Determination system and determination method

Abstract

To determine whether GNSS positioning is accurate.SOLUTION: An acquisition unit acquires position data indicating the position of a work vehicle based on GNSS, and a determination unit determines the accuracy of the position data based on vehicle body data and the position data of the work vehicle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a determination system and a determination method. [Background technology]

[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 of the blade based on the identified position. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2015 / 083469 Summary of the Invention [Problem to be solved by the invention]

[0004] GNSS positioning is performed by calculating the difference between the time of transmission and the time of reception of radio waves transmitted from GNSS satellites. Therefore, if multipath occurs due to terrain or structures, the positioning results may not be accurate. An object of the present disclosure is to provide a determination system and a determination method capable of determining whether or not positioning using a GNSS is accurate. [Means for solving the problem]

[0005] According to one aspect of the present disclosure, the determination system includes an acquisition unit that acquires position data indicating the position of a work vehicle based on GNSS, and a determination unit that determines the accuracy of the position data based on the body data of the work vehicle and the position data. Effect of the Invention

[0006] According to the above aspect, the determination system can determine whether or not the positioning by the GNSS is accurate. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a side view of a work vehicle according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing the internal configuration of a driver's cab according to the first embodiment. [Diagram 3] 1 is a schematic diagram showing a power system of a work vehicle according to a first embodiment. [Figure 4] 1 is a diagram showing the configuration of a measurement system and a control device of a work vehicle according to a first embodiment. [Diagram 5] 4 is a flowchart showing a method for determining the accuracy of a GNSS sensor according to the first embodiment. [Figure 6] 10 is a flowchart showing a method for determining the accuracy of a GNSS sensor according to a second embodiment. [Figure 7] FIG. 11 is a diagram showing the configuration of a measurement system and a control device of a work vehicle according to a third embodiment. [Figure 8] FIG. 13 is a diagram showing the configuration of a measurement system and a control device of a work vehicle according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] First embodiment Hereinafter, the embodiments 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. The 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 under the vehicle body 110. The traveling device 120 includes a pair of crawlers 121 and a sprocket 122. The pair of crawlers 121 are provided on the left and right sides of the vehicle body 110. The crawlers 121 are rotated by being driven by the sprocket 122, causing the work vehicle 100 to travel.

[0010] The work machine 130 is used for excavating and transporting an excavation target such as soil 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 expands and contracts due to hydraulic oil, thereby driving the lift frame 131 and the blade 132 in the raising or lowering direction.

[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 expands and contracts due to hydraulic oil, thereby driving the ripper 134 in a lifting or lowering direction.

[0013] The operator's cab 140 is a space where an operator rides in and operates the work vehicle 100. The operator's cab 140 is provided on an upper part of the vehicle body 110. 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 check the status of the work vehicle 100 by visually checking the console 142. The blade operating lever 143 is operated to set the amount of movement for raising or lowering the blade 132. The blade operating lever 143 receives a lowering operation when tilted forward, and receives a raising operation when tilted backward. The ripper operation lever 144 is operated to set the amount of movement for the raising or lowering operation of the ripper 134. The ripper operation lever 144 receives a lowering operation by being tilted forward, and receives a raising operation by being tilted backward. In addition, the blade operation lever 143 may receive a tilt operation for rotating the blade 132 about an axis in the front-to-rear direction, and an angle operation for rotating the blade 132 about an axis in the up-down direction. The travel operation lever 145 is operated to set the traveling direction of the travel device 120. The travel operation lever 145 accepts a forward operation when tilted forward, and a reverse operation when tilted backward. The travel operation lever 145 also accepts a left turn operation when tilted left, and a right turn operation when tilted right. The travel operation lever 145 is also provided with a gear change button for inputting a speed step. The brake pedal 146 is operated to brake the running device 120 . The deceleration pedal 147 is operated to reduce the rotation speed of the running gear 120 .

[0015] 《Power system》 FIG. 3 is a schematic diagram showing the power system of the work vehicle according to the first embodiment. The work vehicle 100 is equipped with an engine 210, a PTO 220 (Power Take Off), a pair of HSTs 230 (Hydro Static Transmissions), 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 the input shaft and outputs it from the output shaft. The HST 230 includes a hydraulic pump that is 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 the 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 the hydraulic oil to other destinations such as a steering clutch (not shown).

[0017] Measurement system 4 is a diagram showing the configuration of a measurement system and a control device of the work vehicle 100 according to the first embodiment. The measurement system of the work vehicle 100 acquires vehicle body data that represents the state of the work vehicle 100. The work vehicle 100 is equipped with a rotation sensor 310, a dynamometer 320, a hydraulic sensor 330, an IMU 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 front-rear direction of the vehicle body, a Y axis extending in the left-right direction of the vehicle body, and a Z axis extending in the up-down direction of the vehicle body. The rotation direction of the vehicle body 110 about the X axis is the roll direction, the rotation direction of the vehicle body 110 about the Y axis is the pitch direction, and the rotation direction of the vehicle body 110 about the Z axis is 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. Since 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 the work vehicle 100 according to other embodiments may detect the rotation angle of the lift frame 131 with other sensors such as an encoder.

[0023] The ripper stroke sensor 360 is provided in 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 blade tip of the ripper in the vehicle body coordinate system. Note that the work vehicle 100 according to other embodiments may detect the rotation angle of the ripper 134 with another sensor such as an encoder. Note that the work vehicle 100 according to other embodiments may not 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 operation amount of the ripper operation 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 the global coordinate system based on signals from GNSS satellites. The GNSS sensor 370 may perform RTK (Real Time Kinematic) 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, as the measurement data, the position and orientation, as well as accuracy information indicating the positioning accuracy. The accuracy information may indicate, for example, whether correction by the fixed station was successful or not, or the number of satellites that were able to be measured. 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 the 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 according to the amount of operation of each operating device in the cab 140 (the console 142, the blade operating lever 143, the ripper operating lever 144, the travel operating lever 145, the brake pedal 146, and the deceleration pedal 147). The control device 400 also measures the position of the work vehicle 100 based on the measurement data of the measurement system, and displays it on the console 142. The control device 400 may autonomously control the power system based on the position of the work vehicle 100 measured based on the measurement data of the measurement system.

[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] The storage 450 is a non-transitory tangible storage medium. Examples of the storage 450 include a magnetic disk, a magneto-optical disk, and a semiconductor memory. The storage 450 may be an internal medium directly connected to the bus of the control device 400, or an external medium connected to the control device 400 via the interface 470 or a communication line. The storage 450 stores a program for controlling the work vehicle 100. The storage 450 also stores a motion state model 451, which is a machine learning model for calculating the speed and angular velocity of the 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 LSI (Large Scale Integrated Circuit) such as a PLD (Programmable Logic Device) in addition to or instead of the above configuration. Examples of PLDs include PAL (Programmable Array Logic), GAL (Generic Array Logic), CPLD (Complex Programmable Logic Device), and FPGA (Field Programmable Gate Array). In this case, some or all of the functions realized by the processor 410 may be realized by the integrated circuit.

[0029] By executing the 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 second movement amount estimation unit 415, a 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 hydraulic sensor 330, the IMU 340, the blade stroke sensor 350, the ripper stroke sensor 360, and the GNSS sensor 370. In other words, the measurement data acquisition unit 412 acquires measurement data on the yaw angle of the body 110, the roll angle of the body 110, the pitch angle of the 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 machine 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 machine height calculation unit 413 calculates the height of the cutting edge of the blade 132 in the vehicle body coordinate system from the dimensional information of the vehicle body 110 stored in advance and the measurement data of the stroke amount of the blade lift cylinder 133. The work machine 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 estimating unit 414 estimates the speed and angular velocity of the work vehicle 100 by inputting the operation amount acquired by the measurement data acquiring unit 412 and the measurement data acquired by the measurement data acquiring unit 412 into the motion state model 451.

[0034] The second movement amount estimation unit 415 estimates the speed and angular velocity of the work vehicle 100 based on the measurement data of the GNSS sensor 370 acquired by the measurement data acquisition unit 412. Specifically, the second movement amount estimation unit 415 calculates the turning angular velocity of the work vehicle 100 based on the difference between the orientation indicated by the latest measurement data of the GNSS sensor 370 acquired by the measurement data acquisition unit 412 and the orientation indicated by the previous measurement data. The second movement amount estimation unit 415 calculates the speed of the work vehicle 100 in the global coordinate system based on the difference between the three-dimensional position indicated by the latest measurement data of the GNSS sensor 370 acquired by the measurement data acquisition unit 412 and the three-dimensional position indicated by the previous measurement data, and converts the speed in the global coordinate system into velocities in the X-axis, Y-axis, and Z-axis directions based on the work vehicle 100 as a reference based on the orientation indicated by the latest measurement data of the GNSS sensor 370.

[0035] The determination unit 416 determines whether the measurement data of the GNSS sensor 370 is accurate based on the velocity and angular velocity estimated by the first movement amount estimation unit 414 and the velocity and angular velocity estimated by the second movement amount estimation unit 415. Specifically, the determination unit 416 determines that the measurement data of the GNSS sensor 370 is accurate when the difference between the velocity in the X-axis direction estimated by the first movement amount estimation unit 414 and the velocity in the X-axis direction estimated by the second movement amount estimation unit 415, the difference between the velocity in the Y-axis direction estimated by the first movement amount estimation unit 414 and the velocity in the Y-axis direction estimated by the second movement amount estimation unit 415, the difference between the velocity in the Z-axis direction estimated by the first movement amount estimation unit 414 and the velocity in the Z-axis direction estimated by the second movement amount estimation unit 415, and the difference between the rotation angular velocity estimated by the first movement amount estimation unit 414 and the rotation angular velocity estimated by the second movement amount estimation unit 415 are all smaller than a predetermined threshold value.

[0036] The output unit 417 outputs the position and orientation indicated by the measurement data of the GNSS sensor 370 to the console 142. If the determination unit 416 determines that the measurement data of the GNSS sensor 370 is not accurate, the output unit 417 outputs a warning indicating that the GNSS sensor 370 may be inaccurate.

[0037] "Motion state model" The motion state model 451 according to the first embodiment receives the operation amount of the travel operation lever 145, the rotation speed 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 stage, the height of the blade 132, and the height of the ripper 134, and outputs the speed in the X-axis direction, the speed in the Y-axis direction, the speed in the Z-axis direction, the angular velocity around the X-axis (roll angular velocity), the angular velocity around the Y-axis (pitch angular velocity), and the angular velocity around the Z-axis (turning angular velocity) of 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 with a CNN or an RNN. In particular, when the motion state model 451 is configured with a recurrent neural network such as LSTM (Long Short Term Memory) or Transformer, the motion state of the work vehicle 100 can be appropriately estimated according to 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 stage, the height of the blade 132, and the height of the ripper 134 to estimate the motion state. As described below, 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 stage, the output of the engine 210, and the pressure of the hydraulic motor of the HST 230.

[0038] The motion state model 451 is trained using a learning data set consisting of a combination of the following input samples and output samples. The input samples are 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 pressure of the HST 230, the power of the engine 210, the speed stage, the height of the blade 132, and the height of the ripper 134. The output samples are the speed in the X-axis direction, the speed in the Y-axis direction, the speed in 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 speed 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 number of revolutions of the sprocket 122 has a strong correlation with the amount of movement of the work vehicle 100. In general autonomous navigation, the amount of movement is often calculated from the number of revolutions. However, when slippage occurs in the crawler 121, the amount of movement calculated from the number of revolutions of the sprocket 122 may differ from the actual amount of movement.

[0040] The measurement data of the IMU 340 has a strong correlation with the angular velocity and tilt angle of the work vehicle 100. In general autonomous navigation, the traveling direction of the vehicle body is often calculated from the angular velocity and acceleration of the IMU 340. On the other hand, when the work vehicle 100 is traveling while performing work, the vehicle body 110 vibrates, and therefore, there is a possibility that noise due to the vibrations may be added to the measurement data of the 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 operation lever 145 and the rotation speed of the sprocket 122 relates to the reaction force that the work vehicle 100 receives from the work target. In addition, measurement data related to the power of the travel gear 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 target and the slip caused by this.

[0043] The speed gear is related to slippage caused by 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 the static friction force acting on traveling gear 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] Thereafter, 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 rotational speed of the hydraulic motor of the HST 230 and the sprocket 122 increases. When the rotational speed of the hydraulic motor of the HST 230 increases, the pressure between the hydraulic pump and the hydraulic motor of the HST 230 decreases. The decrease in the pressure of the HST 230 increases the rotational speed of the input shaft of the HST 230, and the rotational speed of the engine 210 increases. For this reason, if the movement amount of the work vehicle 100 is calculated directly from the rotational speed of the sprocket 122, the error in the movement amount will be large. On the other hand, the motion state model 451 can calculate the movement amount while suppressing the effect of slippage by calculating 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 stage, the output of the engine 210, and the pressure of the hydraulic motor of the HST 230.

[0046] In addition, when the work vehicle 100 receives a reaction force from the work target, the traveling gear 120 may float due to the reaction force. For example, when the traveling gear 120 advances while the blade 132 receives a reaction force, the vehicle body 110 may advance while the front of the traveling gear 120 floats. In this case, since the traveling direction of the work vehicle 100 and the tilt angle of the vehicle body 110 measured by the IMU 340 do not match, a deviation occurs in the moving direction in general autonomous navigation. On the other hand, the motion state model 451 can estimate the traveling direction of the work vehicle 100 even if the traveling gear 120 floats by calculating the moving 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 traveling operation lever 145, the output of the engine 210, and the pressure of the hydraulic motor of the HST 230. Note that the tilt angle output by the motion state model 451 may be the tilt angle of the traveling direction of the work vehicle 100, not the tilt angle of the vehicle body 110.

[0047] How to determine the accuracy of the GNSS sensor 370 Next, a method for determining the accuracy of the GNSS sensor 370 according to the first embodiment will be described. Fig. 5 is a flowchart showing the method for determining the accuracy of the GNSS sensor 370 according to the first embodiment. The control device 400 repeatedly executes the flowchart shown in Fig. 5 while the work vehicle 100 is operating.

[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 hydraulic sensor 330, the IMU 340, the blade stroke sensor 350, the ripper stroke sensor 360, and the GNSS sensor 370 (step S2). Next, 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).

[0049] The first movement amount estimation unit 414 inputs the operation amount and speed stage 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, to the motion state model 451. As a result, the first movement amount estimation unit 414 estimates the speed in the X-axis direction, the speed in the Y-axis direction, the speed in the Z-axis direction, and the turning angular velocity of the work vehicle 100 (step S4).

[0050] The second movement amount estimation unit 415 estimates the speed in the X-axis direction, the Y-axis direction, the Z-axis direction and the turning angular velocity of the work vehicle 100 based on the measurement data of the GNSS sensor 370 acquired by the measurement data acquisition unit 412 (step S5).

[0051] The determination unit 416 calculates the difference between the velocity in the X-axis direction, the velocity in the Y-axis direction, the velocity in the Z-axis direction, and the turning angular velocity estimated by the first movement amount estimation unit 414 and the second movement amount estimation unit 415 (step S6). The determination unit 416 determines whether or not each of the calculated differences is smaller than a predetermined threshold value (step S7). If all the differences are smaller than the threshold value (step S7: YES), the determination unit 416 determines that the measurement data of the GNSS sensor 370 is accurate. The output unit 417 outputs the position and orientation indicated by the measurement data of the GNSS sensor 370 acquired in step S2 to the console 142 (step S8).

[0052] If at least one difference is equal to or greater than the threshold (step S7: NO), the determination unit 416 determines that the measurement data of the GNSS sensor 370 is inaccurate. The output unit 417 outputs a warning indicating that the measurement data of the GNSS sensor 370 is inaccurate to the console 142 (step S9). The output unit 417 may output the position and orientation indicated by the measurement data of the GNSS sensor 370 acquired in step S2 to the console 142, or may output only a warning.

[0053] Actions and Effects In this way, the control device 400 according to the first embodiment includes a measurement data acquisition unit 412, a first movement amount estimation unit 414, and a determination unit 416. The measurement data acquisition unit 412 acquires position data indicating the position of the work vehicle 100 based on the GNSS. The first movement amount estimation unit 414 estimates a value related to the movement amount of the work vehicle 100 based on the vehicle body data of the work vehicle 100. The determination unit 416 determines the accuracy of the position data based on the value related to the movement amount and the position data. As a result, when the accuracy of the measurement data of the GNSS sensor 370 decreases due to the influence of multipath or the like, the position indicated by the measurement data will deviate significantly from the past position, and the deviation from the movement amount calculated from the vehicle body data will become large. Therefore, the control device 400 according to the first embodiment can determine the accuracy of the measurement data of the GNSS sensor 370.

[0054] Moreover, the control device 400 according to the first embodiment estimates the travel distance using a value related to the power of the traveling device 120 of the work vehicle 100 and a value related to the state of the work machine 130. Both the power of the traveling device 120 and the state of the work machine 130 are related to the slippage and floating of the traveling device 120, so by using these, the travel distance of the work vehicle 100 can be accurately estimated. On the other hand, the control device 400 according to other embodiments may estimate the travel distance by autonomous navigation from the rotation speed of the sprocket 122, for example, without using the power of the traveling device 120 and the state of the work machine 130. For example, in an environment where the influence of the slippage and floating of the work vehicle 100 is small, the accuracy of the measurement data of the GNSS sensor 370 can be determined even if the travel distance estimated by autonomous navigation is used. Moreover, the control device 400 according to other embodiments may estimate the travel distance of the work vehicle 100 using one of the power of the traveling device 120 and the state of the work machine 130.

[0055] Second embodiment The control device 400 according to the second embodiment outputs the estimation accuracy of each value in addition to the velocity and angular velocity as the estimation result of the first movement amount estimation unit 414. The first movement amount estimation unit 414 outputs the estimation accuracy as a variance-covariance matrix having a dimension of the number of items to be estimated. For example, the first movement amount estimation unit 414 can calculate the estimation accuracy by obtaining the variance of the estimation result from the result of inference by a plurality of motion state models 451. Also, for example, the first movement amount estimation unit 414 may output the average value of the velocity, angular velocity, and tilt angle and the standard deviation as the estimation accuracy by using the motion state model 451 that has been trained to output the average value and standard deviation of a Gaussian distribution as the estimation result.

[0056] How to determine the accuracy of the GNSS sensor 370 Next, a method for determining the accuracy of the GNSS sensor 370 according to the second embodiment will be described. Fig. 6 is a flowchart showing a method for determining the accuracy of the GNSS sensor 370 according to the second embodiment. The control device 400 repeatedly executes the flowchart shown in Fig. 6 while the work vehicle 100 is operating.

[0057] The operation amount acquisition unit 411 acquires the operation amount and the speed gear of the travel operation lever 145 (step S31). The measurement data acquisition unit 412 acquires measurement data from the rotation sensor 310, the dynamometer 320, the hydraulic sensor 330, the IMU 340, the blade stroke sensor 350, the ripper stroke sensor 360, and the GNSS sensor 370 (step S32). Next, 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 S33).

[0058] The first movement amount estimator 414 inputs the operation amount and speed stage of the travel operation lever 145 acquired in step S31, the rotation speeds of the left and right sprockets 122 acquired in step S32, 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 S33, to the motion state model 451. As a result, the first movement amount estimator 414 estimates the speed in the X-axis direction, the speed in the Y-axis direction, the speed in the Z-axis direction, and the turning angular velocity of the work vehicle 100, and outputs a variance-covariance matrix indicating the reliability (step S34).

[0059] The determination unit 416 determines whether the reliability represented by the variance-covariance matrix is ​​equal to or greater than a predetermined threshold (step S35). For example, the determination unit 416 may regard the reciprocal of the average value of the variances, which are diagonal components of the variance-covariance matrix, as the reliability.

[0060] If the reliability is greater than or equal to the threshold (step S35: YES), the second movement distance estimation unit 415 estimates the speed in the X-axis direction, the speed in the Y-axis direction, the speed in the Z-axis direction and the turning angular velocity of the work vehicle 100 based on the measurement data of the GNSS sensor 370 acquired by the measurement data acquisition unit 412 (step S36).

[0061] The determination unit 416 calculates the difference between the velocity in the X-axis direction, the velocity in the Y-axis direction, the velocity in the Z-axis direction, and the turning angular velocity estimated by the first movement amount estimation unit 414 and the second movement amount estimation unit 415 (step S37). The determination unit 416 determines whether or not each of the calculated differences is smaller than a predetermined threshold value (step S38). If all the differences are smaller than the threshold value (step S38: YES), the determination unit 416 determines that the measurement data of the GNSS sensor 370 is accurate. The output unit 417 outputs the position and orientation indicated by the measurement data of the GNSS sensor 370 acquired in step S32 to the console 142 (step S39).

[0062] If at least one difference is equal to or greater than the threshold (step S38: NO), the determination unit 416 determines that the measurement data of the GNSS sensor 370 is inaccurate. The output unit 417 outputs a warning indicating that the measurement data of the GNSS sensor 370 is inaccurate to the console 142 (step S40). The output unit 417 may output the position and orientation indicated by the measurement data of the GNSS sensor 370 acquired in step S2 to the console 142, or may output only a warning.

[0063] If the reliability is less than the threshold (step S35: NO), the output unit 417 outputs a message indicating that the accuracy of the measurement data of the GNSS sensor 370 cannot be determined to the console 142 (step S41). The output unit 417 may output the position and orientation indicated by the measurement data of the GNSS sensor 370 acquired in step S2 to the console 142, or may output only the message.

[0064] Third embodiment 7 is a diagram showing the configuration of a measurement system and a control device of the work vehicle 100 according to the third embodiment. The work vehicle 100 according to the third embodiment further includes an imaging device 380 as a measurement system for capturing an image of a work target of the work vehicle 100. Examples of the imaging device 380 include a camera, LiDAR, and a laser scanner. The measurement data of the imaging device 380 is a two-dimensional image or a range image.

[0065] The first movement amount estimating unit 414 according to the third embodiment inputs the measurement data of the imaging device 380 to the motion state model 451 to estimate the speed, acceleration, and tilt angle of the work vehicle 100. The motion state model 451 according to the third embodiment further inputs the measurement data of the imaging device 380 in addition to 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 stage, the height of the blade 132, and the height of the ripper 134. Instead of the measurement data of the imaging device 380 itself, feature amount data extracted from the measurement data may be input to the motion state model 451. The feature amount of the measurement data of the imaging device 380 may be obtained, for example, from the intermediate layer of a convolutional autoencoder.

[0066] The measurement data of the imaging device 380 relates to slippage caused by a 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 likely to slip. Therefore, the image, which is the measurement data of the imaging device 380, and its feature values ​​may reflect the properties of the work object and the ground.

[0067] Furthermore, when the motion state model 451 is configured as a regression type neural network, the measurement data of the imaging device 380 correlates with the movement amount and angular velocity of the work vehicle 100. When the work vehicle 100 travels, the scenery captured in the image, which is the measurement data of the imaging device 380, changes. The magnitude of the change in the scenery over time differs depending on the movement amount and angular velocity of the work vehicle 100. Furthermore, when the imaging device 380 is a LiDAR, the measurement data indicates distance. The change in distance correlates with the movement amount of the work vehicle 100.

[0068] Therefore, the first movement amount estimating section 414 according to the third embodiment can improve the reliability by estimating the position and orientation of the work vehicle 100 using the measurement data of the imaging device 380.

[0069] Fourth embodiment The work vehicle 100 according to the first embodiment determines the accuracy of the GNSS sensor 370 based on the difference in speed and acceleration. In contrast, the control device 400 according to the fourth embodiment estimates the position and orientation of the work vehicle 100 from the estimated amount of movement, and determines the accuracy of the GNSS sensor 370 based on the difference in position and orientation.

[0070] 8 is a diagram showing the configuration of a measurement system and a control device of a work vehicle 100 according to the fourth embodiment. The control device 400 according to the fourth embodiment includes a position estimation unit 418 instead of the second movement amount estimation unit 415 according to the first embodiment.

[0071] The position estimation unit 418 estimates the current position, orientation, and inclination angle of the work vehicle 100 based on the previous estimation results of the position, orientation, and inclination angle of the work vehicle 100 and the speed, angular velocity, and inclination angle of the work vehicle 100 estimated by the first movement amount estimation unit 414. The position estimation unit 418 may be realized by, for example, a Bayes filter. In other words, the position estimation unit 418 may be a Bayes filter that estimates the position, orientation, and inclination angle at time t using the estimation results of the position and inclination angle at time t-1 as a "state (posterior belief)", the speed and angular velocity of the work vehicle 100 at time t estimated by the first movement amount estimation unit 414 as a "control value", and the inclination angle of the work vehicle 100 at time t estimated by the first movement amount estimation unit 414 as an "observation value".

[0072] The determination unit 416 according to the fourth embodiment determines the accuracy of the GNSS sensor 370 based on the difference between the position and orientation indicated by the measurement data of the GNSS sensor 370 and the position and orientation estimated by the position estimation unit 418.

[0073] Fifth embodiment The control device 400 according to the above-described embodiments estimates the amount of movement of the work vehicle 100, and determines the accuracy of the GNSS sensor 370 based on the amount of movement. In contrast, the control device 400 according to the fifth embodiment determines the accuracy of the GNSS sensor 370 without estimating the amount of movement. Therefore, the control device 400 according to the fifth embodiment does not need to be equipped with the first movement amount estimating unit 414 and the second movement amount estimating unit 415.

[0074] In the storage 450 according to the fifth embodiment, a GNSS determination model is stored instead of the motion state model 451. The GNSS determination model outputs a value indicating the accuracy of the GNSS sensor 370 by inputting the operation amount of the travel operation lever 145, the rotation speed 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 stage, the height of the blade 132, the height of the ripper 134, and the measurement value of the GNSS sensor 370. The GNSS determination model is a machine learning model such as a neural network. The GNSS determination model may be configured with a CNN or an RNN. In particular, when the GNSS determination model is configured with a neural network that refers to past steps such as LSTM (Long Short Term Memory) or Transformer, the accuracy of the GNSS sensor 370 can be appropriately estimated according to the slip state of the work vehicle 100 according to changes in the state over time. Note that the Transformer is a neural network that can refer to information of past steps by Attention.

[0075] The GNSS determination model is trained using a learning data set consisting of a combination of the following input samples and output samples. The input samples are 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 pressure of the HST 230, the power of the engine 210, the speed stage, the height of the blade 132, and the height of the ripper 134, and the measurement value of the GNSS sensor 370. The output sample is a value indicating the accuracy of the GNSS sensor 370. The value indicating the accuracy of the GNSS sensor 370 may be a value calculated from the calculation result of the motion state model 451 according to the above-mentioned embodiment and the measurement data of the GNSS sensor 370. For example, the ratio between the speed indicated by the calculation result of the motion state model 451 and the speed calculated from the measurement data of the GNSS sensor 370 can be set as the value indicating the accuracy of the GNSS sensor 370. In addition, the value indicating the accuracy of the GNSS sensor 370 may be a value calculated by comparing the position measured by a total station with the position indicated by the measurement data of the GNSS sensor 370.

[0076] Other Embodiments Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes are possible. That is, in other embodiments, the order of the above-mentioned processes may be changed as appropriate. Also, some of the processes may be executed in parallel. The control device 400 according to the embodiment described above may be configured by a single computer, or the configuration of the control device 400 may be divided and arranged among multiple computers, and the multiple computers may cooperate with each other to function as the control device 400. In this case, some of the computers constituting the control device 400 may be mounted inside the work vehicle 100, and other computers may be provided outside the work vehicle 100.

[0077] The work vehicle 100 according to the embodiment described above includes the HST 230 as a power transmission device, but is not limited thereto. For example, the power transmission device of the work vehicle 100 according to another embodiment may be an HMT (hydraulic mechanical continuously variable transmission) that performs speed change control by combining the HST 230 and a planetary gear mechanism. 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 slip caused by this. This is because when the engine 210 and the power transmission device are connected, the influence of the reaction force appears on the engine 210. Therefore, 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 by inputting the measurement data of the dynamometer 320 into the motion state model 451. Also, for example, the power transmission device of the work vehicle 100 according to another embodiment may be an EMT (Electric Mechanical Transmission) 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 movement amount of the work vehicle 100 by inputting measurement data of the electric motor current value to 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.

[0078] Furthermore, the determination unit 416 of the control device 400 according to the embodiment described above determines the accuracy of the GNSS sensor 370 by comparing the speed and angular velocity of the work vehicle 100 calculated by the motion state model 451 with the speed and angular velocity calculated from the measurement data of the GNSS sensor 370, but is not limited to this. For example, the determination unit 416 according to other embodiments may determine the accuracy of the GNSS sensor 370 by comparing the position indicated by the measurement data of the GNSS sensor with the position of the work vehicle 100 calculated from the calculation results of the motion state model 451.

[0079] 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 or a motor grader. 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.

[0080] Furthermore, the control device 400 according to the embodiment described above displays the estimated position, orientation, and tilt angle of the work vehicle 100 on the console 142, but is not limited to this. For example, the control device 400 according to other embodiments may execute autonomous control that controls the drive system based on the estimated position, orientation, and tilt angle of the work vehicle 100. [Explanation of symbols]

[0081] 100...work vehicle 110...body 120...traveling device 121...crawler 122...sprocket 123...traveling motor 130...working 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...traveling 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 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 machine height calculation unit 414: First movement amount estimation unit 415: Second movement amount estimation unit 416: Determination unit 417: Output unit 418: Position estimation unit 430: Main memory 450: Storage 451: Motion state model 470: Interface

Claims

1. An acquisition unit that acquires position data indicating a position of the work vehicle based on a GNSS; a determination unit that determines the accuracy of the position data based on the vehicle body data of the work vehicle and the position data; A determination system comprising:

2. An estimation unit that estimates a value related to a movement amount of the work vehicle based on vehicle body data of the work vehicle, the determination unit determines accuracy of the position data based on the value related to the movement amount and the position data. The determination system according to claim 1 .

3. The determination unit determines that the position data is accurate when a difference between the value related to the movement amount and the position data when the value is converted into an amount of the same type is smaller than a predetermined threshold value. The determination system according to claim 2 .

4. The estimation unit further outputs a reliability of a value related to the movement amount of the work vehicle, The determination unit determines that the position data is accurate when the reliability is equal to or greater than a predetermined threshold and a difference between the value related to the movement amount and the position data when the value is converted into an amount of the same type is smaller than a predetermined threshold. The determination system according to claim 3 .

5. The determination unit determines the accuracy of the position data by inputting the vehicle body data and the position data to a trained model trained to output the accuracy of the position data from the vehicle body data of the work vehicle and the position data measured based on the GNSS. The determination system according to claim 1 .

6. The estimation unit estimates the value related to the movement amount by inputting the vehicle body data to a trained model trained to output a value related to the movement amount from the vehicle body data. The determination system according to any one of claims 2 to 4.

7. The vehicle body data includes a value related to the power of a running body of the work vehicle. The determination system according to any one of claims 1 to 5.

8. The vehicle body data includes a value related to a state of a work implement of the work vehicle. The determination system according to any one of claims 1 to 5.

9. The vehicle body data further includes measurement data of an imaging device that images the outside of the work vehicle. The determination system according to any one of claims 1 to 5.

10. acquiring position data indicating a position of a work vehicle based on a GNSS; determining accuracy of the position data based on vehicle body data of the work vehicle and the position data; The determination method includes:

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