JPS60200109A - Automatic measurement of three-dimensional shape - Google Patents

Abstract

PURPOSE:To make it possible to automatically measure a three-dimensional shape in a non-contact state, by attaching an optical system equipped with a light source and a light receiving position detector to the leading end of a robot and performing the measurement of a distance in an orthogonal axial direction while the robot is allowed to perform surface scanning. CONSTITUTION:X-axis and Y-axis coordinates data for prescribing the operative position of a robot 10 and Z-axis coordinates data for locating an optical system consisting of a light source 2 and a light receiving position detector 5 in the operable range of an object 1 to be measured are inputted to a robot control apparatus 15 prior to measurement and the optical system is made movable on one axis among X-, Y- and Z-axis by servo control so as to bring the output signal of the light receiving position detector 5 to zero. In measurement, the light receiving position detector 5 is operated every when the robot 10 is moved to each operative position for the purpose of surface scanning to move the robot 10 on one axis and the coordinates value of one axis, at the point of time when the zero signal is generated, is detected and coordinates data of remaining two axes at each operation position are taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic three-dimensional shape measuring method for automatically determining Al1 of the shape of a three-dimensional curved surface such as an outer panel of an automobile.

Conventionally, when measuring a three-dimensional shape, a stylus that is movable in horizontal and vertical planes is manually set at successive measurement points, and the X
, Y and Z axis coordinate values were read with a position detector. Therefore, not only is there a risk that the object to be measured may be damaged by the stylus, but automatic measurement is also impossible.

Therefore, it is an object of the present invention to provide a method for automatically measuring three-dimensional shapes in a non-contact manner. By scanning, the above object was achieved by using two-axis coordinate data for surface scanning and distance measurement data in orthogonal axis directions at each operating position as measurement data. Also,
As shown in FIG. 1, the non-contact distance measuring optical system includes a light source 2 that irradiates a light beam onto a measurement object 1, and a spot image reflected through an imaging lens 3, which measures the coincidence and misalignment of a spot image with respect to a light receiving axis 4. and a light receiving position detector 5 for detecting the light receiving position. Then, the robot is moved in the orthogonal axis direction so that the output signal of this detector becomes zero due to coincidence, and distance measurement is performed based on the amount of movement.

Next, the present invention will be explained based on an apparatus for carrying out the invention.

In FIG. 2, 11 is a telescopic and rotatable body of the robot 10, and 12 is a slidable arm.

13 is a hand that was played several times by arm 12. This hand includes a light source such as a laser oscillator 2 that irradiates the measurement object 1 with a light beam as shown in FIG. An optical system consisting of a camera including a light-receiving position detector 5 for receiving an image is shown facing toward the camera. The light receiving position detector 5 is, for example, a PS using a well-known silicon photodiode as a sensor for detecting the position of a light spot.
D (Position 5 sensitiveDevice
Using e), the output current of the PSD is converted into voltage by an arithmetic circuit, and when the spot image coincides with the light receiving axis, it becomes a zero signal, and when it shifts upward or downward, it becomes the position of the corresponding positive or negative level. generate a signal. 15 is Ropop) 10
It is a robot control device that controls the operating position of the trunk 11.
Movement on the Z axis, rotation of the trunk 11 and arm I due to the expansion and contraction of
A surface defined by the X-axis and the Y-axis is scanned by the second slide.

FIG. 3 shows a Z-axis control section 20 that controls the servo motor 7 that drives the cylinder 11 to expand and contract, in the robot control device 15;
An additional circuit section 3o according to the present invention is shown. Z-axis control section 20
Among them, 21 is a position detector that generates a signal corresponding to the Z-axis position of the barrel 11 in conjunction with the servo motor 7; for example, a comparator that compares the indicated value of the rotary encoder 8 with each Y-axis coordinate data An; 22 is a D/A converter, and 23 is a tri-eight. Of the additional circuit section 30, 31 is a comparator that compares the output signal of the light receiving position detector 5 with the cello level;
32 is an amplifier, 33 is an analog switch, 34 is a zero detection circuit that detects the zero output of the amplifier 32, and 35 is a register that records the indicated value of the position detector 8 at the time when the zero output occurs. The analog switch 33 is the robot lO
The output of the amplifier 32 is selected by a selection signal generated by the robot control device 15 each time the robot moves to each operating position.

This selection signal is also supplied to the zero detection circuit 34,
A zero detection operation is performed for each manual effort.

The operation is as follows.

Prior to measurement, the X-axis and Y-axis coordinate data that define the operating position of the robot 10 and the optical systems 2 to 5 are located in front of the surface of the object to be measured 7 and within their movable range. Y-axis coordinate data is input to the robot control device 15 as numerical data from, for example, a CAD system. During measurement, the robot 10 first defines the X and Y axis positions using the coordinate data Xi and Yl, and also the coordinate data Z
By supplying l to the comparator 21, the position in the Z-axis direction is defined.

Therefore, the optical systems 2 to 5 are positioned at the measurement point a.

Subsequently, when the selection signal is supplied, the analog switch 33 is switched. In this state, a reflected spot from the measuring object l directly below the measuring point a is incident on the optical position detector 5 with a deviation from the light receiving axis 4, and the comparator 31 detects the corresponding polarity and amplitude error. Generating a signal. Therefore, the servo motor 7 lowers the optical systems 2 to 5 by a distance Zl'.

Then, the zero detection circuit 34 detects the zero output of the amplifier 32, which indicates the end of this distance measuring operation of the robot 10, and causes the register 35 to record the indicated value Zl+ZI' of the light receiving position detector 8 at that time. However, if the coordinate values of measurement point a are set inside the measurement object l, unlike the case shown in the figure,
The servo motor 7 moves the optical systems 2 to 5 upward in response to the error signal of the opposite polarity from the comparator 31, and the indicated value becomes Zl-Zl'.

Next, the robot motion corresponding to the coordinate data X2, Y2, 22 of the measurement point S is performed, and in response to the primary selection signal, the scanning circuit 30 similarly performs a distance measuring operation on the Y axis, and the register 3
5, the indicated value Z2+22' of the measurement point is recorded. Thereafter, each time the robot 10 moves to measurement points c, d, etc., the Z-axis indicated values Z3+23', Z4+24
'... is obtained. Furthermore, by repeating such horizontal scanning of the object to be measured in the vertical direction, the Ropont 10 calculates the three-dimensional shape of the entire surface of the object to be measured, along with the Y-axis and Y-axis coordinate values each time. Measurement data Xl,
Yl, Zl+Zl'; X2. Y2. Z2+Z2'
; ・-・-=-; Xn, Yn, Zn+Zn' are obtained.

In the above-mentioned embodiment, the robot distance measurement operation in the Z-axis direction was performed only by the expansion and contraction of the trunk 11, but a rotary/swiveling robot that does not extend or contract may also be used to scan the surface in the same way and perform the orthogonal distance measurement operation. It is possible to perform ranging in the direction. Furthermore, the direction of distance measurement is not limited to the vertical direction, but can also be, for example, the horizontal direction. In FIG. 3, the comparator 31 is connected to the light receiving position detector 5.
It is also possible to replace the output signal with a voltage amplifier.

Since then, according to the present invention, an optical system using the principle of triangulation method has been installed at the tip of the robot (7), and the distance measurement in the orthogonal axis direction is performed while scanning the surface of the robot. It becomes possible to measure the shape. In addition, the detector that receives the spot image of the optical system outputs a zero signal when it matches the light receiving axis, and outputs a position signal corresponding to the deviation, making it possible to easily and accurately measure using servo control. Become.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a distance measuring method using triangulation according to the present invention, and FIG. 2 is a schematic configuration diagram of an apparatus implementing the present invention.
FIG. 3 is a block circuit diagram of the main part thereof, and FIG. 4 is an explanatory diagram of its operation. ■...Object to be measured, 2...Light source, 5...Representative of light receiving position detector Masaharu Fukudome 1 Figure 2 Figure 4

Claims (1)

[Claims] Light receiving position detection that outputs a zero signal when a spot image of a light source that irradiates a light beam onto an object to be measured and its reflected beam beam coincides with the light receiving axis, and outputs a position signal with a corresponding level and polarity when the spot image deviates from the light receiving axis. An optical system equipped with a detector is attached to the tip of the robot, and the robot is moved on one of the three axes of X, Y, and Z axes by servo control so that the output signal of the light receiving position detector becomes zero. coordinate data for scanning a plane defined by the remaining two axes, and the coordinate data of the one axis in which the light receiving position detector can operate at each coordinate data position. actuating the coordinate data as operation position data, and each time the robot moves to each operation position for the plane scanning, actuating the light receiving position detector to move the robot on the one axis; The coordinate value of the one axis at the time when the zero signal is generated is detected, and the coordinate data of the remaining two axes at each operating position and the detected coordinate value of the one axis are converted into measurement data. An automatic measuring method for three-dimensional shapes, characterized by: