JPS60141495A - Method of detecting position in welding robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The invention relates to a top surface detection method in a welding robot.

In general, welding port d? In many cases, workpieces of the same shape are repeatedly welded, and in this case, the welding robot is controlled by the same program, but since there are errors in setting the workpieces and tacking accuracy, it is common to misjudge the welding start point. A subroutine that automatically detects the start end of each workpiece is executed to prevent the workpiece from getting stuck. Note that as long as the starting position of the welding line is accurately detected, the welding torch can be controlled by tracing the actual welding line using the arc sensor even if the welding line is slightly deviated from the teaching position.

Conventionally, when performing the above-mentioned starting edge detection, for example, considering the case where the top surface position of the workpiece 1 is detected as shown in FIG. 1, the welding wire is 2, and the welding torch 3 is moved at low speed. During this low-speed movement, whether or not the welding wire 2 has come into contact with the workpiece 1 is detected from the change in the current flowing through the welding wire 2.
When it comes into contact with the workpiece], the 8-contact torch 3 is stopped, and the welding stop JJ-position 1h is moved from the moving distance of the welding torch 3 (
When I started eating, I tried to memorize 1 as ``a''.

〃) Karu wire touch sensor stand, Alo at the detection position
, ``degree i;
There is a problem that the welding torch 3 cannot be moved at low speed until the welding torch 2 contacts the workpiece 1. Furthermore, the maximum distance that the welding torch 3 can be moved at low speed using the wire touch sensor is, for example, About 4 cnl is determined, and when moving welding ↑ ↑ 21 - chi 3 to daching point P1, welding and Work 1 may interfere, or the above 73
There is one problem in which the welding wire 2 does not oscillate to the workpiece 1 after a long distance and comes to a temporary stop.

The present invention has been made in view of the above-mentioned circumstances.
I? The object of the present invention is to provide a method for detecting the position of a welding robot with a high degree of accuracy and which can be detected in field time.

According to this invention, the above wire touch sensor and an ultrasonic sensor that measures distance using ultrasonic waves are used together, and the distance to the workpiece is first measured by the ultrasonic sensor, and the welding torch is moved at high speed to a position in front of the workpiece. Then, the welding wire is moved at low speed until it comes into contact with the workpiece using a wire touch sensor, thereby achieving the above object.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Figure 3 is a block diagram showing an example of an ultrasonic sensor.
An explanation will be given with reference to an example of movement of a welding torch according to the method of the present invention shown in the figure and a flowchart shown in FIG.

First, when the welding torch 10 reaches the workpiece position detection point P10 (FIG. 4), the robot control device 11 gives a start command to the microcomputer 12 to cause the ultrasonic sensor to detect the workpiece position. -=r The microcomputer 12 drives the pulse oscillator 13 to oscillate one ultrasonic pulse, and calculates the time from the oscillation point to the il side - node 7. ．． . 1f(1:(sonic wave transmitting element -
714 is a 13-karat Luss oscillator.
C Therefore, il ¥4 of 1.9 rus for work 15 I
Send η゛ wave, receive super follow-up wave 161d, work] 5
Receives the reflected ultrasound waves and converts them into electricity 41'';
and add a filter 17Vc. The Hf1 wave oscillating element 4 and the ultrasonic receiving element 16 are respectively disposed on both sides of the welding torch 10, as shown in FIG.

The filter 17 cuts out all the junk other than the desired received signal, and the received signal d1 that has passed through this filter 17 is amplified R51.
The signal is amplified by V) 8, converted to digital 4.1 by a converter 19, and then added to the microcomputer 12.

The time when the signal applied from the microcomputer 12 and the A/I converter 19 exceeds a preset threshold is determined to be the time when the harmonic wave or pulse is received, and at that point, the above-mentioned launch 11. ! Finish the open side of time from point f, and cut it (rule ■ Distance ill in work 15 from Terade 1 and Kimi speed etc.
Fish out L (year 4 figure). Furthermore, the 12 microcomputers have previously stored a distance slightly larger than the sum of the opening side error of the ultrasonic sensor and the error of the wire protrusion length in welding 1 and 10, and the distance L71 calculated in the above 9
・The distance from ra was decreased, and the b′ eyes 141 (= L −
h) is output as 9 as the distance that the welding torch 10 should move, and this distance data is output to the robot handle control device 11.

The robot control device 11 moves the welding torch 10 by a distance t at high speed based on the distance data applied from the microcomputer 12, and after the high speed movement is finished, the wire touch sensor starts operating, and as shown in Fig. 2. As shown, move the welding torch at low speed so that the welding wire comes into contact with the workpiece.

In this way, the welding wire can be brought into contact with the workpiece in a short time without being deformed, and from the difference between the position at this time and the position of the workpiece position detection point PIO, the workpiece 15
can detect the position of

Note that if the distance measurement time by the ultrasonic sensor is sufficiently faster than the moving speed of the welding torch,
The above-mentioned distance ^I measurement may be performed sequentially while the hand is moving.

According to the present invention, by using an ultrasonic sensor and a wire touch sensor together,
Knowledge 11! It is possible to detect the confidence of 1 mu shield between f. It's 1.
1i:11 some time before d1'i 1st wave center VC
Since it is possible to detect the distance between
The starting point can be set far enough away from the workpiece, and for example, the starting point can be detected. I can do something.

181 side ti: '+ medium nIf Akizume 1 residence IH position by conventional wire touch sensor) r8
Figure 2 is a flowchart showing its operation, Figure 3 is a block diagram showing an example of an ultrasonic center, and Figure 4 is a schematic diagram used to explain the non-inventive method V. Diagram of the movement mode of the welding torch used, 2 (Fig.
This is an old flowchart for explaining the figure.

11)...〃, 4y torch, 11...donkey? Control unit [h, 12...Micro converter, 13...
- Hals oscillator, 14... Ultrasonic transmitting element, 15...
- Work, 16... Ultrasonic receiving element, 17... Filter, 18... Amplifier, 19... A/D converter.

Figure 5

Claims (2)

[Claims] (1) Measure the distance on the workpiece 1 with an ultrasonic sensor placed near the welding torch 3, and
The welding process is performed to a position a preset distance before
・-The welding torch is moved at high speed, and then 11] is applied to the welding wire, and the welding torch is moved at low speed. The welding robot can (6) detects the position of the workpiece by detecting the welding torch, stops the low-speed movement of the welding torch, and detects the position of the workpiece from the distance of movement of the welding torch. (2) The preset distance in i%ii is the distance Aff set based on the difference between tTl' and 1ljlJfl of the ultrasonic sensor.Filj 4th (1) Clause 1 of the invitation request:
Method for detecting position 11'1'' in a welding funnel on L''.