JPH04173004A - Steering control apparatus of automatic traveling working vehicle - Google Patents

Abstract

PURPOSE:To turn front wheels and rear wheels in opposite directions at the maximum steering angle and to maximize the turning performance of a working vehicle by positioning the center of a front sensor outside of the curvature orbit of a guide cable and the center of a rear sensor inside of the curvature orbit in the case of turning the vehicle at minimum curvature radius. CONSTITUTION:In the case of turning an automatic traveling lawn mower at minimum curvature radius, the center 18 of a front pickup coil 11 is positioned outside of the curvature orbit of a guide cable 5. Accordingly, the front wheels 2 are turned at the maximum steering angle toward the inside of the curvature orbit of the guide cable 5. On the other hand, the center 19 of a rear pickup coil 14 is positioned outside of the curvature orbit of the guide cable 5 and the rear wheels 3 are turned at the maximum steering angle toward the outside of the curvature orbit of the guide cable 5. Accordingly, the front wheel 2 and the rear wheel 3 are turned in opposite phase mode and steered at maximum steering angle to maximize the turning performance of the automatic traveling lawn mower.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to automatic driving work in which front wheels and rear wheels are freely steerable and the vehicle automatically travels along a guide that is buried or laid in a work area. This invention relates to a vehicle steering control device.

Conventional technologyCurrently, we are developing an autonomous work vehicle for rough terrain that uses autonomous vehicle control technology to perform unmanned lawn mowing work on golf courses without the need for operators to operate the course. ,
Practical implementation is underway.

As a steering control device for such an automated driving vehicle, magnetic materials, induction cables, and other derivatives are buried in the work area, and sensors that detect these derivatives are fixedly installed on the automated driving vehicle. Generally speaking, the steering control is performed so that the guide body is located in the center of the autonomous work vehicle based on the detection results.

Problems to be Solved by the Invention Therefore, in steering control, first, the amount of deviation between the sensor and the guide is determined based on the detection results of the sensors, and then the steering wheels necessary to eliminate the amount of deviation are determined. The steering angle of the vehicle is determined, and the steering wheels are controlled using the determined steering angle. For this reason, two judgment processes are required, one for determining the amount of bias and the other for determining the steering angle, making the mechanism complicated.

In addition, the surface of the work area where the automated driving vehicle travels has many unevenness and slopes, making it easy for skidding to occur. It's not easy.

Furthermore, when turning a work vehicle whose front wheels and rear wheels are steerable, steering control using an antiphase mode in which the front and rear wheels are steered in opposite directions is widely used. In the automatic driving work vehicle, as described in Japanese Utility Model Application Publication No. 2-31405, there is a judgment means for judging whether or not a turning state has been entered, and a mode switching means for switching to the opposite phase mode based on the judgment result. etc., making the mechanism even more complex. If the turning state cannot be determined or is delayed, the turning performance cannot be fully demonstrated.

Means for Solving the Problems An automatic system in which the m1 wheels connected to the front wheel steering device and the rear wheels connected to the rear wheel steering device can be steered freely and automatically travels along guides arranged in the work area. In the traveling work vehicle, a front moving member and a rear moving member movable in the left and right direction are provided at the front and rear of the automatic traveling work vehicle, and a drive unit for moving these moving members is provided, and the front portion detects the guide body. A sensor is located in front of the front wheel and attached to the front moving member, and a rear sensor for detecting the guide is located in front of the rear wheel and attached to the rear moving member, and the sensor is mounted in the moving direction of the front sensor. The front wheel steering device and the front moving member are connected so that the front wheels are steered in the direction of movement of the rear sensor, and the rear wheel steering device is configured to steer the rear wheels in the direction of movement of the rear sensor. and the rear moving member, determining the amount of deviation between the sensor and the guide based on the detection result from the sensor, and moving the moving member in a direction that makes the determined amount of deviation equal to par 0''. a control unit that outputs a signal to the drive unit,
When the autonomous working vehicle turns with a minimum curvature, the sensor center of the front sensor is located outside the curvature locus of the guide body, and the sensor center of the rear sensor is located inside the curvature locus of the guide body. The said derivative was arrange|positioned and the said moving member was attached.

The amount of deviation between the front sensor and the induction body is determined in the control unit based on the detection result from the front sensor, and the amount of deviation between the rear sensor and the induction body is determined in the control unit based on the detection result from the rear sensor. A signal is output from the control unit to the drive unit to move the partial moving member and the rear moving member in the direction that makes the amount of deviation “0°”, and as these moving members move, the moving member The front sensor and the rear sensor attached to the body move in the direction closer to the guide.Then, as the moving member moves, the front wheel steering device and the rear wheel steering device are driven, and the front sensor and the rear sensor move in the direction of movement of the front sensor. The front wheels are steered toward the rear sensor, and the rear wheels are steered toward the movement direction of the rear sensor.Furthermore, when the autonomous work vehicle turns with the minimum curvature,
Since the sensor center of the front sensor is located outside the curvature locus of the induction body and the sensor center of the rear sensor is located inside the curvature locus of the induction body, the front wheels and rear wheels are steered in opposite directions at the maximum steering angle. The turning performance of the autonomous driving work vehicle is maximized.

Example An embodiment of the present invention will be described based on the drawings.

A mower 4 is attached to the abdomen of an autonomous lawn mower 1, which is an autonomous working vehicle, and is located between a front wheel 2 and a rear wheel 3 so as to be movable up and down. On the other hand, a guide cable 5, which is a derivative, is buried underground in the work area where the self-driving lawn mower 1 runs, along a travel course on which the self-driving lawn mower 1 travels, and both ends of the guide cable 5 are buried underground. section is connected to a signal oscillator 6. The front wheels 2 are connected to a front wheel steering device 7, and the rear wheels 3 are connected to a rear wheel steering device M8.

A front moving member 10 that extends in the front-rear direction and is rotatable in a horizontal plane around a support shaft 9 is attached to the front of the automatic lawn mower 1. A pair of left and right front pickup coils 11, which are front sensors for detecting signals from the induction cable 5, are positioned and fixed in front of the axle of the front wheel 2. Note that the front wheel steering device 7 and the front moving member 1O are connected so that the front wheels 2 are steered in the direction of rotation of the front pickup coil 11.

Further, a rear moving member 13 that extends in the front-rear direction and is rotatable in a horizontal plane around a support shaft 12 is attached to the rear of the automatic mower l.
A pair of left and right rear big up coils 1, which are rear sensors that detect signals from the induction cable 5, are installed at the tip of the
4 is located and fixed in front of the axle of the rear wheel 3. Note that the rear wheel steering device 8 and the rear moving member 13 are connected so that the rear wheel 3 is steered in the direction of the rotational force of the rear pickup coil 14.

Next, the self-driving lawn mower 1 includes a control unit 15 which is a control unit to which the pickup coil 11.14 is connected, and a control unit 15 which is connected to the control unit 15 and connected to the front moving member 10. A front wheel steering drive device 16, which is a drive section, and a rear wheel steering drive device 17, which is a drive section, are connected to the control unit 15 and to the rear moving member I3. Note that the control unit 15 controls the front pickup coil 11 and the induction cable 5 based on the detection results from the front pickup coil 11.
The amount of bias is determined, and then the determined amount of bias is set to 0.”
A signal for rotating the front moving member 10 in the direction is calculated, and this signal is output to the front wheel steering drive device 16. The control unit 15 also controls the rear pickup coil 1 based on the detection result from the rear pickup coil 4.
4 and the guide cable 5 is determined, and furthermore, a signal for rotating the rear moving member 13 in a direction that makes the determined amount of bias 11 On is calculated, and this signal is transmitted to the rear wheel. It is output to the steering drive device 17.

Here, as shown in FIG. 5, the sensor center 18 of the front pickup coil 11 is located outside the curvature locus of the guide cable 5 when the automatic mower 1 is turned with the minimum curvature, The guide cable 5 is arranged such that the sensor center 19 of the rear pickup coil 14 is located inside the curvature locus of the guide cable 5.
is buried therein, and the dimensions and mounting state of the moving member 10.13 are set.

In such a configuration, Fig. 3 shows the self-driving lawn mower 1.
This shows that the running position of is off the induction cable 5, and the amount of deviation between the front pickup coil 11 and the induction cable 5 is II X II based on the detection result from the front pickup coil 11. , the amount of deviation between the rear pickup coil 14 and the induction cable 5 is 'X'' based on the detection result from the rear pickup coil 14.
'' is determined by the control unit 15.

Furthermore, the front pickup coil 11 and the induction cable 5
The member 1 moves part i in the direction that makes the amount of deviation "'O".
The control unit 15 calculates a signal for rotating the rear pickup coil 14 and a signal for rotating the rear moving member 13 in a direction that makes the amount of deviation between the rear pickup coil 14 and the induction cable 5 'O'''. Ru.

These signals then drive the front wheel steering drive system [16
is output to the rear wheel steering drive device 17, and as shown in FIG.
1, 1.4 sensor center 18.19 moves onto the guide cable 5, and as the moving member 10.13 rotates, the steering device 7.8 is driven and the front wheels 2 and rear wheels 3 are steered. Directed.

Here, when the self-driving lawnmower 1 is turned with the minimum curvature, the sensor center 18 of the front pickup coil ll is located outside the curvature locus of the guide cable 5, so the front wheel 2 is steered inward at the maximum steering angle. On the other hand, since the sensor center 19 of the rear pickup coil 14 is located outside the curvature locus of the guide cable 5, the rear wheel 3 is steered at the maximum steering angle toward the outside of the curvature locus of the guide cable 5. Therefore, the front wheels 2 and the rear wheels 3 are steered in the opposite phase mode and are also steered at the maximum steering angle, and the turning performance of the automatic mower I is maximized.

Effects of the Invention The present invention, as described above, determines the amount of deviation between the front sensor and the inductor and the amount of deviation between the rear sensor and the inductor, and moves the front moving member and the rear part in the direction of turning these deviations on. A control unit is provided to connect the front wheel steering device and the front moving member so that the front wheels are steered in the direction in which the front sensor moves as the front moving member moves, and the front moving member is connected to the front moving member. Means for determining the steering angles of the front wheels and rear wheels by connecting the rear wheel steering device and the rear moving member so that the rear wheels are steered in the direction in which the rear sensor moves as the moving member moves. This eliminates the need for the control mechanism, which simplifies the control mechanism, and because the front and rear wheels are steered independently, the accuracy of driving the self-driving work vehicle along the guide is greatly improved. Furthermore, when the self-driving work vehicle turns with the minimum curvature, the sensor center of the front sensor is located outside the curvature locus of the guide, and the sensor center of the rear sensor is located inside the curvature locus of the guide. By arranging the guide and attaching the movable member so that Therefore, the turning performance of the automatic traveling work vehicle can be maximized.

[Brief explanation of drawings]

Figure ml shows one embodiment of the present invention. Figure 1 is a block diagram showing the steering control system, Figure 2 is a side view showing the entire automatic driving lawn mower, and Figures 3 and 4. 5 is an explanatory diagram showing the steering control operation, and FIG. 5 is an explanatory diagram showing the steering control state when turning with the minimum curvature. l...Automated driving work vehicle, 2...Front wheel, 3...Rear wheel, 5...Inductor, 7...Front wheel steering device, 8
... Rear wheel steering device, 10... Front moving member, 1]... Front sensor, 13... Rear moving member, 14
... Rear sensor, 15... Control section, 16.17...
Drive unit, 18° 19...Sensor center -,, -"-";'i -1=zu Town J, 3 Fig.

Claims (1)

[Claims] In an automatic driving work vehicle, the front wheels connected to a front wheel steering device and the rear wheels connected to a rear wheel steering device are steerable and automatically travel along guides installed in a work area. A movable front moving member and a rear moving member are provided at the front and rear of the automatic traveling work vehicle, and a drive unit for moving these moving members is provided, and a front sensor for detecting the guide body is located in front of the front wheels. and is attached to the front moving member, and a rear sensor for detecting the guide is located forward of the rear wheels and attached to the rear moving member, and the front wheels are steered in the moving direction of the front sensor. The front wheel steering device and the front moving member are connected so that the rear wheel steering device and the front moving member are connected so that the rear wheel is steered in the moving direction of the rear sensor. and determining the amount of deviation between the sensor and the induction body based on the detection result from the sensor, and outputting a signal to the drive unit to move the moving member in a direction to set the determined amount of deviation to "0". A control unit is provided to position the sensor center of the front sensor on the outside of the curvature locus of the guide body when the automatic traveling work vehicle turns with a minimum curvature, and to position the sensor center of the rear sensor on the outside of the curvature locus of the guide body. A steering control device for an automatic traveling work vehicle, characterized in that the guide body is disposed so as to be located inside, and the moving member is attached.