JP2582807B2 - Work line teaching method for industrial robots - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for teaching a work line, in which an industrial robot previously stores a work line for cutting or welding using an optical sensor.

[Conventional technology]

For example, Japanese Patent Application Laid-Open No.
There is a technique disclosed in Japanese Patent Publication No. 108485. In this technology, a tape is attached to a work centering on a work line, an optical sensor is moved in a direction intersecting the tape, and the boundary of the tape is detected based on the difference in the amount of reflected light from the work surface and the tape surface. I try to teach a line.

[Problems to be solved by the invention]

However, in the above-described method, the amount of light reflected on the optical sensor fluctuates due to unevenness or inclination of the surface of the work, so that the detected signal is unstable. Since the light amount signal cannot be obtained, the boundary between the work surface and the tape surface cannot always be reliably detected with the same setting, so that there is a problem that the working line cannot be accurately and reliably taught. The present invention seeks to solve such a problem.

[Means for solving the problem]

To this end, the method of teaching a working line to an industrial robot according to the present invention is, as illustrated in the accompanying drawings, attached to a wrist section 18 of an industrial robot and irradiates a work with a laser beam for measurement toward the work, and In the method for teaching a work line to an industrial robot using an optical sensor 45 for receiving reflected light from a robot, a model work V having a peripheral edge Va cut along the work line is installed at a position higher than the surroundings, The expression sensor 45 is perpendicular to the surface of the model work V in a state where the measuring laser light is irradiated to a position close to the peripheral edge Va on the model work V, and the distance from the surface is set to a predetermined value. Moving the optical sensor 45 in the direction intersecting the peripheral edge Va while maintaining the state of the first step.
A second step of storing, in a storage device, a position at which the distance to the surface detected by the sensor 45 increases discontinuously;
The operation of the third step of moving to the next position approaching Va is repeated.

[Action]

The optical sensor 45 is maintained in the predetermined state with respect to the model work V, and the irradiation position of the measurement laser beam irradiated on the surface of the model work V is moved in a direction intersecting the peripheral edge Va, and the model work V The position where the distance from the surface of the laser beam discontinuously increases, that is, the position where the measuring laser beam intersects and deviates from the peripheral edge Va is stored in the industrial robot. Next, the optical sensor is moved to the next position and performs the same operation.
Teaches work lines of the same shape as Va.

〔The invention's effect〕

As described above, the present invention detects the work line defined by the cut edge of the model work by the discontinuous increase in the distance between the optical sensor and the surface of the model work, and therefore, detects the work line on the surface of the model work. The detected distance signal does not change even if the amount of reflected light to the optical sensor changes due to unevenness or inclination, and the distance signal changes even if the reflectance of the surface changes due to the material of the model work, etc. There is no.
Thus, if the measuring laser beam intersects the periphery of the model work, the distance signal increases discontinuously, so that the working line can be reliably detected. Therefore, according to the present invention, it is possible to always reliably detect the periphery of the model work even if the unevenness, inclination, material, or the like of the surface of the model work changes, and to teach the working line accurately and reliably.

〔Example〕

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

First, an industrial robot for laser processing to which the present embodiment is applied will be described. As shown in FIG. 2, the main unit 10 of the industrial robot includes a rectangular coordinate system part and a polar coordinate system part. Bed 11
A pair of guide members 13 fixed on a plurality of columns 12 erected at the first, a first linear motion member 14 guided and supported by the vertical direction, and a second linear member guided and supported by the horizontal direction A moving member 15 and an elevating member guided and supported by the moving member 15 in the vertical direction.
The movement of each member 14, 15, 16 is controlled by the robot controller 30 via servo motors 19, 20, 21 respectively, and the respective positions are detected by the encoders 22, 23, 24 and fed back. ing. The part of the polar coordinate system includes a turning member 17 rotatably supported around a vertical axis by an elevating member 16, and a wrist portion 18 supported thereby so as to be rotatable around a horizontal axis. Are controlled by the robot controller 30 via a servo motor and an encoder (not shown), and are fed back.

A processing laser beam oscillated by a processing laser oscillator 25 is guided to a laser torch 27 attached to the wrist section 18 through an optical guide path 26 having a built-in reflecting mirror at each bent portion, and focused by a processing lens. Then, the light is irradiated onto the processing surface of the workpiece W positioned and supported on the base 11 via the mounting jig 29.

As shown in FIGS. 1, 2, and 5, an optical sensor 45 is fixed to the wrist section 18 on the side opposite to the laser torch 27. The optical sensor 45 includes a laser oscillator (not shown) that emits a laser beam for measurement in the opposite direction coaxially with the laser torch 27, and a light position detecting element (FIG. 3) that receives light reflected from the surface of the model work V. (Indicated by reference numeral 46). The light position detecting element (hereinafter simply referred to as PSD) 46 has electrodes at both ends, and outputs a current corresponding to the amount of received light and a light receiving position in the longitudinal direction on the light receiving surface from the electrodes at both ends. .

As shown in FIG. 2, the robot controller 30 has a central processing unit (hereinafter simply referred to as a CPU) 31, a memory 32, and a pulse generation circuit 33 as main components, and the CPU 31 operates via interfaces 34 and 35, respectively. Board 41 and teaching box 4
Connected to encoder 2 via interface 36
2, 23, 24, etc., and to the optical sensor 45 via the interface 37 and the sensor controller 50. Also, the pulse generation circuit 33 is connected to the drive unit 40
Are connected to servo motors 19, 20, 21 and the like.

As shown in FIG. 3, the sensor controller 50 includes a distance calculating circuit 51, first and second distance comparators 53 and 54 and a distance setting device 55 related thereto, and a light amount calculating circuit 52 and a light amount comparing circuit related thereto. The output currents ia and ib from the electrodes at both ends of the PSD 46 are sent to the distance calculating circuit 51 and the light amount calculating circuit 52. The distance calculation circuit 51 calculates the light receiving position on the PSD 46 based on the following formula (ia−ib) / (ia + ib) or a calculation formula based thereon, and calculates the optical sensor 45 and the surface of the model work V by the principle of triangulation. The first distance comparator 53 compares the calculated distance with the set distance stored in the distance setter 55, and sends the comparison result to the CPU 31. The second distance comparator 5
Numeral 4 is to transmit the result to the CPU 31 if the distance calculated by the distance calculation circuit 51 is compared with time and a discontinuous change is detected. The light amount calculation circuit 52 calculates the amount of light received by the PSD 46 based on the following formula ia + ib or a calculation formula similar thereto, and the light amount comparator 56 calculates this light amount at the peak light amount stored in the peak light amount storage circuit 57. This detects that the optical sensor 45 is perpendicular to the surface of the model work V, and sends the result to the CPU 31.

Next, the teaching method of this embodiment will be described with reference to FIGS.

As shown in FIG. 1, first, a model work V having a peripheral edge Va cut along a working line (refer to a reference sign Wa of a work W in FIG. 5) is positioned higher than a surrounding bed 11 by a mounting jig 25. To support. Next, the teaching box 42 is operated to rotate the wrist unit 18 to index the optical sensor 45 to the model work V side, and then irradiate a measuring laser beam to start teaching the working line according to the flowchart of FIG. .

First, in step 100, the manual movement button of the teaching box 42 is operated to operate the main body device 10 of the industrial robot, and the wrist unit 18 is moved to move the optical sensor 45, and the measuring laser light is applied to the model work V. The temporary positioning is performed at a position where the first position P1 close to the peripheral edge Va is irradiated. In the following step 101, the optical sensor 45 is made perpendicular to the surface of the model work V. For this, first, the wrist unit 18 is caused to perform a tilting operation so that the measuring laser light swings in two orthogonal directions about the position P1. In each of the tilting operations, the peak light intensity signal value from the light intensity calculation circuit 52 in the first tilting operation is stored in the peak light intensity storage device 57, and the light intensity comparator 56 outputs the light intensity signal in the second tilting operation. The value is compared with the light quantity signal value at the first peak, and when the light quantity signal value at the peak is matched, a signal is sent to the CPU 31 to stop each tilting operation.
Is perpendicular to the surface of the model work V. In the following step 102, the distance between the optical sensor 45 and the surface of the model work V is set to a predetermined value. In this case, the wrist unit 18 is moved in the approach direction with respect to the model work V, and the first distance comparator 53 compares the distance signal value from the distance calculation circuit 51 with a predetermined value stored in the distance setting unit 55. When the values match, a signal is sent to the CPU 31 to stop the movement in the approach direction.

In the subsequent step 103, the irradiation position of the measuring laser light is shifted from the first temporary position P1 to the model work while the teaching box 42 is operated to keep the optical sensor 45 perpendicular to the model work V and at a predetermined distance. The wrist unit 18 is moved so as to move in a direction orthogonal to the peripheral edge Va of V. During this movement, the second distance comparator 54 temporally compares the distance signal from the distance calculation circuit 51, and the irradiation position of the measurement laser beam from the optical sensor 45 is changed to the model work at the first teaching position Q1. If it is detected that the distance signal has increased discontinuously outside the peripheral edge Va of V, a signal is sent to the CPU 31 and the operation proceeds from step 104 to step 105 to stop the movement of the optical sensor 45. Next, when the position teaching button of the teaching box 42 is pressed, the position data is transmitted from the encoders 22, 23, 24, etc. in step 106, and stored in the memory 32 to store the first teaching position Q1.

In this state, since the teaching position still remains, the operation proceeds from step 107 to step 108, and the manual sensor button of the teaching box 42 is operated to move the optical sensor 45 to the next temporary position P2 along the peripheral edge Va. Let the above steps 100-106
Is repeated, and the second teaching position Q2 is stored. By repeating the above operation, a large number of teaching positions are sequentially stored and stored in the memory 32, and if all the teaching positions are stored,
The teaching according to the present embodiment ends. A large number of teaching positions stored as described above are created by the CPU 31 on the same working line as the peripheral edge Va.

Next, the model work V is removed, and as shown in FIG.
The work W to be processed is positioned and supported by the mounting jig 29, and the wrist unit 18 is rotated to index the laser torch 27 to the work W side. Then, by irradiating the processing laser light from the laser torch 27 and operating the robot sensor device 30 based on the taught working line, the work W is processed by the processing laser light focused on the surface thereof as indicated by a broken line. It is cut along the line Wa.

According to the above embodiment, the distance signal from the distance calculation circuit 51 in a state where the measurement laser light is irradiated on the model work V is kept constant even if the amount of reflected light from the model work V changes. Since it increases discontinuously due to the deviation from the peripheral edge Va, the work line can always be taught with a certain degree of reliability regardless of the material and surface condition of the model work V.

It is needless to say that the present invention is not limited to the planar model work V as shown in the above embodiment, but can be implemented using a three-dimensional model work.

Further, the present invention may be carried out by painting the surface of the model work V white along the peripheral edge Va. In this case, the operation of making the optical sensor 45 vertical in step 101 is performed when the measuring laser beam is used. What is necessary is just to perform it in the state irradiated to the non-painting position.

[Brief description of the drawings]

1 to 4 show an embodiment of a method for teaching a working line to an industrial robot according to the present invention. FIG. 1 is a perspective view of a main part showing an embodiment, and FIG. 2 is an applied industrial robot. 3 is a block diagram of a sensor controller, FIG. 4 is a flowchart showing a teaching operation, and FIG. 5 is a view showing a cutting work state of a work after teaching. EXPLANATION OF SYMBOLS 18: Wrist part, 45: Optical sensor, V: Model work, Va: Periphery.

Claims (1)

(57) [Claims] A work line teaching method for an industrial robot using an optical sensor attached to a wrist portion of the industrial robot and irradiating a measuring laser beam to the work and receiving reflected light from the work. In, a model work having an edge cut along a working line is installed at a position higher than the periphery, and the optical sensor is irradiated with a laser beam for measuring the optical sensor at a position close to the edge on the model work. A first step of making the model work perpendicular to the surface of the model work and setting a distance from the surface to a predetermined value in the state, and moving the optical sensor in a direction intersecting the periphery while maintaining the state of the first step. A second step of storing, in a storage device, a position at which the distance to the surface detected by the optical sensor discontinuously increases, and then the optical sensor Working line teaching method for an industrial robot and repeating the operation consisting of a third step of moving to the next position close to the periphery of the serial model work.