JP7042732B2 - Automatic steering system and automatic steering method - Google Patents

Description

The present invention relates to an automatic steering system and an automatic steering method for automatically traveling a work vehicle along a set turning circle.

The agricultural work vehicle according to Patent Document 1 is provided with a GPS receiving device that receives radio waves from GPS satellites, and automatically travels so as to follow a target route based on the calculated position of the own vehicle. In straight-ahead driving, if the vehicle body deviates from the linear target path, that is, if the control reference point installed on the vehicle body center line deviates from the target path, the position deviation (positional deviation) and the directional deviation Steering control is performed based on (direction deviation). In turning, the center of the front wheel on the front side of the vehicle body is set as the control reference position, and the control reference position with respect to the tangential vector of the vehicle body passing through the intersection of the straight line connecting the center of the turning path and the control reference position and the turning path. The position deviation and the orientation deviation are calculated. Steering control is performed based on the calculated position deviation and azimuth deviation.

Japanese Unexamined Patent Publication No. 2002-358122

In the steering control according to Patent Document 1, in order to obtain the position deviation (position deviation amount) and the orientation deviation (direction deviation amount), the intersection of the straight line connecting the turning center of the turning path and the control reference position and the turning path. It is necessary to calculate the tangent vector of the vehicle body passing through the above, but the calculation of the tangent vector takes a long time because the calculation load is high. In addition, since a work vehicle uses a smaller turning radius than a passenger car, the tangent vector changes rapidly during turning, and it is necessary to calculate the tangent vector with a high calculation load in a short time. be. In order to do this, a high cost arithmetic function is required.

Further, the influence of the steering control on the vehicle body and the field differs depending on whether the vehicle body is inside or outside the turning path. For example, when the vehicle body is outside the turning path, the steering direction is the same and the steering amount is only increased. On the other hand, when the vehicle body is inside the turning path, not only the steering amount increases, but also the steering direction is steered in the opposite direction before and after the control. Therefore, if steering control is performed using both the displacement amount and the azimuth deviation amount, when the vehicle body is inside the turning path, the steering direction is reversed and the steering angle change amount becomes too large, and the vehicle body travels. In some cases, it became unstable and the field was damaged.

In view of such circumstances, there is a demand for an automatic steering system capable of calculating the amount of positional deviation and the amount of directional deviation at high speed by a simple calculation method in turning traveling, and capable of accurate and appropriate steering control.

The automatic steering system according to an embodiment of the present invention is an automatic steering system that automatically travels a work vehicle along a set turning circle, and has a reference point calculation unit for calculating the position of a reference point in the work vehicle. A reference straight line calculation unit that calculates a straight line passing through the center of the turning circle and the reference point as a reference straight line, a vehicle body orientation calculation unit that calculates a vehicle body orientation indicating the direction of the vehicle body of the work vehicle, and the reference point. As shown, the directional deviation amount calculation unit that calculates the intersection angle between the line perpendicular to the reference straight line and the vehicle body azimuth as the directional deviation amount, and the deviation direction determination unit that determines the positional relationship between the reference point and the outer circumference of the turning circle. And, when the reference point is located inside the outer circumference of the turning circle, a steering control unit that outputs a steering amount that reduces the directional deviation amount is provided.

When the work vehicle is displaced to the outside of the turning circle, steering control is performed so that the steering direction is the same as the current steering direction and the steering amount is large in order to return the work vehicle to the turning circle which is the turning path. Will be done. On the other hand, when the work vehicle is displaced inside the turning circle, the steering direction is steered so as to be opposite to the current steering direction in order to return the work vehicle to the turning circle which is the turning path. Control is done. Therefore, when the work vehicle is displaced inward of the turning circle, the work vehicle may turn sharply, the running stability of the work vehicle may deteriorate, or the field may be damaged by the turn of the work vehicle. In order to solve such a problem, when the work vehicle is displaced inside the turning circle, the steering control is based only on the amount of directional deviation, unlike the case where the work vehicle is displaced outside the turning circle. Will be done. As a result, it is possible to suppress the sudden turning of the work vehicle, deteriorate the running stability of the work vehicle, and prevent the field from being damaged by the turning of the work vehicle, enabling accurate and appropriate steering control. Become.

Further, it is preferable that the steering control unit calculates and outputs the steering amount by the PID control method or the PI control method using the current steering amount and the directional deviation amount as input parameters.

With such a configuration, the amount of directional deviation is fed back over time, and appropriate steering control is performed more quickly and accurately.

Further, when the position deviation amount calculation unit for calculating the distance from the intersection of the reference straight line and the turning circle to the reference point as the positioning deviation amount is provided and the reference point is located outside the outer periphery of the turning circle. It is preferable that the steering control unit outputs a steering amount in which the displacement amount and the orientation deviation amount are small.

With such a configuration, when the work vehicle is displaced to the outside of the turning circle, quick and fine steering control can be performed based on the displacement amount and the azimuth deviation amount, and the work vehicle is displaced to the turning circle. If it is displaced inward, the work vehicle is prevented from turning suddenly, and accurate and appropriate steering control is possible.

Further, it is preferable that the steering control unit calculates and outputs the steering amount by the PID control method or the PI control method using the current steering amount, the position deviation amount, and the azimuth deviation amount as input parameters.

With such a configuration, the amount of misalignment and the amount of misalignment are fed back over time, and appropriate steering control is performed more quickly and accurately.

The automatic steering method according to an embodiment of the present invention is an automatic steering method for automatically traveling a work vehicle along a set turning circle, and includes a step of calculating the position of a reference point on the work vehicle and the turning. A process of calculating a straight line passing through the center of a circle and the reference point as a reference straight line, a process of calculating a vehicle body orientation indicating the direction of the vehicle body of the work vehicle, and a line passing through the reference point and perpendicular to the reference straight line. A step of calculating the intersection angle with the vehicle body orientation as an orientation deviation amount, a step of determining the positional relationship between the reference point and the outer periphery of the turning circle, and the reference point being located inside the outer periphery of the turning circle. In this case, a step of outputting a steering amount that reduces the amount of misalignment is provided.

In this way, when the work vehicle is displaced inside the turning circle, it is possible to make it different from the case where the working vehicle is displaced outside the turning circle, and steering control is performed based only on the amount of directional deviation. Will be. As a result, it is possible to suppress the sudden turning of the work vehicle, deteriorate the running stability of the work vehicle, and prevent the field from being damaged by the turning of the work vehicle, enabling accurate and appropriate steering control. Become.

Further, it is preferable that the output steering amount is calculated by a PID control method or a PI control method with the current steering amount and the directional deviation amount as input parameters.

With such a configuration, the amount of directional deviation is fed back over time, and appropriate steering control is performed more quickly and accurately.

Further, the step of calculating the distance from the intersection of the reference straight line and the turning circle to the reference point as the amount of misalignment is provided, and when the reference point is located outside the outer circumference of the turning circle, the output is performed. The steering amount is preferably a steering amount in which the misalignment amount and the misorientation amount are small.

With such a configuration, when the work vehicle is displaced to the outside of the turning circle, quick and fine steering control can be performed based on the displacement amount and the azimuth deviation amount, and the work vehicle is displaced to the turning circle. If it is displaced inward, the work vehicle is prevented from turning suddenly, and accurate and appropriate steering control is possible.

Further, it is preferable that the output steering amount is calculated by a PID control method or a PI control method with the current steering amount, the position deviation amount, and the azimuth deviation amount as input parameters.

With such a configuration, the amount of misalignment and the amount of misalignment are fed back over time, and appropriate steering control is performed more quickly and accurately.

In the automatic steering system and the automatic steering method, the control gain in the PID control method and the PI control method is such that the reference point is located outside the outer circumference of the turning circle when the reference point is located outside the outer circumference of the turning circle. It may be larger than the case where it is located inside the outer circumference of.

As described above, when the work vehicle is deviated to the inside of the turning circle, the control gain can be made smaller than when the work vehicle is deviated to the outside, and the steering control amount with respect to the deviating amount can be made smaller. As a result, the work vehicle is surely suppressed from turning suddenly, and accurate and more appropriate steering control becomes possible.

Further, when the misalignment amount is larger than a predetermined value, the misalignment amount may be excluded from the input parameter.

With such a configuration, even when the amount of deviation is large, excessive steering control is suppressed and sudden turning is suppressed.

Further, when the azimuth deviation amount is smaller than a predetermined angle, the azimuth deviation amount may be excluded from the input parameter.

With such a configuration, sensitive turning is suppressed and running stability is ensured.

Further, as the turning circle, a sharp turning turning circle and a slow turning turning circle having a radius larger than that of the sharp turning turning circle may be selectively prepared.

With such a configuration, it is possible to make an appropriate turn according to the work situation.

It is a side view of a combine as an example of a work vehicle which adopted an automatic steering system. It is a figure which shows the outline of the automatic traveling of a combine. It is a figure which shows the traveling route in automatic traveling. It is a figure which shows the example of the turning travel path using the reverse movement. It is a figure which shows the example of the turning travel path using the reverse movement. It is a functional block diagram which shows the structure of the control system of a combine. It is explanatory drawing explaining the basic principle used when calculating a misalignment amount and a misorientation amount. It is a schematic diagram which shows another embodiment in the turning control. It is a schematic diagram which shows another embodiment in the turning control. It is a schematic diagram which shows another embodiment in the turning control. It is a schematic diagram which shows another embodiment in the turning control. It is explanatory drawing explaining the basic principle used when calculating the position deviation amount and the azimuth deviation amount when the vehicle body is inside. It is a figure which shows the process of a turning control in order.

Next, an ordinary combine harvester will be described as an example of a working machine capable of automatically traveling by adopting the automatic steering system of the present invention. In the present specification, unless otherwise specified, "front" (direction of arrow F shown in FIG. 1) means front in the vehicle body front-rear direction (traveling direction), and "rear" (arrow B shown in FIG. 1). Direction) means the rear in the vehicle body front-rear direction (traveling direction). Further, the left-right direction or the lateral direction means a vehicle body crossing direction (vehicle body width direction) orthogonal to the vehicle body front-rear direction. "Up" (direction of arrow U shown in FIG. 1) and "down" (direction of arrow D shown in FIG. 1) are positional relationships in the vertical direction (vertical direction) of the vehicle body, and are relationships in height above the ground. show.

As shown in FIG. 1, this combine includes a traveling vehicle body (corresponding to a work vehicle) 10, a crawler type traveling device 11, a driving unit 12, a threshing device 13, a grain tank 14, a harvesting unit H, a transport device 16, and grains. It is equipped with a grain ejection device 18 and a vehicle position detection module 80.

The traveling device 11 is provided in the lower part of the traveling vehicle body 10 (hereinafter, simply referred to as the vehicle body 10). The combine is configured to be self-propelled by the traveling device 11. The traveling device 11 is a steering traveling device composed of a pair of left and right crawler mechanisms (traveling units). The crawler speed of the left crawler mechanism (left traveling unit) and the crawler speed of the right crawler mechanism (right traveling unit) can be adjusted independently, and by adjusting this speed difference, the orientation of the vehicle body 10 in the traveling direction can be adjusted. Be changed. The driving unit 12, the threshing device 13, and the grain tank 14 are provided on the upper side of the traveling device 11 and form the upper part of the vehicle body 10. The driver unit 12 can be boarded by a driver who drives the combine harvester and a monitor who monitors the work of the combine harvester. Usually, the driver and the observer are also used. When the driver and the observer are different persons, the observer may monitor the work of the combine from outside the combine harvester.

The grain discharge device 18 is connected to the rear lower portion of the grain tank 14. Further, the own vehicle position detection module 80 is attached to the front upper portion of the driving unit 12.

The harvesting section H is provided at the front portion of the combine. The transport device 16 is connected to the rear side of the harvesting section H. Further, the harvesting unit H has a cutting mechanism 15 and a reel 17. The cutting mechanism 15 cuts the planted culm in the field. Further, the reel 17 is driven to rotate and scrapes the planted culm to be harvested. With this configuration, the harvesting unit H harvests the grain (a kind of agricultural product) in the field. Then, the combine can be run by the traveling device 11 while harvesting the grains in the field by the harvesting unit H.

The cut grain culm cut by the cutting mechanism 15 is conveyed to the threshing device 13 by the conveying device 16. In the threshing device 13, the harvested grain culm is threshed. The grains obtained by the threshing treatment are stored in the grain tank 14. The grains stored in the grain tank 14 are discharged to the outside of the machine by the grain discharging device 18.

A communication terminal 2 is arranged in the driving unit 12. In the present embodiment, the communication terminal 2 is fixed to the driving unit 12. However, the present invention is not limited to this, and the communication terminal 2 may be configured to be detachable from the driving unit 12. Further, the communication terminal 2 may be taken out of the combine harvester.

As shown in FIG. 2, this combine automatically travels along a travel route set in the field. For this purpose, the position of the own vehicle is required. The own vehicle position detection module 80 includes a satellite navigation module 81 and an inertial navigation module 82. The satellite navigation module 81 receives a GNSS (global navigation satellite system) signal (including a GPS signal) from the artificial satellite GS, and outputs positioning data for calculating the position of the own vehicle. The inertial navigation module 82 incorporates a gyro acceleration sensor and a magnetic orientation sensor, and outputs a position vector indicating an instantaneous traveling direction. The inertial navigation module 82 is used to complement the vehicle position calculation by the satellite navigation module 81. The inertial navigation module 82 may be arranged at a different location from the satellite navigation module 81.

The procedure for harvesting in the field with this combine is as described below.

First, the driver / observer manually operates the combine harvester and, as shown in FIG. 2, performs a harvesting run so as to orbit along the boundary line of the field in the outer peripheral portion of the field. As a result, the area that has become the already cut land (already worked area) is set as the outer peripheral area SA. Then, the area left as uncut land (unworked land) inside the outer peripheral area SA is set as the work target area CA. FIG. 2 shows an example of the outer peripheral region SA and the work target region CA.

Further, at this time, in order to secure a certain width of the outer peripheral region SA, the driver causes the combine to travel two or three laps. In this traveling, the width of the outer peripheral region SA is expanded by the working width of the combine every time the combine makes one round. After the first two to three laps, the width of the outer peripheral region SA becomes about two to three times the working width of the combine. This orbital running may be performed by automatic running based on the out-of-field shape data given in advance.

The outer peripheral region SA is used as a space for the combine to change direction when performing a harvesting run in the work target region CA. Further, the outer peripheral region SA is also used as a space for movement such as when moving to a grain discharge place or when moving to a refueling place after the harvesting run is finished.

The carrier CV shown in FIG. 2 can collect and transport the grains discharged from the combine. At the time of grain discharge, the combine moves to the vicinity of the carrier CV and then discharges the grains to the carrier CV by the grain discharge device 18.

When the outer peripheral area SA and the work target area CA are set, the traveling route in the work target area CA is calculated as shown in FIG. The calculated travel route is sequentially set based on the work travel pattern, and the combine automatically travels along the set travel route. As a turning pattern for turning, this combine repeats a U-turn pattern that changes direction along a U-shaped turning path as shown in FIG. 3 and forward / backward movement as shown in FIG. It has an α-turning pattern that changes direction and a switchback turning pattern that changes direction in a region narrower than the U-turning pattern with reverse travel as shown in FIG. In the α turning pattern of FIG. 4, a 90 ° turning turning path is shown. In this turning turn, the route reaches the transition destination travel route L2 from the transition source travel route L1 via the forward travel route ML1, the reverse travel route ML2, and the forward travel route ML3. The switchback turning pattern of FIG. 5 shows a 180 ° turn-back turning running used in a route transition in a straight reciprocating running. Similarly, in this turning turn travel, the route reaches the transition destination travel route L2 from the transition source travel route L1 via the forward travel route ML4, the reverse travel route ML5, and the forward travel route ML6. Such turning traveling including reverse movement is also performed when the grain tank 14 is full and the combine that has left the traveling path of the work target area CA aligns with the carrier CV.

FIG. 6 shows a combine control system using the automatic steering system according to the present invention. The control system of the combine is from a control unit 5 consisting of a large number of electronic control units called ECUs and various input / output devices that perform signal communication (data communication) with the control unit 5 through a wiring network such as an in-vehicle LAN. It is configured.

The notification device 62 is a device for notifying a driver or the like of a work traveling state or various warnings, and is a buzzer, a lamp, a speaker, a display, or the like. The communication unit 66 is used for the control system of this combine to exchange data with the communication terminal 2 or with a management computer installed at a remote location. The communication terminal 2 also includes a tablet computer operated by a monitor standing in the field, a driver / monitor who is on board the combine, a computer installed at home or a management office, and the like. The control unit 5 is a core element of this control system and is shown as an aggregate of a plurality of ECUs. The signal from the vehicle position detection module 80 is input to the control unit 5 through the vehicle-mounted LAN.

The control unit 5 includes an output processing unit 503 and an input processing unit 502 as input / output interfaces. The output processing unit 503 is connected to various operating devices 70 via the device driver 65. The operating equipment 70 includes a traveling equipment group 71, which is a traveling-related device, and a working equipment group 72, which is a work-related device. The traveling device group 71 includes, for example, a steering device 710, an engine device, a speed change device, a braking device, and the like. The work equipment group 72 includes a harvesting unit H (see FIG. 1), a threshing device 13 (see FIG. 1), a transport device 16 (see FIG. 1), a power control device in the grain discharge device 18 (see FIG. 1), and the like. include.

A traveling state sensor group 63, a working state sensor group 64, a traveling operation unit 90, and the like are connected to the input processing unit 502. The traveling state sensor group 63 includes an engine rotation speed sensor, an overheat detection sensor, a brake pedal position detection sensor, a shift position detection sensor, a steering position detection sensor, and the like. The work state sensor group 64 includes a sensor for detecting the driving state of the harvesting work device (harvesting unit H, threshing device 13, transport device 16, grain discharging device 18), a sensor for detecting the state of the grain and the grain, and the like. It is included.

The traveling operation unit 90 is a general term for operating tools that are manually operated by the driver and whose operation signals are input to the control unit 5. The traveling operation unit 90 includes a main speed change operation tool 91, a steering operation tool 92, a mode operation tool 93, an automatic start operation tool 94, and the like. In the manual driving mode, the crawler speed of the left crawler mechanism and the crawler speed of the right crawler mechanism are adjusted by swinging the steering operation tool 92 from the neutral position to the left and right. 1) The orientation is changed. In the present invention, the operation of changing the direction in which the vehicle body 10 travels is collectively referred to as steering, and not only changing the direction of the wheels or the like but also adjusting the speeds of the left and right crawlers is also referred to as steering. The mode operating tool 93 has a function of giving a command to the control unit 5 for switching between an automatic driving mode in which automatic driving is performed and a manual driving mode in which manual driving is performed. The automatic start operation tool 94 has a function of giving a final automatic start command to the control unit 5 for starting automatic traveling. The transition from the automatic driving mode to the manual driving mode may be automatically performed by software regardless of the operation by the mode operating tool 93. For example, when a situation occurs in which automatic driving is impossible, the control unit 5 forcibly executes a transition from the automatic driving mode to the manual driving mode.

The control unit 5 includes a notification unit 501, a travel control unit 51, a work control unit 52, a travel mode management unit 53, a travel route setting unit 54, a vehicle position calculation unit 55, a vehicle body orientation calculation unit 56, and a misalignment amount calculation unit. 57, an orientation deviation amount calculation unit 58, and a reference straight line calculation unit 59 are provided. The notification unit 501 generates notification data based on a command or the like from each functional unit of the control unit 5, and supplies the notification data to the notification device 62. The own vehicle position calculation unit 55 calculates the own vehicle position, which is the map coordinates (or field coordinates) of the preset reference point of the vehicle body 10, based on the positioning data sequentially sent from the own vehicle position detection module 80. do. That is, the own vehicle position calculation unit 55 functions as a reference point calculation unit for calculating the position of the reference point of the vehicle body 10. This reference point includes a vehicle body reference point and a turning reference point, which will be described later. The vehicle body orientation calculation unit 56 obtains a traveling locus in a minute time from the own vehicle position sequentially calculated by the own vehicle position calculation unit 55, and determines the vehicle body orientation indicating the direction of the vehicle body 10 in the traveling direction. Further, the vehicle body direction calculation unit 56 can also determine the vehicle body direction based on the direction data included in the output data from the inertial navigation module 82.

The travel control unit 51 has an engine control function, a steering control function, a vehicle speed control function, and the like, and gives a control signal to the travel equipment group 71. The work control unit 52 is a harvesting work device (harvesting unit H (see FIG. 1), threshing device 13 (see FIG. 1), transport device 16 (see FIG. 1), grain discharging device 18 (see FIG. 1), etc.). A control signal is given to the work equipment group 72 in order to control the movement.

The misalignment direction determination unit 509 included in the travel control unit 51 shifts the vehicle body 10 inward or outward of the turning path based on the misalignment amount calculated by the misalignment amount calculation unit 57 described later. Determine if it is. The steering control unit 510 included in the travel control unit 51 is based on at least one of the position shift amount calculated by the position shift amount calculation unit 57 and the direction shift amount calculated by the direction shift amount calculation unit 58. The steering amount is calculated and output to the steering device 710. That is, the steering control unit 510 determines the amount of misalignment and the amount of directional deviation between the target travel path set by the travel route setting unit 54 and the vehicle position calculated by the vehicle position calculation unit 55. Steering control (turning control) is performed so that at least one becomes smaller. In this embodiment, a PID control method or a PI control method is adopted for the steering control unit 510. Of course, other control methods may be adopted. This combine can be driven by both automatic driving in which harvesting work is performed by automatic driving and manual driving in which harvesting work is performed by manual driving. Therefore, the travel control unit 51 further includes a manual travel control unit 511 and an automatic travel control unit 512. When performing automatic driving, an automatic driving mode is set, and for manual driving, a manual driving mode is set. As described above, the switching of the traveling mode is managed by the traveling mode management unit 53.

The steering control unit 510 of the travel control unit 51 may have a different steering control configuration depending on whether the vehicle body 10 is displaced inward or outward of the turning path. For example, when the vehicle body 10 is deviated to the outside of the turning path, the steering amount is calculated based on the misalignment amount and the directional deviation amount, and is output to the steering device 710. Further, when the vehicle body 10 is deviated to the inside of the turning path, the steering amount is calculated based only on the directional deviation amount without considering the misalignment amount, and is output to the steering device 710. By controlling in this way, it is possible to prevent the steering direction from being reversed and the steering angle change amount to be too large, resulting in instability in 10 running of the vehicle body and roughening of the field. As a result, in turning, the amount of misalignment and the amount of misorientation can be calculated at high speed by a simple calculation method, and accurate and appropriate steering control becomes possible.

When the automatic driving mode is set, the automatic driving control unit 512, in cooperation with the steering control unit 510, generates a control signal for changing the vehicle speed including automatic steering and stopping, and controls the traveling equipment group 71. .. At that time, the control signal regarding the vehicle speed change is generated based on the vehicle speed value set in advance.

The travel route setting unit 54 sequentially selects a travel route including a managed turning route and sets it as a travel target route. The swivel path is essentially an arc of a swivel circle. The arc-shaped turning path is defined by the center of the turning circle and the radius of the turning circle. Assuming that the vehicle body 10 travels on the turning path accurately, the center of the turning circle is the turning center of the vehicle body 10. The travel route managed by the travel route setting unit 54 can be generated by the travel route setting unit 54 by the route calculation algorithm, but the one generated by the communication terminal 2 or the management computer at a remote location is downloaded. It is also possible to use.

When the manual driving mode is selected, the manual driving control unit 511 generates a control signal based on the operation by the driver and controls the traveling equipment group 71 to realize the manual driving. The travel route calculated by the travel route setting unit 54 can be used for the purpose of guidance for the combine to travel along the travel route even in manual operation.

The misalignment amount calculation unit 57 calculates the misalignment, which is the distance between the travel route set by the travel route setting unit 54 and the vehicle position calculated by the vehicle position calculation unit 55. The directional deviation amount calculation unit 58 calculates the angle difference between the extension direction of the travel path set by the travel route setting unit 54 and the vehicle body orientation calculated by the vehicle body orientation calculation unit 56 as the directional deviation. In this embodiment, the own vehicle position calculated by the own vehicle position calculation unit 55 is set as a turning reference point which is a point on which the vehicle rides on the turning path defined by the turning circle in an ideal turning running without deviation. .. Of course, even in ideal driving without deviation in a straight traveling path, this turning reference point rides on the straight traveling path, so that the turning reference point can be used as a vehicle body reference point in the straight traveling path. In that case, the turning reference point and the vehicle body reference point are the same.

The reference straight line calculation unit 59 calculates the reference straight line. The reference straight line is used for the calculation of the misalignment amount by the misalignment amount calculation unit 57 and the calculation of the misalignment calculation by the misalignment amount calculation unit 58 in the turning run. Next, the relationship between the reference straight line, the amount of misalignment, and the amount of misorientation will be described with reference to FIG. 7.

7 and 12 show the relationship between the turning circle C and the vehicle body 10 set when turning from the pre-turning travel path, which is the travel path before turning, to the post-turning travel path, which is the travel destination of the turning destination. Shows. In the example shown in FIG. 7, the traveling path before turning and the traveling path after turning are orthogonal to each other, and the turning path is a 90 ° arc of the turning circle C. Further, the vehicle body 10 is displaced to the outside of the turning circle C. In the example shown in FIG. 12, the traveling path before turning and the traveling path after turning are in a parallel relationship, and the turning path is a 180 ° arc of the turning circle C. Further, the vehicle body 10 is displaced inward of the turning circle C. The relationship between the pre-turning path and the post-turning path is an example, and in either case, it is assumed that the vehicle body 10 shifts to the inside or outside of the turning circle C. The reference numerals used in the explanations of FIGS. 7 and 12 are defined as follows. C represents a swirling circle. P is the center of the turning circle C. The coordinate value of the center P of the turning circle is (X, Y) and is managed by the traveling route setting unit 54. R is the radius of the turning circle C. The VP is a turning reference point (vehicle body reference point) of the vehicle body 10, and is represented by coordinate values (x, y). The coordinate values (x, y) of the turning reference point VP are calculated by the own vehicle position calculation unit 55. CL is a vehicle body center line which is a center line extending in the front-rear direction of the vehicle body 10. d is the distance between the center P of the turning circle and the turning reference point VP. BL is a straight line connecting two points, the center P of the turning circle and the turning reference point VP, and this straight line is the "reference straight line". PL is a straight line that passes through the turning reference point VP and is perpendicular to the reference straight line BL, and is hereinafter referred to as “direction reference line”.

FIG. 7 shows a state in which the vehicle body 10 is in the middle of turning, and the vehicle body 10 is displaced to the outside of the turning circle C and the vehicle body direction (vehicle body center line CL) is displaced to the right side with respect to the directional reference line PL. ing. Further, FIG. 12 shows a state in which the vehicle body 10 is in the middle of turning, and the vehicle body 10 is displaced inside the turning circle C and the vehicle body orientation (vehicle body center line CL) on the left side with respect to the directional reference line PL. Is out of alignment. The reference straight line calculation unit 59 obtains a linear formula connecting two points, the center P of the turning circle and the turning reference point VP, and calculates the reference straight line BL. The misalignment amount calculation unit 57 calculates the distance d between two points between the center P of the turning circle and the turning reference point VP, and calculates the misalignment amount δ by subtracting R from the distance d between the two points. In this subtraction, the positive and negative signs are taken into consideration, and if the subtraction value is negative, the vehicle body 10 is displaced inside the turning circle C, and if the subtraction value is positive, the vehicle body 10 is the turning circle C. It will be misaligned to the outside of. The deviation direction determination unit 509 determines the positive / negative sign of the positional deviation amount δ, and determines whether the vehicle body 10 is displaced inward or outward of the turning circle C. The directional deviation amount calculation unit 58 calculates the angle (intersection angle) formed by the vehicle body center line CL and the directional reference line PL as the directional deviation amount θ. If the directional deviation amount θ is a positive value, the vehicle body 10 is displaced to the right in the traveling direction, and if the directional deviation amount θ is a negative value, the vehicle body 10 is displaced to the left in the traveling direction. It will be. In this way, the displacement amount δ and the azimuth deviation amount θ are calculated and given to the steering control unit 510 in minute traveling units, so that the steering amount based on the PID or PI control is output.

An example of a procedure for calculating the steering amount in a turning run is shown below with reference to FIGS. 6, 7, and 12.

(1) The coordinate values (x, y) of the turning reference point VP, which is the position of the vehicle body 10 of the vehicle body 10, are acquired from the vehicle position calculation unit 55 (step # 1 in FIG. 13).

(2) A linear equation of the reference straight line BL is obtained (step # 2 in FIG. 13).

(3) The distance d between two points, which is the length between the center P of the turning circle C and the turning reference point VP, is obtained (step # 3 in FIG. 13).

(4) The radius R of the turning circle C is subtracted from the distance d between the two points, and the value is taken as the misalignment amount δ (step # 4 in FIG. 13).

(5) A linear equation of the vehicle body center line CL is obtained based on the vehicle body orientation from the vehicle body orientation calculation unit 56 (step # 5 in FIG. 13).

(6) The directional reference line PL perpendicular to the reference straight line BL is calculated based on the linear equation of the reference straight line BL, and the angle (intersection angle) formed by the vehicle body center line CL and the directional reference line PL is used as the directional deviation amount θ. It is calculated (step # 6 in FIG. 13).

(7) From the positive and negative signs of the misalignment amount δ, it is determined whether the vehicle body 10 is displaced inward or outward of the turning circle C (step # 7 in FIG. 13).

(8) When the vehicle is displaced outward, the steering amount is calculated from the positional deviation amount δ and the directional deviation amount θ (step # 8 in FIG. 13).

(9) When the vehicle is displaced to the outside, the steering amount is calculated from the positional deviation amount δ and the directional deviation amount θ (step # 9 in FIG. 13).

In this way, by making the steering control different depending on whether the vehicle body 10 is displaced inward or outward with respect to the turning circle C, steering control suitable for the situation becomes possible. When the vehicle body 10 is displaced inward with respect to the turning circle C, the vehicle body 10 that is turning inward tends to turn outward, the amount of displacement in the turning direction increases, and a sharp turn is performed. become. When such a turn is performed, the running stability of the vehicle body 10 is lowered or the field is roughened. Therefore, by making the steering control different according to the positional relationship of the vehicle body 10 with respect to the turning circle C, it is possible to suppress the displacement amount in the turning direction and avoid a sudden turning. For example, when the vehicle body 10 is displaced outward with respect to the turning circle C, steering control is performed using the positional deviation amount δ and the directional deviation amount θ, and the vehicle body 10 is displaced inward with respect to the turning circle C. If this is the case, steering control is performed using only the directional deviation amount θ without considering the position deviation amount δ. As a result, parameters for determining the amount of displacement in the turning direction and the like are reduced, and sudden turning is suppressed. As a result, it is possible to perform appropriate steering control that can suppress the deterioration of the running stability of the vehicle body 10 and the roughening of the field.

If, instead of (3) and (4), the intersection of the reference straight line BL and the turning circle C can be easily obtained, the distance between the obtained intersection and the turning reference point VP is calculated. As a result, the amount of misalignment δ can be obtained. If a straight line that passes through the reference point and is perpendicular to the reference straight line can be easily obtained, change to (6) and directly set the angle (intersection angle) between the vehicle body center line CL and the reference straight line BL. The value obtained by subtracting 90 ° from the angle may be used as the orientation deviation amount θ.

Next, the measures to be taken when a turning running error occurs due to automatic steering using a turning circle are listed.
(A) FIG. 8 shows a situation in which a misalignment amount δ occurs at the end of turning in a turning running on a set turning circle C (the radius of the turning circle C is R). As the cause of such a turning deviation, there are considered to be a plurality of causes such as "the orientation of the vehicle body 10 is shifted at the start of turning" or "the actual turning radius is increased due to slipping in the field or the like". Therefore, it is difficult to take decisive measures. In order to solve this problem, an optimized turning circle Co capable of appropriately turning is calculated from the actual positions and directions of the vehicle body 10 at the start and end of turning. As shown in FIG. 8, the straight line K1 passing through the turning reference point VP of the vehicle body 10 at the start of turning and perpendicular to the vehicle body center line CL and the vehicle body center line CL passing through the turning reference point VP of the vehicle body 10 at the end of turning. Find the intersection with the straight line K2 perpendicular to, and the circle passing through the turning reference point VP of the vehicle body 10 at the start of turning and the turning reference point VP of the vehicle body 10 at the end of turning is the optimized turning circle. Yes, it has a radius Rc. In the subsequent turning run, by setting this optimized turning circle Co, turning running with less turning deviation can be expected.

(B) FIG. 9 shows that when a turning running error occurs in the turning running in the set turning circle C, the turning running error is taken into consideration in the next turning running to realize a turning running with less turning deviation. It shows the measures to try. Here, a function: F (δ) for deriving the shift amount ΔL of the turning start point required to eliminate the misalignment amount δ is used with the misalignment amount δ generated in the first turning run as an input parameter. .. Such a function F (δ) can be created through simulations and experiments. It is expected that the shift amount ΔL derived by the function F (δ) will shift the planned turn start point Ps of the next turn path to the modified turn start point Pc to reduce the turn shift in the next turn run. ..

(C) FIG. 10 shows a turning deviation improving measure similar to the turning deviation improving measure shown in FIG. Here, a function: G (δ) for deriving the adjustment amount ΔR of the radius of the turning circle required to eliminate the misalignment amount δ is used with the misalignment amount δ generated in the first turning run as an input parameter. Be done. Such a function G (δ) can also be created through simulations and experiments. In the next turning run, the optimized turning circle Co having the radius Rc adjusted by the adjustment amount ΔR derived by the function G (δ) is used in place of the turning circle C. At that time, the center P of the turning circle also moves to the new center P'. By using this optimized turning circle Co, it is expected that the turning deviation will be reduced.

(D) FIG. 11 shows the directional deviation amount θs of the vehicle body 10 at the start of turning and the directional deviation amount of the vehicle body 10 at the end of turning when a turning running error occurs in the turning running in the set turning circle C. This describes a measure for adjusting the turning circle set in the next turning running by using θe and, to realize turning running with less turning deviation. Therefore, here, the directional deviation amount θs at the start of turning and the directional deviation amount θe at the start of turning are used as input parameters, and the adjustment amount ΔR of the radius of the turning circle C required to eliminate the turning deviation is derived. Function: J (θs, θe) is used. Such a function J (θs, θe) can also be created through simulations and experiments. In the next turning run, the turning deviation is reduced by using the optimized turning circle Co having the radius Rc adjusted by the adjustment amount ΔR derived by the function J (θs, θe) instead of the turning circle C. There is expected.

(E) It is empirically known that the turning radius based on the turning trajectory of the actual combine varies depending on the amount of grains stored in the grain tank 14. As described above, the turning running error caused by the stored grain amount V can be improved by setting a turning circle whose radius is adjusted by the stored grain amount V. For this purpose, a function: H (V) for deriving the adjustment amount ΔR of the radius of the swirling circle is used with the stored grain amount V as an input parameter. At that time, it is preferable that the adjustment amount ΔR when V = 0 is set to 0, and the adjustment amount up to the full amount is gradually increased.

In the countermeasures (A) to (E) described above, it was assumed that the turning circle in which the turning deviation occurred and the turning circle to be turned next have the same radius, but if the turning circles have different radii. On the other hand, when the above-mentioned measures are applied, the problem due to the difference in radius of the swirling circle can be solved by using the correction coefficient table for correcting the difference in radius prepared in advance.

[Another Embodiment] (1) When the misalignment amount δ is smaller than a predetermined predetermined value (threshold value) δT ₁ when controlling the steering amount, the steering control unit 510 causes the misalignment amount δ. The steering amount may be calculated based only on the orientation deviation amount θ without using. As a result, sensitive turning is suppressed and running stability is ensured.

(2) When the misalignment amount δ is larger than a predetermined value (threshold value) δT ₂ , the steering control unit 510 does not use the misalignment amount θ and steers only based on the misalignment amount δ. May be calculated. As a result, even when the amount of misalignment is large, excessive steering control is suppressed and sudden turning is suppressed.

(3) When the directional deviation amount θ is smaller than a predetermined angle (threshold value) θT ₃ , the steering control unit 510 does not use the directional deviation amount θ and steers only based on the misalignment amount δ. May be calculated. As a result, sensitive turning is suppressed and running stability is ensured.

(4) When the vehicle body 10 is determined to be displaced inward of the turning circle C by the deviation direction determination unit 509, the steering control unit 510 uses the control gain used for steering control, and the vehicle body 10 determines that the vehicle body 10 is displaced inside the turning circle C. It may be made smaller than the case where it is displaced to the outside, and the steering control may be performed gently when it is determined that the vehicle body 10 is displaced to the inside of the turning circle C. For example, the control gain when the vehicle body 10 is displaced to the outside of the turning circle C is 0.8, and the control gain when the vehicle body 10 is displaced to the inside of the turning circle C is 0.6. As a result, when the vehicle body 10 is displaced inward of the turning circle C, excessive steering control is suppressed and sudden turning is suppressed.

(5) Since the actual turning of the combine is affected by the amount of grains stored in the grain tank 7, the steering control unit 510 is stored in the grain tank 7 when calculating the steering amount. The amount of grains (fir weight) may be taken into consideration.

(6) In the above-described embodiment, the turning circle used for the turning path is included in the traveling path generated by the traveling route creation algorithm for the field or artificially generated, and is included in the traveling path during traveling. , The travel route setting unit 54 sequentially sets the target travel route. At that time, an example in which the radius of the turning circle is automatically changed based on the occurrence of turning deviation or the like has also been described. In addition to this, a configuration in which the radius of the turning circle is artificially changed may be adopted. For example, there are multiple turning modes such as "gentle mode" in which a turning circle with a large radius (turning circle for slow turning) is set and "high speed mode" in which a turning circle with a small radius (turning circle for sharp turning) is selected. An artificial operation tool that can be selected may be provided. When the "gentle mode" is selected, turning that does not disturb the field as much as possible is realized, and when the "high speed mode" is selected, the turning running time is shortened and the working time is shortened. The actual turning radius of the vehicle body 10 is determined by the difference in crawler speed between the left and right crawler mechanisms or the speed difference between the left and right drive wheels, but in the hydraulic transmission mechanism that transmits the traveling power to the crawler mechanism and the drive wheels. It is also possible to adjust the turning radius by adjusting the hydraulic pressure.

(7) In the above-described embodiment, the own vehicle position detection module 80 is a combination of the satellite navigation module 81 and the inertial navigation module 82, but only the satellite navigation module 81 may be used. Further, a method of calculating the position of the own vehicle and the direction of the vehicle body based on the image taken by the camera may be adopted.

(8) Each functional unit shown in FIG. 6 is divided mainly for the purpose of explanation. In practice, each functional unit may be integrated with other functional units or may be divided into a plurality of functional units. Further, among the functional units built in the control unit 5, all of the travel mode management unit 53, the travel route setting unit 54, the position deviation amount calculation unit 57, the orientation deviation amount calculation unit 58, and the reference straight line calculation unit 59. , Or a part of it is built on a portable communication terminal 2 (tablet computer, etc.) that can be connected to the control unit 5, and adopts a configuration that exchanges data with the control unit 5 via wireless or in-vehicle LAN. May be good.

It should be noted that the configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in other embodiments as long as there is no contradiction. , The embodiments disclosed in the present specification are examples, and the embodiments of the present invention are not limited thereto, and can be appropriately modified without departing from the object of the present invention.

The present invention is applicable not only to a normal type combine but also to a self-removing type combine.
It can also be applied to various harvesters such as corn harvesters, potato harvesters, carrot harvesters and sugar cane harvesters, and field work vehicles such as rice transplanters and tractors. Furthermore, it can be applied to lawn mowers and construction machines.

10 Traveling vehicle (working vehicle)
55 Own vehicle position calculation unit (reference point calculation unit)
56 Body orientation calculation unit 57 Position deviation amount calculation unit 58 Direction deviation amount calculation unit 59 Reference straight line calculation unit 509 Misalignment judgment unit 510 Steering control unit BL Reference straight line C Turning circle CL Vehicle body center line (vehicle body orientation)
P center PL directional reference line VP turning reference point (reference point)
δ Positional deviation θ Directional deviation

Claims (16)

It is an automatic steering system that automatically drives the work vehicle along the set turning circle.
A reference point calculation unit that calculates the position of the reference point in the work vehicle,
A reference straight line calculation unit that calculates a straight line passing through the center of the turning circle and the reference point as a reference straight line.
A vehicle body orientation calculation unit that calculates a vehicle body orientation indicating the orientation of the vehicle body of the work vehicle, and a vehicle body orientation calculation unit.
An orientation deviation amount calculation unit that calculates the intersection angle between the line passing through the reference point and perpendicular to the reference straight line and the vehicle body orientation as the orientation deviation amount.
A deviation direction determination unit that determines the positional relationship between the reference point and the outer circumference of the turning circle, and
An automatic steering system including a steering control unit that outputs a steering amount that reduces the directional deviation amount when the reference point is located inside the outer circumference of the turning circle. The automatic steering system according to claim 1, wherein the steering control unit calculates and outputs the steering amount by a PID control method or a PI control method using the current steering amount and the directional deviation amount as input parameters. It is provided with a misalignment amount calculation unit that calculates the distance from the intersection of the reference straight line and the swivel circle to the reference point as the misalignment amount.
The automatic steering according to claim 1 or 2, wherein when the reference point is located outside the outer circumference of the turning circle, the steering control unit outputs a steering amount in which the misalignment amount and the azimuth deviation amount are small. system. The automatic according to claim 3, wherein the steering control unit calculates and outputs the steering amount by a PID control method or a PI control method using the current steering amount, the position deviation amount, and the orientation deviation amount as input parameters. Steering system. The control gain in the PID control method and the PI control method is larger when the reference point is located outside the outer circumference of the turning circle than when the reference point is located inside the outer circumference of the turning circle. The automatic steering system according to claim 4. The automatic steering system according to claim 4 or 5, wherein when the misalignment amount is larger than a predetermined value, the misalignment amount is excluded from the input parameters. The automatic steering system according to any one of claims 4 to 6, wherein when the directional deviation amount is smaller than a predetermined angle, the directional deviation amount is excluded from the input parameter. The automatic according to any one of claims 1 to 7, wherein a sharp turning circle and a slow turning circle having a radius larger than that of the sharp turning circle can be selected as the turning circle. Steering system. It is an automatic steering method that automatically drives the work vehicle along the set turning circle.
The process of calculating the position of the reference point in the work vehicle and
A process of calculating a straight line passing through the center of the turning circle and the reference point as a reference straight line, and
The process of calculating the vehicle body orientation indicating the orientation of the vehicle body of the work vehicle, and
The process of calculating the intersection angle between the line passing through the reference point and perpendicular to the reference straight line and the vehicle body azimuth as the directional deviation amount, and
The step of determining the positional relationship between the reference point and the outer circumference of the turning circle, and
An automatic steering method including a step of outputting a steering amount in which the directional deviation amount becomes smaller when the reference point is located inside the outer circumference of the turning circle. The automatic steering method according to claim 9, wherein the output steering amount is calculated by a PID control method or a PI control method with the current steering amount and the directional deviation amount as input parameters. A step of calculating the distance from the intersection of the reference straight line and the turning circle to the reference point as the amount of misalignment is provided.
The automatic according to claim 9 or 10, wherein when the reference point is located outside the outer circumference of the turning circle, the output steering amount is a steering amount in which the misalignment amount and the azimuth deviation amount are small. Steering method. The automatic steering method according to claim 11, wherein the output steering amount is calculated by a PID control method or a PI control method using the current steering amount, the position deviation amount, and the directional deviation amount as input parameters. The control gain in the PID control method and the PI control method is larger when the reference point is located outside the outer circumference of the turning circle than when the reference point is located inside the outer circumference of the turning circle. The automatic steering method according to claim 12. The automatic steering method according to claim 12 or 13, wherein when the misalignment amount is larger than a predetermined value, the misalignment amount is excluded from the input parameter. The automatic steering method according to any one of claims 12 to 14, wherein when the directional deviation amount is smaller than a predetermined angle, the directional deviation amount is excluded from the input parameter. The automatic according to any one of claims 9 to 15, wherein a sharp turning circle and a slow turning circle having a radius larger than that of the sharp turning circle can be selected as the turning circle. Steering method.

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