JPH04303216A - Position detector for unmanned carrier - Google Patents

Abstract

PURPOSE:To detect the position of an unmanned carrier, which is moving within a prescribed range, with a high precision in a simple constitution by obtaining the absolute position of the unmanned carrier by means of angles of a camera part in horizontal and vertical directions by calculation. CONSTITUTION:A light source 2 is mounted on an unmanned carrier 1 moved within the prescribed range, and a camera part 4 is set at such certain height that the range of movement of the unmanned carrier 1 is covered, and this camera part 4 photographs a light source 2 and has the tracking function to control the angle of photographing so that the image of the light source 2 is always in the center of the taken picture. That is, a two-axis driving mechanism 5 which varies the angle of photographing, namely, a vertical angle theta1 and a horizontal angle of the camera part 4 independently of each other, and this mechanism 5 is so controlled that the image of the light source 2 picked up by the camera part 4 is always in the center of the taken picture, and the tracking control of the angle of photographing of the camera part 4 is performed. The absolute position of the unmanned carrier 1 is obtained by calculation in accordance with the angle of deflection in the horizontal and the angle of inclination in the vertical direction of the camera part 4.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position detection device for an automatic guided vehicle that moves within a predetermined range and transports equipment, luggage, etc.

0002

[Prior Art] Conventionally, when controlling the movement of this type of automated guided vehicle, the method of using so-called guide wires, which involves pasting magnetic tape or optical tape along the travel route or embedding electric wires to guide the movement, has been used. However, in this case,
There is a problem in that it takes time and effort to lay the guide wire. In addition, as a method that does not use guide lines as described above, the position of the automatic guided vehicle is detected from the amount of rotation of the gyro or wheels,
There is a method of guiding an automatic guided vehicle based on this, but since this type of position detection can only detect relative positions, there is a problem that errors accumulate and accuracy deteriorates.

[0003] Therefore, in order to precisely control the movement of an automatic guided vehicle without installing guide lines, it is necessary to detect the absolute position of the automatic guided vehicle. Publication (G01C 15/0
0) (hereinafter referred to as the first publication), a pair of light emitting and receiving parts consisting of a light emitting part and a light receiving part are directed to a predetermined position where the movement range of the robot (automated guided vehicle) is desired and the robot, respectively. The robot's position is detected from the angle formed by the pointing direction when one light receiving section receives light from the other light emitting section.

Alternatively, as shown in Japanese Patent Application Laid-Open No. 62-297705 (G01B 11/00) (hereinafter referred to as the second publication), light from a fixed light source attached to the ceiling etc. is used in an automatic guided vehicle. Focus the light with a lens device and C
It is possible to calculate the position coordinates of an automatic guided vehicle from the incident position on the CD matrix,
) (hereinafter referred to as the 3rd Publication), multiple light sources installed on an automatic guided vehicle are used as beacons to be photographed by a camera, and visual information from the beacons is converted into a video signal to obtain position information. .

[0005]

[Problems to be Solved by the Invention] In the case of the above-mentioned conventional position detection device, in the case of the first publication, it is necessary to provide two sets of light emitting/receiving sections, one at the desired position of the movement range, and the other at the robot. It is necessary to drive and control these so that the light emitting/receiving part at a predetermined position and the light emitting/receiving part of the robot face each other so that each of them can be oriented freely.In this case, each light emitting/receiving part must be oriented with respect to two axes, horizontal and vertical. There is a problem in that the number of driving parts increases and the configuration becomes complicated.

Furthermore, in the case of the second publication, since the lens device, CCD matrix, etc. are placed on the moving automatic guided vehicle, errors occur in the determined position coordinates due to distortion of the floor surface and tilt of the automatic guided vehicle. There are still problems with accuracy, and
In the case of the third publication, the detection range is narrow because the field of view of the camera is limited, and multiple cameras are required to cover the entire movement range of the automatic guided vehicle, which has the disadvantage of complicating the configuration. be.

[0007] The present invention has been made in consideration of such problems of the conventional technology, and its purpose is to detect the absolute position of an automatic guided vehicle with high accuracy using a simple configuration. The purpose of the present invention is to provide a position detection device for an automatic guided vehicle that can perform the following tasks.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the position detection device for an automatic guided vehicle of the present invention includes a light source mounted on the upper part of an automatic guided vehicle that moves within a predetermined range; The system is equipped with a camera section that is installed at a certain height overlooking the moving range of the automatic guided vehicle and has a tracking function that photographs the light source and controls the photographing angle so that the image of the light source is always at the center of the imaging screen. The absolute position of the automatic guided vehicle is calculated from the horizontal shake angle and vertical tilt angle of the camera unit.

[0009]

[Operation] When photographing a light source mounted on an automatic guided vehicle, the camera unit installed at a certain height is set at a photographing angle, that is, in the horizontal direction of the camera unit, so that the image is always in the center of the imaging screen. In order to make the vertical angle follow the movement of the automatic guided vehicle, by using these horizontal and vertical angles and the vertical distance between the camera unit and the light source, The absolute position of an automated guided vehicle can be calculated.

0010

[Example] An example will be explained with reference to the drawings. Figure 1
As shown in , a light source 2 is mounted on the top of an automatic guided vehicle 1 that moves within a predetermined range, and a camera 4 that photographs the light source 2 is mounted on a ceiling 3 that can sufficiently see the entire movement range of the automatic guided vehicle 1. In addition, a two-axis drive mechanism 5 is provided to independently vary the photographing angle of the camera 4, that is, the vertical angle θ1 and the horizontal angle θ2, so that the image of the light source 2 photographed by the camera 4 is always at the center of the photographic screen. The two-axis drive mechanism 5 is controlled so that the shooting angle of the camera 4 is tracked.

Vertical angle θ1 which is the photographing angle of camera 4
and the horizontal angle θ2 are detected independently by encoders attached to each rotating shaft of the two-axis drive mechanism 5. The vertical distance h between the light source 2 at a predetermined height mounted on the automatic guided vehicle 1 and the camera 4 at a predetermined height installed on the ceiling 3 is constant and must be determined in advance. As shown in Fig. 1, the horizontal distance l between the light source 2 on the automatic guided vehicle 1 and the vertical axis of rotation of the camera 4 can be calculated using the following formula using the vertical angle θ1 of the camera 4. It can be found by 1.

0012

[Math 1]

Therefore, as shown in FIG.
Horizontal direction with the origin (Z axis) at the vertical rotation axis of
The position (x, y) of the light source 2 in the Y coordinate, that is, the position (x, y) of the automatic guided vehicle 1, can be calculated from the following equations 2 and 3 using the horizontal angle θ2 of the camera 4.

[0014]

[Math 2]

[0015]

[Math 3]

As a result, by controlling the angle of the camera 4 installed on the ceiling 3 by following the light source 2 of the automatic guided vehicle 1, and detecting the vertical angle θ1 and horizontal angle θ2 of the camera 4 at this time, the unmanned The absolute position of the guided vehicle 1 can be easily calculated, and the movement of the automatic guided vehicle 1 can be controlled with high precision.

[0017]

[Effects of the Invention] Since the present invention is constructed as described above, it produces the following effects. The camera unit that photographs the light source of the automatic guided vehicle is tracked so that the image of the light source is in the center of the imaging screen, and the absolute position of the automatic guided vehicle is calculated from the horizontal and vertical angles of the camera unit at this time. Because the system is determined by Furthermore, since the automatic guided vehicle is only equipped with a light source, highly accurate position detection is possible even if the floor surface is distorted or tilted.

[Brief explanation of the drawing]

FIG. 1 is a front view showing one embodiment of a position detection device for an automatic guided vehicle according to the present invention.

FIG. 2 is a plan view of FIG. 1;

[Explanation of symbols]

1 Automatic guided vehicle 2. Light source 4 Camera

Claims (1)

[Claims] 1. A position detection device for an automatic guided vehicle that moves within a predetermined range, wherein a light source mounted on the top of the automatic guided vehicle and a position at a certain height overlooking the moving range of the automatic guided vehicle are provided. and a camera section that is installed and has a tracking function for photographing the light source and controlling the photographing angle so that the image of the light source is always at the center of the imaging screen, and the camera section has a horizontal shake angle and a vertical tilt of the camera section. A position detection device for an automatic guided vehicle, characterized in that the absolute position of the automatic guided vehicle is calculated from an angle.