JPH0442707A - Travel control method for mobile vehicle - Google Patents

Abstract

PURPOSE:To perform acceleration/deceleration control of a travel drive motor so that the relative speed to a preceding vehicle will be zero by mounting a distance sensor outputting the distance to the preceding vehicle as a distance data and a microcomputer and then operating the relative speed to the preceding vehicle based on the distance data. CONSTITUTION:Each mobile vehicle 1 traveling on a same track takes in a distance data to a preceding vehicle from a distance sensor 3 and operates a relative speed 8V to the preceding vehicle. The relative speed 8V is then added to a current speed V1 thus operating a target speed V2 corresponding to the traveling speed of the preceding vehicle. The target speed V2 is then compared with the current speed V1. If V2=V1, traveling is sustained with the current speed V1 whereas if V2<V1, a deceleration command is provided to a motor controller 5 in order to start deceleration control and if V2>V1, an acceleration command is provided to the motor controller 5 in order to start acceleration control. Consequently, the distance between mobile vehicles is maintained approximately constant.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention provides a system for maintaining a constant inter-vehicle distance between a plurality of self-propelled carts that run on a fixed route such as an assembly work line. This invention relates to a traveling control method for driving.

(Prior art and its problems) In a work line that performs assembly, etc., multiple self-propelled transport carts loaded with workpieces are moved at a predetermined speed while maintaining an inter-vehicle distance according to the total length of the loaded workpieces. You need to run it. In such a case, a known method for controlling running is to give a speed command pulse signal to each self-propelled bogie from a common signal line, and to make each self-propelled bogie run synchronously at a speed proportional to the pulse frequency of this pulse signal. ing.

With this pulse command type travel control method, is it possible to maintain a preset inter-vehicle distance and make multiple self-propelled carts travel synchronously? There are cases where the worker or the worker artificially causes the machine to decelerate and stop temporarily. In such a case, is it possible for each self-propelled trolley behind the stopped trolley to automatically stop with the front vehicle detection sensor working to prevent rear-end collisions while closing the following distance, or is it possible to automatically return to the original following distance when restarting? cannot be returned to.

Also, is there a known method of controlling the travel of a self-propelled bogie using a front vehicle detection sensor for preventing rear-end collisions? The sensor is set to a detection distance that is slightly larger than the deceleration and stopping distance at the vehicle speed, and deceleration and stop control is performed using an on signal when the distance between the vehicle in front and the vehicle in front becomes shorter than the detection distance of the sensor. This is because the start acceleration control is only performed using the off signal when the distance between the vehicle and the vehicle in front becomes longer than the detection distance of the sensor.
Naturally, it is impossible to keep the inter-vehicle distance between each self-propelled bogie constant regardless of the traveling speed.

(Means for Solving the Problems) In order to solve the conventional problems as described above, the present invention has the following features:
- A self-propelled trolley that runs on footlight roads is equipped with a distance sensor and a microcomputer that outputs the changing distance between the vehicle and the vehicle in front as distance data. The microcomputer calculates the relative speed to the vehicle in front, and the microcomputer calculates the relative speed to the vehicle in front.
The present invention proposes a traveling control method for a self-propelled bogie, which is characterized by controlling the acceleration and deceleration of a traveling drive motor via a motor controller.

(Example) An example of the present invention will be described below based on the attached illustrative drawings.

In Fig. 1, l is a self-propelled bogie that runs on a track, and uses a reflector 2 attached to the rear end of each self-propelled bogie 1 to measure the changing inter-vehicle distance between it and the vehicle in front. Optical reflective distance sensor 3 that outputs distance data as it is (of course,
Other types of distance sensors may be used as long as they output changing inter-vehicle distance as distance data), a microcomputer 4, a motor 6 controlled by a motor controller 5, and a motor 6 driven by the motor 6. The motor 6 includes a drive wheel 7 and a pulse encoder 8 operatively connected to the motor 6.

The microcomputer 4 has the distance sensor 3
A program that calculates the rate of change in the inter-vehicle distance S to the vehicle in front, that is, the relative speed δ with respect to the vehicle in front, from distance data constantly provided by A program that calculates v1, calculates a target speed ■2 corresponding to the traveling speed of the vehicle in front from this current speed ■1 and the relative speed δV, and based on a comparison between this target speed ■2 and the current speed ■1. A travel control program for giving a deceleration command or an acceleration command to the motor controller 5 is set.

This running control program will be explained in detail based on the flowchart in FIG. 2. Each self-propelled bogie 1 on the same track will
Each vehicle travels forward by rotationally driving the driving wheels 7 by the motor 6. In this driving state, the following distance data between the vehicle in front and the vehicle in front is acquired from the distance sensor 3, and the amount of change in distance data per unit time (the (rate of change in distance), that is, the relative speed δV with respect to the vehicle in front. Then, the relative speed δV is added to the current speed (1) calculated based on the pulse transmission frequency from the pulse encoder 8, and a target speed v2 corresponding to the traveling speed of the vehicle in front is calculated. Then, this target speed V2 is compared with the current speed V1, and if V2=Vl, the vehicle continues traveling at the current speed Vl, and V
If 2<Vl, a deceleration command is given to the motor controller 5 to perform deceleration control, and if V2>Vl, an acceleration command is given to the motor controller 5 to perform acceleration control.

In other words, when traveling at the same speed as the own vehicle or the vehicle in front, δ
Since V20, V2=Vl, and the vehicle continues to travel at the current speed Vl. If the speed of the front vehicle becomes lower than the speed of the own force, δv〉0, so V2<Vl, and the deceleration control of the own force is started. If the speed of the front vehicle increases than the speed of the own force, δV〈0, so V2> It becomes Vl and acceleration control of the own army starts.

(Operations and Effects of the Invention) As described above, according to the self-propelled trolley travel control method of the present invention, the relative speed (rate of change in inter-vehicle distance) to the vehicle in front calculated based on distance data from the distance sensor is zero. Since the acceleration and deceleration control of the travel drive motor is performed so that the vehicle in front of the vehicle decelerates and accelerates, the vehicle in front automatically decelerates and accelerates, and when the vehicle in front stops, the vehicle in front also stops, and the vehicle in front of the vehicle starts. At the same time, the own vehicle also starts, so as long as acceleration/deceleration control is performed with the same deceleration and acceleration, the inter-vehicle distance between the front and rear self-propelled carts 1 is always kept approximately constant.

In other words, regardless of the initial inter-vehicle distance, it is possible to always maintain the initial inter-vehicle distance and make each self-propelled vehicle on the same track travel synchronously, so that each self-propelled vehicle on the work line By using this to control the running of a moving bogie, even if a self-propelled bogie is temporarily decelerated and stopped due to human operation, the self-propelled bogie will continue to follow the stopped bogie (each self-propelled bogie can be set arbitrarily for each of these bogies). This allows for synchronous deceleration, stopping, and simultaneous start and acceleration while maintaining the minimum required distance between vehicles, ensuring reliable collision prevention, minimizing lost time, and working efficiently. I can carry it out.

[Brief explanation of the drawing]

Figure 1 is a block diagram explaining the configuration of the self-propelled trolley, Figure 2
The figure is a flowchart explaining the control procedure.

Claims (1)

[Claims] A self-propelled trolley that runs on a fixed route is equipped with a distance sensor and a microcomputer that directly outputs the changing inter-vehicle distance to the vehicle in front as distance data. A traveling control method for a self-propelled bogie, characterized in that a computer calculates a relative speed with respect to the vehicle in front, and the microcomputer performs acceleration/deceleration control of a traveling drive motor via a motor controller so that the relative speed becomes zero. .