JPH0650740A - Degree-of-levelness detection, detection of three-dimensional position and correction of three-dimensional position - Google Patents

Abstract

PURPOSE:To make possible the detection of a degree of levelness with sufficient precision and an inexpensive facility cost by measuring a distance with at least three optical sensors. CONSTITUTION:For instance, a flange 12 of a silencer 1 is pressed on a flat plate 3, which is pressed on a support part 5 through a resilient member 4. And a degree of inclination of a face of the flat plate 3 with the resilient member 4 is the same as the face of the flange 12 of the silencer 1. In addition, three laser displacement sensors 6 are set upward in order to measure a distance of a ground level to a lower face of the flat plate 3 and arranged in almost a triangle. Accordingly, if the distance of respective laser displacement sensors 6 to the lower face of the flat plate 3 is measured, the degree of the inclination of the flat plate 3 can be easily known and at the same time a quantity of vertical dislocation can be also found. And an arm 21 and a hand 22 of a robot 2 are moved and the silencer 1 is distorted for the purpose of correcting and levelling the degree of the inclination of the flat plate 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a horizontal level detecting method and a horizontal level detecting method.
The present invention relates to a dimensional position detecting method and a three-dimensional position correcting method. In particular, it relates to a horizontality detection method, a three-dimensional position detection method, and a three-dimensional position correction method used in a jigless welding system using a robot.

[0002]

2. Description of the Related Art In recent welding systems, a robot is often used to eliminate jigs in order to handle welding of various parts. Jig-less with a robot means that the robot's hand holds the workpiece.
Another robot is used for welding. This is a method in which the robot's hand that is in charge of transportation is regarded as a jig and does not require a dedicated jig, so the equipment can be simplified. However, since the welded part may be displaced due to variations in parts, welding distortion, etc., it is necessary to detect the position and correct the position in order to improve the welding quality and yield.

As a positioning method in the jigless welding method, conventionally, a three-dimensional position detecting method by image processing and a structure light method are known.

First, a method for detecting a three-dimensional position by image processing using an industrial television camera is used, for example, in an automobile assembly line. In this case, at least three gauges provided in advance at the lower part of the vehicle body are used. Each of the holes is observed by using at least three cameras, the direction and distance from the camera are obtained for each of the three gauge holes by the arithmetic device, and the three-dimensional position of the vehicle body is detected.

Next, the structure light method is a method of irradiating a laser slit light from a light emitting device toward a hole and receiving the reflected light using a CCD camera to obtain the direction and distance from the camera. . Also in this case,
At least three sets in which the light emitter and the CCD camera are integrated are prepared to detect the three-dimensional position.

[0006]

However, in these prior arts, the equipment cost is high in all cases, and the image processing method using an industrial television camera is particularly disadvantageous.
It is weak against ambient light and lacks stability. The structure light method has a complicated system. More importantly, the accuracy is poor in all methods, and the accuracy is 0.5 in welding.
If it is less than or equal to mm, it is not practical, but it is about 0.8 mm by the method by the image processing performed using the industrial television camera, and about 1.5 mm by the method by the structure light.

An object of the present invention is to eliminate this drawback, and has a high level of accuracy, a low facility cost, a high practical value, a levelness detecting method, a three-dimensional position detecting method, and a three-dimensional position correcting method. And to provide a method. In particular, when welding a pipe to a flange, it is an object of the present invention to provide a welding position detecting method and a correcting method for a deformed component such as a silencer that processes exhaust gas noise of an automobile.

[0008]

Of the above objects, the first
The purpose (horizontality detection method) is to place an object to be measured whose flat surface is a flat surface on a flat plate (3) through an elastic member (4) supported by a support stand (5), This is achieved by the horizontality detecting method in which at least three optical sensors (6) are vertically provided around the support table and the inclination of the flat plate with respect to the horizontal plane is detected.

Among the above-mentioned purposes, the second purpose (a method for detecting a three-dimensional position) is that the lower surface is a flat surface and a columnar shape is formed on the upper surface of the elastic member (4) supported by the support base (5). An object to be measured having a portion is placed and pressed on the flat plate (3), and at least three optical sensors (6) are vertically provided around the support table to detect the inclination of the flat plate with respect to the horizontal plane. ,
Using the detected inclination, the lower surface of the measured object is corrected to be horizontal, the columnar portion of the measured object is supported vertically, and the columnar portion partially blocks light. , Irradiating at least two light beams (8) horizontally toward the columnar portion, and based on the ratio of the cross-sectional area of each of the light beams and the cross-sectional area of the received light beam, the object to be measured is This is achieved by a three-dimensional position detecting method that detects a horizontal position.

Among the above-mentioned objects, the third object (method of correcting the three-dimensional position) is that the lower surface is a flat surface and the columnar shape is on the upper surface through the elastic member (4) supported by the support base (5). An object to be measured having a portion is placed and pressed on the flat plate (3), and at least three optical sensors (6) are vertically provided around the support table to detect the inclination of the flat plate with respect to the horizontal plane. ,
Using the detected inclination, the lower surface of the measured object is corrected to be horizontal, the columnar portion of the measured object is supported vertically, and the columnar portion partially blocks light. , Irradiating at least two light beams (8) horizontally toward the columnar portion, and based on the ratio of the cross-sectional area of each of the light beams and the cross-sectional area of the received light beam, the object to be measured is The horizontal position is detected, and the columnar portion of the object to be measured is corrected to a predetermined position based on the detected value 3
This is achieved by the method of correcting the dimensional position.

[0011]

When the pipe is welded to the flange, the parameter representing the welded position is composed of the inclination of the circumference of the flange on which the pipe is welded and the center position of this circumference.

The inclination of the circumference to be welded, that is, the inclination of the surface of the flange can be detected by providing three optical sensors vertically and measuring the distance from the optical sensor to the surface of the flange. Furthermore, if a flat plate that is parallel to the surface of the flange and is larger than the flange is prepared, and the flange is pressed against this flat plate and the inclination of this flat plate with respect to the horizontal plane is detected, the position of the flange may shift slightly in the horizontal direction. However, since the measurement can be performed on a large surface, the detection accuracy can be improved.

The center position of the circumference to be welded is corrected by using the inclination of the surface of the flange with respect to the horizontal plane to make the flat plate horizontal, and then the axial position of the pipe is adjusted so that at least two light beams are applied to the pipe. It can be obtained based on the ratio between the cross-sectional area of each light beam and the cross-sectional area of the received light.

In order to weld the pipe to the flange, the horizontal position of the pipe may be detected and the detected value may be used to correct the pipe to a predetermined position.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A horizontality detecting method, a three-dimensional position detecting method, and a three-dimensional position correcting method according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a horizontality detecting method according to the present invention. 1
Is a silencer, and a silencer flange 12 is temporarily welded to a silencer pipe 11. The levelness of the flange 12 of the silencer 1 is being detected in order to properly weld this temporary weld. 13 is a welded part. Reference numeral 2 is a robot that functions as a jig. Reference numeral 21 is a robot arm, and 22 is a robot hand, which holds the body of the silencer 1 and presses the flange 12 of the silencer against the flat plate 3. The flat plate 3 is pressed against the supporting portion 5 via the elastic member 4. The elastic member 4 causes the flat plate 3
The inclination of the surface of is the same as the inclination of the surface of the flange 12 of the silencer 1. Reference numeral 6 denotes a laser displacement sensor, which is installed upward so that the distance from the ground level to the lower surface of the flat plate 3 can be measured. Further, since there are three laser displacement sensors 6 arranged in a substantially equilateral triangle, the inclination of the flat plate 3 can be easily known by measuring the distance from each laser displacement sensor 6 to the lower surface of the flat plate 3. You can At the same time, the amount of deviation in the vertical direction can be known.

To correct the inclination of the flat plate 3 to make it horizontal,
The arm 21 and the hand 22 of the robot 2 may be moved to twist the silencer 1.

FIG. 2 is a diagram showing a horizontal position detecting method according to the present invention. Using the correction values for the tilt and vertical deviation of the flange 12 of the silencer 1 obtained by the method described with reference to FIG. 1, the robot arm 21 and the hand 22 are driven to correct the tilt and vertical deviation. After that, the pipe 11 of the silencer 1 is held vertically and at the correct height. Reference numeral 7 denotes a light emitter using a semiconductor laser as a light source, which emits two sets of parallel light beams 8 having a width of 30 mm at right angles to each other. Then, the pipe 11 of the silencer 1 is partially irradiated. Reference numeral 9 is a light receiver, and the coordinates of the horizontal position can be known by measuring the ratio of the light beam 8 before and after being blocked by the pipe 11 of the silencer 1. When a laser beam is used, the diffraction of light is reduced, and the repeat accuracy is 30 μm and the accuracy is high.

Further, by using the correction value of the horizontal position obtained by the method described in FIG. 2, the arm 21 and the hand 22 of the robot 2 can be driven and horizontally moved to the correct welding position.

[0020]

As described above, according to the present invention,
By measuring the distance using three optical sensors, the levelness can be obtained with sufficient accuracy and low equipment cost.
Further, by measuring the amount of light received by the two sets of light beams, the horizontal position can be obtained with sufficient accuracy and low equipment cost.
Therefore, for example, even a deformed part such as a silencer for processing exhaust gas noise of an automobile is very effective in welding a pipe to a flange.

[Brief description of drawings]

FIG. 1 is a diagram showing a horizontality detection method according to the present invention.

FIG. 2 is a diagram showing a horizontal position detecting method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Silencer 2 Robot 3 Flat plate according to the present invention 4 Elastic member according to the present invention 5 Support part according to the present invention 6 Laser displacement sensor according to the present invention 7 Light emitting device using a semiconductor laser according to the present invention as a light source 8 According to the present invention Light beam 9 Optical receiver according to the present invention 11 Silencer pipe 12 Silencer flange 13 Welded portion 21 Robot arm 22 Robot hand

Claims (3)

[Claims] 1. An object to be measured having a flat bottom surface is placed and pressed on a flat plate (3) through an elastic member (4) supported by a support base (5), and at least the periphery of the support base is pressed. A horizontality detecting method, wherein three optical sensors (6) are provided vertically to detect an inclination of the flat plate with respect to a horizontal plane. 2. An object to be measured having a flat lower surface and a columnar portion on the upper surface thereof is placed and pressed on a flat plate (3) through an elastic member (4) supported by a support base (5), At least three optical sensors (6) are vertically provided around the support to detect the inclination of the flat plate with respect to the horizontal plane, and the detected inclination is used to make the lower surface of the object to be measured horizontal. Correction, the columnar portion of the object to be measured is vertically supported, and at least two light beams (8) are irradiated horizontally toward the columnar portion so as to be partially shielded by the columnar portion. A three-dimensional position detecting method is characterized in that the horizontal position of the object to be measured is detected based on the ratio of the cross-sectional area of each of the light beams and the cross-sectional area of the received light beam. 3. An object to be measured having a flat lower surface and a columnar portion on an upper surface thereof is placed and pressed on a flat plate (3) through an elastic member (4) supported by a support base (5), At least three optical sensors (6) are vertically provided around the support to detect the inclination of the flat plate with respect to the horizontal plane, and the detected inclination is used to make the lower surface of the object to be measured horizontal. Correction, the columnar portion of the object to be measured is vertically supported, and at least two light beams (8) are irradiated horizontally toward the columnar portion so as to be partially shielded by the columnar portion. , The horizontal position of the measured object is detected based on the ratio of the cross-sectional area of each of the light beams and the received cross-sectional area, and the columnar portion of the measured object is predetermined based on the detected value. A method for correcting a three-dimensional position, which comprises correcting the position.