JPH04161813A - Apparatus for measuring two-dimensional position and direction of moving object - Google Patents

Abstract

PURPOSE:To achieve a highly accurate measurement efficiently by using only one corner cube to calculate the position and the direction of a moving object from a distance between the moving object and a reflection mirror and both detection angles thereof when a reflected laser light is received from the reflection mirror. CONSTITUTION:An angle theta between a corner cube 2 and a cylindrical surface mirror 3 is measured by an angle detector 16 with an automatically conveying truck 1 at a position P. In utilization for a semi-fixed path type, multiple sets of the corner cube 2 and the cylindrical surface mirror 3 are set as targets T (T1, T2... and Tn) separately and arranged at a proper interval along a guidance path WO. If so, the conveying truck 1 runs freely to the subsequent position/direction detecting point D1 correcting the direction thereof from the position and direction (x,y,phi) determined at the first position/direction detecting point D. In utilization for autonomous running, the position and direction measured at the position P is replaced with the position and direction measured at the position P is replaced with the position and direction measured autonomously to delete cumulative errors.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a two-dimensional position and direction measuring device for a moving object, which is applied to guiding automatic guided vehicles used in various production lines and the like.

BACKGROUND OF THE INVENTION In recent years, automation in the manufacturing industry has progressed, and automation of position measurement of moving objects such as automatic guided vehicles in production lines has become very important. Furthermore, there are many moving objects that require non-contact position measurement.

Generally, for example, a fixed route guidance method such as an electromagnetic induction method or an optical guidance method is used to guide an automatic guided vehicle.

Problems to be Solved by the Invention However, with these fixed-route guidance systems such as electromagnetic induction and optical guidance, it is difficult to change the layout of the travel route. There is an urgent need to put a self-driving type or self-driving type into practical use. As a semi-fixed path type, one using a laser or a marker has been devised, but it is difficult to implement it. In addition, there are self-propelled types that use wheel rotation measurement or gyros, but all self-propelled types involve accumulation of errors, so it is necessary to periodically correct the cumulative errors. There is.

On the other hand, as shown in Japanese Unexamined Patent Publication No. 62-254007, a method has been proposed in which the angle between three corner cubes installed at a distance from a moving object is measured using a laser beam, and the position is detected. However, the corner cube is a very expensive optical element, and the problem is that the corner cube accounts for most of the material cost of this system. Furthermore, by using the 311 corner cube, three angles must be measured, and the influence of measurement errors is unavoidable.

The present invention was made in view of the above-mentioned circumstances, and aims to reduce costs by using only one corner cube, and is less affected by errors in angle measurement, and is suitable for semi-fixed light path guidance systems. It is an object of the present invention to provide a two-dimensional position and direction measuring device for a moving object that is easy to deal with and correct accumulated errors of a self-propelled moving object.

Means for Solving the Problems In order to achieve the above object, the present invention includes one reflecting mirror installed at an arbitrary position parallel to the position measurement plane of a moving object, and an extension of the reflecting surface of this reflecting mirror. one corner cube arranged at a predetermined interval on a line; and a corner cube provided on the moving object to receive each reflected laser beam when the laser beam is irradiated to the reflecting mirror and the corner cube; a rotating laser projector/receiver that detects the angle between the moving object and the direction of the moving object, and the angle between the moving object and the reflecting mirror when the reflected laser beam is received from the reflecting mirror. The system is configured to calculate the position and direction of a moving object from the distance and both detection angles.

According to the present invention, the corner cube and the reflecting mirror are irradiated with a laser beam from the laser rotating projector/receiver provided on the moving object, and the reflected laser beam is received, whereby the interaction between the corner cube and the reflecting mirror is achieved. The angle between the moving object and the angle between the direction of the moving object and the reflecting mirror are detected, and the position and direction of the moving object are determined from the distance between the moving object and the reflecting mirror when receiving the reflected laser beam and both detection angles. is automatically calculated.

Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a configuration diagram showing a two-dimensional position and direction measuring device for a moving object, which is an embodiment of the present invention.

In the figure, l is an automatic guided vehicle as a moving object whose position is measured. 2 is a corner cube installed at a two-dimensional arbitrary position (x+, y+) (coordinate values are known) away from the automatic guided vehicle l, and 3 is the corner cube 2 above.
A reflecting mirror, for example, a cylindrical mirror, is located at a position (xo, yo) a predetermined distance away from the mirror and parallel to the position measurement plane 4 (FIG. 2). In addition, this cylindrical mirror 3 has its side facing toward the corner cube 2,
Moreover, the corner cube 2 is set to be located on the extension surface of the reflective surface of the cylindrical mirror 3 within measurement accuracy (FIG. 2).

The automatic guided vehicle 1 is equipped with a rotary laser projector/receiver 5 that irradiates the corner cube 2 and the cylindrical mirror 3 with a laser beam 8 and receives reflected laser beam 15. The configuration of this rotating laser projector/receiver 5 will be explained with reference to FIG.

In FIG. 3, 7 is a laser oscillator that emits a laser beam 8, 9 is an L-shaped mount that is driven to rotate at high speed around the optical axis of the laser beam 8 by a motor 1O, and a half mirror 11 is 4
It is supported at an angle of 5 degrees. 12 is a collimator lens that converts the laser beam 8 from the laser oscillator 7 into parallel light, and 13 is a cylindrical lens that spreads the laser beam from the collimator lens 12 in one direction.

Reference numeral 14 denotes a photodiode as a light-receiving element fixed to a vertical piece of the pedestal 9, which receives reflected light 15 when the laser beam 8 is irradiated onto the corner cube 2 or the cylindrical mirror 3. 16 is an angle detection device attached to the motor lO, and the photodiode 1
The angle θ between the corner cube 2 and the cylindrical mirror 3 and the angle θH between the cylindrical mirror 3 and the direction of the automatic guided vehicle 1 are detected from the angle detection signal output from the cylindrical mirror 3. . Note that as the corner cube 2 and the cylindrical mirror 3, those whose sizes are smaller than the position measurement accuracy are used.

Next, the operation of the above configuration will be explained.

It is assumed that an automatic guided vehicle 1, which is a position detection object and is equipped with a rotating laser projector/receiver 5, travels as indicated by arrow 0 in FIG. In the laser rotating light projector/receiver 5, the laser beam 8 from the laser oscillator 7 is converted into parallel light by a collimator lens 12, and then expanded in one direction by a cylindrical lens 13, and a half mirror rotated by a motor IO. 11
This irradiates the corner cube 2 and cylindrical mirror 3 side.

When the automatic guided vehicle 1 is at the position Q shown in FIG.
Since the reflected light 15L is not received by the photodiode 14, the angle detection signal is output only once in one rotation. 14 receives the reflected light 15 from both the corner cube 2 and the cylindrical mirror 3, so the angle detection signal is output twice in one rotation.

At position P in FIG. 1, the automatic guided vehicle l measures the angle θ between the corner cube 2 and the cylindrical mirror 3 using the angle detection device ff116.

On the other hand, the following relational expression can be obtained from the geometrical relationship shown in FIG.

n = (xt -xo)2* (yl, -yo)
2------・(1)+: If you are in the +X direction of the cylindrical mirror -: If you are in the -X direction of the cylindrical mirror y=Ax+B ・・・・・・・・・・・・
・・・・・・(3) A = (Xl −XO)/(y
o -yl) ""-" (4) B = (xo2-
xox1+ yo2- yt yo)/ (yo -y
+) ・・・・・・・・・・・・・・・・・・(5
) L=cross/lan θ ・・・・・・・
・・・・・・・・・・・・(6) φ= tan (yo
-y) / (xo -x) -〇H...
・・・・・・・・・(7) Substituting the above measurement angle θ into the above equations (2) to (6), we get
The position (x, y) of the automated guided vehicle can be determined.

The direction Φ of the automatic guided vehicle is determined by measuring the angle θH between the cylindrical mirror and the direction of the automatic guided vehicle, and substituting it into equation (7).

When this is used in a semi-fixed path type, as shown in FIG.

If the automatic guided vehicle l is arranged at appropriate intervals along the guide route Wo as T2...Tn), the automatic guided vehicle l can move to the position and direction (X ,
y, φ), corrects the direction and freely travels toward the primary position/direction detection point.By repeating the same process, the automated guided vehicle l travels along the guide path Wo along the trajectory shown by W. do. At the curve point, it is assumed that the required angle is turned without control at a preset radius. This rotation does not require much precision.

Furthermore, when using the vehicle for self-sustaining travel, the cumulative error can be eliminated by replacing the position and direction measured as described above with the self-measured position and direction at position P in FIG.

In this way, one corner cube 2 and a cylindrical mirror 3
A relatively simple configuration using the present invention can be used in a semi-fixed path type automatic guided vehicle guiding device, and it is also possible to correct cumulative errors in a self-supporting automatic guided vehicle guiding device. In particular, since the number of corner cubes 2 is only one, the cost occupied by the corner cube 2 is low and it can be manufactured at low cost, and the parts to be attached to the fixing points are only two, the corner cube 2 and the cylindrical mirror 3. Since only one piece is required, it is possible to simplify the position measurement of the fixed point.Furthermore, since it is only necessary to measure one angle for position measurement, there is little error in angle measurement and high precision can be obtained. I can do it.

By the way, in the above embodiment, the cylindrical mirror 3 is used as the reflecting mirror.
However, if the height of the laser rotation projector/receiver 5 of the automatic guided vehicle 1 is not affected by suspension, etc. and the amount of variation is small, a plane mirror may be used instead of the cylindrical mirror 3.

Effects of the Invention As described above, the present invention combines a corner cube and a reflecting mirror into one (
[By using a simple configuration in combination with a laser rotating emitter and receiver, it is possible to easily configure a semi-fixed path type guidance system or correct the cumulative error of an autonomous type. Since only one is required, costs can be reduced, and the number of corners to be measured can be reduced, making it possible to achieve high measurement accuracy.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing a two-dimensional position and direction measuring device for a moving object according to an embodiment of the present invention, and FIG. 2 is a diagram showing the arrangement relationship between a corner cube and a cylindrical mirror. FIG. 3 is a configuration diagram showing a laser rotary projector/receiver, and FIG. 4 is an explanatory diagram when the present invention is applied to a semi-fixed path type automatic guided vehicle guiding device. 1... Moving object, 2... Corner cube, 3...
Reflector, 4... Position measurement plane, 5... Laser rotation projector/receiver, 8... Laser light, 15... Reflected laser light,
L...distance, θ, θ gate...detection angle.

Claims (1)

[Claims] (1) one reflecting mirror installed at an arbitrary position parallel to the position measurement plane of the moving object; one corner cube placed at a predetermined interval on an extension of the reflecting surface of this reflecting mirror;
Provided on the moving object to receive each reflected laser beam when the laser beam is irradiated to the reflecting mirror and the corner cube, and to detect the angle between the corner cube and the reflecting mirror and the direction of the reflecting mirror and the moving object. The position and direction of the moving object are calculated from the distance between the moving object and the reflecting mirror when receiving the reflected laser light from the reflecting mirror and the detection angles of both of the above. A two-dimensional position and direction measuring device for a moving object, characterized in that the device is configured to measure the two-dimensional position and direction of a moving object.