JPH03257604A - Steering controller for automatic traveling truck - Google Patents

Abstract

PURPOSE:To improve the accuracy of traveling along a guide by estimating the embedding state of the guide based on the result of detecting the guide by sensors, which are provided in front, central and rear parts, and controlling the steering of steering wheels at a reference steering operation angle based on the estimation. CONSTITUTION:Front pickup coils 7 and 8 detect an A point on an guide cable 5, central pickup coils 9 and 10 detect a B point on the guide cable 5 and rear pickup coils 11 and 12 detect a C point on the guide cable 5. Detected results are inputted from the respective pickup coils 7-12 to a predictive arithmetic means and this predictive arithmetic means estimates that the guide cable 5 is linearly embedded. Further, based on the prediction of the predictive arithmetic means, steering control signals are outputted from a controller 17 to steering devices 13 and 14, and the steering of front and rear wheels 2 and 3 is controlled at the reference steering angle. Thus, an automatic traveling truck is made to travel along guides.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a steering control device for an automated driving vehicle that travels unmanned along a set travel course.

Conventional technologyCurrently, by applying the control technology of self-driving vehicles, we are developing an autonomous work vehicle for rough terrain that aims to perform lawn mowing work etc. unmanned on golf course courses without operator control. , and its practical application is progressing.

As a steering control device for such an automated driving work vehicle, a guide is buried underground in the work area along the travel course on which the automated driving work vehicle will travel, and a pair of left and right sensors to detect this guide is installed during the automated driving work. It is generally installed in a vehicle and controls the steering of an autonomous work vehicle based on the detection results from the sensors so that the marker is located at an intermediate position between the left and right sensors.

In addition, in such a steering control device, there is a straight running mode in which the reference steering angle of the steering wheel is set to 0° when the buried guide is in a straight line, and a straight running mode in which the reference steering angle of the steering wheel is set to 0°'' when the buried guide is in an arc shape. Some models have a turning mode in which the reference steering angle of the steering wheel is set to a predetermined angle, and are designed to switch between the straight-ahead mode and the turning mode by detecting markers, etc. installed in the work area. .

Problem to be Solved by the Invention When driving by switching to the turning driving mode, the reference steering angle of the steering wheel is fixed by data such as a program, and the detection of the derivative by this reference steering angle and the sensor is performed. The steering wheel is controlled based on the result. Therefore, if there are variations in the buried state of the guide at each turning point, the fixed reference steering angle in turning driving mode will not be able to turn that turning point, causing the automated driving vehicle to skid. Even in the case where such problems do not occur, it is necessary to turn while repeating steering operations, which has the drawback of increasing the frequency of steering operations and damaging the grass as the frequency of steering operations increases.

Means for Solving the Problems A derivative is buried underground in the work area where the automatic driving work vehicle is to travel along the travel course of the automatic driving work vehicle, and a sensor for detecting the derivative is installed in the front part of the automatic driving work vehicle. and a prediction calculation means provided in the center and rear part of the guide, which predicts the buried state of the induction body based on the detection result of the induction body by the sensor, and adjusts the steering wheel to a reference steering operation angle based on the prediction of the prediction calculation means. and a control device for steering control.

Function: Sensors installed at the front, center, and rear of the self-driving work vehicle detect the derivative, and based on the detection results, the predictive calculation means predicts the buried state of the derivative. The control device controls the steering wheels to a reference steering angle, and the autonomous work vehicle travels along the guide.

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

A front wheel 2 which is a steering wheel and a rear wheel 3 which is a steering wheel are provided on the abdomen of an automatic driving lawn mower 1 which is an automatic driving work vehicle.
Further, a mower 4 is installed between the front wheels 2 and the rear wheels 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. An excitation current power supply device 6 is connected. Note that by passing a low frequency current from the excitation current power supply device 6 to the induction cable 5, an alternating magnetic field is generated from the induction cable 5.

The guide cable 5 is installed in the front part of the self-driving lawn mower 1.
A pair of left and right pickup coils 7.8, which are sensors for detecting the alternating magnetic field from the lawnmower, are provided, and a pair of left and right pickup coils 9, 10, which are sensors, are also provided in the center of the automatic mower 1. Furthermore, a pair of left and right pickup coils 11 and 12, which are sensors, are also provided at the rear of the automatic lawnmower l. Further, the self-driving lawn mower 1 is provided with a front wheel steering device 13 connected to the front wheels 2 and a rear wheel steering device 14 connected to the rear wheels 3, and further controls the amount of steering operation of the front wheels 2. A front wheel turning angle sensor 15 for detecting the steering angle and a rear wheel turning angle sensor 16 for detecting the amount of steering operation of the rear wheels 3 are provided. The distance between the front pickup coil 7°8 and the center pickup coil 9, 10 and the distance between the center pickup coil 9, 10 and the rear pickup coil 11, 12 are set equal. .

Next, the pickup coils 7 to 12 and the turning angle sensor 15°16 are connected to the automatic mower 1, and the induction cable 5 is connected to the pickup coils 7 to 12 based on the detection results from the pickup coils 7 to 12. A control device 1 having predictive calculation means (not shown) for predicting the buried state of
7 is provided. Note that from the control device 17,
the front wheels 2 and the rear wheels 3 based on the prediction of the prediction calculation means;
A steering control signal necessary for controlling the steering angle to the reference steering angle is output to the steering device 13, 14, and a steering control signal corresponding to skidding of the automatic mower 1 is output to the steering device 13, 14. Output to devices 13.14.

In such a configuration, first, the induction cable 5 is connected to the fourth
A case will be described in which the vehicle travels through a location buried in a straight line as shown by the dashed line in the figure.

The front pickup coil 7.8 detects point A on the induction cable 5, the central pickup coils 9, 10 detects point B on the induction cable 5, and the rear pickup coil 11.12 detects point A on the induction cable 5. Detect point C on 5. Here, since the point A is located in the middle of the pickup coil 7.8, the detection voltages of the pickup coil 7.8 become equal, and similarly, the detection voltages of the pickup coils 9 and 10 that detected the B point become equal, and , the detection voltages of the pickup coils 11 and 12 that detected point C become equal.

Then, the detection results from each of the pickup coils 7 to 12 are input to the prediction calculation means, and the prediction calculation means predicts that the induction cable 5 is buried in a straight line.

Further, based on the prediction by the prediction calculation means, a steering control signal is output from the control device 17 to the steering device 13, 14, and the front wheels 2 and rear wheels 3 are controlled to be steered to the reference steering angle. In addition, since the guiding cable 5 is buried in a straight line and the self-driving lawn mower 1 is driven straight, the reference steering angles of the front wheels 2 and rear wheels 3 are both "Oo".
” becomes.

Next, a case where the induction cable 5 is buried in an arc shape as shown by the broken line in FIG. 4 will be described. Point A on the induction cable 5 is detected by the pickup coils 7 and 8 at the front, point D on the induction cable 5 is detected by the pickup coils 9 and 10 at the center, and point D on the induction cable 5 is detected by the pickup coils 11 and 12 at the rear. Point C on 5 is detected.

Here, since point A is located in the middle of pickup coil 7.8, the voltages detected by pickup coil 7.8 are equal, and similarly, the voltages detected by pickup coil 10.11, which detected point C, are equal. On the other hand, since point D is located biased toward the pickup coil 10 from the midpoint between the pickup coils 9 and 10, the detection voltage of the pickup coil 10 increases and the detection voltage of the pickup coil 9 decreases.

Then, the detection results from each pickup coil 7 to 12 are input to the prediction calculation means, and the prediction calculation means predicts that the induction cable 5 is buried in an arc shape with the center on the left side of the automatic mower 1. Ru. Further, based on the prediction by the prediction calculation means, a steering control signal is output from the control device 17 to the steering device 13, 14, and the front wheels 2 and rear wheels 3 are controlled to be steered to the reference steering angle. Note that this reference steering angle is "α°" toward the left on the front wheel 2 side, and "α°" toward the right on the rear wheel 3 side. In addition, this standard steering operation angle “
α°'' changes depending on the difference in detected voltages of the pickup coils 9 and 10, and can be obtained by calculation based on the difference in detected voltages or from a data table corresponding to the difference in detected voltages.

Therefore, if the buried radius of the guide cable 5 buried in an arc is different at the turning point of the self-driving lawn mower l, the reference steering angle of the steering wheels 2 and 3 can be changed according to the buried radius. The self-driving lawnmower 1 turns with a reference steering angle corresponding to each buried radius.

Effects of the Invention As described above, the present invention provides sensors for detecting markers buried underground in a work area at the front, center, and rear of an autonomous working vehicle, and detects markers based on the detection results of the guides by the sensors. The buried state of the guide body is predicted by the prediction calculation means, and based on the prediction, the steering wheel is controlled to the standard steering angle by the control device. Therefore, it is possible to improve the accuracy of running along the guide and reduce the frequency of steering operations when turning, and by reducing the frequency of steering operations, it is possible to This has effects such as being able to reduce damage to the lawn caused by the facing wheels.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a block diagram showing a steering control system, FIG. 2 is a side view showing the entire self-driving lawn mower, and FIG. 3 is a front view thereof. FIG. 4 is an explanatory diagram of the turning running state.

Claims (1)

[Claims] Derivatives are buried underground along the travel course of the automatic driving work vehicle in a work area where the automatic driving work vehicle is to travel, and sensors for detecting the derivatives are installed at the front, center, and rear of the automatic driving work vehicle. a prediction calculation means for predicting the buried state of the guide based on the detection result of the guide by the sensor; and a control device for controlling the steering wheel to a reference steering angle based on the prediction of the prediction calculation means. A steering control device for an autonomous working vehicle, characterized in that it is provided with: