JPS63102892A - Uncontrolled movement preventive method of robot - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention particularly relates to a robot runaway prevention method suitable for use in multi-jointed robots.

"Conventional technology" In conventional factories, for example, the teaching play pack type lohosoto used for painting work sometimes causes runaway during operation (a state in which the robot does not operate according to commands). This may be caused by a malfunction due to a clogged servo valve or a disconnection of the servo command signal line. Therefore, in order to prevent the robot from running out of control due to the causes mentioned above, We check the stored data, perform range checks, etc. However, these checks are only checks of the data necessary for the robot's operation, and are performed based on the state of the robot in operation. isn't it.

``Problem to be solved by the invention'' In order to detect the robot's running state, it is sufficient to compare the robot's current position data with the robot's target position data given for each axis of the robot. , the target position data is always in advance, and the robot operates with a certain delay time so as to follow the target position data.

For this reason, it has been extremely difficult to establish a correspondence between the robot's current position data and target position data.

This invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method for preventing a robot from running out of control, which can easily detect the runaway state of a robot and prevent the robot from going out of control. It is intended to.

"Means for Solving the Problem" This invention obtains the motion range data of each axis of a robot from position data that defines the motion of the robot, and stores the motion range of each axis in a memory in a robot control device. Data is written in advance, the position of each axis of the robot is detected when the robot's motion is replayed, and the detected position data of each axis is compared with the motion range data of each axis stored in the memory. Then, based on the comparison result, it is determined whether the robot's position at the time of motion reproduction is within the motion range represented by the motion range data, and if it is determined that it is outside the motion range, the robot The system is characterized in that it stops the operation of the system and also issues an alarm.

"Operation" According to the present invention, the motion range data of each axis of the robot is stored in a part of the memory. Then, when reproducing the robot's motion, the position data of each axis is compared with the above-mentioned motion range data, and it is determined whether or not the motion range is outside the motion range represented by the motion range data. Stops the operation and issues an alarm. Therefore, according to the present invention, it is possible to easily prevent a robot from running out of control by simply performing simple arithmetic processing, and it is also possible to prevent a robot from running out of control without requiring the addition of mechanical or electrical devices.

"Embodiment" Hereinafter, an embodiment in which the present invention is applied to a painting robot will be described with reference to the drawings.

Note that the painting robot in this embodiment is a robot having six axes of freedom.

FIG. 1 is a block diagram showing the configuration of a control circuit of the same embodiment. In this figure, l is the central processing unit (CPU), and the CPU contains a program memory (ROM) that stores programs necessary for robot control; and 2, temporary calculation results and input/output related information. A computer memory (RAM) 3 is connected by a bus 4a. The memory 3 stores a data table TBL3 (FIG. 4).

A program identification code (program name, etc.) is stored at address lI of this data table TBL3.
Address 21-21. Maximum value data and minimum value data from the first axis to the sixth axis of the robot are stored. Address 21. Data representing the allowable error width is stored in .

Further, at addresses 31 to 3n, position data of teaching points from the first point to the nth point are stored. End mark data is stored at address 3n+1.

FIG. 5 is a data table showing in more detail the position data of the teaching point of the first point in the data table shown in FIG. Addresses A1 to A in the data table store teaching position data for each axis at the first point. Furthermore, address E stores on/off control information that supports turning on and off a spray gun, etc., and addresses T1 and Sl store point movement time information and teaching speed information, respectively. C.P.U.I.
Further, an I10 bus 4b is connected to the I10 bus 4b. 5 is a robot position memory (RAM). The memory 5 is connected to the bus 4b and is used to store position data of each axis of the robot arm and auxiliary signals such as external input/output signals.
A data table TBL5 as shown in FIG. 6 is stored. Address ADO-A D5 in this data table TBL5 stores current position information on each axis of the robot. This current position information is obtained by sampling the output of the potentiometer provided on each axis of the robot, which is controlled in a closed loop.
Converted to digital data by D converter, CPU
It was stored at the above address A Do = A D 5 by i. Ru. Reference numeral 6 denotes an external memory, which is an auxiliary memory for use when the amount of information to be stored in the robot position memory RAM 5 is too large to be stored. Reference numeral 7 denotes an external memory for connecting the bus 4b and the external memory 6. external memory interface, 8 a manual operation switch, 9 an I10 interface for connecting the manual operation switch 8 to the bus 4b, 10 a monitor for data display, l! 13.15 is an I10 interface for inputting/outputting the data to be displayed on the bus 4b to the monitor IO, and 13.15 is an I10 interface for inputting/outputting the servo control data on the bus 4b.

12-1-12-6 is a servo control circuit,
This is a circuit for closed-loop control of the drive servo valves for each axis of the robot based on the servo control data.

Feedback data regarding the current position of each axis is sent to this servo control circuit from potentiometers (not shown) provided on each axis of the robot body. A timer 14 is connected to the bus 4a and outputs an interrupt request signal at preset time intervals.

Next, the operation of this embodiment will be described with reference to the flowcharts of FIGS. 2 and 3. FIG. 2 shows a main program for robot control, and FIG. 3 shows a subroutine to be executed by the CPU when an interrupt request is generated from the timer 14. .

First, set the origin at a position sufficiently far away from the workpiece, and then
Control (Point T o Point C
(ontrol) to guide and teach the robot arm. As a result, the position data of the teaching point is obtained, and this data is captured and stored in addresses 31 to 3n of the data table TBL3. Furthermore, the maximum value and minimum value position data are calculated for each shaft part from the position data of each shaft part, and the address 2. ~2□. When these teaching operations and data storage are completed, an operation check (replay) is performed, and when these are completed, the start button is pressed (step St). In the subsequent step S2, initial processing is performed, and initial resets or presets are performed on each register, timer, counter, etc. in the control circuit of the robot. Proceeding to step S3, the timer 14 for generating an interrupt signal is activated.

Proceeding to step S4, the CPUI stores the program memory R.
The control programs stored in OM2 are sequentially read out, and each axis of the robot is controlled based on the data stored in data table TBL3 stored in computer memory RAM3. In the following step S5, it is determined whether the interrupt request from the timer is being accepted or not, and if the answer is [NO], the process returns to step S4. on the other hand[
YES], the process advances to step S6, and the CPU
rl as a flag (I/F) indicating that interrupts are being accepted.
J is set, the operation according to the main program that has been executed up to that point is temporarily interrupted, and the subroutine shown in FIG. 3 is executed.

That is, when proceeding to step SBI, the CPUI sends feedback data regarding the current position of each axis to the above I10.
After importing via the interfaces 13-1-13 to 13-6 and the bus 4b and performing necessary processing, position data P Do = P indicating the current position of each axis of the robot.
D5 is stored in each axis at predetermined addresses ADO to AD6 shown in FIG. 6 of the robot position memory 5. Then, the process advances to step SB2. In step SB2, the maximum value and minimum value data D2. ~D 2.
2 (FIG. 4) is read out. Proceeding to the subsequent step SB3, the current position data PD, -PD of each axis taken in step SBI, and the maximum value and minimum value data D2 . ~D21. are compared respectively. Position data PD
If the o-PDS is within the range defined by the corresponding maximum value and minimum value data (in case of YES), the process advances to step SB6.

When the process advances to step SB6, the CPU operation returns to the main program position at the time the interrupt occurred.

On the other hand, in step SB3, if it is not within the above range (
In the case of No), the process proceeds to step 5I34 to stop the robot, and in the following step SB5, an alarm is generated.

As described above, in this embodiment, the robot's operation is always internally monitored at the timing of the interrupt request by the timer, so it is possible to prevent the robot from running out of control, and to prevent the robot from running out of control. It is safe because it stops immediately and an alarm is issued.

"Effects of the Invention" As explained above, according to the present invention, it is possible to prevent a robot from running out of control by simply performing simple arithmetic processing without installing any new mechanical or electrical devices. This has the effect of making it possible to construct a robot runaway prevention mechanism easily and at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a control circuit according to an embodiment of the present invention, FIG. 2 is a flowchart showing the flow of the main program of the same embodiment, and FIG. 3 is a flowchart showing the flow of the interrupt processing program. , Figure 4 shows memory 3
Figure 5 shows the details of the teaching point position data in the data table Tl3L3, and Figure 6 shows the current position information from the 1st axis to the 6th axis. Stored data table T
It is a figure which shows BL5. 1...Central processing unit, 3...Computer memory, 5...Robot position memory.

Claims (1)

[Claims] Obtain the motion range data for each axis of the robot from the position data that defines the robot's motion, write the motion range data for each axis in the memory in the robot control device in advance, and use the robot's motion range data when reproducing the robot motion. The position of each axis is detected, and the detected position data of each axis is compared with the movement range data of each axis stored in the memory, and from the comparison result, the position of the robot when reproducing the movement is determined. It is determined whether or not the robot is within the motion range represented by the motion range data, and if it is determined that the robot is outside the motion range, the robot's motion is stopped or an alarm is issued. A method for preventing a robot from running out of control.