JPH01161412A - Automatic steering control system - Google Patents

Abstract

PURPOSE:To attain automatic steering control excellent in stability and responsiveness over a wide traveling speed area by dividing a deviation between a total feedback value and an objective value b a fixed gain, finding out the objective value of the inverse of a rotating radius of a vehicle body and controlling right and left driving motors. CONSTITUTION:When a steering command (a rotational speed increment/ decrement command value (of right and left driving motors from a traveling speed command value T) DELTAT is determined so that the angular speed of a vehicle body does snot exceed a preliminarily determined allowable value ¦omegaal¦, the rotational radius of the vehicle body 1 corresponding to a deviation from a traveling course to be changed with time is determined within a range in which the angular speed omega does not exceed the allowable value ¦omegaal¦, so that stability can be held even when the traveling speed is increased. Thereby, automatic steering control excellent in stability and responsiveness over the wide traveling speed area can be attained by selecting the gain GR' for determining the objective value I/R' of the inverse of the rotational radius of the vehicle body 1 and the allowable value ¦omegaal¦ of the angular speed omega to proper values.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic steering control system for an automatic guided vehicle over a wide range of travel speeds from slow speeds to high speeds.

In conventional automatic steering control systems, deviations from the driving course are detected using various combinations of lateral displacement, the differential value of the lateral displacement based on the traveling distance, the integral value of the lateral displacement based on the traveling distance, and the attitude angle. Steering control was performed by multiplying by a constant gain and giving feedback, but during the procedure for determining the steering command value, the steering condition (turning radius of the vehicle body) was changed according to the deviation from the driving course according to the driving speed. Since there was no element to control the speed, the feedback gain that can ensure responsiveness in the low speed range deteriorated stability in the high speed range.
In addition, there was a problem in that when the feedback gain is in a state where stability can be ensured at high speeds, responsiveness at low speeds becomes poor, and good stability and responsiveness can only be maintained at narrow running speeds. .

In order to solve these problems, the present invention introduces an element that changes the steering condition (vehicle body turning radius) corresponding to the deviation from the traveling course according to the traveling speed into the procedure for determining the steering command value. Its purpose is to enable stable and highly responsive automatic steering control over a wide range of travel speeds from very slow to high speeds.

Fig. 1 shows an example of the vehicle body (hereinafter referred to as the vehicle body) of an automatic guided vehicle that automatically steers with the left and right drive wheels to which the present invention is applied, and Fig. FIG. 2 is an example of a block diagram of an automatic steering control system when applied to a vehicle body that performs steering.

1 is the vehicle body, 2 and 2 are the left and right drive wheels, 3 is the left and right drive mechanism consisting of a drive motor, a motor controller, a deceleration mechanism, and the drive wheels, etc., ω is the vehicle body angular velocity, and E is the lateral speed defined in Fig. 1. displacement, ψ is the attitude angle defined in Fig. 1, R is the turning radius of the vehicle body 1, d1/dD is the value obtained by differentiating the detected value of the lateral displacement l by the distance traveled by the vehicle body 1 in the traveling course direction, J [-
dD is the value obtained by integrating the detected value of the lateral displacement β over the traveling distance of the vehicle body 1 in the traveling course direction, Gψ is the feedback gain of the attitude angle ψ or the differential value d//dD of the lateral displacement β, and GIl
is the feedback gain of the lateral displacement l, and G and L are the lateral displacement l
TL is the rotation speed command value of the left drive motor, T, I are the rotation speed command value of the right drive motor, T is the travel speed command value, ΔT is the steering command value (travel speed command 1/R' is the target value of the reciprocal of the turning radius, GR' is the gain that determines the target value 1/R' of the reciprocal of the turning radius, f ( ω) is the target value of the reciprocal of the turning radius 1/
This is the content of calculating the steering command value ΔT from R'.

The lateral displacement l and the attitude angle ψ can be calculated using various sensors according to various existing induction methods (for example, a pickup coil in the case of an electromagnetic induction method), or using a computer, electric circuit, etc. from the sensor detection values. To detect. Differential value dJ/dD of lateral displacement l.

The integral value f1-dD of the lateral displacement l is calculated and detected by a computer, an electric circuit, etc. from the detected value of the lateral displacement l and the rotational speed of the left and right drive wheels detected by an encoder or the like.

In the automatic steering control system shown in FIG. 2, the rotational speed command values T, , T, of the left and right drive motors are expressed as in equation (1).

Contents for calculating the steering command value (rotational speed increase/decrease command value of the left and right drive motors from the running speed command value T) ΔT f (ω)
is expressed as in equation (2).

In equation (2), W is the distance between the left and right driving wheels shown in FIG. 1, and 1ωaβ1 is a predetermined allowable value of the vehicle angular velocity ω. Further, the stone is the target value of the vehicle body angular velocity ω determined from the target value 1/R' of the reciprocal of the turning radius R of the vehicle body 1 and the detected traveling speed value V, and is expressed as in equation (3).

Here, the target value of the reciprocal of the turning radius of the vehicle body 1 is 1/R' (4
) is expressed as the formula.

−・−・−・−・・−・−・・・・・・・・・・・・・(4)
As shown in equation (4), the total amount of feedback is expressed as the gain GR'
The process of determining a target value 1/R' of the reciprocal of the turning radius R by dividing by 1/R' and outputting a steering output so that the vehicle body 1 is brought into a steering state corresponding to the target value is performed independently of the traveling speed. This process of determining the target value 1/R' of the reciprocal of the turning radius R has the effect of maintaining stability when the traveling speed is slow, but as the traveling speed increases, the effect becomes smaller.

Therefore, as shown in equation (2), set the steering command (rotational speed increase/decrease command value of the left and right drive motors from the traveling speed command value T) 8T so that the vehicle body angular velocity ω does not exceed the predetermined allowable value 10Baxl. For example, the turning radius R of the vehicle body 1 corresponding to the deviation from the driving course from time to time is determined by the vehicle angular velocity ω.
Since it is determined within a range that does not exceed the allowable value 1ωa11, it has the effect of maintaining stability even when the traveling speed increases.

Therefore, the gain GR' that determines the target value 1/R' of the reciprocal of the turning radius R of the vehicle body 1 and the allowable value lωaf of the vehicle angular velocity ω
If fl is selected to an appropriate value, stable and highly responsive automatic steering control can be performed over a wide range of travel speeds.

Note that the calculations in equations (1) to (4) are processed by a computer or an equivalent calculation by an electric circuit or the like.

As explained above, the present invention can arbitrarily change the steering condition (turning radius of the vehicle body) corresponding to the deviation from the driving course depending on the driving speed, so it is stable and responsive over a wide range of driving speeds. This has the advantage of providing good automatic steering control.

This is possible using various existing guidance methods (electromagnetic induction, optical induction,
It is applicable to magnetic guidance, visual guidance, autonomous guidance, etc.).

[Brief explanation of the drawing]

FIG. 1 shows an example of a vehicle body to which the present invention is applied and which is steered by left and right drive wheels, and FIG. 2 is an example of a block diagram of an automatic steering control system when the present invention is applied to a vehicle body as shown in FIG. be. 1...Vehicle body 2.2...-Left and right drive wheels 3--Drive mechanism procedure Display Patent Application No. 320016 of 1988 2, Title of the invention Automatic steering control system 3, Relationship to the case of the person making the amendment Patent applicant address ■617 2-1-1 Higashijintari, Nagaokakyo-shi, Kyoto Name Nippon Transport Co., Ltd. Ki Co., Ltd. Representative: Rentabe Yamaoka 4, Agent

Claims (1)

[Claims] As the deviation from the driving course, lateral displacement, the differential value of the lateral displacement based on the traveling distance, the integral value of the lateral displacement based on the traveling distance, and the attitude angle are detected in various combinations, and each detected amount is multiplied by a gain and fed back to determine the left and right In an automated guided vehicle that performs automatic steering control using the drive wheels, the target value of the reciprocal of the vehicle's turning radius is determined by dividing the deviation between the total amount of feedback and the target value by a certain gain, and the vehicle's angular velocity is adjusted to a predetermined allowable value. By calculating and outputting the rotation speed command value of the left and right drive motors according to the target value of the reciprocal of the turning radius and the travel speed command value under the condition that the rotation speed is not exceeded, An automatic steering control system that is characterized by its ability to perform automatic steering control that is stable and responsive.