JPS6316309A - Drive control system for unmanned traveling object - Google Patents

Abstract

PURPOSE:To avoid an obstacle in the shortest distance for an unmanned traveling object with no useless action by using an obstacle detector utilizing >=2 ultrasonic waves and avoiding the obstacle so that the envelope curve of the locus of the traveling object has a contact with the external form of the obstacle in a recognizing range of the obstacle. CONSTITUTION:The reflection of ultrasonic waves received from ultrasonic wave obstacles 30a-30c of a vehicle is utilized to detect an obstacle existing in the traveling direction of the vehicle. The recognizing range of the output of ultrasonic waves is increased and reduced with a high traveling speed and a low traveling speed of the vehicle respectively. Thus the possibility of collision is surely decided. If an obstacle E is recognized, the vehicle is controlled to avoid the obstacle so that the envelope of the vehicle traveling locus has a contact with the external form of the obstacle in a recognizing range.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a traveling control method for a moving object, and particularly to a technology that is effective when used in a traveling control method for an unmanned moving object that can move without a pilot. .

[Prior Art] In recent years, various technologies have been researched to allow moving objects such as automobiles and guided vehicles to run unmanned. Some of them have already been put into practical use.

In contrast, by giving course information to the control system of an unmanned vehicle,
A method has also been proposed that allows the vehicle to travel independently while recognizing its own location.

In the case of non-guided unmanned vehicles such as those mentioned above, if there is an obstacle in the way of the traveling course, the vehicle must either stop traveling or
Actions to avoid obstacles are required. Therefore, conventionally, some unmanned moving bodies are equipped with ultrasonic sensors or the like to detect the presence or absence of obstacles in front of the vehicle in the direction of travel.

[Problems to be solved by the invention] Conventional unmanned moving objects equipped with ultrasonic sensors, etc. only detect the presence of obstacles. In such cases, even in situations where there was no danger of a collision, the vehicle would stop, treating the object as an obstacle.

Furthermore, since there was no effective method for avoiding obstacles, there was a problem in that unnecessary avoidance operations were often required.

[Objective of the Invention] The object of the present invention is to reliably identify obstacles that may collide with objects that have no possibility of colliding, and avoid them only when necessary. An object of the present invention is to provide a running control system for an unmanned moving body that can avoid objects.

[Means for solving the problem] Two or more devices that emit directional signals such as ultrasonic waves are installed, emitted in the direction of travel, and the reflected waves are detected to detect signals ahead in the direction of travel. Detects an object, measures the distance to the object, determines whether it is an obstacle in relation to the vehicle's running speed, and, if an obstacle is recognized, calculates the trajectory of the object within the recognition range. The avoidance operation is performed so that the envelope touches the outline of the obstacle.

[Effects] According to the above means, the faster the vehicle is traveling, the wider the obstacle recognition range is, and the slower the vehicle is traveling, the narrower the recognition range is, and the more the vehicle is traveling, the wider the recognition range is, and the slower the vehicle is traveling, the narrower the recognition range is. Become.

[Embodiment] FIG. 1 shows an embodiment of a travel control system to which the travel control method for a moving body according to the present invention is applied.

A rear wheel 5a as a running drive wheel having a differential mechanism 6;
Encoders 20a and 20b for detecting the rotation speed are provided corresponding to each of the encoders 20a and 20b.
Detection signals (pulses) from a and 20b are counted by pulse counters 24a and 24b, and the controller 25
through the I10 interface circuit in the computer (
(CPU) 22. The computer 22 determines the travel distance by taking the average value of the rotation speeds of the left and right wheels counted by the pulse counters 24a and 24b, and also determines the direction of travel of the vehicle from the difference in rotation speeds.

The computer 22 also includes pulse counters 24a and 2.
The IC recognizes its own position by the signal from 4b.
According to the course information read into the internal main memory from a storage device 26 such as a cassette, the travel drive motor 7 as a rotation drive means and the steering motor 11 as a turning drive means are controlled to move the vehicle along a predetermined course. It is designed to run.

Moreover, in this embodiment, in order to detect obstacles that exist particularly in the direction of travel while driving, the obstacle consists of a transmitter that emits highly directional signals such as ultrasonic waves, and a receiver that detects the reflected waves. An object detection means 30 is provided, and based on the detection signal from this detector, a computer determines whether or not the object is an obstacle, and if it is determined to be an obstacle,
Evasive actions are taken according to appropriate procedures.

Although not particularly limited, in this embodiment, three obstacle detection means 30 are provided, and
As shown in Fig. 4, the detection means 30a is used to detect the center of the vehicle in the direction of travel, and the detection means 30b and 30c are used to detect the diagonally left front and right diagonally front, respectively, and the vehicle is expected to move as a whole. It is designed to detect obstacles within the range.

FIG. 2 shows a configuration example of a control circuit of the obstacle detection means 30.

The driver 28 that drives the transmitter 31 is the computer 2
For example, based on the reference clock A supplied from 1.
A drive signal is supplied to the transmitter 31 at second intervals to cause it to emit a transmission wave B (see FIG. 3), and a start signal is sent to the counter 29 to start counting. When the emitted transmission wave B hits an object in front of the vehicle in the direction of travel and the reflected wave C is reflected by the receiver 32, the counting operation of the counter 29 is stopped at the time when the reflected wave is detected. (The driver 28 and counter 29 are provided in the controller 25 in the circuit shown in FIG. 1).

At this time, the time during which the counter 29 is operating is proportional to the distance from the vehicle to the object in front of it in the direction of travel. Therefore, the computer 22 reads the value counted by the counter 29 from the time the transmitted wave B is emitted until the reflected wave C is detected, and calculates the distance between the vehicle and the object in the traveling direction.

Then, in relation to the speed of the vehicle at that time, it is compared with a preset distance to determine whether the object is an obstacle, and if it is determined to be an obstacle, a predetermined avoidance action is taken. It is now possible to do this.

That is, if the transmission period of the transmitter 31 is set to 1 second or less, the direction in which the vehicle travels in 1 second can be considered to be within a very small range left and right from the center line of the vehicle body. On the other hand, the distance that the vehicle is expected to travel within one cycle differs depending on whether the vehicle speed is fast or slow, and the faster the vehicle is, the farther it will travel, so it is necessary to widen the range that should be recognized as an obstacle.

Therefore, in this embodiment, the obstacle recognition range is changed according to the vehicle speed, and when the vehicle speed is fast, the obstacle recognition range (indicated by diagonal lines) is widened as shown in FIG. The time is narrowed as shown in Figure 4 (B). In other words, the obstacle recognition cylinder BD is made to be slightly larger than the vehicle's expected travel range. As a result, even if the object is in the same direction of travel, an object located at the position shown by the symbol E in Fig. 4(B) is considered an obstacle when the vehicle speed is fast, but when the vehicle speed is slow, it is considered an obstacle. Therefore, if it is a moving object, or if the vehicle is changing direction and moves out of the direction of travel before entering the vehicle's obstacle recognition range, it will not be recognized as an obstacle. .

Conventional unmanned vehicles equipped with obstacle detection means stop or take evasive action when the vehicle is recognized as an obstacle in the above cases, but in this embodiment, the vehicle speed is slow and fast. Since the obstacle recognition standards differ from time to time, unnecessary stops and avoidance actions are not performed.

The unmanned vehicle of this embodiment is provided with an input operation device 27 such as a keyboard (see FIG. 1) so that the recognition distance can be set from the outside in accordance with the vehicle speed.

Next, an example of the procedure of the obstacle avoidance operation performed by the computer 22 after the obstacle has been recognized as described above will be explained.

The unmanned moving body of this embodiment first determines whether or not it is an obstacle based on the detection signals from the obstacle detection means 30a to 30c as described above, and once it is recognized as an obstacle, it temporarily stops. Then, it is determined whether the obstacle is on the left or right side of the vehicle center line based on the detection signals from the obstacle detection means 30a to 30c. This type of determination can be easily performed if there are two or more obstacle detection means as in the above embodiment.

Next, the steering device is actuated to change the direction of the vehicle in the direction opposite to the side where the obstacle was recognized, and then the travel drive device is actuated. The maximum avoidance steering angle at this time may be set in advance using a keyboard or the like.

Then, when the obstacle is no longer recognized, the steering device is operated to return to the original course, that is, in the opposite direction to the avoidance direction. Then, if the obstacle is recognized again, the direction is corrected to avoid it.

By repeating the above operations, as shown in Figure 5,
The vehicle performs an avoidance operation so that the envelope of the movement trajectory of the obstacle recognition range Fi as the unmanned vehicle moves comes into contact with the outer shape of the obstacle E. At this time, since the actual vehicle always moves outside the envelope of the obstacle recognition range, contact between the vehicle and the obstacle is reliably avoided. Moreover, since no extra evasive action is required, the vehicle can return to its original driving course in the shortest possible distance.

In addition, in the above embodiment, it was explained that it is determined whether the obstacle is on the left or right side of the vehicle center line and the vehicle is steered to the opposite side. If not, it may be set in advance to avoid it to either the left or the right.

In the above embodiment, ultrasonic waves are used as highly directional signals, but it is also possible to detect obstacles by using infrared rays or by emitting radio waves with a directional antenna and detecting the reflected waves. It may also be detected.

[Effects of the Invention] As explained above, this invention provides two or more devices that emit directional signals such as ultrasonic waves, emits them in the direction of travel, detects the reflected waves, and detects the reflected waves. The system detects objects ahead in the direction of travel, measures the distance to the object, and determines whether it is an obstacle based on the relationship with the vehicle's traveling speed, so the faster the vehicle is traveling, the more The recognition range of obstacles becomes wider, and the lower the driving speed, the narrower the recognition Ra8 range becomes.This function allows you to reliably identify obstacles that may or may not collide with you. It can be avoided only when necessary. Also,
When an obstacle is recognized, avoidance action is performed so that the envelope of the movement trajectory within the recognition range touches the outline of the obstacle, so there is no need for extra avoidance action, and the process can be performed over the shortest distance. This has the effect of being able to avoid obstacles.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a block diagram showing an embodiment of a travel control system to which the mobile object travel control method according to the present invention is applied. FIG. 2 is a configuration example of an obstacle detection circuit. FIG. 3 is an explanatory diagram showing the operation timing of the obstacle detection circuit. FIGS. 4 (A) and (B) are planar explanations showing the difference in recognition range due to the difference in distance to the obstacle. FIG. 5 is an explanatory diagram showing a method of obstacle avoidance operation. 2...Front wheels, 5a, 5b...Traveling drive wheels (
(rear wheel), 7... rotational drive means (travel drive motor),
11...Turning drive means (steering motor), 22...
...Control device (computer), 30...Obstacle detection means, 31...Ultrasonic transmitter, 32...Receiver. Figure 2 Figure 3 ≠)

Claims (1)

[Claims] (1) It is equipped with a traveling drive wheel and its rotational drive means, a wheel coupled to a steering shaft and its turning drive means, and a control device that performs drive control of the rotational drive means and the turning drive means, and is capable of independent movement. An unmanned mobile object configured to include an obstacle detection means for detecting an obstacle by transmitting a directional medium and detecting the reflected wave, and detecting an obstacle based on a detection signal from the obstacle detection means. It calculates the distance to the object and determines whether it is an obstacle according to the vehicle speed at that time, and if it is recognized as an obstacle, the envelope of the movement trajectory of the obstacle recognition range is determined to be an obstacle. A traveling control method for an unmanned moving object, characterized in that an avoidance operation is performed so as to touch the outer shape of the object.