JPH07104831A - Automatic position teaching method for robot using laser sensor - Google Patents

Abstract

PURPOSE:To automatically teach a robot positions including a lot of teaching points. CONSTITUTION:A welding torch 2 and a laser sensor 3 are fitted to the arm top part of a main body 1 of the robot. The laser sensor 3 deflectively scans a sensing area on the side in a robot advancing direction with laser beams and picks up the image of the locus with a CCD camera. Based on the picked-up image, sensor data expressing the position of welding lines P1, L1, R1, L2 and P2 are calculated inside a sensor controller 10. The sensor data are converted into robot data inside a robot controller 20 and used for the position correcting calculation of the robot. As the preliminary position teaching, only a start point P1 and an end point P2 are taught, and the move of the robot is executed by real-time tracking utilizing the laser sensor 3 and the sensor controller 10. In that case, points to be the teaching points at suitable intervals and frequency are selectively designated from robot position data, for which the correcting calculation is performed, and teaching data containing a lot of teaching point data are automatically prepared.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic position teaching method for a robot using a laser sensor, and more specifically, a robot for moving a work line such as a welding line in real time by using the laser sensor. On the other hand, the present invention relates to a method for automatically performing position teaching corresponding to the work line.

[0002]

2. Description of the Related Art Generally, in order to perform a predetermined work while moving a robot along a work line such as a welding line, it is necessary to teach the position of the robot. In that case, if it is only considered to make the robot follow the route along the work line, the position teaching in which a small number of points are designated as teaching points is adopted by adopting the known real-time tracking method using a laser sensor. It is possible to achieve a tentative purpose by executing. However, in the actual robot work, the movement speed specified / specified
It is necessary to execute a program under various desired conditions by creating a program including various commands for changing, designating / changing the robot posture on the way, and movements of hands and tools. It is important to specify the teaching point.

However, when the position teaching of the robot is performed by the teaching playback system, it takes a lot of man-hours to carry out the position teaching including a large number of teaching points, and the operator's work load is not increased. I can't. If offline data regarding work lines is prepared in advance, it is possible to perform position teaching offline, but this is limited to cases where sufficient offline data is available. It is customary that a considerable work is required to process the position data of the teaching program.

[0004]

As described above, in order to teach the position of the robot in a form including a sufficient number of teaching points, a large work load is often involved, and the work efficiency of the entire robot work is reduced. It was a factor that hindered improvement. An object of the present invention is to solve this problem by providing a position teaching method capable of automatically teaching the position of a robot including a sufficient number of teaching points.

[0005]

According to the present invention, "a preliminary position teaching relating to a work line is given to a robot which supports a laser sensor for sensing a work line position in a region on the robot advancing direction side with respect to a tool tip point. A step of moving the robot along the work line while correcting the preliminary position teaching data by the work line position sensing by the laser sensor; and a step of moving the robot along the work line during the movement. The above technical problem is achieved by the "automatic position teaching method of a robot using a laser sensor including a step of creating teaching position data expressing the working line based on the working line position sensing data."

[0006]

According to the present invention, in a system having a tracking function using a laser sensor, tracking can be executed by preliminary position teaching in which only a small number of teaching points are designated. Paying attention to the fact that the position is sensed and work line position data (sensor data or that converted into robot data) is acquired, and teaching data including many teaching points is automatically created based on those data. It is a thing.

The preliminary teaching and the tracking movement based on it may be performed by a conventional method.
Teaching data can also be created by simple software processing.
It is sufficient to selectively store work line position data (sensor data or data obtained by converting it into robot data) (see Examples described later).

According to the present invention, since the teaching work required of the operator is only preliminary position teaching for a small number of teaching points, the number of man-hours required for position teaching of the robot can be greatly reduced.

Further, since the teaching point is designated by a sequence of points along the actual work line and its position data is created according to a certain rule based on the data acquired at the time of executing the tracking using the laser sensor, There is a feature that the reliability of the data is high and the subsequent data processing is easy.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates an overall arrangement when the automatic position teaching method of the present invention is applied to a case where a welding torch and a robot carrying a laser sensor are used to perform a welding operation. In the figure, the robot body is generally designated by a reference numeral 1, and a welding torch 2 and a laser sensor 3 are attached to the arm tip end portion. The laser sensor 3 includes a laser oscillator, a laser beam deflector, and a CCD.
A known camera equipped with a camera can be used. The laser sensor 3 is connected to the sensor control device 10, and the robot body 1 is connected to the robot control device 20. On the other hand, as will be described later, the sensor control device 10 and the robot control device 20 are connected via an appropriate communication interface and have a function of mutually performing serial communication of sensor data and the like according to a dedicated protocol.

A work 4 is welded to the plate-shaped member 5. In welding, the first straight line portion L1 (starting point P1), the arc portion R1 and the second straight line portion L2 (end point P2) in which the lower edge portion of the workpiece 4 in contact with the plate member 5 is used as a welding line, and the laser sensor is used. It is assumed that this is executed by the movement of the robot by the real-time tracking method using 3. The position of the welding line is detected by the laser sensor 3
The irradiation point trajectory of the deflected laser beam 3a is imaged by a CCD camera, and the welding line position is determined from the bending point position of the irradiation point trajectory.

Therefore, in the case of this example, if the tip 2a of the welding torch 2 is set as the tool tip point and position teaching is performed to the robot having the teaching points at points P1 and P2, the robot follows the welding line. Will move. As described above, in order to carry out the actual welding work under desired conditions, it is necessary to perform position teaching including a considerable number of teaching points.

Therefore, first, the position teaching having the point P1 as the start point and the point P2 as the end point is preliminarily executed for the robot, and then the regenerative operation of the robot is performed by the real-time tracking system using the laser sensor 3. An appropriate number of teaching points are newly designated based on the welding line position data. A series of processes are automatically executed by software processing using the CPUs of the robot controller 10 and the sensor controller 20, as described below.

FIG. 2 is a main block diagram illustrating the configuration of the robot system in this embodiment, centering on the schematic configurations of the robot control device 10 and the sensor control device 20 used in the case shown in FIG. It is a figure. The entire system includes a sensor control device 10, a robot control device 20, a robot body 1, a laser sensor 3, and a welding torch controller 30 that controls the operations of the welding torch 2. The sensor control device 10 includes a central processing unit (hereinafter referred to as CPU) 11, and the CPU 11 includes a frame memory 12, a control software memory 13 including a ROM, and a program memory 14 including a RAM. A data memory 15, which is composed of a non-volatile RAM, a sensor interface 16, an image processor 17, and a communication interface 18 are connected via a bus 19.

A laser sensor 3 is connected to the sensor interface 16, and the sensing operation of the laser sensor 3 and the capture of a video signal are periodically executed by a command from the CPU 11. The communication interface 18 is connected to the communication interface 27 on the robot controller 20 side, and serial communication of sensor data and the like is mutually performed according to a dedicated protocol via the both, as described above.

The image captured by the field of view of the CCD camera of the laser sensor 3 is converted into a grayscale grayscale image and stored in the frame memory 12. The image processor 17 processes the image stored in the frame memory 12 into C
It has a function of processing in accordance with a command from the PU 11. In the control software memory 13, a control program for the CPU 11 to control the laser sensor 3, a calibration program for setting the sensor coordinate system using a jig, and various data to the robot side at appropriate timing. The program etc. for transmission are stored.

A TV for visually recognizing an image captured by the CCD camera and an image called from the frame memory 12.
The monitor can also be connected via a monitor interface (not shown).

On the other hand, the robot controller 20 has a central processing unit (CPU) 21, and the CPU 21 includes a ROM 22 storing a control program, a RAM 23 used for temporary storage of calculation data, and a teaching. A memory 24 composed of a non-volatile RAM for storing data and various set values, and an axis controller 25 for controlling each axis of the robot body 1.
It is connected to a teaching operation panel 26 (including a servo circuit), a manual operation of a robot, coordinate system setting, position teaching, an automatic operation (reproducing operation) command, and a communication interface 18 on the sensor control device 10 side. The communication interface 27 is connected via the bus 28.

The communication interface 27 is connected to the communication interface 18 on the sensor control device 10 side, while being connected to the welding torch controller 30, and C
The welding torch controller 3 is controlled by a control signal from the PU 21.
The operation of 0 (ON / OFF, welding voltage / welding current value, etc.) is controlled.

The above system configuration and functions are basically the same as those of the welding robot system with a laser sensor for performing the welding work by the conventional real-time tracking system, but in order to embody the present invention and implement it,
An automatic position teaching program for executing the processing described in the flowchart of FIG. 3 is stored in the nonvolatile memory 24 of the robot controller 20. Hereinafter, a procedure and a process for executing automatic position teaching will be described with reference to the flowchart of FIG.

First, as a preparation for executing the automatic position teaching, the preliminary teaching and the teaching point selection rule are set. From the viewpoint of work efficiency, it is generally preferable to carry out the preliminary teaching by designating as few teaching points as possible. However, if the welding line (generally the work line, the same applies hereinafter) is discontinuous or the welding line shape is complicated, the teaching point is such that the teaching point is such that the real-time tracking by the laser sensor 3 is not hindered. It may be necessary at some stage.

Here, as shown in FIG. 1, P1
Preliminary position teaching is performed by using two points (start point) and P2 (end point) as teaching points. Preliminary position teaching is carried out by operating the teaching operation panel 26 of the robot controller 20 by a teaching / playback method by manual jog feed (offline teaching is also possible). The welding line includes the arc portion R1, but "Chokusen" is designated as the operation type, and the passage of the arc portion R1 is processed by the position correction tracking using the laser sensor 3.

The teaching point selection rule defines the distribution or density of teaching points designated along the welding line. For example, (1) points on the welding line where position sensing is performed by the laser sensor 3 ( (Hereinafter referred to as “sensing point”), a method of selecting and designating one teaching point each time the robot moves a predetermined distance measured from the teaching point designated by the preliminary position teaching, or (2) There is a method of selecting and designating a teaching point for every fixed number counting from the teaching point designated by the preliminary position teaching from the sensing point sequence. Here, the method (1) is adopted, and a predetermined distance (reference distance between adjacent teaching points) is defined as d. For example, d is set to be about several tenths to several tenths of the total length of the straight line portions L1 and L2 or the circular arc portion R1. In particular, if necessary, the value of d may be changed for each section.

Under the above preparations, the automatic position teaching process outlined in the flowchart of FIG. 3 is started. The processing is executed in such a manner that main processing performed on the robot controller 20 side and sub processing performed on the sensor controller 10 side are performed in parallel. It is assumed that the robot body 1 is in standby at an initial position close to the point P1 with necessary coordinate system settings (base coordinate system, tool coordinate system, sensor coordinate system, etc.) completed.

First, the teaching operation panel 26 of the robot controller 20 is operated to start the main process and the sub process at the same time.
In the main processing, one block of the program including the position data of the teaching point P1 designated by the preliminary position teaching is read (step S1), and the movement from the initial position to the point P1 is started (step S2). At the timing when the sensing area of the laser sensor 3 starts to overlap the welding line, a command to start sensing by the laser sensor 3 is transmitted to the sensor control device 10 via the communication interfaces 27 and 18 (step S3).

On the sensor control device 10 side, the start / deflection of the laser beam and the preparation for imaging of the CCD camera are completed at the same time as the start of the sub-process, and immediately the robot control device 20 is ready to wait for the transmission of the sensing start command (step T
1). When the sensing start command is received in step S3 of the main process, the sensing by the laser sensor 3 is started (first sensing execution; step T2), the image of the laser beam trajectory scanning the sensing area is captured, and image processing is performed. By software processing using the processor 17, sensor data representing a position (sensing point position) where the laser beam crosses the welding line (L1 R1 L2) is created (step T3) and stored in the data memory 15 (step T4). In the data memory 15,
It is assumed that an area where the sensor data of a plurality of sensing points can be written cyclically is secured.

Thereafter, the sensing using the laser sensor 3 and the subsequent storage of the sensor data are periodically repeated until the sensing end command is transmitted from the robot controller 20 (main processing, see step S13). That is, in step T5, it is confirmed whether or not a command is received from the robot controller 20, and if a sensor data transmission command is received, the sensor data is transmitted (step T6 → step T7), and the process returns to step T2 and thereafter. Then, the next sensing process (step T2 to step S5) is executed. If no command is received from the robot controller 20 in step T5, the process directly returns to step T2.

In the main process, in step S4 following step S3, the teaching point P2 designated by the preliminary position teaching is set.
Read one program block containing the position data of
Start interpolation calculation of teaching path between P1 and P2. Then
In order to execute real-time tracking, a command for transmitting sensor data indicating the position of the sensing point is transmitted to the sensor control device 10 via the communication interfaces 27 and 18, and necessary sensor data is received (step S).
6). The corresponding processing on the sensor control device 10 side is
It is executed in steps T5 to T7 during the sub-processing.

The CPU 21 of the robot controller 20 converts the received sensor data into robot data (step S7), calculates a corrected robot movement target position (step S8), and moves the robot to the corrected target position. (Tracking execution; step S9). Here, the distance between the calculated target position and the previously designated teaching point (initially P1) is calculated, and it is judged whether or not the reference value d is reached (step S10). If so, the position data of the corrected position (sensing point position) is stored and saved in a predetermined area in the nonvolatile memory 24 (step S11).

Whether the interpolation points remain (that is,
It is confirmed whether the robot has reached by P2), and if the robot remains, the processes of steps S5 to S12 are repeated. In step S10, if NO, step S1
1 through step S10 to step S12
Heading to is as shown in the flow chart.

When the robot continues to move along the welding line L1 R1 L2 and reaches P2, a negative determination is made for the first time in step S12, and the process advances to step S13 to send a sensing end command to the sensor control device 10. To be done.

When the sensor control device 10 receives this,
No judgment was made for the first time in step T6 of the sub-processing,
The sensing operation of the laser sensor 3 is stopped, and the process ends.

On the other hand, on the robot controller 20 side, after the robot reaches the end point P2, in step S14, the position data of a large number of sensing points stored in step S11 are sequentially read out, and P1 and P2 are used as teaching points at both ends. Create teaching data.

That is, when there are n points of Q1, Q2, Q3, Q4 ... Qn-1, Qn where the position data is stored, the points are created by automatic position teaching. Teaching data includes P1, Q1, Q along the welding line path.
2, Q3, Q4 ... Qn-1, Qn, P2 total n + 2
The position data of each teaching point will be included. The created teaching data is stored in the non-volatile memory 24 of the robot controller 20, and the whole process is completed.

Although the embodiment in which the automatic position teaching method of the present invention is applied to the welding robot shown in FIG. 1 has been described above, the technical idea of the present invention can be applied to other applications. No particular explanation is required. Also, various modifications can be considered regarding the configuration of the system used when implementing the present invention. For example, instead of the configuration shown in FIG. 2, a laser sensor via a sensor interface, a necessary image processing processor, a frame memory, etc., and a CPU of a robot control device.
It is also possible to adopt a configuration in which the robot controller is incorporated in the form of a bus connection to the robot controller.

The teaching data once created according to the present invention is transferred to another host computer or the like, and further processed (for example, straight line portions L1 and L2 and circular arc portion R).
It goes without saying that teaching points may be added to the boundary portion of 1 and the teaching points may be thinned out near the centers of the straight line portions L1 and L2.

Further, instead of the process (step S11) in the above embodiment, the sensor data of the sensing point is separately stored according to the selection rule, and the sensor data newly stored after the completion of the tracking movement between P1 and P2 is converted into the robot data. Modifications such as conversion and creation of teaching point position data may be appropriately performed.

[0038]

According to the present invention, it is possible to perform position teaching (preliminary position teaching) for a small number of teaching points.
Using the tracking function using a laser sensor, position teaching including many teaching points is automatically executed,
The number of man-hours required for robot position teaching can be greatly reduced.

Further, the teaching point is designated by a point sequence along the actual work line, and its position data is created according to a certain rule based on the data acquired at the time of executing the tracking using the laser sensor. The reliability of the data is high and the subsequent data processing is easy.

[Brief description of drawings]

FIG. 1 is a view showing an example of the overall arrangement when the automatic position teaching method of the present invention is applied to a case where welding work is performed using a robot carrying a welding torch and a laser sensor.

FIG. 2 is a principal block diagram illustrating the configuration of a robot system in an embodiment, centering on the schematic configurations of a robot control device and a sensor control device used in the case shown in FIG.

[Fig. 3] Both CPs of the robot controller and the sensor controller
7 is a flowchart outlining an automatic position teaching process executed by U.

[Explanation of symbols]

 1 Robot body 2 Welding torch 2a Welding torch tip (tool tip point) 3 Laser sensor 3a Laser beam 4 Work piece 5 Plate member 10 Sensor control device 11 CPU (sensor control device) 12 Frame memory 13 Control software memory 14 Program memory 15 Data Memory 16 Sensor Interface 17 Image Processor 18 Communication Interface (Sensor Controller) 19 Bus (Sensor Controller) 20 Robot Controller 21 CPU (Robot Controller) 22 Memory (ROM) 23 Memory (RAM) 24 Nonvolatile Memory 25 Axis Controller 26 Teaching operation panel 27 Communication interface (robot controller) 28 Bus (robot controller) 30 Welding torch controller P1 Welding line start point P2 Welding line end point L1, L2 Straight line part R1 Arc part

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G05B 19/19 H 9064-3H

Claims (1)

[Claims] 1. A step of performing preliminary position teaching related to the work line to a robot that supports a laser sensor that senses a work line position in a region on the robot traveling direction side with respect to the tool tip point, and the preliminary position. Moving the robot along the work line while correcting the teaching data by the work line position sensing by the laser sensor, and based on the work line position sensing data acquired by the laser sensor during the movement. A method for automatically teaching a robot position using a laser sensor including a step of creating teaching position data representing a work line.