JPS5999203A - Stepped point detecting method by optical range finder - Google Patents

Abstract

PURPOSE:To detect a stepped point of a body easily and accurately at high speed by detecting the position of the maximum or minimum value among differences between data which are at distance corresponding to the diameter of spot light in the scanning direction in a distance data sequence obtained by performing the scanning of an optical range finder. CONSTITUTION:The optical range finder 10 is fitted to the hand, etc., of a robot and a scan on a line C of the body 11 with the step is made to detect an image of the light spot 8 which is formed on the body 11 by the light source 2 and lens 3 of a spot light irradiating device 1 through the lens system 5 and photodetecting sensor 6 of a photodetector 4, thereby obtaining the distance data sequence through a controller 7. Difference between data which are distant from each other by a 0.5mm. scanning-directional spot diameter in the data sequence obtained by sensing at intervals of 0.1mm. in the scanning direction are calculated successively to detect the position of the maximum or minimum value, thereby detecting the stepped point of the body 11 easily and accurately at high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for processing distance data obtained by an optical rangefinder.

Conventional configurations and their problems In recent years, compact, lightweight, and easy-to-handle optical rangefinders that use spot light have been developed, and are now being actively used for position detection. Ta. Most of its uses include measuring the distance to an object at several points and processing the obtained data to detect positional deviations of congruent objects. The spot light diameter used for sensing with an optical distance meter is usually a circle or an ellipse of about 11IIrQ. If the object surface is close to a flat surface and the entire spotlight is irradiated onto the flat surface, accurate distance data to the object surface can be obtained using the optical rangefinder, but the spot light may be located at a step point on the object surface. For example, at point P in Figure 2, the spot light image is divided into two or more parts and is imaged on the sensor of the light receiving part of the optical rangefinder, so as shown in Figure 8 (a). A distance data string with an intermediate value indicating a slope that does not exist in reality is obtained, and this distance data string with an intermediate value is extended by a distance in the scanning direction corresponding to the spot light diameter in the scanning direction. It is difficult to accurately detect the step point. In other words.

Since a position sensor (a sensor that outputs the position of the center of gravity of the light quantity of a spot light image as an electrical signal) is used as a sensor in the light receiving section, the detection accuracy is poor for a distance corresponding to the spot light diameter in the scanning direction. It is also possible to detect the step point from the position of the data string that has the median value of the distance data corresponding to the two plane parts forming the step from the obtained distance data string, but due to dust etc. If the surface is uneven or the object is tilted,
Determining the straight line equation itself requires complicated processing,
It is not practical because it takes a long time to process the data. In addition, when the spot light diameter is made smaller, the amount of light received changes greatly due to the influence of the object surface, and the amount of light itself decreases, so the control circuit for this purpose has a very sensitive light amount adjustment function. This is difficult to implement as it requires measures against optical and electrical noise. Also, Fig. 8(b)
Even if you simply calculate the difference between adjacent data like this, not only will multiple maximum or minimum values of the difference have the same value, but it is also easy to misrecognize it due to the influence of dust, noise, etc. .

Purpose of the Invention The present invention has been made with the above-mentioned points in mind, and is applicable when the surface of an object is sloped, such as a welding work, or when the surface is uneven due to small particles, etc. The purpose of the present invention is to provide a method that can accurately and quickly detect the step point of an object using a microcomputer or the like, even when the object is in the opposite direction.

Structure of the Invention The step point detection method of the present invention includes a spot light irradiation device for creating a spot light image on the surface of an object, and a spot light irradiation device that receives the spot light image and forms an image on a sensor, which corresponds to the image formation position on the sensor. The distance to the object surface is measured by scanning the irradiated light of an optical distance meter consisting of a light receiving device that converts it into an electric signal, and a distance data string to the object surface is obtained at every fixed distance in the scanning direction. , a difference data string is created by sequentially taking the difference between the distance data string and the distance data sensed at a distance corresponding to the spot light diameter in the scanning direction, and the maximum value or the minimum value in this data string is calculated. It is characterized in that the position of the data held is determined to be the position of a step point on the object surface.

Description of Embodiment The configuration of the optical rangefinder (10) will be briefly explained based on FIG. ) and photodetector (
4), the spot light irradiation device (1) connects a light source (2) such as a laser diode or light emitting diode to a lens system (3).
), it can be irradiated as a spot light (8) of a predetermined size and uniform intensity. The light receiving device (4) is fixed so that its optical axis forms an angle θ with the optical axis of the spot light irradiation device (1), and the positions of surfaces A and B are now determined by the lens system ( 5) and the position of the spot light image formed on the light receiving sensor (6) such as a position sensor. The distance data obtained by the light receiving device (4) is transferred to the control device (7) and processed by a microcomputer or the like.

The optical distance meter 01 is installed on a robot's hand, etc., and scans on line C in FIG.
A sensing command signal is sent to the control device (7) of the optical distance meter OI every time. For optical rangefinder 0 old, make the plane formed by the optical axis of the spot light irradiation device (1) and the optical axis of the light receiving device (4) almost parallel to the side (11a) of the object 0υ that constitutes the step, and set the scanning direction. It should cross the side Uta) of the object 01) almost at right angles. This is because the shape of the spot light (8) is an ellipse whose long axis is in the direction of the plane formed by the optical axes of the spot light irradiation device (1) and the light receiving device (4).
This is to make the received light image (the image formed on the light receiving device) less susceptible to the influence of the slope. Note that the spot light (8) has a short axis D
T (hereinafter referred to as spot diameter) is approximately 0.51111 + long axis 1.0 nm.

Note that the spot light (8) can be changed depending on the detection accuracy.

In this way, a distance data string as shown in FIG. 8(a) is obtained by the optical distance meter 01 based on the sensing command signal. To detect a step point from this data string, the spot light diameter in the scanning direction is D7'' 0.5 with respect to the data string sensed every 0.1++ m in the scanning direction.
If the differences between data separated by mm are taken sequentially, a sequence of points as shown in FIG. 8(c) can be obtained. For example, the first data Yi(
However, the difference between i=1:] and the data at the 6th position Yi+5=Y6 is taken to obtain the data at the (i+3)th=4th position. This process is repeated sequentially.

This can be expressed as "i0s = yi0, -Yi. The position Xp of the maximum value of the difference data string obtained by such processing corresponds well to the second P point position.

By processing in this way, it is possible to detect a position that has data that includes all the parts affected by the spot light diameter DT, and only at this time the difference value becomes the maximum or minimum value, so it is easy to detect the difference in level. can be determined.

In Fig. 4, when the groove welding workpiece o2 has an uneven surface and a gap as shown in (a), the optical distance meter On is attached to the swinging device and the distance is 0.1 in the scanning direction.
If sensing is performed for each M, a distance data string as shown in (b) can be obtained. Spot light diameter D1- in two scanning directions
= 0.5 tm, but considering the elliptical shape of the spot light and the intensity distribution of the light, that is, the amount of light, 0.3 in the scanning direction.
The difference Y between the data sensed at a distance from the body is taken sequentially.
This gives (c). Find the points X1 and Xm in the scanning direction corresponding to the maximum and minimum values of Y' from the difference data string, and set it as Xm - Xl to find the gap of the groove welding workpiece O, and calculate the welding current and voltage. etc. are determined, and T(
Xm-1-XI), the position of the welding line can be determined, and automatic welding becomes possible by sending this information to a robot or the like.

In the above embodiment, the optical distance meter OI is oscillated to scan, but the same effect can be obtained by swaying the light from the light source (2) with a mirror or the like.

According to the present invention, as described in the detailed description of the invention, the following effects can be obtained.

■ Sequentially take the differences before the distance corresponding to the spot light diameter DT in the scanning direction of the distance data string obtained by scanning with an optical distance meter, and find the position corresponding to the maximum or minimum value. Since points are simply detected as step points, simple software or hardware processing is sufficient.

■ It is accurate because the maximum or minimum value of the difference is almost unique.

■ Even if there is a slope such as a welding workpiece, etc., or if the surface is uneven due to dust etc., it can be easily detected.

- By continuously repeating the detection operation, the gap and position of the groove weld line, the lap joint position, etc. can be detected, and automatic welding can be performed by linking with a robot etc.

■ Data processing can be performed at high speed even with a microcomputer, and the equipment itself can be made simple and inexpensive.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an optical distance meter, Fig. 2 is a perspective view of a step detection device for an object, Fig. 8 (a), (b), and (c) are examples of distance data, examples of differences from adjacent ones, Graphs of examples of differences according to the present invention, FIGS. 4(a), 4(b), and 4(c) respectively represent a cross-sectional view of a groove welding workpiece, a distance data sequence diagram, and a difference map according to the present invention. (1)...Spot light irradiation device, (2)...Light source,
(4)...Light receiving device, (6)...Light receiving sensor, (7
)...control device, (8)...spot light, 01...
・Optical rangefinder agent Yoshihiro Morimoto Figure 3 Y' Figure 4 Procedural amendment (contract) Dear Commissioner of the Japan Patent Office “1゛°1 to 6゜2, Name of the invention Method for detecting step points using optical rangefinders 3, Relationship with the case of the person making the amendment Patent applicant name (582) Matsushita Electric Industrial Co., Ltd. 4, agent Address 1-6-171 Tachiuribori, Nishi-ku, Osaka, SSO
i-Amano Building Telephone Osaka 06 (532) 4025 (
Name (6808) Patent Attorney Yoshihiro Morimoto i5,
date (shipment date) Showa year, month, day 6, number of inventions increased by 7 due to amendment, subject of amendment #4 Detailed description of the invention in book I drawings of the detailed description of the scope of claims in the description Brief explanation column 8, contents of amendment (1) ■ Detailed explanation of the invention in Ming #I (1) Page 2, line 1, page 2, line 10, page 13, line 1 2nd to 14th line and the 17th line of the same page, page 4, line 17, page 5, line 8 and the 9th line of the same page, page 6, line 2, and line 4 of the same page "Optical distance meter" in lines 4 to 6 of the same page, line 10 of the same page, line 18 of page 7, line 12 of page 8, and line 18 of the same page. Correct that to "optical rangefinder." (2) In the second line of page 7, correct the phrase "day column" to read "data column." ■ In the brief description of the drawings in the specification column 0, page 9, line 16, and page 10, line 4, "optical distance meter" is corrected to "optical distance meter." ■As per appendix in the claims section of the specification (2) 2. Claims ■: A spot light irradiation device for creating a spot light image on the surface of an object, and a spot light irradiation device that receives the spot light image and displays it on a sensor. The distance to the object surface is measured by scanning the irradiated light of the optical rangefinder, which is composed of a light receiving device that forms an image and converts it into an R-air signal corresponding to the image position on the sensor. A distance data string to the object surface is obtained for each fixed distance, and the difference between the distance data string and distance data sensed at a distance corresponding to the spot light diameter in the scanning direction is sequentially calculated to generate difference data. A method for detecting a step point using an optical rangefinder, which creates a series of differential data and determines the position of the data having the maximum or minimum value as the position of the step point on the surface of an object. (3) 17-

Claims (1)

[Claims] 1. Consisting of a spot light irradiation device for creating a spot light image on the surface of an object, and a light receiving device for receiving the spot light image, forming it on a sensor, and converting it into an electrical signal corresponding to the image formation position on the sensor. The distance to the object surface is measured by scanning the irradiation light of the optical distance meter, and a distance data string to the object surface is obtained at every fixed distance in the scanning direction, and the distance data string is A difference data sequence is created by sequentially taking the difference between the distance data and the distance data sensed at a distance corresponding to the spot diameter of the object. A method of detecting a step point using an optical distance meter to determine the position of the step point.