JP2023167080A - Automatic traveling method, automatic traveling system and automatic traveling program - Google Patents

Abstract

To provide an automatic traveling method, an automatic traveling system and an automatic traveling program capable of improving accuracy of the azimuth angle of a work vehicle.SOLUTION: An acquisition processing part 112 acquires a measurement azimuth angle D0 measured by an inertial measurement device 165 for measuring the azimuth angle of a work vehicle 10. An adjustment processing part 115 adjusts weight corresponding to the measurement azimuth angle D0 on the basis of vehicle speed Vf of the work vehicle 10. An estimation processing part 116 estimates an azimuth angle D1 corresponding to a present attitude of the work vehicle 10, on the basis of the measurement azimuth angle D0 with the weight adjusted by the adjustment processing part 115, positional information of the work vehicle 10, and angle speed information of the vehicle 10. A traveling processing part 111 allows automatic traveling of the work vehicle 10 on the basis of the azimuth angle D1 estimated by the estimation processing part 116.SELECTED DRAWING: Figure 5

Description

The present invention relates to an automatic driving method, an automatic driving system, and an automatic driving program that allow a work vehicle to travel automatically.

2. Description of the Related Art Work vehicles are known that automatically travel by traveling along a preset target route based on position information of the work vehicle. For example, there is a technology for automatically driving a work vehicle along the target route by setting a forward target point on the target route and controlling the steering so that the work vehicle heads toward the forward target point based on the azimuth of the work vehicle. known (for example, see Patent Document 1).

JP2020-080743A

By the way, as devices for calculating the azimuth of a work vehicle, there are azimuth angle sensors, inertial measurement devices, and the like. The inertial measurement device measures the orientation of the vehicle body using a 3-axis gyro sensor and a 3-axis acceleration sensor, so when the work vehicle travels at low speed, the output value obtained from each sensor becomes small. . As a result, the accuracy of the azimuth angle of the work vehicle decreases, causing a problem that the traveling accuracy decreases.

An object of the present invention is to provide an automatic driving method, an automatic driving system, and an automatic driving program that can improve the accuracy of the azimuth angle of a work vehicle.

The automatic driving method according to the present invention includes acquiring a measured azimuth measured by a measurement unit that measures the azimuth of a working vehicle, and calculating a weight corresponding to the measured azimuth based on the vehicle speed of the working vehicle. and the measured azimuth whose weight is adjusted according to the vehicle speed, the position information of the work vehicle, and the angular velocity information of the work vehicle to correspond to the current posture of the work vehicle. The present invention is an automatic driving method for estimating an azimuth angle and automatically driving the work vehicle based on the estimated azimuth angle.

Further, the automatic driving method according to the present invention includes the steps of: acquiring a measured azimuth measured by a measurement unit that measures an azimuth of a working vehicle; estimating an azimuth corresponding to the current posture of the working vehicle based on vehicle angular velocity information; and estimating the measured azimuth and the estimated azimuth based on the vehicle speed of the working vehicle. This is an automatic driving method that selects either one as an output azimuth and causes the work vehicle to automatically travel based on the output azimuth.

The automatic driving system according to the present invention includes an acquisition processing section, an estimation processing section, and a driving processing section. The acquisition processing unit acquires a measured azimuth measured by a measurement unit that measures an azimuth of the work vehicle. The estimation processing unit adjusts a weight corresponding to the measurement azimuth acquired by the acquisition processing unit based on the vehicle speed of the work vehicle, and the measurement azimuth with the adjusted weight and the measurement azimuth of the work vehicle. An azimuth corresponding to the current attitude of the work vehicle is estimated based on the position information and the angular velocity information of the work vehicle. The travel processing section causes the work vehicle to travel automatically based on the azimuth estimated by the estimation processing section.

The automatic driving program according to the present invention acquires a measured azimuth measured by a measurement unit that measures the azimuth of a working vehicle, and calculates a weight corresponding to the measured azimuth based on the vehicle speed of the working vehicle. and the measured azimuth whose weight is adjusted according to the vehicle speed, the position information of the work vehicle, and the angular velocity information of the work vehicle to correspond to the current posture of the work vehicle. This is an automatic driving program for causing one or more processors to estimate an azimuth and cause the work vehicle to automatically travel based on the estimated azimuth.

According to the present invention, it is possible to provide an automatic driving method, an automatic driving system, and an automatic driving program that can improve the accuracy of the azimuth angle of a work vehicle.

FIG. 1 is a block diagram showing the configuration of an automatic driving system according to Embodiment 1 of the present invention. FIG. 2 is an external view showing an example of a work vehicle according to an embodiment of the present invention. FIG. 3 is a diagram illustrating an example of a target route of a work vehicle according to an embodiment of the present invention. FIG. 4 is a diagram showing an example of a running state of the work vehicle according to the embodiment of the present invention. FIG. 5 is a block diagram showing a specific configuration of a vehicle control device according to Embodiment 1 of the present invention. FIG. 6 is a diagram illustrating an example of a method for determining an estimation target section in the vehicle control device according to the embodiment of the present invention. FIG. 7 is a graph showing an example of a parameter adjustment method in the vehicle control device according to the first embodiment of the present invention. FIG. 8 is a block diagram showing another configuration of the vehicle control device according to Embodiment 1 of the present invention. FIG. 9 is a flowchart illustrating an example of an automatic driving process procedure executed by the automatic driving system according to the first embodiment of the present invention. FIG. 10 is a block diagram showing the configuration of an automatic driving system according to Embodiment 2 of the present invention. FIG. 11 is a block diagram showing a specific configuration of a vehicle control device according to Embodiment 2 of the present invention. FIG. 12 is a graph showing an example of an azimuth determining method in the vehicle control device according to the second embodiment of the present invention. FIG. 13A is a diagram illustrating another example of a method for determining an estimation target section in the vehicle control device according to the embodiment of the present invention. FIG. 13B is a diagram illustrating another example of a method for determining an estimation target section in the vehicle control device according to the embodiment of the present invention. FIG. 14A is a diagram illustrating another example of a method for resetting estimated values in the vehicle control device according to the embodiment of the present invention. FIG. 14B is a diagram illustrating another example of a method for resetting estimated values in the vehicle control device according to the embodiment of the present invention. FIG. 14C is a diagram illustrating another example of a method for resetting estimated values in the vehicle control device according to the embodiment of the present invention.

The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.

[Embodiment 1]
As shown in FIG. 1, an automatic driving system 1 according to Embodiment 1 of the present invention includes a work vehicle 10 and an operation terminal 20. Work vehicle 10 and operation terminal 20 can communicate via communication network N1. For example, the work vehicle 10 and the operating terminal 20 can communicate via a mobile phone network, a packet network, or a wireless LAN. The automatic driving system 1 is a system for automatically driving a work vehicle 10 within a field F.

In this embodiment, a case where the work vehicle 10 is a tractor will be described as an example. Note that in other embodiments, the work vehicle 10 may be a rice transplanter, a combine harvester, a construction machine, a snowplow, or the like. The work vehicle 10 is configured to be able to automatically travel (autonomously) within the field F (see FIG. 3) following a preset target route R. Note that the work vehicle 10 can perform predetermined work while automatically traveling within the field F.

The work vehicle 10 automatically travels along a target route R generated in advance for the field F based on the position information of the current position of the work vehicle 10 calculated by the positioning unit 16. Note that the target route R includes a work route (straight route R1) (solid line portion in FIG. 3) where the work machine 14 performs work, and a non-work route (swivel route R2) (shown in FIG. 3) where the work machine 14 does not perform work. From the work start position S to the work end position G, it includes a plurality of straight routes R1 and a plurality of turning routes R2. The target route R shown in FIG. 3 indicates a route in which the work vehicle 10 automatically travels on each of a straight route R1 and a turning route R2.

For example, in a field F shown in FIG. 3, the work vehicle 10 reciprocates in parallel along a plurality of straight routes R1 from a work start position S to a work end position G, and performs work using the work implement 14 on each straight route R1. The target route R is not limited to the route shown in FIG. 3, but is appropriately set depending on the work content.

Note that the work vehicle 10 may be one in which an operator is on board and automatically travel along the target route R in accordance with the operator's operations, or may be one in which the work vehicle 10 automatically travels only on a straight route. For example, an operator can board the work vehicle 10 and drive the work vehicle 10 while switching between automatic travel (automatic steering) on a straight route R1 and manual travel (manual steering) on a turning route R2. It's okay. Further, for example, the operator may board the work vehicle 10 and while performing an operation (accelerator operation, brake operation, etc.) to change the vehicle speed (traveling speed), the operator may ride the target route R or a part of the target route R (for example, a straight route R1) may be able to travel automatically. Further, the work vehicle 10 may automatically travel along the target route R while controlling the vehicle speed according to vehicle speed information set for each work route. Furthermore, the work vehicle 10 may automatically travel along the target route R without an operator on board.

The operating terminal 20 displays various information regarding the work performed by the work vehicle 10 on a display unit, receives an operator's operation, and executes processing according to the operation. For example, the operator operates the operating terminal 20 to set information necessary for automatic driving, or outputs a work start instruction (or an automatic driving start instruction) to the work vehicle 10. Further, the operating terminal 20 displays information such as the working status and driving status of the working vehicle 10 during automatic driving. The operator can grasp the work status and traveling status on the operating terminal 20. The operating terminal 20 is, for example, a portable terminal (such as a tablet terminal) that can be carried by an operator, and is a device that can be attached to and detached from the work vehicle 10. Further, the operating terminal 20 may be a device fixed to the work vehicle 10.

[Work vehicle 10]
As shown in FIGS. 1 and 2, the work vehicle 10 includes a vehicle control device 11, a storage section 12, a traveling device 13, a working machine 14, a communication section 15, a positioning unit 16, and the like. The vehicle control device 11 is electrically connected to a storage section 12, a traveling device 13, a working machine 14, a positioning unit 16, and the like. Note that the vehicle control device 11 and the positioning unit 16 may be able to communicate wirelessly.

The communication unit 15 connects the work vehicle 10 to the communication network N1 by wire or wirelessly, and executes data communication according to a predetermined communication protocol with an external device such as the operating terminal 20 via the communication network N1. communication interface.

The storage unit 12 is a nonvolatile storage unit such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) that stores various information. The storage unit 12 stores control programs such as an automatic driving program for causing the vehicle control device 11 to execute automatic driving processing (see FIG. 9), which will be described later. For example, the automatic driving program is recorded non-temporarily on a computer-readable recording medium such as a flash ROM, EEPROM, CD, or DVD, and is read by a predetermined reading device (not shown) and stored in the storage unit 12. is memorized. Note that the automatic driving program may be downloaded from a server (not shown) to the work vehicle 10 via the communication network N1 and stored in the storage unit 12. Further, the storage unit 12 may store route data of the target route R generated by the operation terminal 20.

The traveling device 13 is a drive unit that causes the work vehicle 10 to travel. As shown in FIG. 2, the traveling device 13 includes an engine 131, front wheels 132, rear wheels 133, a transmission 134, a front axle 135, a rear axle 136, a handle 137, and the like. Note that the front wheels 132 and the rear wheels 133 are provided on the left and right sides of the work vehicle 10, respectively. Further, the traveling device 13 is not limited to a wheel type including front wheels 132 and rear wheels 133, but may be a crawler type including crawlers provided on the left and right sides of the work vehicle 10.

The engine 131 is a driving source such as a diesel engine or a gasoline engine that is driven using fuel supplied to a fuel tank (not shown). The traveling device 13 may include an electric motor as a drive source together with or in place of the engine 131. Note that a generator (not shown) is connected to the engine 131, and power is supplied from the generator to electrical components such as the vehicle control device 11 provided in the work vehicle 10, a battery, and the like. Note that the battery is charged by power supplied from the generator. Electrical components such as the vehicle control device 11 and the positioning unit 16 provided in the work vehicle 10 can be driven by the electric power supplied from the battery even after the engine 131 is stopped.

The driving force of engine 131 is transmitted to front wheels 132 via transmission 134 and front axle 135, and then transmitted to rear wheels 133 via transmission 134 and rear axle 136. Further, the driving force of the engine 131 is also transmitted to the working machine 14 via a PTO shaft (not shown). When the work vehicle 10 performs automatic travel, the travel device 13 performs a travel operation according to commands from the vehicle control device 11.

The work machine 14 may be, for example, a tiller, a trencher, a mower, a plow, a fertilizer applicator, a seeding machine, a spreader, etc., and may be detachable from the work vehicle 10. Thereby, the work vehicle 10 can perform various works using each of the work machines 14. FIG. 2 shows a tiller as an example of the work implement 14. As shown in FIG.

The handle 137 is an operating section operated by the operator or the vehicle control device 11. For example, in the traveling device 13, the angle of the front wheels 132 is changed by an unillustrated hydraulic power steering mechanism or the like in response to the operation of the handle 137 by the vehicle control device 11, and the traveling direction of the work vehicle 10 is changed.

In addition to the handle 137, the traveling device 13 includes a shift lever, an accelerator, a brake, etc. (not shown) that are operated by the vehicle control device 11. In the traveling device 13, the gear of the transmission 134 is switched to a forward gear or a reverse gear in response to the operation of the shift lever by the vehicle control device 11, and the traveling mode of the work vehicle 10 is switched to forward or reverse. . The vehicle control device 11 also controls the rotation speed of the engine 131 by operating the accelerator. Further, the vehicle control device 11 operates the brake to brake rotation of the front wheels 132 and the rear wheels 133 using electromagnetic brakes.

The positioning unit 16 is a communication device that includes a positioning control section 161, a storage section 162, a communication section 163, a positioning antenna 164, an inertial measurement unit (IMU) 165, and the like. For example, as shown in FIG. 2, the positioning unit 16 is provided in the upper part of a cabin 138 in which an operator rides. Further, the installation location of the positioning unit 16 is not limited to the cabin 138. Further, the positioning control section 161, the storage section 162, the communication section 163, the positioning antenna 164, and the inertial measurement device 165 of the positioning unit 16 may be distributed and arranged at different positions in the work vehicle 10. Note that, as described above, the battery is connected to the positioning unit 16, and the positioning unit 16 can operate even when the engine 131 is stopped. Further, as the positioning unit 16, for example, a mobile phone terminal, a smartphone, a tablet terminal, or the like may be used instead.

The positioning control unit 161 is a computer system including one or more processors and storage memories such as nonvolatile memory and RAM. The storage unit 162 is a nonvolatile memory that stores a program for causing the positioning control unit 161 to execute positioning processing, and data such as positioning information and movement information. For example, the program is recorded non-temporarily on a computer-readable recording medium such as a flash ROM, EEPROM, CD, or DVD, and is read by a predetermined reading device (not shown) and stored in the storage unit 162. be done. Note that the program may be downloaded from a server (not shown) to the positioning unit 16 via the communication network N1 and stored in the storage section 162.

The communication unit 163 connects the positioning unit 16 to the communication network N1 by wire or wirelessly, and performs data communication according to a predetermined communication protocol with an external device such as a base station (not shown) via the communication network N1. It is a communication interface for execution. The positioning antenna 164 is an antenna that receives radio waves (GNSS signals) transmitted from a satellite.

The positioning control unit 161 calculates the current position of the work vehicle 10 based on the GNSS signal that the positioning antenna 164 receives from a satellite. For example, when the work vehicle 10 automatically travels in the field F, when the positioning antenna 164 receives radio waves (transmission time, orbit information, etc.) transmitted from each of a plurality of satellites, the positioning control unit 161 The distance between antenna 164 and each satellite is calculated, and the current position (latitude and longitude) of work vehicle 10 is calculated based on the calculated distance. Furthermore, the positioning control unit 161 uses a real-time kinematic method (RTK-GPS positioning method (RTK method) to calculate the current position of the work vehicle 10 using correction information corresponding to a base station (reference station) close to the work vehicle 10. )) positioning may be performed. In this way, the work vehicle 10 automatically travels using positioning information based on the RTK method. Note that the current position of the work vehicle 10 may be the same as the positioning position (for example, the position of the positioning antenna 164), or may be a position shifted from the positioning position.

The inertial measurement device 165 includes a 3-axis gyro sensor, a 3-axis acceleration sensor, and the like, and measures the posture of the work vehicle 10 while it is running. For example, the inertial measurement device 165 measures the azimuth of the body of the work vehicle 10. In addition, the inertial measurement device 165 measures the azimuth of the working vehicle 10 during automatic travel and transmits the measurement result (measured azimuth D0) to the vehicle control device 11 (see FIG. 5). The inertial measurement device 165 is an example of the measurement unit of the present invention.

The vehicle control device 11 includes control devices such as a CPU, ROM, and RAM. The CPU is a processor that executes various types of arithmetic processing. The ROM is a non-volatile storage unit that stores in advance control programs such as a BIOS and an OS for causing the CPU to execute various arithmetic processes. The RAM is a volatile or nonvolatile storage unit that stores various information, and is used as a temporary storage memory (work area) for various processes executed by the CPU. The vehicle control device 11 controls the work vehicle 10 by causing the CPU to execute various control programs stored in advance in the ROM or the storage unit 12.

Specifically, as shown in FIG. 1, the vehicle control device 11 includes a travel processing section 111, an acquisition processing section 112, a section determination processing section 113, a reset determination processing section 114, an adjustment processing section 115, an estimation processing section 116, It includes various processing units such as an output processing unit 117. The vehicle control device 11 functions as the various processing units by causing the CPU to execute various processes according to the automatic driving program. Further, a part or all of the processing section may be constituted by an electronic circuit. Note that the automatic driving program may be a program for causing a plurality of processors to function as the processing units.

The travel processing unit 111 controls the travel of the work vehicle 10 . Specifically, the travel processing unit 111 causes the work vehicle 10 to automatically travel along the target route R based on position information indicating the current position of the work vehicle 10 measured by the positioning control unit 161. For example, when the positioning state becomes a state where RTK positioning is possible and the operator presses a start button on the operation screen (not shown) of the operation terminal 20, the operation terminal 20 outputs a work start instruction to the work vehicle 10. When the travel processing unit 111 acquires the work start instruction from the operating terminal 20 , the travel processing unit 111 starts automatic travel of the work vehicle 10 based on position information indicating the current position of the work vehicle 10 measured by the positioning control unit 161 .

Further, the travel processing unit 111 controls the steering angle (handle turning angle) of the work vehicle 10 (steering control) to control the travel direction of the work vehicle 10 . FIG. 4 shows an example of a running state of the work vehicle 10. In the state shown in FIG. 4, the current position P0 of the work vehicle 10 is separated from the target route R by a distance L1. The symbol α1 indicates the current azimuth angle (current azimuth angle) with respect to the target route R, and the symbol θ1 indicates the current steering angle. Here, when the target point P1 (forward target point) is set in front of the work vehicle 10 and on the target route R, and if the target azimuth angle of the work vehicle 10 is α2, the target steering angle θ of the work vehicle 10 is: α1+θ1+α2”. The travel processing unit 111 calculates the current position P0 (position information) measured by the positioning control unit 161, the target azimuth α2 obtained from the current position P0 and the target point P1, the current azimuth α1, and the current steering angle θ1. The target steering angle θ is calculated based on. The travel processing unit 111 then controls the steering angle of the work vehicle 10 based on the target steering angle θ to control the travel direction of the work vehicle 10.

As described above, the travel processing unit 111 causes the work vehicle 10 to automatically travel along the target route R based on the position information and the target steering angle θ. Thereby, the work vehicle 10 performs work using the work machine 14 while automatically traveling along the target route R. Note that the target route R is generated, for example, by the operating terminal 20. The work vehicle 10 acquires the route data of the target route R from the operating terminal 20, and automatically travels within the field F according to the target route R (see FIG. 3).

Further, when the travel processing unit 111 receives a work stop instruction from the operation terminal 20, it stops the automatic travel of the work vehicle 10. For example, when the operator presses a stop button on the operation screen (not shown) of the operation terminal 20, the operation terminal 20 outputs a work stop instruction to the work vehicle 10. When the travel processing unit 111 acquires the work stop instruction from the operating terminal 20, it stops the automatic travel of the work vehicle 10. As a result, the work vehicle 10 stops automatically traveling, and the work by the work machine 14 is stopped. The travel processing section 111 is an example of the travel processing section of the present invention.

As described above, in order to cause the work vehicle 10 to automatically travel along the target route R, it is necessary to measure the current azimuth of the work vehicle 10 with high precision and control the steering angle. However, in the conventional technology, when the work vehicle 10 travels at low speed, a problem arises in which the accuracy of the azimuth of the work vehicle 10 decreases (the azimuth drifts). As a result, the traveling accuracy of the work vehicle 10 deteriorates. On the other hand, the automatic driving system according to the present embodiment can improve the accuracy of the azimuth of the work vehicle, as described below. A specific example of the vehicle control device 11 will be described below with reference to FIG.

The acquisition processing unit 112 acquires the azimuth (hereinafter referred to as measurement azimuth D0) measured by the inertial measurement device 165 that measures the azimuth of the work vehicle 10. The inertial measurement device 165 measures the measurement azimuth D0 at a predetermined period when the automatic traveling of the work vehicle 10 starts, and transmits the measured azimuth D0 to the vehicle control device 11. The acquisition processing unit 112 acquires the measured azimuth D0 from the inertial measurement device 165 at a predetermined period. As shown in FIG. 5, the acquisition processing unit 112 outputs information on the measurement azimuth D0 acquired from the inertial measurement device 165 to the estimation processing unit 116 and the output processing unit 117. The acquisition processing unit 112 is an example of an acquisition processing unit of the present invention.

The section determination processing unit 113 determines whether the travel route (traveling section) of the work vehicle 10 is an estimation target section for estimating the azimuth. Specifically, the section determination processing unit 113 determines whether the travel route is the estimation target section based on the route information d0.

Here, for example, the vehicle speed Vf of the work vehicle 10 is set to a low speed (for example, 1 km/h) on the straight route R1 where high work accuracy is required, and is set to a high speed (for example, 2 km/h) on the turning route R2 where no work is performed. is set to . In this case, as shown in FIG. 6, the section determination processing unit 113 determines that it is the estimation target section when the traveling route is the straight route R1, and determines that the estimation target section is the one when the traveling route is the turning route R2. It is determined that there is no. As shown in FIG. 5, the section determination processing unit 113 determines that the traveling route of the work vehicle 10 is a section subject to azimuth estimation, or that the traveling route of the working vehicle 10 is not a section subject to azimuth estimation. The determination result d1 shown is output to the reset determination processing section 114 and the output processing section 117.

The reset determination processing unit 114 determines whether or not to reset the estimated value in the estimation processing unit 116 that estimates the azimuth (current azimuth) of the work vehicle 10. Specifically, the reset determination processing unit 114 determines whether to reset the cumulative error of the estimated value (posture state) of the Kalman filter KF that estimates the azimuth D1 of the work vehicle 10. For example, as shown in FIG. 5, the reset determination processing unit 114 resets the estimated value based on the determination result d1 of the section determination processing unit 113, the reset determination information d2, and the vehicle speed Vf of the work vehicle 10. Determine whether or not. The reset determination information d2 is information that defines the timing for resetting the estimated value, and is information that indicates the starting point Rp of the straight route R1 (the estimation target section), as shown in FIG. 6, for example. Note that the reset determination information d2 may be information (position information, information indicating an automatic driving state, route information, etc.) determined according to the method of setting the starting point Rp.

For example, the reset determination processing unit 114 determines to reset the estimated value when the work vehicle 10 is located at the starting point Rp of the straight route R1 and the vehicle speed Vf is less than or equal to a predetermined vehicle speed (for example, 2 km/h). As shown in FIG. 5, the reset determination processing unit 114 transmits the determination result Rf indicating that the estimated value in the estimation processing unit 116 is to be reset or that the estimated value in the estimation processing unit 116 is not to be reset. Output to.

The adjustment processing unit 115 sets information (parameter Pf) for adjusting the weight corresponding to the measured azimuth angle D0 based on the vehicle speed Vf of the work vehicle 10, and outputs it to the estimation processing unit 116. Specifically, the adjustment processing unit 115 adjusts the parameter Pf used in the azimuth estimation process in the estimation processing unit 116 according to the vehicle speed Vf of the work vehicle 10. The adjustment processing unit 115 outputs the adjusted parameter Pf to the estimation processing unit 116. The parameter Pf is, for example, the variance in the observation of the azimuth angle in the Kalman filter KF of the estimation processing unit 116, and corresponds to the Kalman gain parameter. A specific example of the parameter Pf will be described later.

The estimation processing unit 116 estimates an azimuth D1 (current azimuth α1 in FIG. 4) corresponding to the current attitude of the work vehicle 10. Specifically, the estimation processing section 116 is configured with a Kalman filter KF, and the Kalman filter KF uses the determination result Rf of the reset determination processing section 114, the parameter Pf set in the adjustment processing section 115, the position information f1, The azimuth D1 of the work vehicle 10 is estimated based on the angular velocity information f2 and the measured azimuth D0 acquired from the acquisition processing unit 112. The position information f1 is information (positioning information) indicating the position of the work vehicle 10 measured by the positioning control unit 161. The angular velocity information f2 is information on the angular velocity of the work vehicle 10 measured by the inertial measurement device 165. Note that the angular velocity information f2 may include acceleration information of the work vehicle 10. The Kalman filter KF calculates an estimated state value (azimuth angle) indicating the posture state of the work vehicle 10 including the roll angle, pitch angle, and yaw angle, based on the position information f1 and the angular velocity information f2.

Furthermore, the Kalman filter KF calculates the estimated state value (azimuth) based on the state estimated by the estimation model and the state estimated from the observed value (measured azimuth D0). Furthermore, the Kalman filter KF estimates the azimuth by adjusting the weight of the state estimated by the estimation model and the weight of the state estimated by the observed value (measured azimuth D0) using a parameter Pf corresponding to the vehicle speed Vf. do. For example, the Kalman filter KF uses the estimated value x(k ) can be determined using the formula "x(k)=K*x1(k)+(1-K)*x2(k)". The coefficient K (where 0<K<1) in the above equation corresponds to the parameter Pf. As shown in the above equation, the smaller the parameter Pf (coefficient K), the greater the weight of the state (x2(k)) estimated by the observed value (measured azimuth D0), and the more dominant the measured azimuth D0 becomes. Furthermore, the larger the parameter Pf is, the greater the weight of the state (x1(k)) estimated by the estimation model becomes, and the measured azimuth D0 becomes non-dominant.

Furthermore, the Kalman filter KF calculates the azimuth D1 based on a parameter (weight) set according to the vehicle speed Vf of the work vehicle 10. For example, as shown in FIG. 7, the adjustment processing unit 115 sets the parameter Pf to "Pf1" (the first parameter of the present invention) when the vehicle speed Vf is 2 km/h (the first vehicle speed of the present invention) or more. That is, the adjustment processing unit 115 determines that when the vehicle speed Vf is 2 km/h or more, the weight of the state (x2(k)) estimated by the measured azimuth angle D0 increases, and the state (x1(k)) estimated by the estimation model increases. A parameter Pf1 that gives a smaller weight to k)) (a parameter Pf1 that makes the measured azimuth D0 dominant in the azimuth estimation result) is set.

Further, the adjustment processing unit 115 sets the parameter Pf to "Pf2" (second parameter of the present invention) (however, Pf1<Pf2) when the vehicle speed Vf is 1 km/h (second vehicle speed of the present invention) or less. . That is, the adjustment processing unit 115 determines that when the vehicle speed Vf is 1 km/h or less, the weight of the state (x1(k)) estimated by the estimation model becomes large, and the state (x2(k)) estimated by the measured azimuth angle D0 increases. Set a parameter Pf2 in which the weight of k)) becomes smaller (parameter Pf2 in which the measured azimuth angle D0 becomes non-dominant in the azimuth estimation result).

Further, the adjustment processing unit 115 sets a parameter Pf that linearly changes (gradually decreases) according to the vehicle speed Vf while the vehicle speed Vf is from 1 km/h to 2 km/h.

When the Kalman filter KF obtains the parameter Pf1 when the vehicle speed Vf is 2 km/h or more, the weight of the state estimated by the measured azimuth D0 increases, that is, calculates the azimuth D1 where the measured azimuth D0 becomes dominant. do.

Furthermore, when the parameter Pf2 is acquired when the vehicle speed Vf is 1 km/h or less, the Kalman filter KF selects the azimuth D1 at which the weight of the state estimated by the estimation model increases, that is, the measured azimuth D0 becomes non-dominant. calculate.

In addition, when the Kalman filter KF obtains the parameter Pf interpolated according to the vehicle speed Vf when the vehicle speed Vf is from 1 km/h to 2 km/h, the Kalman filter KF calculates the weight of the state estimated by the estimation model according to the parameter Pf. , calculates the azimuth D1 in which the weight of the state estimated by the measured azimuth D0 according to the parameter Pf is adjusted.

In this way, the estimation processing unit 116 adjusts the weight corresponding to the measured azimuth D0 based on the vehicle speed Vf of the work vehicle 10, and combines the weight-adjusted measurement azimuth D0 with the position information of the work vehicle 10. , and the angular velocity information of the work vehicle 10, the azimuth angle D1 corresponding to the current posture of the work vehicle 10 is estimated. For example, the estimation processing unit 116 uses a Kalman filter KF to which the measured azimuth D0, a parameter Pf that adjusts the weight of the state estimated from the measured azimuth D0, and the position information f1 and angular velocity information f2 of the work vehicle 10 are input. The azimuth angle D1 is estimated using . Furthermore, the Kalman filter KF estimates the azimuth D1 such that the slower the vehicle speed Vf of the work vehicle 10, the smaller the weight of the state estimated from the measured azimuth D0, and the faster the vehicle speed Vf of the work vehicle 10, the smaller the weight of the state estimated from the measured azimuth D0. The azimuth D1 is estimated so that the weight of the state estimated from the azimuth D0 becomes large.

In addition, when an operator boards the work vehicle 10, the operator may be able to change the vehicle speed Vf of the work vehicle 10 that travels automatically. For example, the operator may be able to operate a gear shift lever (not shown) of the work vehicle 10 to change the vehicle speed Vf of the work vehicle 10 during automatic travel. In this case, the estimation processing unit 116 estimates the azimuth D1 based on the parameter Pf according to the vehicle speed changing operation by the operator.

The estimation processing section 116 outputs information on the azimuth D1, which is the estimation result, to the output processing section 117.

Note that the Kalman filter KF executes the estimation process after resetting the cumulative error of the estimated value. For example, when the work vehicle 10 reaches the starting point Rp of the straight route R1 and the vehicle speed Vf of the work vehicle 10 is less than or equal to a predetermined vehicle speed (2 km/h in the above example), the estimation processing unit 116 resets the reset determination processing unit 114. When the determination result Rf (see FIG. 5) indicating that the estimated value is to be reset is obtained, the Kalman filter KF resets the estimated value and then executes the estimation process. Thereby, the Kalman filter KF can reset the cumulative error of the estimated value, and therefore can obtain an appropriate estimated value. The estimation processing section 116 is an example of an estimation processing section of the present invention.

The output processing unit 117 outputs an output azimuth D2 (current azimuth α1 shown in FIG. 4) that is used for travel processing (for example, steering control) of the travel processing unit 111. Specifically, the output processing unit 117 selects either the measured azimuth D0 or the estimated azimuth D1 as the output azimuth D2 based on route information regarding the route traveled by the work vehicle 10. That is, the output processing unit 117 switches the output azimuth D2 to the measurement azimuth D0 or the azimuth D1 based on the route information.

For example, as shown in FIG. 5, the output processing unit 117 acquires the determination result d1 from the section determination processing unit 113, acquires the azimuth D1 from the estimation processing unit 116, and acquires the measured azimuth D0 from the acquisition processing unit 112. Then, based on the determination result d1, the measured azimuth D0 or the azimuth D1 is output to the travel processing unit 111 as the output azimuth D2.

For example, when the travel route of the work vehicle 10 is a straight route R1 (see FIG. 6) corresponding to low-speed travel, the output processing unit 117 performs travel processing using the azimuth D1 acquired from the estimation processing unit 116 as the output azimuth D2. It outputs to section 111. On the other hand, when the travel route of the work vehicle 10 is the turning route R2 (see FIG. 6) corresponding to high-speed travel, the output processing unit 117 uses the measured azimuth D0 measured by the inertial measurement device 165 as the output azimuth D2. It is output to the travel processing section 111.

As another embodiment, as shown in FIG. 8, the output processing unit 117 selects either the measured azimuth D0 or the estimated azimuth D1 based on the route information and the vehicle speed Vf of the work vehicle 10. It may be selected as the output azimuth D2. For example, when the traveling route of the work vehicle 10 is the straight route R1 and the vehicle speed Vf of the work vehicle 10 is less than a predetermined vehicle speed (for example, 2 km/h), the output processing unit 117 acquires information from the estimation processing unit 116. The calculated azimuth D1 is output to the travel processing unit 111 as an output azimuth D2, and the travel route of the work vehicle 10 is the straight route R1, and the vehicle speed Vf of the work vehicle 10 is a predetermined vehicle speed (for example, 2 km/h or 2 km). /h), the measured azimuth D0 measured by the inertial measurement device 165 is output to the travel processing unit 111 as the output azimuth D2.

The traveling processing unit 111 sets the output azimuth D2 output by the output processing unit 117 to the above-mentioned current azimuth α1 (see FIG. 4) (α1=D2), and sets the target steering angle θ of the work vehicle 10 (θ=α1+θ1+α2). is calculated, and the steering angle of the work vehicle 10 is controlled based on the target steering angle θ. In this way, the travel processing unit 111 causes the work vehicle 10 to travel automatically based on the azimuth D1 estimated by the estimation processing unit 116. Thereby, the work vehicle 10 can automatically travel along the target route R with high precision even when traveling at low speed.

[Operation terminal 20]
As shown in FIG. 1, the operation terminal 20 is an information processing device that includes an operation control section 21, a storage section 22, an operation display section 23, a communication section 24, and the like. The operation terminal 20 may be configured with a mobile terminal such as a tablet terminal or a smartphone.

The communication unit 24 connects the operation terminal 20 to the communication network N1 by wire or wirelessly, and performs data communication with external devices such as one or more work vehicles 10 via the communication network N1 according to a predetermined communication protocol. It is a communication interface for executing.

The operation display unit 23 is a user interface that includes a display unit such as a liquid crystal display or an organic EL display that displays various information, and an operation unit such as a touch panel, mouse, or keyboard that receives operations. The operator can register various information (work vehicle information, field information, work information, etc. to be described later) by operating the operation section on the operation screen displayed on the display section. Further, the operator can instruct the work vehicle 10 to start work by operating the operation section. In addition, when the work vehicle 10 runs unmanned, the operator, at a location away from the work vehicle 10, can make the work vehicle 10 automatically travel along the target route R within the field F based on the travel trajectory displayed on the operation terminal 20. It may be possible to grasp the state.

The storage unit 22 is a nonvolatile storage unit such as an HDD or an SSD that stores various information. The storage unit 22 stores a control program for causing the operation control unit 21 to execute predetermined control processing. For example, the control program is recorded non-temporarily on a computer-readable recording medium such as a flash ROM, EEPROM, CD, or DVD, and is read by a predetermined reading device (not shown) included in the operating terminal 20. and is stored in the storage unit 22. Note that the control program may be downloaded from a server (not shown) to the operation terminal 20 via the communication network N1 and stored in the storage unit 22. Furthermore, the storage unit 22 may store work information transmitted from the work vehicle 10.

Furthermore, a dedicated application for automatically driving the work vehicle 10 is installed in the storage unit 22 . The operation control unit 21 activates the dedicated application and performs processing for setting various information regarding the work vehicle 10, processing for generating a target route R for the work vehicle 10, instructing the work vehicle 10 to start work, and the like.

The operation control unit 21 includes control devices such as a CPU, ROM, and RAM. The CPU is a processor that executes various types of arithmetic processing. The ROM is a non-volatile storage unit that stores in advance control programs such as a BIOS and an OS for causing the CPU to execute various arithmetic processes. The RAM is a volatile or nonvolatile storage unit that stores various information, and is used as a temporary storage memory (work area) for various processes executed by the CPU. The operation control unit 21 controls the operation terminal 20 by executing various control programs stored in advance in the ROM or storage unit 22 on the CPU.

Specifically, the operation control unit 21 sets information regarding the work vehicle 10 (hereinafter referred to as work vehicle information). The operation control unit 21 determines the model of the work vehicle 10 , the position where the positioning antenna 164 is attached on the work vehicle 10 , the type of work implement 14 , the size and shape of the work implement 14 , and the position of the work implement 14 with respect to the work vehicle 10 The information is set by the operator performing a registration operation on the operation terminal 20.

The operation control unit 21 also sets information regarding the field F (hereinafter referred to as field information). The operation control unit 21 registers information such as the position and shape of the field F, the work start position S to start the work, the work end position G to end the work, and the work direction by performing an operation to register it on the operation terminal 20. Set information. Note that the working direction means the direction in which the working vehicle 10 travels while working with the working machine 14 in an area excluding the headland, non-working area, etc. from the field F.

The information on the position and shape of the field F can be obtained by, for example, an operator boarding the work vehicle 10 and driving it around the outer circumference of the field F, and recording the transition of the position information of the positioning antenna 164 at that time. You can get it automatically by doing this. In addition, the position and shape of the field F are determined based on a polygon obtained by the operator specifying multiple points on the map by operating the operating terminal 20 with the map displayed on the operating terminal 20. You can also obtain it. The area specified by the acquired position and shape of the field F is an area (driving area) in which the work vehicle 10 can travel.

The operation control unit 21 also sets information regarding how to specifically perform the work (hereinafter referred to as work information). The operation control unit 21 includes, as work information, whether or not there is cooperative work between the work vehicle 10 (unmanned tractor) and the manned work vehicle 10, and the number of skips, which is the number of work routes skipped when the work vehicle 10 turns in a headland. , the width of headland, the width of non-cultivated land, etc. can be set.

Further, the operation control unit 21 generates a target route R, which is a route along which the work vehicle 10 automatically travels, based on the setting information. The target route R of this embodiment includes a work route (straight route R1) where the work machine 14 performs work and a non-work route (swivel route R2) where the work machine 14 does not work (see FIG. 3). The operation control unit 21 can generate and store a target route R for the work vehicle 10 based on each of the setting information.

Specifically, the operation control unit 21 generates the target route R (see FIG. 3) based on the work start position S and the work end position G registered in the field setting. The target route R is not limited to the route shown in FIG.

Further, the operation control unit 21 sets information on the vehicle speed Vf of the work vehicle 10 in association with the target route R. For example, the operator can set the vehicle speed Vf during work (the traveling speed on the straight route R1), the vehicle speed when turning (the traveling speed on the turning route R2), and the like. The operation control unit 21 registers the set vehicle speed information in association with the target route R. The operation control unit 21 outputs route data of the generated target route R to the work vehicle 10. Further, the operation control unit 21 outputs a work start instruction and a work end instruction to the work vehicle 10 based on the operator's operation.

Further, the operation control unit 21 receives an instruction operation to start work (work start instruction operation), an instruction operation to stop the work of the automatically traveling work vehicle 10 (work stop instruction operation), etc. from the operator. Upon receiving the work start instruction operation, the operation control unit 21 outputs the work start instruction to the work vehicle 10. Thereby, the vehicle control device 11 of the work vehicle 10 acquires the work start instruction from the operation terminal 20. Upon acquiring the work start instruction, the vehicle control device 11 causes the work vehicle 10 to start working and traveling. Further, upon receiving the work stop instruction operation, the operation control unit 21 outputs the work stop instruction to the work vehicle 10. Thereby, the vehicle control device 11 of the work vehicle 10 acquires the work stop instruction from the operation terminal 20. Upon acquiring the work stop instruction, the vehicle control device 11 stops the work and traveling of the work vehicle 10.

When the work vehicle 10 receives the route data of the target route R transferred from the operating terminal 20, the work vehicle 10 stores it in the storage unit 12. The work vehicle 10 is configured to be able to run automatically when the current position is located within the field F, and is configured so that it cannot run automatically when the current position is located outside the field F. There is. Further, the work vehicle 10 is configured to be able to travel automatically when the current position matches the work start position S, for example.

When the current position of the work vehicle 10 matches the work start position S, when the operator presses the start button on the operation screen to instruct the work vehicle 10 to start work, the vehicle control device 11 causes the work implement 14 to perform the work. Start. That is, the operation control unit 21 allows the work vehicle 10 to travel automatically on the condition that the current position matches the work start position S. Note that the conditions for permitting automatic travel of the work vehicle 10 are not limited to the above conditions.

Based on the information on the target route R, the vehicle control device 11 causes the work vehicle 10 to automatically travel from the work start position S to the work end position G, and raises and lowers the work machine 14 to execute the work. Further, the vehicle control device 11 causes the work vehicle 10 to travel automatically while changing the vehicle speed Vf of the work vehicle 10 based on the vehicle speed Vf associated with the target route R. For example, the vehicle control device 11 sets the vehicle speed Vf to "1 km/h" when the work vehicle 10 travels on the straight route R1, and sets the vehicle speed Vf to "2 km/h" when the work vehicle 10 travels on the turning route R2. h" to cause the work vehicle 10 to travel automatically.

Further, the vehicle control device 11 may cause the work vehicle 10 to automatically travel from the work end position G to the entrance of the field F when the work vehicle 10 finishes the work. When the work vehicle 10 is automatically traveling, the operation control unit 21 can receive the status (position, vehicle speed, etc.) of the work vehicle 10 from the work vehicle 10 and display it on the operation display unit 23.

Note that the operating terminal 20 may be able to access a website (agricultural support site) of an agricultural support service provided by a server (not shown) via the communication network N1. In this case, the operation terminal 20 can function as an operation terminal for the server by executing a browser program by the operation control unit 21. The server includes each of the above-mentioned processing units and executes each process.

[Automatic driving processing]
Hereinafter, an example of the automatic driving process executed by the automatic driving system 1 will be described with reference to FIG. 9.

Note that the present invention can be regarded as an invention of an automatic driving method that executes one or more steps included in the automatic driving process. Furthermore, one or more steps included in the automatic driving process described here may be omitted as appropriate. Note that the steps in the automatic driving process may be executed in a different order as long as similar effects are produced. Furthermore, here, a case will be described in which the vehicle control device 11 executes each step in the automatic driving process, but an automatic driving system in which one or more processors execute each step in the automatic driving process in a distributed manner Other embodiments of the method are also contemplated.

Here, it is assumed that the operation control unit 21 has set a target route R (see FIG. 3) for the field F including a straight route R1 and a turning route R2.

In step S1, the vehicle control device 11 of the work vehicle 10 starts automatic travel. Specifically, when the operation control unit 21 receives a work start instruction operation from the operator, the vehicle control device 11 starts automatic traveling according to the target route R. For example, the vehicle control device 11 starts automatic travel when the current position of the work vehicle 10 matches the work start position S (the starting position of the straight route R1).

Next, in step S2, the vehicle control device 11 obtains the measured azimuth D0 from the inertial measurement device 165. The vehicle control device 11 acquires the measured azimuth D0 at a predetermined period.

Next, in step S3, the vehicle control device 11 determines whether the travel route (traveling section) of the work vehicle 10 is an azimuth estimation target section. For example, the section determination processing unit 113 determines whether the travel route is the straight route R1 based on the route information d0. The vehicle control device 11 determines that the traveling route is the estimation target section when the traveling route is the straight route R1, and determines that the traveling route is not the estimation target section when the traveling route is the turning route R2. When the vehicle control device 11 determines that the travel route is the estimation target section (S3: Yes), the vehicle control device 11 moves the process to step S4. On the other hand, when the vehicle control device 11 determines that the travel route is not the estimation target section (S3: No), the process proceeds to step S31.

In step S4, the operation control unit 21 resets the cumulative error of the estimated value in the Kalman filter KF (see FIG. 5).

Next, in step S5, the operation control unit 21 adjusts the parameter Pf used for calculating the estimated value in the Kalman filter KF, based on the vehicle speed Vf of the work vehicle 10. Specifically, the operation control unit 21 sets a parameter Pf that decreases as the vehicle speed Vf of the work vehicle 10 becomes faster and increases as the vehicle speed Vf of the work vehicle 10 becomes slower. For example, as shown in FIG. 7, the vehicle control device 11 sets parameter Pf1 when vehicle speed Vf is 2 km/h or more, sets parameter Pf2 when vehicle speed Vf is 1 km/h or less, and sets parameter Pf2 when vehicle speed Vf is 1 km/h or less. From 1 km/h to 2 km/h, a parameter Pf that linearly changes (gradually decreases) according to the vehicle speed Vf is set.

In addition, when the vehicle speed Vf is 2 km/h or more, the operation control unit 21 assumes that the state estimated by the measured azimuth D0 (the above-mentioned estimated value "x2(k)") has a large weight, and is estimated by the estimation model. A parameter Pf1 (parameter Pf1 in which the measured azimuth angle D0 becomes dominant in the estimated value in the Kalman filter KF) is set so that the weight of the state (the above-mentioned estimated value "x1(k)") becomes small. In addition, the operation control unit 21 uses a parameter Pf2 (Kalman filter A parameter Pf2) is set so that the measured azimuth angle D0 becomes non-dominant in the estimated value in KF.

Next, in step S6, the operation control unit 21 estimates the azimuth D1 (current azimuth α1 in FIG. 4) corresponding to the current attitude of the work vehicle 10. For example, the operation control unit 21 estimates the azimuth D1 based on the parameter Pf set according to the vehicle speed Vf of the work vehicle 10 in the Kalman filter KF. For example, the Kalman filter KF estimates the azimuth D1 using the parameter Pf1 when the vehicle speed Vf is 2 km/h or more. Furthermore, the Kalman filter KF estimates the azimuth D1 using the parameter Pf2 when the vehicle speed Vf is 1 km/h or less. Furthermore, when the vehicle speed Vf is between 1 km/h and 2 km/h, the Kalman filter KF estimates the azimuth D1 using the parameter Pf interpolated from the linear characteristic (see FIG. 7).

In this way, the operation control unit 21 estimates the azimuth D1 so that the faster the vehicle speed Vf of the work vehicle 10, the greater the weight of the state estimated from the measured azimuth D0 (the estimated element becomes weaker), and The azimuth D1 is estimated such that the slower the vehicle speed Vf of the vehicle 10, the smaller the weight of the state estimated from the measured azimuth D0 (the stronger the estimation element).

Next, in step S7, the operation control unit 21 outputs the estimated azimuth D1 as an output azimuth D2 (see FIG. 5). On the other hand, in step S31, the operation control unit 21 outputs the measured azimuth D0 measured by the inertial measurement device 165 as the output azimuth D2 (see FIG. 5).

In this way, when the travel route of the work vehicle 10 is the straight route R1 (see FIG. 6) corresponding to low-speed travel (S3: Yes), the operation control unit 21 sets the estimated azimuth D1 as the output azimuth D2. Output (S7). On the other hand, when the travel route of the work vehicle 10 is the turning route R2 (see FIG. 6) corresponding to high-speed travel (S3: No), the operation control unit 21 calculates the measured azimuth D0 measured by the inertial measurement device 165. It is output as the output azimuth D2 (S31).

Next, in step S8, the operation control unit 21 calculates the target steering angle θ of the work vehicle 10 based on the output azimuth D2. For example, the operation control unit 21 determines the target steering angle θ (θ=α1+θ1+α2) of the work vehicle 10 based on the current azimuth angle α1 (output azimuth angle D2), the current steering angle θ1, and the target azimuth angle α2. Calculate (see Figure 4).

Next, in step S9, the operation control unit 21 controls the steering angle of the work vehicle 10 based on the target steering angle θ, and controls automatic travel of the work vehicle 10.

Next, in step S10, the vehicle control device 11 determines whether the work vehicle 10 has finished its work. For example, when the work vehicle 10 reaches the work end position G (S10: Yes), the vehicle control device 11 ends the process. On the other hand, if the work vehicle 10 has not reached the work end position G (S10: No), the process moves to step S2 and the above-described process is repeated. As described above, the automatic driving system 1 executes the automatic driving process.

As described above, the automatic driving system 1 according to the first embodiment acquires the measured azimuth D0 measured by the measurement unit (inertial measurement device 165) that measures the azimuth of the work vehicle 10, and obtains the measured azimuth D0 of the work vehicle 10. Based on the vehicle speed Vf, the weight corresponding to the measured azimuth D0 is adjusted, and the measured azimuth D0 whose weight is adjusted according to the vehicle speed Vf, the position information of the work vehicle 10, and the angular velocity information of the work vehicle 10 are combined. Based on this, the azimuth D1 corresponding to the current posture of the work vehicle 10 is estimated, and the work vehicle 10 is caused to travel automatically based on the estimated azimuth D1.

According to the above configuration, it is possible to estimate the azimuth D1 (current azimuth) of the work vehicle 10 by adjusting the weight corresponding to the measured azimuth D0 according to the vehicle speed Vf of the work vehicle 10. For example, when the vehicle speed Vf of the work vehicle 10 is slow (during low-speed running), the weight of the state estimated by the measured azimuth D0 is reduced in the Kalman filter KF (the measured azimuth D0 is made non-dominant), and the azimuth Angle D1 can be estimated. In this way, when the work vehicle 10 travels at low speed, the measured azimuth D0 is not used as is, but the azimuth is adjusted so that the influence (weight) of the measured azimuth D0 on the estimated value of the Kalman filter KF is reduced. Estimate D1. Thereby, the work vehicle 10 can estimate the azimuth D1 with high accuracy even when traveling at low speeds where the measurement accuracy of the azimuth angle decreases. Therefore, the accuracy of the azimuth angle of the work vehicle 10 can be improved, so that highly accurate automatic travel is possible. Furthermore, in sections where azimuth angle estimation processing is unnecessary (for example, high-speed driving sections), the accuracy of automatic driving can be maintained by performing steering control using the conventionally measured azimuth angle D0.

[Embodiment 2]
FIG. 10 is a block diagram showing the configuration of an automatic driving system 1 according to Embodiment 2 of the present invention. Below, differences from the automatic driving system 1 according to the first embodiment will be explained. Note that, in FIG. 10, components having the same functions as those of the automatic driving system 1 according to the first embodiment (see FIG. 1) are denoted by the same reference numerals.

As shown in FIG. 10, in the work vehicle 10 according to the second embodiment, the adjustment processing section 115 (see FIG. 1) is omitted in the vehicle control device 11.

FIG. 11 shows a specific example of the vehicle control device 11 according to the second embodiment. In the vehicle control device 11 according to the second embodiment, the determination result Rf of the reset determination processing section 114, the position information f1, the angular velocity information f2, and the measured azimuth D0 are input to the Kalman filter KF of the estimation processing section 116. . The Kalman filter KF estimates the azimuth D1 of the work vehicle 10 based on the determination result Rf, the position information f1, the angular velocity information f2, and the measured azimuth D0. For example, when the travel route of the work vehicle 10 is a straight route R1 (see FIG. 6) corresponding to low-speed travel, the Kalman filter KF determines the direction of the work vehicle 10 based on the position information f1, the angular velocity information f2, and the measured azimuth D0. Estimate the azimuth D1.

The output processing unit 117 includes the determination result d1 of the section determination processing unit 113, the estimation result (azimuth D1) of the estimation processing unit 116, the measurement result (measured azimuth D0) of the inertial measurement device 165, and the work vehicle 10. The vehicle speed Vf is input. For example, when the vehicle speed Vf becomes less than 2 km/h, the output processing unit 117 outputs the azimuth D1 to the travel processing unit 111 as the output azimuth D2. Furthermore, when the vehicle speed Vf becomes 2 km/h or more, the output processing section 117 outputs the measured azimuth D0 to the traveling processing section 111 as the output azimuth D2.

In this manner, the vehicle control device 11 according to the second embodiment acquires the measured azimuth D0 measured by the inertial measurement device 165 that measures the azimuth of the work vehicle 10, and calculates the measured azimuth D0 and the azimuth of the work vehicle 10. Based on the position information and the angular velocity information of the work vehicle 10, the azimuth D1 corresponding to the current posture of the work vehicle 10 is estimated, and the measured azimuth D0 is estimated based on the vehicle speed Vf of the work vehicle 10. A configuration is provided in which one of the azimuth angles D1 is selected as the output azimuth angle D2, and the work vehicle 10 automatically travels based on the output azimuth angle D2.

As another embodiment, as shown in FIG. 12, the output processing unit 117 sets a predetermined vehicle speed range (for example, 1 km/h to 2 km/h) as a dead zone in order to suppress sudden fluctuations in the output azimuth D2. You may. In this case, the output processing unit 117 outputs the measured azimuth D0 as the output azimuth D2 until the vehicle speed Vf decreases to 1 km/h, and outputs the azimuth D1 when the vehicle speed Vf becomes 1 km/h or less. (estimated azimuth) is output as the output azimuth D2. Further, the output processing unit 117 outputs the azimuth D1 (estimated azimuth) as the output azimuth D2 until the vehicle speed Vf increases to 2 km/h, and when the vehicle speed Vf becomes 2 km/h or more, The measured azimuth D0 is output as the output azimuth D2.

That is, when the vehicle speed Vf of the work vehicle 10 is less than or equal to the first vehicle speed (for example, 1 km/h), the output processing unit 117 selects the estimated azimuth D1 as the output azimuth D2, and sets the vehicle speed Vf of the work vehicle 10 to the estimated azimuth D1. is a second vehicle speed (for example, 1 km/h or 2 km/h) that is higher than the first vehicle speed, the measured azimuth D0 is selected as the output azimuth D2.

In the automatic driving process according to the second embodiment, step S5 of the automatic driving process (see FIG. 9) according to the first embodiment is omitted. Further, in the automatic driving process according to the second embodiment, in step S3 of the automatic driving process according to the first embodiment, the vehicle control device 11 determines that the driving route (travel section) of the work vehicle 10 is an azimuth estimation target area. It is determined whether the vehicle speed Vf of the work vehicle 10 is less than a predetermined vehicle speed. When the vehicle control device 11 determines that the travel route is the estimation target section and the vehicle speed Vf is less than the predetermined vehicle speed (S3: Yes), the process proceeds to step S4. On the other hand, if the vehicle control device 11 determines that the travel route is not in the estimation target section, or if it determines that the vehicle speed Vf is equal to or higher than the predetermined vehicle speed (S3: No), the vehicle control device 11 shifts the process to step S31. let Other processes are the same as the automatic driving process according to the first embodiment.

As described above, the automatic driving system 1 according to the second embodiment acquires the measured azimuth D0 measured by the measurement unit (inertial measurement device 165) that measures the azimuth of the work vehicle 10, and determines the position of the work vehicle 10. Based on the information and the angular velocity information of the work vehicle 10, the azimuth D1 corresponding to the current posture of the work vehicle 10 is estimated, and the estimated azimuth is the measured azimuth D0 based on the vehicle speed Vf of the work vehicle 10. One of the angles D1 and D1 is selected as the output azimuth D2, and the work vehicle 10 automatically travels based on the output azimuth D2.

According to the above configuration, for example, when the vehicle speed Vf of the work vehicle 10 is slow, the work vehicle 10 can be automatically driven based on the azimuth D1 corresponding to the estimated value of the Kalman filter KF. Thereby, the work vehicle 10 can estimate the azimuth D1 with high accuracy even when traveling at low speed. Therefore, the accuracy of the azimuth angle of the work vehicle 10 can be improved, so that highly accurate automatic travel is possible.

[Other embodiments]
Other configuration examples applicable to each of the first and second embodiments described above will be described below.

[Method of determining estimation target section]
In the example shown in FIG. 6, the section determination processing unit 113 determines whether the travel route (traveling section) of the work vehicle 10 is an estimation target section for estimating the azimuth, based on the route information d0. ([Estimation target section determination method 1]). For example, the section determination processing unit 113 determines that the section is the estimation target section when the traveling route is the straight route R1, and determines that the section is not the estimation target section when the traveling route is the turning route R2.

As another example of the method for determining the estimation target section ([Method 2 for determining the estimation target section]), the section determination processing unit 113 determines whether the traveling route of the work vehicle 10 is the estimation target section based on the work information. It may be determined whether or not. FIG. 13A shows an example of the work information. In FIG. 13A, the work vehicle 10 performs a predetermined work (for example, ditch digging work) on the first partial route R1a of the straight route R1, and does not perform any work on the second partial route R1b of the straight route R1. That is, the first partial route R1a is a working route (working section), and the second partial route R1b and the turning route R2 are non-working routes (non-working section).

Here, for example, the vehicle speed Vf of the work vehicle 10 is set to a low speed on a work route where high work accuracy is required, and is set to a high speed on a turning route R2 where no work is performed. In this case, as shown in FIG. 13A, the section determination processing unit 113 determines that the travel route on which the work vehicle 10 performs work is the estimation target section, and determines the travel route on which the work vehicle 10 does not perform the work in the estimation target section. It is determined that it is not the target section. That is, the section determination processing unit 113 determines the work section as the estimation target section, and determines the non-work section as not the estimation target section.

For example, the section determination processing unit 113 determines that the traveling route is the estimation target section when the work implement 14 has descended, and determines that the travel route is not the estimation target section when the work implement 14 has gone up. judge. For example, the section determination processing unit 113 determines that the travel route is the estimation target section when the number of revolutions of the PTO shaft is equal to or higher than the predetermined number of revolutions, and when the number of revolutions of the PTO shaft is less than the predetermined number of revolutions. It is determined that the travel route is not the estimation target section. The lifting state of the working machine 14 and the rotation speed of the PTO shaft are examples of the work information.

As another example of the method for determining the estimation target section ([Method 3 for determining the estimation target section]), the section determination processing unit 113 determines that the travel route of the work vehicle 10 is based on the travel mode of the work vehicle 10. It may be determined whether or not it is a target section. The driving modes include, for example, a first driving mode in which the vehicle automatically travels only on the straight route R1, and a second driving mode in which the vehicle automatically travels on each of the straight route R1 and the turning route R2. In this case, the section determination processing unit 113 determines that the traveling route is the estimation target section when the traveling mode is the first traveling mode, and when the traveling mode is the second traveling mode, It is determined that the travel route is not the estimation target section. It is conceivable that the first travel mode is selected for work that requires precision, and the second travel mode is selected for work that does not require precision. In such a case, by employing determination method 3, it is possible to improve the work accuracy when traveling at low speed on the straight route R1.

As another example of the estimation target interval determination method ([estimation target interval determination method 4]), the interval determination processing unit 113 may combine the determination methods 1 to 3 described above. For example, when the traveling mode is the first traveling mode, the traveling route is the straight route R1, and the working machine 14 is lowered, the section determination processing unit 113 determines that the traveling route is the estimation target section. It is determined that there is. For example, when the traveling mode is the second traveling mode, the traveling route is the straight route R1, and the working machine 14 is lowered, the section determination processing unit 113 changes the traveling route to the estimation target section. It is determined that

Here, immediately after the low-speed work is finished, the measured azimuth D0 has a large drift, so if the estimation process is stopped immediately, the accuracy of the azimuth may deteriorate. For this reason, if automatic travel is to continue even after the low-speed work is finished, it is desirable to continue the azimuth estimation process until the accuracy of the measured azimuth D0 returns. Therefore, as shown in FIG. 13B, for example, when the traveling mode is the second traveling mode, the section determination processing unit 113 selects the first partial route R1a and the first partial route R1a immediately after the work is completed on the first partial route R1a. 2 partial route R1b is determined to be the estimation target section. For example, when the driving mode is the second driving mode, the section determination processing unit 113 selects the straight route R1 and the turning route R2 immediately after the work is completed on the straight route R1 as the estimation target section. It is determined that

The determination result d1 of the section determination processing unit 113 is input to the reset determination processing unit 114, and the reset determination processing unit 114 determines whether or not to reset the cumulative error of the estimated value based on the determination result d1 (see FIG. (See 5th grade). Furthermore, the estimation processing unit 116 executes estimation processing based on the determination result Rf of the reset determination processing unit 114 (see FIG. 5, etc.). That is, the estimation processing unit 116 collects route information regarding the route traveled by the work vehicle 10 (straight route R1, turning route R2), work information regarding the work of the work vehicle 10 (information regarding the work implement 14 and the PTO axis), and the work Based on at least one of the driving mode information regarding the driving mode of the vehicle 10, it is determined whether or not to perform the azimuth estimation process.

Further, the determination result d1 of the section determination processing unit 113 is input to the output processing unit 117, and the output processing unit 117 outputs either the measured azimuth D0 or the estimated azimuth D1 based on the determination result d1. It is output to the travel processing unit 111 as the azimuth D2 (see FIG. 5, etc.). The output processing unit 117 outputs the output azimuth D2 to the travel processing unit 111 based on the determination results d1 by the determination methods 1 to 4 described above (see FIG. 5, etc.). That is, the output processing unit 117 outputs route information regarding the route traveled by the work vehicle 10 (straight route R1, turning route R2), work information regarding the work of the work vehicle 10 (information regarding the work implement 14, PTO axis), and the work information. Based on at least one of the driving mode information regarding the driving mode of the vehicle 10, one of the measured azimuth D0 and the azimuth D1 is selected as the output azimuth D2 and output to the driving processing section 111.

[How to reset estimated value]
In the example shown in FIG. 6, the reset determination processing unit 114 determines whether the work vehicle 10 has reached the estimation target section, and when determining that the work vehicle 10 has reached the estimation target section, the Kalman filter KF Reset the cumulative error of the estimated value ([Estimated value reset method 1]). For example, the Kalman filter KF resets the cumulative error of the estimated value at the timing when the work vehicle 10 reaches the starting point Rp of the straight route R1.

As another example of the estimated value reset method ([estimated value reset method 2]), for example, as shown in FIG. The estimated value may be reset at the timing when the point Rs is reached. In the example shown in FIG. 14A, the straight route R1c includes two low-speed travel sections, and in this case, the Kalman filter KF calculates the estimated value at the timing when the starting point Rs of the first low-speed travel section is reached. The estimated value is not reset at the timing when the start point of the next low-speed driving section is reached.

As another example of the estimated value reset method ([Estimated value reset method 3]), for example, as shown in FIG. The estimated value may be reset at the timing when Rt is reached. In the example shown in FIG. 14B, the straight route R1c includes two low-speed travel sections, and in this case, the Kalman filter KF calculates the estimated value at the timing when the starting point Rt of the first low-speed travel section is reached. Furthermore, the estimated value is also reset at the timing when the starting point Rt of the next low-speed traveling section is reached.

As another example of the estimated value reset method ([estimated value reset method 4]), for example, as shown in FIG. After the start, the estimated value may be reset at the timing when the vehicle reaches the point Rx after traveling in the waiting section (after a predetermined time has elapsed or after traveling a predetermined distance). In the example shown in FIG. 14B, the straight route R1c includes two low-speed travel sections, and in this case, the Kalman filter KF reaches a point Rx that is separated by the waiting section from the starting point of the first low-speed travel section. The estimated value is reset at the timing when the vehicle reaches the point Rx that is separated by the waiting section from the starting point of the next low-speed driving section. In this way, when the influence of azimuth drift is small immediately after the start of low-speed work, the vehicle control device 11 uses the measured azimuth angle D0 for the predetermined section (standby section) immediately after the start of the low-speed traveling section. Steering control may also be used. Note that it is desirable that the vehicle control device 11 adjust the predetermined time or the predetermined distance corresponding to the waiting section so that the estimated value of the Kalman filter KF can be reset at an appropriate timing.

The automatic driving system of the present invention may be configured by the work vehicle 10 alone, or may be configured by the vehicle control device 11 alone. Further, the present invention may be implemented as an estimation device, an estimation method, and an estimation program that estimate the azimuth of the work vehicle 10. In this case, the estimation device may include each processing section of the vehicle control device 11. Further, the automatic driving system may be mounted on the work vehicle 10 or may be mounted on the operating terminal 20.

[Additional notes to the invention]
Hereinafter, a summary of the invention extracted from the above-described embodiments will be added. Note that each configuration and each processing function described in the following supplementary notes can be selected and combined as desired.

<Additional note 1>
Obtaining the measured azimuth measured by a measurement unit that measures the azimuth of the work vehicle;
adjusting a weight corresponding to the measured azimuth based on the vehicle speed of the work vehicle;
An azimuth corresponding to the current posture of the work vehicle is estimated based on the measured azimuth whose weight is adjusted according to the vehicle speed, position information of the work vehicle, and angular velocity information of the work vehicle. And,
Automatically driving the work vehicle based on the estimated azimuth;
Automated driving method to perform.

<Additional note 2>
estimating the azimuth such that the slower the vehicle speed of the work vehicle, the smaller the weight of the state estimated from the measured azimuth;
Automatic driving method described in Appendix 1.

<Additional note 3>
When the vehicle speed of the work vehicle is a first vehicle speed or higher, estimating the azimuth by setting a first parameter such that a state estimated from the measured azimuth is dominant in the azimuth estimation result;
A second parameter is set such that a state estimated from the measured azimuth angle becomes non-dominant in the azimuth estimation result when the vehicle speed of the work vehicle is a second vehicle speed or less that is slower than the first vehicle speed. estimating the azimuth angle;
The automatic driving method described in Supplementary note 1 or 2.

<Additional note 4>
Between the first vehicle speed and the second vehicle speed, a parameter that linearly changes depending on the vehicle speed is set to estimate the azimuth.
Automatic driving method described in Appendix 3.

<Additional note 5>
The measured azimuth and the estimated azimuth are based on at least one of route information regarding the route traveled by the work vehicle, work information regarding the work of the work vehicle, and travel mode information regarding the travel mode of the work vehicle. further performing selecting one of the azimuths as the output azimuth;
causing the work vehicle to travel automatically based on the output azimuth;
The automatic driving method described in any of Supplementary Notes 1 to 4.

<Additional note 6>
When the vehicle speed of the work vehicle is less than a predetermined vehicle speed, the estimated azimuth is selected as the output azimuth, and when the vehicle speed of the work vehicle is greater than or equal to the predetermined vehicle speed, the measured azimuth is selected as the output azimuth. Select as corner,
Automatic driving method described in Appendix 5.

<Additional note 7>
estimating the azimuth using a Kalman filter into which the measured azimuth, a parameter according to the vehicle speed of the work vehicle, position information of the work vehicle, and angular velocity information of the work vehicle are input;
The automatic driving method described in any of Supplementary Notes 1 to 6.

<Additional note 8>
Obtaining the measured azimuth measured by a measurement unit that measures the azimuth of the work vehicle;
estimating an azimuth corresponding to a current posture of the work vehicle based on the measured azimuth, position information of the work vehicle, and angular velocity information of the work vehicle;
Selecting either the measured azimuth angle or the estimated azimuth angle as an output azimuth angle based on the vehicle speed of the work vehicle;
Automatically driving the work vehicle based on the output azimuth;
Automated driving method to perform.

<Additional note 9>
selecting the measured azimuth as the output azimuth when the vehicle speed of the work vehicle is a first vehicle speed or higher;
selecting the estimated azimuth as the output azimuth when the vehicle speed of the work vehicle is below the first vehicle speed and below a second vehicle speed;
Automatic driving method described in Appendix 8.

<Additional note 10>
Executing the azimuth estimation process based on at least one of route information regarding a route traveled by the work vehicle, work information regarding work performed by the work vehicle, and travel mode information regarding a travel mode of the work vehicle. determine whether or not
The automatic driving method described in any one of Supplementary Notes 1 to 9.

1: Automated driving system 10: Work vehicle 11: Vehicle control device 16: Positioning unit 20: Operation terminal 111: Travel processing section 112: Acquisition processing section 113: Section judgment processing section 114: Reset judgment processing section 115: Adjustment processing section 116 : Estimation processing unit 117 : Output processing unit 161 : Positioning control unit 165 : Inertial measurement device (measurement unit)
D0: Measurement azimuth D1: Azimuth D2: Output azimuth F: Field KF: Kalman filter Pf: Parameter Pf1: Parameter (first parameter)
Pf2: Parameter (second parameter)
R: Target route R1: Straight route R2: Turning route Rf: Judgment result Vf: Vehicle speed d0: Route information d1: Judgment result d2: Reset judgment information f1: Position information f2: Angular velocity information

Claims (12)

Obtaining the measured azimuth measured by a measurement unit that measures the azimuth of the work vehicle;
adjusting a weight corresponding to the measured azimuth based on the vehicle speed of the work vehicle;
An azimuth corresponding to the current posture of the work vehicle is estimated based on the measured azimuth whose weight is adjusted according to the vehicle speed, position information of the work vehicle, and angular velocity information of the work vehicle. And,
Automatically driving the work vehicle based on the estimated azimuth;
Automated driving method to perform. estimating the azimuth such that the slower the vehicle speed of the work vehicle, the smaller the weight of the state estimated from the measured azimuth;
The automatic driving method according to claim 1. When the vehicle speed of the work vehicle is a first vehicle speed or higher, estimating the azimuth by setting a first parameter such that a state estimated from the measured azimuth is dominant in the azimuth estimation result;
A second parameter is set such that a state estimated from the measured azimuth angle becomes non-dominant in the azimuth estimation result when the vehicle speed of the work vehicle is a second vehicle speed or less that is slower than the first vehicle speed. estimating the azimuth angle;
The automatic driving method according to claim 1. Between the first vehicle speed and the second vehicle speed, a parameter that linearly changes depending on the vehicle speed is set to estimate the azimuth.
The automatic driving method according to claim 3. The measured azimuth and the estimated azimuth are based on at least one of route information regarding the route traveled by the work vehicle, work information regarding the work of the work vehicle, and travel mode information regarding the travel mode of the work vehicle. further performing selecting one of the azimuths as the output azimuth;
causing the work vehicle to travel automatically based on the output azimuth;
The automatic driving method according to any one of claims 1 to 4. When the vehicle speed of the work vehicle is less than a predetermined vehicle speed, the estimated azimuth is selected as the output azimuth, and when the vehicle speed of the work vehicle is greater than or equal to the predetermined vehicle speed, the measured azimuth is selected as the output azimuth. Select as corner,
The automatic driving method according to claim 5. estimating the azimuth using a Kalman filter into which the measured azimuth, a parameter according to the vehicle speed of the work vehicle, position information of the work vehicle, and angular velocity information of the work vehicle are input;
The automatic driving method according to any one of claims 1 to 4. Obtaining the measured azimuth measured by a measurement unit that measures the azimuth of the work vehicle;
estimating an azimuth corresponding to a current posture of the work vehicle based on the measured azimuth, position information of the work vehicle, and angular velocity information of the work vehicle;
Selecting either the measured azimuth angle or the estimated azimuth angle as an output azimuth angle based on the vehicle speed of the work vehicle;
Automatically driving the work vehicle based on the output azimuth;
Automated driving method to perform. selecting the measured azimuth as the output azimuth when the vehicle speed of the work vehicle is a first vehicle speed or higher;
selecting the estimated azimuth as the output azimuth when the vehicle speed of the work vehicle is below the first vehicle speed and below a second vehicle speed;
The automatic driving method according to claim 8. Executing the azimuth estimation process based on at least one of route information regarding a route traveled by the work vehicle, work information regarding work performed by the work vehicle, and travel mode information regarding a travel mode of the work vehicle. determine whether or not
The automatic driving method according to claim 1 or 8. an acquisition processing unit that acquires the measured azimuth measured by the measurement unit that measures the azimuth of the work vehicle;
Based on the vehicle speed of the work vehicle, a weight corresponding to the measurement azimuth acquired by the acquisition processing unit is adjusted, and the measurement azimuth with the adjusted weight, the position information of the work vehicle, and the work an estimation processing unit that estimates an azimuth corresponding to the current posture of the work vehicle based on the angular velocity information of the vehicle;
a travel processing unit that automatically travels the work vehicle based on the azimuth estimated by the estimation processing unit;
An automated driving system equipped with Obtaining the measured azimuth measured by a measurement unit that measures the azimuth of the work vehicle;
adjusting a weight corresponding to the measured azimuth based on the vehicle speed of the work vehicle;
An azimuth corresponding to the current posture of the work vehicle is estimated based on the measured azimuth whose weight is adjusted according to the vehicle speed, position information of the work vehicle, and angular velocity information of the work vehicle. And,
Automatically driving the work vehicle based on the estimated azimuth;
An automatic driving program that causes one or more processors to execute.