JPH04176782A - Turning run control method for unmanned carrying vehicle - Google Patents

Abstract

PURPOSE:To prevent an overshoot during turning run and enhance the turning speed by conducting a low speed run in sections having high steering angle speeds of steering just after turning start and just before turning end, and conducting a high speed run in a section having a low steering angle speed of steering. CONSTITUTION:An unmanned carrying vehicle 1 runs at high speed at the time of linear run on a running course 30, and when it gets in a turning section, a low-speed turning run is conducted in the section from a point A to a point B just after the turning start point in which the steering angle speed is high and a steering handle is largely steered. Then, in the section from the point B to a point C just before turning end in which the steering angle speed is low and the steering handle remains steered, a high-speed turning run is conducted. Thereafter, in the section from the point C to a point D of the turning end in which the steering angle is high and the steering handle is again largely steered, a low-speed turning run is conducted. When the point D is passed, a high-speed linear run is conducted to run the vehicle at a high speed. Thus, the balance of the vehicle body is held so that the vehicle is never run out from a scheduled track, an overshoot during the turning run is prevented, and the turning speed can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for controlling turning movement of an automated guided vehicle such as an autonomous forklift.

[Prior Art] Conventionally, when this type of automatic guided vehicle turns, the speed is sufficiently reduced just before entering the turning stroke, and the vehicle turns at a constant, reduced speed during the turn.

Furthermore, in this turning movement, the turning speed must be made slower as the turning radius becomes smaller.

[Problems to be Solved by the Invention] Incidentally, the smaller the turning radius during turning, the larger the steering angle. Therefore, when an automated guided vehicle enters a turning stroke, if the vehicle speed is high, the time delay for the steering to reach the required turning angle with respect to the planned trajectory will cause overshoot and deviate from the trajectory. . The same thing happens when you finish a turn and start driving in a straight line. For this reason, when turning, the vehicle has no choice but to turn at a slow speed that prevents steering delay.

The present invention solves the above-mentioned problems, and aims to provide a method for controlling turning movement of an automatic guided vehicle, which can prevent overshoot during turning movement of the guided vehicle and increase the turning speed.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a method for controlling turning movement of an automatic guided vehicle that performs steering control so that the vehicle starts traveling in a straight line, travels in a turning direction, and then travels in a straight line again. The vehicle is configured to travel at a low speed in the sections where the steering angular velocity is high immediately after the turn and immediately before the end of the turn, and to travel at high speed in the section where the steering angular velocity is low between the sections.

[Operation] According to the above configuration, when the automatic guided vehicle enters the turning section,
The vehicle travels at low speed in the section where the steering angular velocity is high immediately after the start of a turn and just before the end of the turn, and the vehicle travels at high speed in a section where the steering angular velocity of the steering wheel is low between the above sections.

This allows the overall turning speed to be increased without overshooting the planned trajectory.

[Embodiment] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating a method for controlling turning movement of an automatic guided vehicle according to the present invention. The automatic guided vehicle 1 (hereinafter referred to as the vehicle body) travels at high speed when traveling in a straight line on the traveling course 30, and when entering the turning section, the steering angular velocity is such that the steering is turned significantly from point A to point B immediately after the turning start point. In sections where the speed is large, the vehicle turns at low speed. Next, the vehicle turns at high speed in a section where the steering angular velocity is small, with the steering being turned from point B to point 0 immediately before the end of the turn. Then 0
In the section where the steering angular velocity is large, from point D to point D at the end of the turn, where the steering is turned back to the original position, the vehicle turns at a low speed. After passing point D, the vehicle resumes driving in a straight line at high speed.

The above-mentioned travel control is performed with reference to the position of the vehicle body l obtained by detecting the rolling distance of the wheels, and the travel course, travel speed, and steering data provided in advance.

FIG. 2 shows the configuration of an embodiment of an automatic guided vehicle.

The left and right fixed wheels 2 and 3 provided on the vehicle body 1 are provided with rolling distance detection sensors 4 and 5 that detect the rolling distance of the vehicle body 1.
are provided for each.

The driving and steering wheels 6 of the vehicle body 1 are provided with a steering angle detection sensor 7 that detects the steering angle of the steering of the vehicle body 1 and a drive speed detection sensor 8 that detects the drive speed of the vehicle body 1. Further, the right rear wheel 9 is a driven wheel.

FIG. 3 shows another example configuration of an automatic guided vehicle.

In this example, the drive wheels and the steering wheels are provided separately, and rolling distance detection sensors and drive speed detection sensors 14.15 are provided on the left and right drive wheels 12.13 of the vehicle body 11,
Further, the steering wheel 16 is provided with a steering angle detection sensor 17 .

FIG. 4 shows a functional block configuration for controlling the travel of an automatic guided vehicle. Here, the example of FIG. 2 is used as the automatic guided vehicle.

The traveling speed control device 2o is composed of a microcomputer or the like having calculation and storage functions, and receives detection signals from various sensors such as rolling distance detection sensors 4 and 5, steering angle detection sensor 7, and drive speed detection sensor 8. The vehicle body position is calculated, the deviation from a predetermined running course is determined, and a command signal is determined to eliminate this deviation. This command signal is output to the steering wheel drive section 21 to perform steering control, and a speed signal set according to the traveling course is output to the drive wheel drive section 22 to control the running of the vehicle body 1.

FIG. 5 is a flowchart showing one embodiment of the method of the present invention.

The travel control device 20 inputs signals from various sensors of the vehicle body 1 (step S1), and detects the position of the vehicle body 1 based on signals from the rolling distance detection sensors 4 and 5 (step S1).
2). Next, this detected vehicle position! Based on the pre-held driving course and driving speed, it is determined whether the vehicle is currently in a turning section (S3). If it is not in a turning section (NO in S3), the vehicle continues straight on a straight course. The vehicle determines that the vehicle is in the middle of the road, instructs a straight-line speed, and runs straight ahead (S8).

This straight running speed is assumed to be high.

While continuing the above-mentioned travel, when the vehicle body 1 enters the turning section (YES in S3), the turning start section (A-
(between points B) (S4). this is,
The area in which the vehicle is turning is determined by detecting the vehicle body position by detecting the rolling distance of the wheels. If the vehicle body 1 is in the turning start section, a low speed turn is instructed (35) and the vehicle turns at a low speed.

After that, when the vehicle passes through the turning start section (NO in S4), it is determined whether the turning end section (between points C and D) is reached (S6). If the vehicle body 1 has not yet entered the turning end zone (No in S6), a high-speed turn is instructed (S7
). As a result, even if the vehicle body 1 is turning again, between the turning start section and the turning end section (between points B and C),
Turn around at high speed.

Thereafter, when the vehicle body 1 enters the turning end section (between points C and D), the determination in S6 becomes YES, and a low speed turning is instructed (S5). This allows the vehicle to turn at low speed. After that, when the vehicle body 1 escapes from the turning end section (between points C and D), the determination in S3 becomes No, and it is determined that the vehicle has reached the straight-ahead speed again, and an instruction to travel straight is issued (S8
), driving in a straight line at high speed. Thereafter, the same operation is repeated.

Note that the low-speed running in the turning start section (between points A and B) and the turning end section (between points C and D) may be equivalent to the reduced speed during conventional turning.

Further, the present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible, and the turning start section, the turning end section, and the turning speed between them may be set as appropriate depending on the size of the turning radius. .

[Effects of the Invention] As described above, according to the present invention, the speed is reduced at the start and immediately before the end of a turn when the steering wheel is turned significantly, and the speed is increased during the turn when the steering wheel is not turned, thereby improving the balance of the vehicle body. It is possible to maintain the trajectory without deviating from the planned trajectory, prevent overshoot during turning, and increase the turning speed. Therefore, it is also possible to improve cycle time in warehouses and factories.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a method for controlling the turning speed of an automatic guided vehicle according to the present invention, and FIG. 2 is a diagram showing the configuration of an embodiment of an automatic guided vehicle.
FIG. 3 is a diagram showing another embodiment of the configuration of the automatic guided vehicle, FIG. 4 is a block diagram for controlling the travel of the automatic guided vehicle, and FIG.
The figure is a flowchart of the traveling operation related to the method of the present invention. 1.11... Transport vehicle (vehicle body), 4, 5, 14.15.
...Rolling distance detection sensor, 7, 17... Steering angle detection sensor, 8... Drive speed detection sensor, 20...
Traveling speed control device, 21... Steering wheel drive unit, 22...
- Drive wheel drive section, 30... driving course. Applicant Nippon Yuso Tachibana Co., Ltd. Agent Patent Attorney Yasushi Itatani Otsutsu 1 Figure 2 Figure 3 Tsui [ffl et al.

Claims (1)

[Claims] (1) In a turning control method for an automated guided vehicle in which the steering is controlled so that the vehicle travels in a straight line, turns, and then travels in a straight line again, the vehicle travels at low speed in sections where the steering angular velocity is high immediately after the start of a turn and immediately before the end of a turn. A method for controlling turning movement of an automatic guided vehicle, characterized in that the automatic guided vehicle travels at high speed in the sections where the steering angular velocity of the steering wheel is small between the sections.