JPH03234490A - Control method of robot - Google Patents

Abstract

PURPOSE:To operate a robot at a maximum acceleration by measuring the difference between operation command and actual operation according to an actual load actually mounted on the top end of the robot, using load charge map and maximum acceleration map on the basis of this difference to determine the maximum acceleration, and loading this value into a control system to operate the robot. CONSTITUTION:A load charge map M1 for preliminarily instructing an operation pattern to a robot and determining the difference between operation command and actual operating position on the basis of its playback operation and a map M2 for calculating a maximum acceleration allowed by the robot according to the load charge are formed. The maximum acceleration is determined on the basis of the data at the time of actual use and both the maps M1, M2, and the robot is playback-operated at this acceleration. Hence, the playback operation can be performed within the shortest time without exceeding the maximum acceleration allowed by the robot.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides the following advantages:
The present invention relates to a control method used for a teaching playback type robot that performs playback operations according to its teaching contents.

BACKGROUND OF THE INVENTION Robots that perform assembly work, welding work, etc. can perform various operations by accelerating from a stopped state to a taught speed, or decelerating from an operating speed and stopping.

By the way, when the robot changes its acceleration, the acceleration needs to be less than or equal to the maximum acceleration allowed by the manipulator. If the operation exceeds the maximum acceleration, there is a possibility that the reducer inside the manipulator will be overloaded and damaged. However, in order to complete the taught motion in a short time, it is better to have a large acceleration.

In addition, it is often unclear how much load below the allowable maximum load is attached to the manipulator of this conventional type mouth bot, and generally it is assumed that the allowable maximum load is attached. In this case, the device was operated at the required acceleration or acceleration time. When the operating speed of a teaching playback robot changes rapidly, the robot is controlled to accelerate or decelerate at the maximum acceleration allowed by the robot's manipulator.

Problems to be Solved by the Invention However, in this conventional control method, the maximum acceleration differs depending on the weight of the load attached to the tip of the manipulator. I couldn't get it to work.

The present invention is intended to solve these conventional problems, and aims to provide a method for controlling a robot that can operate at maximum acceleration according to the applied load. .

Means for Solving the Problems In order to achieve the above object, the present invention provides a load map that teaches a movement pattern to the robot in advance and calculates the difference between the movement command and the actual movement position based on the playback movement; A map is created to calculate the maximum allowable acceleration of the robot according to the applied load, the maximum acceleration is determined based on data during actual use and both maps, and the robot is operated for playback using this acceleration.

Therefore, according to the present invention, the playback operation can be performed at the maximum acceleration according to the load on the robot, so the playback operation can be performed in the shortest possible time without exceeding the maximum acceleration allowed by the robot.

Embodiment No. 1 shows a robot control unit in an embodiment of the present invention.
1 is a flowchart showing step 1.

First, a teaching playback type multi-joint robot is prepared, and in step 1, a predetermined movement pattern for measuring the load on each axis is taught to this robot. Here, the direction of gravity is considered for each axis, and an operation pattern in which the load factor of the decelerator becomes the maximum allowable value is taught.

Next, in step 2, loads from ○ to the maximum load WM are sequentially attached to the tip of the bot, that is, the hand, and the motion pattern is operated.Then, in step 3, the data obtained here, that is, the motion A load map M1 is obtained from the data of the load W for the difference △L between the command and the actual operation.Similarly, the load map M1 is calculated for the load W when the load factor of the reducer in the manipulator of the robot maintains the maximum allowable value. A maximum acceleration map M2 is obtained from the data related to the maximum acceleration araax.These maps are shown in FIGS. 2 and 3.

Next, prior to actual use, the tools that will actually be used are attached to the tip of Robo-Rido's manipulator, and in this state the robot is operated in the same movement pattern as described above.

As a result, in step 4, the difference ΔL between the motion command and the actual motion when the speed changes during the motion is measured. Then, in step 5, the maximum acceleration a l1ax in the actual load state corresponding to this difference ΔL is calculated from the load map M1 and the maximum acceleration map M2. Then, data at this maximum acceleration awax is taken into the control system of the robot and processed.

As a result, during actual use, as shown in step 6, when the robot performs a playback operation, it will operate at a maximum acceleration of 8112X together with the attached actual load.

FIG. 4 schematically illustrates the control system of the robot in the embodiment.

Here, 11 is a position control unit that issues a speed command A, 12 is a speed control unit that receives the speed command A and the actual operating speed B, and issues a torque correction output of the deviation correction layer, and 13 is a drive output based on the torque correction output. 15 is a rotary encoder that outputs the actual operating speed B of the motor 14.

Here, the difference ΔL between the operation command and the actual operation described above is represented by the speed command A, and the load WM is determined from this and the load map Ml shown in FIG. Further, the speed control section 12 determines the maximum acceleration a wax corresponding to the applied load from the map M2.

Effects of the Invention As is clear from the above explanation, according to the robot control method of the present invention, the difference ΔL between the motion command and the actual motion is measured according to the actual load actually attached to the tip of the robot, Based on this, the maximum acceleration was determined using the load map and the maximum acceleration map, and this value was taken into the control system to operate the robot, so the robot can operate at the maximum acceleration during actual use, so the same teaching operation This has the advantage that the playback operation can be performed in a shorter time and the setting work is also easier.

[Brief explanation of drawings]

Fig. 1 is a flowchart of robot control operation in one embodiment of the present invention, Fig. 2 is a load map used in the same embodiment, Fig. 3 is a maximum acceleration map used in the same embodiment, and Fig. 4 is the same embodiment. FIG. 2 is a block diagram of a control system of a robot in FIG. Ml...load load map, M2...maximum acceleration map, W...load load, a iax...maximum acceleration,
ΔL...Difference between operation command and actual operation, A...Speed command, B...Movement speed, 11...Position control unit, 12...
- Speed control section, 13... Current control section, 14... Motor, 15... Rotary encoder.

Claims (1)

[Claims] A teaching playback system teaches an articulated robot a predetermined motion pattern, then measures the difference between the motion command to the robot during playback motion and the actual motion position, and attaches the robot to the robot according to the difference. The applied load is calculated and a applied load map is created, and the maximum acceleration that the robot can tolerate is calculated according to the applied load to create a maximum acceleration map.The applied load map and the maximum acceleration are then calculated during actual use. A method for controlling a robot, characterized in that a maximum acceleration corresponding to the difference between the motion command and the actual motion position is determined based on a map, and the robot is caused to perform a playback motion using the maximum acceleration.