JPH02170004A - Three-dimensional position measuring instrument - Google Patents

Abstract

PURPOSE:To measure the hand position of a robot accurately and automatically by fitting an optical distance measuring instrument to the movable part of the robot, etc., and emitting a beam to a target which has 1st and 2nd two-dimensional optical position detecting elements which are installed in parallel at a constant distance. CONSTITUTION:The optical distance measuring instrument 1 consisting of a light beam projector 4 and a photodetector 5 is fitted to the hand 3 of the robot 2 detachably. The light beam from the projector 4 passes the reference point P of the optical distance measuring instrument 1 to stroke on a point R on the 1st two-dimensional optical position detecting element 7 of the target 6 and the reflected light is photodetected by the photodetector 5 to measure the distance (d) between points P and R by trigonometry. Further, the position OR of the point R in a reference coordinate system O is found by the 1st two-dimensional optical position detecting element 7 and the position OT of a point T where the light beam transmitted through the position detecting element 7 strikes on a 2nd two-dimensional position detecting element 8 is known; and then an arithmetic unit 9 measures the three-dimensional position of the reference point P at the hand of the robot 2 accurately and speedily without any trouble.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a three-dimensional position measuring device that three-dimensionally measures a predetermined position of a movable part of an industrial robot or the like.

[Conventional technology]

Currently, in industrial robots such as automatic welding machines, the problem of machine differences is attracting attention.

Machine differences are caused by differences in parameters such as the length between joints and the torsion angle of the structure, even for robots of the same type, due to manufacturing errors, so even if two robots are given the same command, they will not follow the same trajectory. This means not drawing.

[Problem to be solved by the invention]

Therefore, in the past, even when multiple robots were used to perform the same task, the same task had to be taught as many times as there were robots, and when one robot was replaced with another robot, the same task had to be taught again. There were some inconveniences, such as having to do some teaching.

Therefore, many attempts have been made to reduce machine differences by accurately determining and correcting the above parameters for each robot. However, the fact that it required a large amount of man-hours was an obstacle that hindered its widespread use.

The present invention has been made in view of the above, and an object of the present invention is to provide a three-dimensional position measuring device that can automatically measure the hand position of each robot accurately, quickly, and without any effort. The purpose is to

[Means to solve the problem]

In order to achieve the above object, a three-dimensional position measuring device according to the present invention includes an optical distance measuring device that uses the principle of triangulation and is attached to a movable part of a robot, etc., and a light emitted by this optical distance measuring device. a first two-dimensional optical position detection element that reflects a part of the beam to a light receiver of the optical distance measuring device, transmits a part of the beam, and detects the position of the center of gravity of the light beam; a second two-dimensional position detecting element that is installed parallel to and spaced apart from the first two-dimensional optical position detecting element, and detects the position of the center of gravity of the light beam that passes through and hits the first two-dimensional optical position detecting element; and an arithmetic device that processes signals from first and second two-dimensional optical position detection elements that constitute the optical distance measuring device and the target.

[For production]

For example, as shown in FIG. 1, a light beam emitted by an optical distance measuring device 1 disposed on a hand 3 of a robot 2 passes through a reference point P of this optical distance measuring device 1, and a first two-dimensional beam is generated. When the point R hits the position detection element 7, the distance d between PR can be determined by the first two-dimensional optical position detection element 7;

Further, the light beam transmitted through the first two-dimensional position detecting element 7 follows the second two-dimensional optical position detecting element 8, so that the three-dimensional position of the reference point P of the robot's hand can be determined by a calculation device.

〔Example〕

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

FIG. 1 is a conceptual diagram of the present invention. In the figure, 1 is an optical distance measuring device 1 (optical distance sensor) that can be easily attached to and detached from a hand 3 of a robot 2. 1 consists of a light beam projector 4 and a light receiver 5, and the light beam from the light projector 4 hits a target 6 and receives the reflected light at the receiver 5, so that the light beam of the optical distance measuring device 1 is The distance d between the passing reference position P and the surface of the target 6 can be measured based on the principle of triangulation.

The target 6 has a box shape with anti-reflection processing applied to the inner wall, and first and second two-dimensional optical position detection elements 7.8 are placed on the upper and lower sides of the target 6, spaced apart by a certain distance. is installed. This two-dimensional optical position detection element [hereinafter referred to as P
S D (PostLion 5ensiLine
8 is Japanese Patent Application Laid-Open No. 59-5057.
What is shown in Publication No. 9 is a semiconductor layer formed by sequentially bonding an i-type amorphous silicon layer and an n-type amorphous silicon layer to a p-type amorphous silicon layer, and a light-transmitting layer bonded to both surfaces of this semiconductor layer, respectively. a conductive film;
This transparent conductive film is equipped with two pairs of rod-shaped electrodes arranged opposite each other in directions orthogonal to each other, and when a light beam is applied to this, the coordinates of the position hit by this light beam can be electrically determined. It is designed to detect Above side PSD
Among them, the upper PSD reflects a portion of the light beam to the light receiver 5 of the optical distance measuring device 1, and transmits a portion of the light beam.

For simplicity, as shown in Figure 2, the first and second PS
D7.8 assumes that the respective y axes are parallel, and the Z axes are coincident. Also, the upper PSD7
A filter for cutting off wavelengths other than the wavelength of the light beam projector 4 may be attached to the upper surface of the light beam projector 4.

Both the optical distance measuring device 1 and the target 6 PSD7
．． 8 is connected to an arithmetic unit 9 that processes signals from these.

The operation of the above configuration will be explained below.

Attach the optical distance measuring device 1 to the hand 3 of the robot 2,
In addition, with the target 6 at the reference position, for example, in order to simplify the explanation, as shown in FIG.
The reference position O0 of D8 is the origin O of the reference coordinate system O of the measuring jig.
Suppose you set it so that it matches.

The hand 3 of the robot 2 is moved, and the light projector 4 of the optical distance measuring device 1 attached thereto is directed toward a target 6 to project a light beam. This light beam passes through the reference position P of the optical distance measuring device 1 and reaches the first PS above the target 6.
This corresponds to point R of D7. A part of this light beam is reflected and received by the light receiver 5 of the optical distance measuring device 1, thereby determining the distance d between the PRs.

Further, another part of the light beam is absorbed by the first PSD 7 and its output signal is processed and the other part of the light beam is transmitted through the first PSD 7 to reach the target 6. This corresponds to the PSD 80 point T on the lower side, and a part of this corresponds to the second P
It is absorbed by SD8, and its output signal is processed and sent to the second -
〉 Since the distance between OT is known, OTR is triangle o, r
From ORR, it is required.

Therefore, the hand of robot 2 at the reference coordinate OT The three-dimensional position OTP of the third reference point P is −〉−〉−〉 OT P = OT R + RP More sought after.

These calculation processes are performed by a calculation device 9 using an electric circuit and a computer, and thereby the reference point P of the hand 3 of the robot 2 can be measured accurately, quickly, and without much effort.

When used in an actual robot, it is conceivable to measure the reference point P at a plurality of locations within the work space, and thereby determine the relationship between the movement trajectories.

In this case, if you use a tarp/soto that is about the size of your work space, you can measure multiple locations with one target, but in reality it is impossible to make such a large target, so It is conceivable to perform measurements using a jig that combines a plurality of targets with known relationships.

In the above embodiment, the reference position O of → of the reference point P of the hand 3 of the robot 2 with respect to the reference position Oo of the second PSD 8 is set to the origin O of the general reference coordinate system O, as shown in FIG. It is shown by replacing.

〔Effect of the invention〕

According to the present invention, the three-dimensional position in the reference coordinate system of the target 6 of the hand 3 of the robot 2, for example, which is equipped with the optical distance measuring device 1 using the principle of triangulation, can be accurately determined.
Measurements can be made quickly and without much effort.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the concept of the present invention, and FIG. 2 is a schematic explanatory diagram of the operation of an embodiment of the present invention. 1 is an optical distance measuring device, 2 is a robot, 3 is a hand, 5
6 is a light receiver, 6 is a target, 7 and 8 are two-dimensional optical position detection elements, and 9 is an arithmetic unit.

Claims (1)

[Claims] An optical distance measuring device 1 that uses the principle of triangulation and is attached to a movable part of a robot 2 or the like, and a part of the light beam generated by this optical distance measuring device 1 is transmitted to a light receiver of this optical distance measuring device 1. A first two-dimensional optical position detecting element 7 that reflects the light beam to 5, transmits a part of it, and detects the center of gravity position of this light beam, and is spaced a certain distance from this first two-dimensional optical position detecting element 7. and a second two-dimensional position detecting element 8 which is installed in parallel with the first two-dimensional optical position detecting element 7 and which detects the position of the center of gravity of the light beam that passes through the first two-dimensional optical position detecting element 7 and is installed at a predetermined position. A computing device 9 that processes signals from the first and second two-dimensional optical position detection elements 7 and 8 that constitute the optical distance measuring device 1 and the target 6. A three-dimensional position measuring device.