JPH01161414A - Automatic steering control system - Google Patents

Abstract

PURPOSE:To attain stable and accurate automatic steering control by subtracting an offset value corresponding to the radius of curvature of a course and a traveling speed from the feedback value of a steering state in arc-shaped traveling course. CONSTITUTION:If a steering angle detecting value psi goes equal to an offset value psi0 and the detecting value of an angular speed omega of a vehicle body goes equal to an offset value omega0 when a deviation from the traveling course is zero, a steering command value S goes zero and a steering wheel 2 comes to a stanstill. When the traveling course is straight, both the psi0, omega0 are zero, in the case of an arc shape, the psi0, omega0 are respectively set up to offset values corresponding to the radius of curvature of the traveling course and the traveling speed, so that even when the traveling course is straight, stable and accurate automatic steering control can be obtained similarly to the arc-like traveling course.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic steering control system for an automatic guided vehicle that travels on a course formed by a combination of straight lines and arc shapes.

In conventional automatic steering control systems for automated guided vehicles that use steering wheels to perform steering, in addition to detecting deviations from the traveling course and feeding them back, the steering angle and vehicle angular velocity are also detected and fed back as steering conditions, and the total feedback Calculates the rotation speed command value of the steering motor from the deviation of the target value.
Automatic steering control J■ is performed by outputting the output, but since feedback of the steering status is performed in the same form regardless of whether the shape of the driving course is a straight line or an arc, deviations from the driving course on an arc-shaped driving course are There was a problem in that when the vehicle reached zero, the vehicle went straight and there was a deviation from the traveling course, resulting in the vehicle traveling on an arc-shaped course with a certain lateral displacement. In addition, even if the lateral displacement feed gain and gain are increased on an arc-shaped running course to minimize this problem, the lateral displacement will not be completely eliminated, and increasing the gain will cause instability. There was a problem that occurred.

In order to solve these problems, the present invention is characterized by introducing a process that subtracts an offset amount according to the radius of curvature of the course and the running speed from the feedback of the steering condition on an arc-shaped running course. The object of the present invention is to enable stable and accurate automatic steering control to be performed even on an arc-shaped running course as well as on a straight-line running course.

FIG. 1 is an example of an automatic guided vehicle to which the present invention is applied, which is steered by a steering wheel, and shows a state in which the vehicle is traveling on an arc-shaped travel course with zero deviation from the travel course. . 1 is the body of the automated guided vehicle (hereinafter referred to as the vehicle body).
, 2 are steered wheels, and 3 are fixed wheels (wheels that are not steered).

In the state shown in Fig. 1, the vehicle body l has a steering angle of ω and a vehicle angular velocity ω
, must be generated, and these are (1) from the radius of curvature R1 of the driving course, the driving speed V, and the wheel base L.
Equation (2) is expressed as follows.

='ra n-' (-) ・・・−−１−・−−(1) ■ ・−１１−−−−・・・−・ (2) Figure 2 shows the present invention What is the automatic steering side when applied to a car body that is steered by steering wheels as shown in Figure 1? This is an example of a block diagram of the ff1l system, where 4 is a steering mechanism composed of a steering motor, a motor controller, a deceleration mechanism, a steering wheel, etc., l is a lateral displacement, and ε
is the integral value f1·dD of the lateral displacement due to the lateral displacement 2°, the traveling distance of the vehicle body 1, and the time differential value of the lateral displacement l 7! Gains GN and Gs are applied to each detected value of the differential value d1/dD of the lateral displacement l by /d t and the attitude angle ψ or the traveling path of the vehicle body 1 and vID.
1. The amount of feedback of the deviation of the driving course expressed as the value obtained by multiplying GA and Gψ and adding each, ψ is the steering angle, the sail is the offset amount of the steering angle, ω is the vehicle angular velocity, ω is the offset amount of the vehicle angular velocity, Gψ is the steering angle feedback gain, Gω is the vehicle body angular velocity feedback gain, S
is a steering command value (steering motor rotation speed command value).

In the automatic steering control system shown in FIG. 2, the steering command value (steering motor rotational speed command value) S is expressed as in equation (3).

In equation (3), when the deviation ε from the running course is zero,
When the detected steering angle value ψ is equal to the offset amount M and the detected value of the vehicle angular velocity ω is equal to the offset amount ω, the steering command value S becomes 9 and the steered wheels 2 come to rest. Therefore, when the running course is a straight line, both the general and ω are zero, and when it is an arc, the subtraction ω is a value corresponding to the curve radius and running speed of the running course as shown in equations (1) and (2). With an offset amount of , automatic steering control can be performed with the same stability and precision as in the case of a circular arc even if the travel course is a straight line.

The calculations in equations (1)2 to (3) are processed by a computer or equivalent calculations by an electric circuit or the like. Also,
In order to change the value of the offset amount depending on whether the driving course is linear or arcuate, it is necessary to know the timing of transition between the linear and arcuate driving courses of the vehicle body. This can be done by calculating the vehicle body position using a computer or the like based on the rotational speed of the left and right fixed wheels detected by an encoder or the like, or by detecting the position using a magnet and a magnetic sensor buried in the running course.

As explained above, on the arc-shaped driving course,
The vehicle body has a steering condition (
steering angle, vehicle body angular velocity).
This has the advantage that automatic steering control can be performed with the same stability and precision as on a straight course.

[Brief explanation of the drawing]

FIG. 1 is an example of a vehicle body that is steered by steering wheels to which the present invention is applied, and FIG. 2 is an example of an automatic steering control system block diagram when the present invention is applied to a vehicle body as shown in FIG. . 1... Vehicle body 2... Steering wheel 3... Fixed wheel φ... Attitude angle 4 Steering mechanism hand Continuing Nefu official writing (method) 1. Indication of the case Patent Application No. 320018 of 1988 2, Title of the invention Automatic steering control system 3, Person making the amendment Relationship to the case Patent applicant address ■617 2-1-1 Higashijintari, Nagaokakyo City, Kyoto Prefecture Name Name Nippon Yusoki Co., Ltd. Representative: Rentabe Yamaoka 4, Agent

Claims (1)

[Claims] As a deviation from the driving course, lateral displacement, the differential value of the lateral displacement by the traveling distance, the time differential value of the lateral displacement, the attitude angle, and the integral value by the traveling distance of the lateral displacement are detected in various combinations. By detecting and feeding back the angle and vehicle angular velocity, and calculating and outputting the rotational speed command value of the steering motor from the deviation between the total amount of feedback and the target value, automatic guided vehicles that are automatically steered by the steering wheel can control circular arcs. By subtracting the offset amount according to the radius of curvature of the course and the traveling speed from the steering angle and vehicle angular velocity, which are feedback of the steering condition when driving on a circular-shaped driving course, the steering angle and vehicle body angular velocity are fed back. An automatic steering control system that is characterized by performing automatic steering control with the same stability and precision as on a shaped driving course.