JPH02254506A - Steering control method for unattended carriage - Google Patents

Abstract

PURPOSE:To quickly run an unattended carriage by detecting the turn angle of a steering shaft at the time of using the output of a fixed guide sensor for steering control to backward run the carriage and controlling steering so that this turn angle follows up the extent of deviation obtained from the output of a guide sensor. CONSTITUTION:At the time of backward running, outputs of guide sensors 9R and 8L are supplied to input terminals of a comparing circuit 25, and this circuit 25 sends a voltage DELTAV proportional to the extent of deviation of the center of a guide sensor unit from a guide line. At the time of slow running, an output Vtheta of a steering shaft turn angle detector 27 is converted to KbXVtheta by a coefficient circuit 28 and is inputted to an error amplifying circuit 26. This circuit 26 detects the deviation between DELTAV and KaXVtheta, and a steering controller controls a steering motor so that this deviation is zero. Thus, the carriage is quickly run backward.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a steering control method for a three-wheeled automatic guided vehicle.

[Conventional technology]

FIG. 2 shows a conventional three-wheeled automatic guided vehicle of the magnetic guidance type, and numeral 1 indicates a magnetic tape guide wire laid on the road surface.

2 is an automatic guided vehicle, 3 is a steering drive wheel (front wheel), 4.4 is a fixed wheel (rear wheel), 5 is a steering motor, 6 is a steering shaft, 7 is a travel motor, 8 is a forward guide sensor unit, 9 is the reverse guide sensor unit.

The forward guide sensor unit 8 is movable and attached to the steering shaft 6, and detects the magnetic field from the guide wire 1 and sends it to a steering control device (not shown).
This steering control device is a guide sensor unit 8.
The rotation amount of the steering motor 5 is controlled so that the output deviation of the guide sensor 8R18L (the amount of deviation of the guide sensor unit center 0 from the guide line 1) becomes zero, and the steering drive wheel 3 is steered. The reverse guide sensor unit 9 is fixed to the vehicle body.

[Problem to be solved by the invention]

In this type of automatic guided vehicle 2, when traveling forward, the direction of the guide sensor unit 8 is controlled as well as the steering drive wheels 3, so the center of the guide sensor unit 8 follows the guide line 1, and when turning However, in reverse driving where the steering is controlled using the output of the guide sensor unit 9, the center 0 of the guide sensor unit 9 is relative to the guide line 1 when turning. Therefore, in order to run stably, it is necessary to reduce the traveling speed compared to when traveling forward.For this reason, conventionally, when traveling backwards, the forward traveling speed is lowered even in straight traveling sections. hourly speed (e.g. 7.5 km/h)
The automatic transport system is run at a lower speed (for example, 2.0 km/h), and there is a problem in that the work efficiency of the unmanned transportation system is lowered due to this low backward speed control.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a steering control method for an automatic guided vehicle that allows the vehicle to travel backwards at a higher speed than before.

(Means for Solving the Problems) In order to achieve the above object, the present invention detects the sharpness angle of the motor shaft of the steering motor when traveling in reverse, and detects the sharpness angle from the coefficient multiplication value of this sharpness angle and the output of the guide sensor. According to a second aspect of the present invention, the steering control is performed so that the difference between the amount of deviation and the amount of deviation between the steering wheel and the steering wheel is zero. It is.

[Function] In the present invention, when traveling in reverse, the sharp angle of the steering shaft is
Since the steering motor is controlled to follow the amount of deviation detected from the output of the fixed guide sensor, the steering control system is stable even when the vehicle is running at a higher speed than before when turning.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In FIG. 1, 20 is a steering control device 20 mounted on the automatic guided vehicle 2. As shown in FIG. 21R121L is a signal amplification circuit, 22R and 22L are filters, 23R123L
indicates an absolute value circuit. Reference numeral 24 denotes a forward/reverse switching section, which switches both switches SR and SL to the F side when receiving a forward command, and switches switch SR and SL to the F side when receiving a reverse command.
, SL are both switched to the R side. 25 is a comparison circuit that detects the difference between the absolute value circuits 23R and 23L and calculates the difference Δ
(2) is supplied to one input terminal of the error amplification circuit 26.

27 is a steering shaft angle detector, which is connected to the steering shaft 6, and in this embodiment, a potentiometer is used. This steering shaft sharpness angle detector 27
The output Vθ is supplied to the other input terminal of the error amplification circuit 26 through the coefficient circuit 28 and the switch 29. This switch 29 closes when receiving a reverse command.

When the coefficient circuit 28 receives a high speed command, it sets a coefficient Ka, and when it receives a low speed command, it sets a coefficient )(b (>Ka)).

In this configuration, when the automatic guided vehicle 2 is traveling forward, both the switches 5RSSL and 5RSSL are switched to the F side, so the output of the guide sensor 8R is transmitted to the comparison circuit 25 through the signal amplification circuit 21R, filter 22R2, absolute value circuit 23R. is supplied to one input terminal of the guide sensor 8L, and the output of the guide sensor 8L is
Signal amplification circuit 21L, filter 22L5 absolute value circuit 23
is supplied to the other input terminal of the comparator circuit 25 through L,
The comparator circuit 25 is a guide sensor unit 8 for the guide wire 1.
A voltage Δ■ proportional to the amount of deviation of the center O of is sent out. Since the switch 29 is off when the automatic guided vehicle 2 is traveling forward, this deviation amount ΔV is outputted through the error amplification circuit 26, and the steering motor 5 controls the amount of rotation so that this deviation amount Δ■ becomes zero. be done.

When traveling in reverse, both switches SR and SL are switched to the R side, so the output of the guide sensor 9R is transmitted to the signal amplification circuit 2.
1R, is supplied to one input terminal of the comparator circuit 25 through the filter 22R1 and the absolute value circuit 23R, and the guide sensor 8
The output of L is supplied to the other input terminal of the comparator circuit 25 through the signal amplification circuit 21L1 filter 22L and the absolute value circuit 23L, and the comparator circuit 25 is proportional to the amount of deviation of the center 0 of the guide sensor unit 8 with respect to the guide wire 1. Voltage Δ
■Send out. Switch 2 when automatic guided vehicle 2 is running backwards.
9 is on, the output Vθ of the steer shaft sharpness angle detector 27 is changed to KbXV by the coefficient circuit 28 when driving at low speed.
After being converted into θ, it is input to the error amplification circuit 26. The error amplifier circuit 26 detects the deviation between Δ■ and KaXVθ,
The steering control device 10 calculates this deviation (ΔV and KaXV
The steering motor 5 is controlled so that θ) becomes zero.

That is, in this embodiment, the sharpness angle θ of the steering shaft 6
Since the rotation amount of the steering motor 5 is controlled so that a value proportional to the deviation amount ΔV detected from the output of the guide sensor 9R19L is
km/h). Note that the response delay of the steering control system is relatively large, so when driving at high speed, the coefficient Ka set in the coefficient circuit 28 is set to a smaller value than when driving at low speed, from the viewpoint of stability of the control system. It is desirable to do so.

[Effects of the Invention] As explained above, the present invention detects the sharp angle of the steering shaft when traveling in reverse and uses the output of the fixed guide sensor for steering control, and this sharp angle is used as the output of the guide sensor. Because the steering is controlled to follow the amount of deviation obtained from .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a diagram schematically showing a conventional three-wheeled automatic guided vehicle. In the figure, 8R18L, 9R, L-・Guide sensor,
24--forward/reverse switching section, 23R, 24L--absolute value circuit, 25--comparison circuit, 26--error amplification circuit, 27-
Steer shaft sharpness angle detector, 28-・Coefficient circuit, 29-...
switch.

Claims (2)

[Claims] (1) A three-wheel automatic guided vehicle that uses a guide sensor to detect the amount of deviation of the vehicle body with respect to a guide line laid on the road surface, and performs steering control based on the amount of deviation, and has a steering mechanism for the front wheels, In a vehicle that has a movable forward guide sensor supported on the shaft of the steering motor and a fixed reverse guide sensor mounted on the vehicle body, when traveling in reverse, the sharpness angle of the shaft is detected and the sharpness of this sharpness angle is detected. A method for controlling the steering of an automatic guided vehicle, comprising controlling the steering so that the difference between the coefficient multiplication value and the deviation amount becomes zero. (2) The steering control method for an automatic guided vehicle according to claim 1, wherein the coefficient is variable and is set smaller when traveling at high speed than when traveling at low speed.