JP7117886B2 - work vehicle - Google Patents

Description

The present invention relates to a work vehicle capable of automatically traveling along a set travel route.

A vehicle body position and a vehicle body orientation are required for automatic travel along a set travel route. The rice transplanter according to Patent Document 1 is provided with a gyro sensor (one of inertial measurement sensors) that detects the ground displacement of the traveling azimuth of the traveling vehicle body as angular velocity information, and an integral operation means that integrates the detected value of the gyro sensor. Based on the calculated information, the steering mechanism of the traveling vehicle body is automatically controlled so that the traveling orientation matches the target orientation. Since the detected value of the gyro sensor is integrated, the error increases, so the detection error of the gyro sensor is corrected using the azimuth information of the reference sensor using geomagnetism. In order to realize high-precision automatic steering with such a configuration, not only a high-precision gyro sensor but also a high-precision geomagnetic sensor, which has a large structural and cost burden, is required as a reference sensor. .

When the gyro sensor is used in a different temperature environment or geolocation environment than when it was manufactured, different measurement data, ie, errors occur. Since such an error is constant under the same usage environment, the error can be removed by so-called offset cancellation. Patent Document 2 utilizes the fact that if an object is stationary, the offset angular velocity (angular velocity drift) is stationary and therefore its change is small. If the change is greater than the threshold, it is determined that there is a disturbance, and the measurement is redone. An earthmoving machine is disclosed which is captured as an offset angular velocity.

In recent years, as the accuracy of satellite positioning using GNSS satellites has improved, work vehicles have been developed that calculate the vehicle body position and vehicle orientation using satellite positioning data and inertial measurement data such as a gyro sensor. For example, a tractor according to Patent Document 3 includes a satellite positioning sensor that obtains position information and a gyro sensor that obtains azimuth and attitude angles. and the azimuth angle output by . The filtering means estimates the position of the tractor from the azimuth angle of the tractor and the vehicle speed when the accuracy of the position information is lowered.

JP-A-7-172334 JP-A-8-261761 JP 2017-60524 A

High-precision satellite positioning data and high-precision inertial measurement data are required to realize highly accurate automatic driving along a travel route. A satellite positioning module that outputs highly accurate satellite positioning data is expensive. Moreover, even with such a highly accurate satellite positioning module, if the satellite radio wave condition deteriorates, the accuracy of the satellite positioning data deteriorates, or in the worst case, the satellite positioning data cannot be output. Therefore, when the satellite positioning data is bad, it is necessary to automatically run using the inertial measurement data. The elements of the entire control system of the inertial measurement module fluctuate depending on the environment (particularly temperature) in which it is used, and as a result, the output data of the inertial measurement module fluctuates. Furthermore, the yaw angle, which is the most important factor for automatic driving, needs to be appropriately and frequently corrected for variations over time. However, as described above, only techniques using conventional offset cancellation and filtering means have been proposed for correction of the inertial measurement module.
For this reason, there is a demand for a more effective inertial measurement module correction technique that is suitable for a work vehicle that can automatically travel along a set travel route.

A work vehicle according to the present invention is a work vehicle capable of automatically traveling along a set travel route. A position calculation unit, an inertia measurement module that outputs inertial measurement data, a stationary state detection unit that detects the stationary state of the traveling vehicle body, and a straight traveling state detection unit that detects the straight traveling state in which the traveling body is traveling straight ahead. a running state management unit, an automatic running control unit, and an inertial measurement processing unit that manages the inertial measurement module so that the inertial measurement data output from the inertial measurement module is accurate,
The inertial measurement processing unit cancels drift, which is a variation value included in the vehicle orientation derived from the yaw angle, which is one of the inertial measurement data, while the stationary state of the traveling vehicle body is being detected. and an offset correction value calculation unit for calculating an offset correction value, which is a value that offsets the fluctuation value, and a yaw angle that is a natural fluctuation of the yaw angle included in the inertial measurement data while the straight traveling state is detected. A yaw angle correction value calculation section for calculating a yaw angle correction value that cancels out the yaw angle fluctuation error in order to cancel the yaw angle fluctuation error; a yaw angle correction management section that gives a calculation command; and a vehicle body orientation calculation section that calculates a vehicle orientation based on the inertial measurement data corrected by the offset correction value and the yaw angle correction value ,
The automatic driving control unit controls a positional deviation that is a lateral deviation of the vehicle position with respect to the traveling route, and an orientation deviation that is an intersection angle between the vehicle orientation and a target orientation that is the orientation of the traveling route. Automatic travel control is performed based on the steering amount calculated so as to reduce the vehicle body deviation defined by.

According to this configuration, the vehicle orientation derived from the yaw angle, which is one of the inertial measurement data, includes drift of the inertial measurement data based on the environment and sensor characteristics. corrected. Furthermore, the yaw angle variation is corrected using a yaw angle correction value calculated using the drift of the yaw angle signal (yaw axis sensor signal) that occurs when the work vehicle is running straight. In particular, the yaw angle correction value ideally becomes a constant value when the work vehicle equipped with the inertial measurement module is actually traveling straight ahead, so the fluctuation of the yaw angle obtained in this state is offset. A more accurate yaw angle can be obtained by calculating the yaw angle correction value such that the yaw angle correction value is used for correction.

A condition for calculating the yaw angle correction value is that the work vehicle is in a straight running state. Since the work vehicle automatically travels along the set travel route, if the target travel route during automatic travel is a straight line, the work vehicle can be considered to be traveling straight ahead. For this reason, in the preferred embodiment of the present invention, it is a determination condition for determining that the vehicle is in the straight running state that the target travel route used during automatic travel is a straight line. With this configuration, it is possible not only to easily detect the straight traveling state of the work vehicle, but also to grasp how long the straight traveling state will continue. For example, if the straight running is determined to be sudden, the amount of data that can be used to calculate the yaw angle correction value is reduced, so the calculation of the yaw angle correction value may be disabled. It is possible.

In addition, the travel locus can be obtained from the position of the vehicle over time, and whether or not the travel is in a straight-ahead state can be accurately known by checking whether or not the travel locus is straight. Therefore, even if the yaw angle correction value is calculated by predicting that the vehicle is traveling straight ahead, if the travel locus is not straight, the yaw angle correction value can be discarded as inappropriate. For this reason, in a preferred embodiment of the present invention, the fact that the traveling locus calculated based on the vehicle position calculated over time is considered to be a straight line is the determination for determining that the straight traveling state. Used as a condition.

The calculated yaw angle correction value may become an unacceptable value due to disturbance or the like. When a yaw angle correction value that exceeds such a preset yaw angle tolerance value is calculated, the yaw angle correction value is not only discarded, but also the occurrence of a yaw angle tolerance value error is notified to the driver. It is appropriate to Therefore, in a preferred embodiment of the present invention, when the yaw angle correction value calculated by the yaw angle correction value calculator exceeds the yaw angle allowable value, the yaw angle correction value is discarded. Further, when the yaw angle correction value calculated by the yaw angle correction value calculation unit exceeds the yaw angle allowable value, a yaw angle correction value error is notified through the notification device.

Offset cancellation is to remove drift values that fluctuate depending on the environment and sensor characteristics even when the inertial measurement module is stationary. Therefore, the offset correction value for offset cancellation must be calculated when the work vehicle is stationary. In the case of a working vehicle, the stationary state is rarely determined by the driver, but it is preferable to detect the stationary state mechanically. For this reason, in a preferred embodiment of the present invention, a stationary state detection unit for detecting a stationary state of the vehicle body is provided. is given. The work vehicle can basically be considered to be in a stationary state when the engine is stopped, and can be considered to be in a stationary state when the vehicle speed is zero, that is, when the vehicle has stopped. Of course, it is more reliable to consider the stationary state in both engine stop and vehicle stop detection.

As with the yaw angle correction value, if the calculated value of the offset correction value is out of the allowable range, the yaw angle correction value is discarded, and the driver is preferably notified to that effect. . For this reason, in a preferred embodiment of the present invention, when the offset correction value calculated by the offset correction value calculation unit exceeds the offset allowable value, the exceeding of the offset allowable value is notified through the notification device. Further, when the offset correction value calculated by the offset correction value calculator exceeds the offset allowable value, the offset correction value is discarded.

It is the whole rice transplanter side view. It is the whole rice transplanter top view. It is a front view of a rice transplanter. FIG. 4 shows a steering unit; It is a functional block diagram of a control system. FIG. 4 is a flow chart diagram showing a correction routine for satellite positioning data and inertial measurement data; FIG. 10 is an explanatory plan view of the entire field showing the operation of automatic steering control; FIG. 4 is an explanatory diagram showing automatic steering control using an inertial measurement unit; It is a screen view of a liquid crystal display which is one of the display devices.

An embodiment of the present invention will be described with reference to the drawings. Here, a ride-on type rice transplanter (hereinafter simply referred to as a rice transplanter) will be described as an example of the working vehicle of the present invention. As shown in FIG. 2, in this embodiment, the arrow F indicates the front of the running vehicle body C, the arrow B indicates the rear of the traveling vehicle body C, the arrow L indicates the left side of the traveling vehicle body C, and the arrow R points to the right side of the traveling vehicle body C.

As shown in FIGS. 1 to 3, the rice transplanter has a traveling vehicle body C having a pair of left and right steering wheels 10 and a pair of left and right rear wheels 11 as a traveling device, and planting seedlings in a field. A seedling planting device W is provided as a possible working device. A pair of left and right steering wheels 10 are provided on the front side of the traveling vehicle body C and are configured to be able to freely change the direction of the traveling vehicle body C, and a pair of left and right rear wheels 11 are provided on the rear side of the traveling vehicle body C. It is The seedling planting device W is connected to the rear end of the traveling vehicle body C so as to be vertically movable through a link mechanism 21 which is vertically moved by the extension and contraction of a hydraulic cylinder 20 for vertical movement.

A front portion of the traveling vehicle body C is provided with an openable bonnet 12 . A rod-shaped center mascot 14 is provided at the tip of the bonnet 12 as a reference for traveling along the index line drawn on the field by the marker device 33 . The traveling vehicle body C is provided with a body frame 15 extending along the front-rear direction, and a support strut frame 16 is erected on the front part of the body frame 15 .

An engine 13 is provided inside the bonnet 12 . Although not described in detail, the power of the engine 13 is transmitted to the steerable wheels 10 and the rear wheels 11 via an HST (hydrostatic continuously variable transmission) provided in the fuselage, and the power after shifting is electrically driven. It is transmitted to the seedling planting device W via a motor-driven planting clutch (not shown).

The seedling planting device W plants the seedlings taken out from the planting mat-like seedlings placed on the seedling placing table 26 in the field. Although this seedling planting apparatus W is configured for eight-row planting, it may be four-row planting, six-row planting, seven-row planting, or ten-row planting. .

A plurality of (for example, four) normal spare seedling stands 28 and spare seedling stands 29 are provided on the left and right side portions of the bonnet 12 of the traveling vehicle body C. As shown in FIG. Left and right side portions of the hood 12 of the traveling vehicle body C are provided with a pair of left and right auxiliary seedling frames 30 as tall frame members for supporting the normal auxiliary seedling bases 28 and the auxiliary seedling bases 29, respectively. Upper portions of the frames 30 are connected to each other by a connecting frame 31 .

At the central portion of the traveling vehicle body C, a driving section 40 is provided in which various driving operations are performed. The driving section 40 includes a driver's seat 41 , a steering wheel 43 , a main shift lever 44 and an operating lever 45 . The driver's seat 41 is provided in the central portion of the traveling vehicle body C, and is configured so that the driver can sit thereon. The steering handle 43 is configured to enable the steering operation of the steered wheels 10 by manual operation. The main shift lever 44 is configured to be capable of switching between forward and backward travel and changing the running speed. The raising and lowering of the seedling planting device W and the switching of the left and right marker devices 33 are performed by the operating lever 45 . A steering handle 43 , a main shift lever 44 , an operating lever 45 , and the like are provided above a control tower 42 positioned in front of the driver's seat 41 . A boarding step 46 is provided at the foot portion of the driving unit 40 . The boarding step 46 also extends on both left and right sides of the bonnet 12 . A battery 17 that is charged by the rotation of the engine 13 is arranged below the driver's seat 41 .

When the main shift lever 44 is operated, the angle of the swash plate in the HST (not shown) is changed, and the power of the engine 13 is changed steplessly. Although not shown, the HST swashplate angle is controlled by a hydraulic unit equipped with a servo hydraulic controller. A known hydraulic pump, hydraulic motor, or the like is used for the servo hydraulic control device.

When the operation lever 45 is operated to the raised position, a planting clutch (not shown) is disengaged and the power transmission to the seedling planting device W is cut off, and the lifting hydraulic cylinder 20 is actuated to raise the seedling planting device W. , the left and right marker devices 33 are operated to the retracted posture. When the operation lever 45 is operated to the lowered position, the seedling planting device W descends and comes to a state of being in contact with the paddy surface and stopped. When the operation lever 45 is operated to the right marker position in this lowered state, the right marker device 33 changes from the retracted posture to the active posture. When the operation lever 45 is operated to the left marker position, the left marker device 33 changes from the retracted posture to the active posture.

When starting the rice planting work, the driver operates the control lever 45 to lower the seedling planting device W and start the transmission to the seedling planting device W to start the rice planting work. When the rice planting work is to be stopped, the operation lever 45 is operated to raise the seedling planting device W, and the power transmission to the seedling planting device W is cut off.

As shown in FIG. 2, a touch panel type liquid crystal display 48 capable of displaying various information is provided as one of the notification devices 73 (see FIG. 6) on the operation panel 47 above the control tower 42 of the operation section 40. ing. On the right side of the liquid crystal display 48, a push-operation type start point/end point setting switch 91 is provided, and on the left side of the liquid crystal display 48, a push-operation type target setting switch 92 is provided. It should be noted that the configuration may be such that the start point/end point setting switch 91 is provided on the left side of the liquid crystal display 48 and the target setting switch 92 is provided on the right side of the liquid crystal display 48 .

A grip portion of the main shift lever 44 is provided with a push-operated automatic steering switch 93 . The automatic steering switch 93 is of an automatic return type, and commands to switch on/off automatic steering control each time it is pushed. The automatic steering switch 93 is arranged at a position where it can be pushed with, for example, a thumb while the grip portion of the main shift lever 44 is gripped by the hand. Functions of the start/end point setting switch 91, the target setting switch 92, and the automatic steering switch 93 will be described later.

As shown in FIG. 4, the traveling vehicle body C is provided with a steering mechanism U capable of automatically steering the left and right steerable wheels 10 . The steering mechanism U includes a steering operation shaft 64 , a pitman arm 61 , left and right linking mechanisms 62 linked to the pitman arm 61 , a steering motor 66 and a gear mechanism 63 . The steering operation shaft 64 is interlocked with the steering handle 43 via a clutch 67 . The pitman arm 61 is configured to swing as the steering operation shaft 64 rotates. The gear mechanism 63 interlocks the steering motor 66 with the steering operation shaft 64 .

The steering operation shaft 64 is linked to the left and right steered wheels 10 via the pitman arm 61 and the left and right linking mechanisms 62, respectively. A steering angle sensor 65 consisting of a rotary encoder is provided at the lower end of the steering operation shaft 64 , and the amount of rotation of the steering operation shaft 64 is detected by the steering angle sensor 65 .

When the steering mechanism U is to be automatically steered, the steering motor 66 is driven, and the driving force of the steering motor 66 rotates the steering operation shaft 64 to change the steering angle of the steered wheels 10 . there is When automatic steering is not performed, the steering mechanism U can be rotated by manual operation of the steering handle 43 .

This rice transplanter includes a satellite positioning module 81 and an inertial measurement module 82 as positioning units PS. The satellite positioning module 81 uses GPS (Global Positioning System), which is a well-known technology, as an example of a global navigation satellite system (GNSS) that receives radio waves from satellites and detects the position of the aircraft. and has a satellite positioning function to determine the position of the aircraft. In the present embodiment, DGPS (Differential GPS: relative positioning system) is adopted as satellite positioning, but it is also possible to adopt other systems such as RTK-GPS (Real Time Kinematic GPS: interferometric positioning system). be. The inertial measurement module 82 includes a 3-axis gyro sensor and a 3-axis acceleration sensor. The satellite positioning module 81 requires initial processing (warm-up processing) for setting satellite acquisition information and correction information from the base station when power is turned on. Similarly, the inertial measurement module 82 also requires initial processing for setting various correction values for error correction (drift correction, etc.) when the power is turned on.

As shown in FIG. 1, a satellite positioning module 81 including a satellite positioning antenna is attached to the connecting frame 31 via a flat support plate.

In this embodiment, the inertial measurement module 82 has a 6-axis gyro sensor and an acceleration sensor, can detect the angular velocity of the turning angle of the traveling vehicle body C, and obtains the angular displacement of the body direction by integrating the angular velocity. be able to. The inertial measurement module 82 can measure not only the angular velocity of the turning angle of the traveling vehicle body C, but also the angular velocity of the lateral inclination angle of the traveling vehicle body C, the angular velocity of the longitudinal inclination angle of the traveling vehicle body C, and the like. The inertial measurement module 82 is arranged at a lower position on the rear side of the driver's seat 41 and at a lower position in the center of the vehicle body C in the lateral width direction. Inertial measurement module 82 may be co-located with satellite positioning module 81 .

FIG. 5 shows part of the control system in the rice transplanter in the form of a functional block diagram. The control unit CU has an input/output processing unit 50 as an input/output interface. The input/output processing unit 50 is connected to various devices such as the running state detector 74, the working state detector 75, the manual operation unit 90, and the like. In this embodiment, the positioning unit PS described above is connected to the control unit CU via an in-vehicle LAN. An engine control device 25 for driving the engine 13 receives a control signal from an engine control unit 71 connected to the control unit CU via an in-vehicle LAN. The notification device 73 receives a notification signal from the notification unit 72 connected to the control unit CU via the in-vehicle LAN.

The running state detector 74 includes sensors for detecting the running state, such as a vehicle speed sensor, an engine speed sensor, a brake pedal detection sensor, and a parking brake detection sensor. The working state detector 75 includes a sensor for detecting the state of various members constituting the seedling planting apparatus W and a sensor for detecting the amount of seedlings on the seedling placement table 26 .

A manual operation unit 90 consisting of switches, buttons, volumes, etc. gives a control command by manual operation by the driver, and the operation command is input to the control unit CU. The manual operation unit 90 includes the start/end point setting switch 91, the target setting switch 92, the automatic steering switch 93, and the like.

The control unit CU includes a running control unit 51, a work control unit 52, an automatic steering unit 53, a running mode management unit 54, a running state management unit 55, a vehicle position calculation unit 56, an inertia measurement processing unit 57, and the like. ing.

The own vehicle position calculation unit 56 calculates the map coordinates (own vehicle position) of the traveling vehicle body C and the direction (azimuth) of the traveling vehicle body C based on the positioning data sequentially sent from the positioning unit PS. At this time, the position of the own vehicle can be converted to the position of a specific portion of the traveling vehicle body C (for example, the center of the body or the work center of the seedling planting device W).

The traveling control unit 51 provides a steering signal and a vehicle speed signal to the steering mechanism U and traveling equipment group. Since this rice transplanter can carry out rice planting work by automatic traveling or manual traveling, the travel control unit 51 includes an automatic travel control unit 511 and a manual travel control unit 512 . The travel control unit 51 has an engine temporary stop (idling stop) function. The engine temporary stop function temporarily stops the engine 13 when a predetermined condition (engine temporary stop condition) is satisfied. Engine temporary stop conditions include, for example, that the main transmission lever 44 is held at a neutral position, that the brake is operating, that the engine 13 is idling, and that the remaining amount of seedlings on the seedling platform 26 is below a predetermined level. and that the driver is not seated on the driver's seat 41 .

The work control unit 52 controls the raising and lowering of the seedling planting device W and the driving of the seedling planting device W as the traveling vehicle body C travels.

Note that the automatic driving mode is set for automatic driving, and the manual driving mode is set for manual driving. Such running modes are managed by the running mode management unit 54 . When the automatic driving mode is set, the automatic driving control unit 511 receives automatic steering data (steering amount) generated by the automatic steering unit 53 .

The automatic steering section 53 includes a teaching route calculation section 531 , a route setting section 532 , a deviation amount calculation section 533 and a steering amount calculation section 534 . The teaching route calculator 531 calculates data of a reference route defined through teaching travel. The route setting unit 532 sets a target travel route, which is the target of automatic travel, based on the data of the reference route. The deviation amount calculator 533 calculates a vehicle body deviation defined by a position deviation and an azimuth deviation of the traveling vehicle body C with respect to the target travel route. The steering amount calculation section 534 calculates a steering amount that reduces the vehicle body deviation calculated by the deviation amount calculation section 533 .

The running state management unit 55 detects a specific running state based on detection signals from the running state detector 74 and the work state detector 75 . The running state detector 74 includes a stationary state detection section 551 and a straight running state detection section 552 . The stationary state detection unit 551 detects the stationary state based on whether the engine is stopped or the vehicle body is stopped or both. Specifically, the stationary state detection unit 551 detects the stationary state of the traveling vehicle body C with the engine 13 also stopped from the vehicle speed, the engine speed, the position of the main shift lever 44, and the like. The straight traveling state detection unit 552 detects that the traveling vehicle body C is traveling straight. Straight running here is limited to running in a straight line. Therefore, the straight travel state detection unit 552 detects that the target travel route used during automatic travel is a straight line, and that the travel locus calculated based on the vehicle position calculated over time is a straight line. , the straight running state of the running vehicle body C is detected.

The inertial measurement processing unit 57 manages the inertial measurement module 82 so that the inertial measurement data output from the inertial measurement module 82 are accurate values. For this purpose, the inertial measurement processing section 57 includes an offset correction value calculation section 571 , a yaw angle correction value calculation section 572 , a yaw angle correction management section 573 , and a vehicle body direction calculation section 574 . An offset correction value calculation unit 571 calculates an offset correction value and a yaw angle correction value used for correcting inertial measurement data, and a yaw angle correction value calculation unit 572 calculates the yaw angle correction value.

The inertial measurement data output from the inertial measurement module 82 includes drift caused by the environmental temperature, latitude and longitude position unique to the gyro device, even though the traveling vehicle body C is in a stationary state. Therefore, when the stationary state detection unit 551 detects the stationary state of the traveling vehicle body C, an offset correction value calculation command is given to the offset correction value calculation unit 571 . In response to the offset correction value calculation command, the offset correction value calculator 571 calculates a correction value for canceling this drift, that is, an offset correction value.

In the inertial measurement data output from the inertial measurement module 82, the yaw is detected in the inertial measurement data even though the traveling vehicle body C is traveling in a straight line. Includes natural variations in angle. Therefore, when the straight travel state of the traveling vehicle body C is detected by the straight travel state detection unit 552 , a yaw angle correction value calculation command is given to the yaw angle correction value calculation unit 572 . In response to the yaw angle correction value calculation command, the yaw angle correction value calculator 572 calculates a yaw angle correction value for eliminating the yaw angle fluctuation error from the inertial measurement data including the natural fluctuation of the yaw angle.

A rice transplanter that travels in an agricultural field such as a paddy field is highly likely to suddenly slip laterally due to a slip or the like even while traveling in a straight line. The calculated yaw angle correction value becomes inaccurate when a disturbance such as a sudden lateral shift occurs. Therefore, when the yaw angle correction value calculated by the yaw angle correction value calculator 572 exceeds the yaw angle allowable value, a yaw angle correction value error is notified through the notification device 73 . A similar thing can occur in the calculation of the offset correction value. Therefore, when the offset correction value calculated by the offset correction value calculator 571 exceeds the offset allowable value, an offset correction value error is notified through the notification device 73 . When the calculated yaw angle correction value exceeds the yaw angle allowable value, the yaw angle allowable value is discarded. Similarly, when the calculated offset correction value exceeds the offset allowable value, the offset correction value is discarded.

Next, an example of a correction routine for the inertial measurement module 82 during automatic steering (automatic running) will be described using the flowchart of FIG. The right side of FIG. 6 shows a correction routine, and the left side of FIG. 6 shows an automatic steering routine that uses the vehicle heading calculated using the correction value calculated by this positioning unit correction routine. .

In the automatic steering routine of FIG. 6, first, a target travel route having the same orientation as the orientation (reference bearing) of the reference travel route obtained by teaching travel is set (#01). Next, satellite positioning data is read from the satellite positioning module 81 (#02), and the vehicle position is calculated by the own vehicle position calculator 56 (#03). Although omitted in this routine, the vehicle position calculator 56 also calculates the vehicle body position using not only the satellite positioning data but also the inertial measurement data from the inertial measurement module 82 . Vehicle position using satellite positioning data is calculated at intervals of meters, whereas vehicle position using inertial measurement data is calculated at intervals of centimeters.

Further, inertial measurement data is read from the inertial measurement module 82 (#04), and the vehicle body orientation is calculated by the inertial measurement processing section 57 (#05). The yaw angle correction value and the offset correction value calculated in the positioning unit correction routine are used in the calculation of the vehicle body orientation in the inertial measurement processing section 57 .

The data of the set target travel route is developed in the memory (#06), and the amount of deviation of the traveling vehicle body C from the target travel route is calculated based on the calculated vehicle body position and/or vehicle orientation. 533 (#07). Next, the steering amount calculator 534 calculates a steering amount that reduces the amount of vehicle body deviation (#08), and the steering motor 66 is driven based on the calculated steering amount (#09).

In this way, when automatic steering travel is performed for a predetermined distance or for a predetermined time, or when it is detected that the vehicle is approaching the bank, it is checked whether or not the set target travel route has been traveled ( #10). If the currently set target travel route has not been completed (#10, No branch), the process returns to step #02 to continue automatic steering travel along the target travel route. If the target travel route has been completed (#10 Yes branch), the next target travel route is set (#10), the process returns to step #02, and automatic travel is performed. Although omitted in this automatic steering routine, when the automatic travel on the original target travel route is shifted to the automatic travel on the next target travel route, turning travel is performed by manual steering.

In the positioning unit correction routine that cooperates with the automatic steering routine, first, the running state managed by the running state management unit 55 is read (#51). It is checked whether the read running state is a straight running state (#52) or a stationary state (#71).

When it is determined that the vehicle is traveling straight ahead (#52 Yes branch), a yaw angle correction calculation command is output (#53), and yaw angle correction value calculation processing is performed. In the yaw angle correction value calculation process, the fluctuation state of the yaw angle signal value is calculated from the yaw angle signal value accumulated in the memory (#54). At this time, the yaw angle signal value calculated in the non-straight running state and recorded in the memory is removed. A yaw angle correction value is calculated by the yaw angle correction value calculation unit 572 based on the fluctuation state of the yaw angle signal value (#55). Furthermore, it is checked whether the calculated yaw angle correction value is within the allowable range defined by the preset yaw angle allowable value (#56). If the calculated yaw angle correction value is within the allowable range (Yes branch at #56), the yaw angle correction value is rewritten (#57) instead of the previous yaw angle correction value, and the process returns to step #51. The rewritten yaw angle correction value is given to the automatic steering unit 53 and used in step #05 of the automatic steering routine. If the calculated yaw angle correction value is out of the allowable range (#56, No branch), the fact that the calculated yaw angle correction value is outside the allowable range (yaw angle correction value error) is notified through the notification device 73 (#58). The calculated yaw angle correction value is discarded (#59), and the process returns to step #51.

When it is determined that the running state read in step #51 is the stationary state (#71 Yes branch), it is further checked whether other determination conditions for calculating the offset correction value are satisfied (# 72). This determination condition is the stopping of the engine 13, the operation of the brake, and the like. If the determination condition is satisfied (#72 Yes branch), an offset correction value calculation command is output (#73), and the offset correction value calculation process is performed. In the offset correction value calculation process, the fluctuation state (drift) of the inertial measurement data is calculated from the inertial measurement data accumulated in the memory (#74). At that time, the inertial measurement data (drift value) recorded in the memory is removed when the stationary state and the determination condition are not satisfied. The offset correction value is calculated by the offset correction value calculator 571 based on the data indicating the fluctuation state (drift) of the inertial measurement data (#75). Further, it is checked whether the calculated offset correction value is within the allowable range defined by the preset offset allowable value (#76). If the calculated offset correction value is within the allowable range (Yes branch at #76), it is rewritten in place of the previous offset correction value (#77), and the process returns to step #51. The rewritten offset correction value is given to the automatic steering unit 53 and used in step #05 of the automatic steering routine. If the calculated offset correction value is out of the allowable range (#76, No branch), the informing device 73 notifies that the calculated offset correction value is out of the allowable range (offset correction value error) (#78), The calculated offset correction value is discarded (#79), and the process returns to step #51. If the running state is not stationary at step #71 (No branch at #71) and if the determination condition is not satisfied at step #72 (No branch at #72), the process returns to step #51.

As described above, the condition for the yaw angle correction value calculation process is that the vehicle is traveling straight ahead, and the condition for the offset correction value calculation process is that the vehicle is stationary. The rice transplanter works by repeating long-distance straight travel and short-distance turning travel, and stops along the banks to supply seedlings from the seedling transport vehicle. Exceptionally, the engine may be temporarily stopped during straight traveling to replenish seedlings from the spare seedling stand 28 . For this reason, the yaw angle correction value calculation process is performed at relatively short intervals, but the offset correction value calculation process is performed at significantly longer intervals than the yaw angle correction value calculation process. Therefore, the running vehicle body C may be brought to a stationary state using the engine position stop function only for the purpose of performing the offset correction value calculation process. Such a forced offset correction value calculation process is previously notified to the driver.

As shown in FIG. 7, the rice transplanter moves along a linear path along a straight path for seedling planting work, and moves along a straight path for the next seedling planting work movement near the edge of the ridge. Turning and traveling to do so are alternately repeated. At that time, the first linear path is a teaching path that is manually steered, and the subsequent linear paths are arranged in parallel along the teaching path by the path setting unit 532 based on the teaching path information. , the set target travel routes LM(1) to LM(6).

When starting the seedling planting work, the driver positions the traveling vehicle body C at the start point position Ts of the ridge in the field and operates the start point/end point setting switch 91 . At this time, the control unit CU is set to the manual steering mode. Then, while the driver is manually operating, the traveling vehicle body C is caused to travel along the linear shape of the ridge on the side from the start position Ts, and is moved to the end point position Tf near the ridge on the opposite side, and then the start point and end point. The setting switch 91 is operated again. Thereby, the teaching process is executed. That is, a teaching route connecting the start point position Ts and the end point position Tf is set from the position coordinates of the start point position Ts and the position coordinates of the end point position Tf based on the positioning data acquired by the satellite positioning module 81. A direction along this teaching path is set as a reference target azimuth LA. Note that the position coordinates at the end point position Tf are not only the positioning data by the satellite positioning module 81, but also the distance from the start point position Ts based on the vehicle speed sensor (not shown), and the azimuth information of the traveling vehicle body C based on the inertial measurement module 82. , may be calculated based on. Further, the traveling of the traveling vehicle body C between the start position Ts and the end position Tf may be working traveling accompanied by rice planting work, or may be traveling in a non-working state.

After the setting of the teaching route is completed, a 180-degree turning travel is performed in order to move to the starting point position Ls adjacent to the teaching route, where the first target travel route LM(1) is set.
Turning is performed by the driver manually operating the steering wheel 43 .

When the target travel route LM(1) is set by the route setting unit 532 when the target travel route LM(1) is operated when the turning travel is completed and the next route is selected. Next, when the automatic steering switch 93 is operated, automatic steering traveling along the set target traveling route LM(1) is started. If the operation of the target setting switch 92 causes the target travel route LM(1) to be too far from or too close to the teaching route and the seedlings cannot be planted normally, a warning is issued through the reporting device 73. If the position, orientation, etc. of the traveling vehicle body C at the stage when the automatic steering switch 93 is operated are inappropriate for automatic steering, the transition to automatic steering traveling is prohibited, and a warning is issued through the notification device 73. be. Note that the target setting switch 92 and the automatic steering switch 93 may be made common and configured as a single switch.

Adverse conditions for automatic steering travel are that the azimuth deviation of the own aircraft azimuth NA with respect to the target azimuth LA is remarkably large, the direction of the steered wheels 10 is largely displaced to the left and right, and the vehicle speed of the traveling vehicle body C is high. It is exemplified by being too late or being too late. Another example of an adverse condition for automatic steering control is that the number of navigation satellites that can be captured by the satellite positioning module 81 is less than a preset number.

When automatic steering travel is permitted, the travel mode is switched from the manual steering mode to the automatic steering mode, and automatic steering along the target travel route LM(1) is started. The target travel route LM(1) is set along the azimuth of the target azimuth LA in a state adjacent to the teaching route, and is the target travel route LM on which the traveling vehicle body C first travels for work after the teaching process.

When the target setting switch 92 is operated at an arbitrary timing after completion of work travel on the target travel route LM(1), the route setting unit 532 changes the next target travel route LM(2) to the previous target travel route LM( It is set adjacent to the unworked area side of 1). Next, by operating the automatic steering switch 93, automatic steering traveling is started along the newly set target traveling route LM(2), and the traveling vehicle body C travels automatically for work.

After the traveling vehicle body C reaches the end point position Lf(2) of the target travel route LM(2), target travel routes LM(3), LM(4), LM(5), LM(6) are obtained by the same process. , the setting of the target travel route LM after the turning travel and the work travel are repeated.

During automatic steering control, the satellite positioning module 81 acquires information on the position of the aircraft over time. In addition to calculating the vehicle speed, the inertial measurement module 82 measures the relative azimuth change angle ΔNA over time as shown in FIG. 8 . The deviation amount calculation unit 533 calculates the heading NA of the aircraft over time from the point at which the automatic steering is started by integrating the heading change angle ΔNA. Then, the deviation amount calculation unit 533 calculates the deviation between the heading NA and the target heading LA. The steering amount calculation unit 534 calculates the steering amount so that the heading NA of the aircraft matches the target heading LA, and provides the steering amount to the automatic cruise control unit 511 . The automatic travel control unit 511 drives the steering motor 66 based on the given steering amount. As a result, the traveling vehicle body C automatically travels accurately along the target travel route LM.

As shown in FIG. 9, the state of the aircraft is displayed on the screen of the liquid crystal display 48. FIG.
A plurality of display areas such as a work information area 100, a positional deviation information area 101, and a vehicle speed information area 102 are arranged separately on this screen. The work information area 100 displays the date and time of work, work results, and the like at the left end of the upper side of the screen. The positional deviation information area 101 displays the amount of positional deviation of the traveling vehicle body C with respect to the target travel route LM in the upper center. The vehicle speed information area 102 displays the vehicle speed at the upper right end. A large area other than the upper side of the screen is a position information area 104, and the position information area 104 indicates the position of the traveling vehicle body C in the field. A small area at the left end of the position information area 104 is a steering state information area 103. The steering state information area 103 indicates the driving mode executed by the control unit CU, that is, the automatic driving mode (automatic steering) or the manual driving mode ( manual steering). A touch panel operation type software button group 120 is arranged at the right end of the position information area 104 . A physical button group 121 is arranged further to the right of the liquid crystal display 48 .

In the position information area 104, in order to graphically display the amount of deviation calculated by the deviation amount calculation unit 533, the working state of the field around the traveling vehicle body C, the target traveling route LM, and the vehicle symbol SY indicating the traveling vehicle body C are displayed. is displayed. The vehicle body symbol SY is shown in the form of an arrow, and the pointed direction indicates the traveling direction, that is, the vehicle body direction NA. A pointer 110 extending in the traveling direction from the center of the vehicle body symbol SY and a direction scale 111 indicating the angular range of the direction are overwritten to make the deviation between the vehicle body direction NA and the target direction LA easier to visually understand. is displayed. A boundary line 112 indicating the allowable range of misorientation is also displayed. A digital value of misorientation can also be displayed. Through the liquid crystal display 48, the driver can visually recognize lateral deviation and azimuth deviation as deviation amounts of the traveling vehicle body C with respect to the target travel route LM. Of the target travel routes LM, the target travel route LM during work travel is drawn with a thick solid line for easy understanding. Furthermore, in areas where rice planting has already been completed, each planted seedling is displayed in stippled form. As a result, the worked area and the unworked area are clearly distinguished visually. The traces of planted seedlings may be displayed by lines indicating planted streaks other than stippled lines.

[Another embodiment]
The present invention is not limited to the configurations exemplified in the above-described embodiments, and other representative embodiments of the present invention will be exemplified below.

[1] In the above-described embodiment, the turning travel is performed by manual steering, but it may be performed by automatic steering.

[2] In the above-described embodiment, the direction detection accompanied by the yaw angle correction value calculation process and the offset correction value calculation process is used for detecting the vehicle body posture in automatic driving. It is also applicable to a work vehicle configured to notify the deviation of the vehicle body as travel guidance.

[3] Each functional block in the functional block diagram shown in FIG. 5 is divided for easy understanding. Alternatively, each functional block may be further divided or a plurality of functional blocks may be unified. The control unit CU may be composed of a plurality of control units (so-called ECUs) having one or more functional blocks, and the control units may be connected via an in-vehicle LAN.

[4] In the positioning unit correction routine shown in FIG. 5, the yaw angle correction calculation process is performed when the traveling state of the traveling vehicle body C is in the straight traveling state. Of course, it is convenient if the yaw angle correction calculation process is not always performed when the vehicle is running straight, but is performed based on a predetermined elapsed time condition or travel distance condition. Further, instead of this, the yaw angle correction calculation process is arbitrarily performed, and it is determined from the travel locus, the calculated yaw angle, etc. that the traveling vehicle body C is in the straight traveling state when the yaw angle correction calculation process is being performed. Then, the calculated yaw angle correction value may be adopted, and the calculated yaw angle correction value may be discarded unless it is determined that the vehicle is traveling straight ahead.

INDUSTRIAL APPLICABILITY The present invention is applied to a work vehicle that can automatically travel along a set travel route.

51 : Travel control unit 511 : Automatic travel control unit 512 : Manual travel control unit 52 : Work control unit 53 : Automatic steering unit 532 : Route setting unit 533 : Deviation amount calculation unit 534 : Steering amount calculation unit 55 : Travel state management unit 551 : Stationary state detection unit 552 : Straight running state detection unit 56 : Vehicle position calculation unit 57 : Inertia measurement processing unit 571 : Offset correction value calculation unit 572 : Yaw angle correction value calculation unit 573 : Yaw angle correction management unit 574 : Vehicle azimuth calculation unit 72 : Notification unit 73 : Notification device 74 : Running state detector 75 : Working state detector 81 : Satellite positioning module 82 : Inertial measurement module C : Running vehicle body CU : Control device PS : Positioning unit

Claims (9)

A work vehicle capable of automatically traveling along a set travel route,
a satellite positioning module that outputs satellite positioning data;
a vehicle position calculation unit that calculates the vehicle position based on the satellite positioning data;
an inertial measurement module that outputs inertial measurement data;
A running state management unit having a stationary state detection unit that detects a stationary state of the traveling vehicle body and a straight running state detection unit that detects a straight running state in which the traveling body is running straight;
an automatic travel control unit;
an inertial measurement processing unit that manages the inertial measurement module so that inertial measurement data output from the inertial measurement module has an accurate value;
The inertial measurement processing unit
While the stationary state of the running vehicle body is being detected, the variation value is offset in order to cancel the drift, which is the variation value included in the vehicle orientation derived from the yaw angle, which is one of the inertial measurement data. an offset correction value calculator that calculates an offset correction value that is a value;
A yaw angle correction value , which is a value for canceling the yaw angle variation error, which is a natural variation of the yaw angle included in the inertial measurement data while the straight traveling state is detected. a yaw angle correction value calculator that calculates
a yaw angle correction management unit that gives a yaw angle correction value calculation command to the yaw angle correction value calculation unit in a straight running state;
a vehicle azimuth calculation unit that calculates a vehicle azimuth based on the inertial measurement data corrected by the offset correction value and the yaw angle correction value ;
The automatic driving control unit controls a positional deviation that is a lateral deviation of the vehicle position with respect to the traveling route, and an orientation deviation that is an intersection angle between the vehicle orientation and a target orientation that is the orientation of the traveling route. Work vehicle that performs automatic travel control based on the steering amount calculated to reduce the vehicle body deviation defined by 2. The work vehicle according to claim 1, wherein the fact that the target travel route used during automatic travel is a straight line is a determination condition for determining that the vehicle is in the straight travel state. 3. The determination condition according to claim 1 or 2, wherein it is a determination condition for determining that the straight running state is that a running locus calculated based on the vehicle position calculated over time is regarded as a straight line. work vehicle. 4. The apparatus according to any one of claims 1 to 3, wherein when the yaw angle correction value calculated by the yaw angle correction value calculator exceeds a yaw angle allowable value, a yaw angle correction value error is notified through a notification device. Work vehicle as described. 5. The operation according to any one of claims 1 to 4, wherein when the yaw angle correction value calculated by the yaw angle correction value calculation unit exceeds a yaw angle allowable value, the yaw angle allowable value is discarded. car. 6. The vehicle according to any one of claims 1 to 5, further comprising a stationary state detection unit for detecting a stationary state of the vehicle body, and when the stationary state is detected, an offset correction value calculation command is given to the offset correction value calculation unit. Work vehicle described in the paragraph. 7. The work vehicle according to claim 6, wherein the stationary state detection unit detects the stationary state based on an engine stop and/or a vehicle body stop. 8. The work vehicle according to any one of claims 1 to 7, wherein when the offset correction value calculated by the offset correction value calculation unit exceeds the offset allowable value, the exceeding of the offset allowable value is notified through a notification device. . The work vehicle according to any one of claims 1 to 8, wherein the offset correction value is discarded when the offset correction value calculated by the offset correction value calculation unit exceeds an offset allowable value.

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