein the detection unit detects slippage of the vehicle based on a value obtained by inputting the vehicle body data into a trained model trained to output the presence or absence of slippage of the vehicle from the vehicle body data.

4. A work vehicle detection system according to any one of claims 1 to 3, wherein the vehicle body data further includes a value relating to a state of a work implement of the work vehicle.

5. A work vehicle detection system according to any one of claims 1 to 3, wherein the vehicle body data further includes measurement data from an imaging device that images the outside of the work vehicle.

6. A work vehicle detection system according to any one of claims 1 to 3, further comprising a control unit that outputs a control signal for the work vehicle based on the result of the slip detection.

7. A method for detecting a work vehicle, comprising: detecting slippage of a running body of the work vehicle based on vehicle body data including at least a value related to the power of the running body of the work vehicle and a value related to the rotation speed of the running body.

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