Industrial Robot Compliant Control Mode for Program Adjustment
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Solution Overview
Problem
The existing methods for programming industrial robots are time-consuming and require manual adjustment of target points, which ties up production equipment and delays the start of production, as off-line programmed positions may deviate from actual positions in the real robot cell.
Innovation Solution
A method that automatically adjusts the positions of target points by switching the robot controller to compliant control mode, allowing the manipulator to move the tool arm until the work object is clamped, and then storing the positions to adjust the program instructions, enabling automatic adjustment of all target points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual adjustment of target points is used, then positioning accuracy is improved, but programming time increases significantly
Solution Approach 1:
The robot system automatically adjusts its own target point positions by using the compliant control mode to feel the work object and determine actual positions, eliminating the need for manual measurement and programming adjustments
Solution Approach 2:
The controller dynamically changes the stiffness parameter of the manipulator by switching between normal control mode (high stiffness) and compliant control mode (low stiffness), enabling the robot to adaptively adjust to position deviations without manual intervention
2Measurement precision
If robot operates in normal control mode, then positioning precision is improved, but ability to absorb external forces deteriorates
Solution Approach 1:
The robot controller dynamically switches between normal control mode and compliant control mode depending on the operational requirements, allowing the manipulator to be stiff during positioning and compliant during contact with the work object
Solution Approach 2:
The stiffness parameter of the manipulator is changed by adjusting controller gains, allowing the robot to transition from a rigid positioning state to a compliant force-absorbing state as needed
3Force
If robot operates in compliant control mode, then ability to absorb external forces is improved, but positioning precision deteriorates
Solution Approach 1:
The robot dynamically switches between compliant control mode for force absorption and normal control mode for precise positioning, optimizing performance for each specific task phase
Solution Approach 2:
The robot uses compliant control mode preliminarily to detect work object position and then switches to normal control mode for precise positioning, preparing the system in advance for the next operation phase
Data Source
AI summary
A method for adjusting a program including program instructions for controlling an industrial robot to carry out work at a plurality of target points on a work object. The robot includes a tool having two arms adapted to clamp the work object and at least one of the arms is arranged movable relative the other arm in an opening and a closing direction, a manipulator adapted to hold the tool or the work object, and a controller controlling the movements of the manipulator and the tool arm and configured to switch between a normal control mode and a compliant control mode in which the manipulator has a reduced stiffness in at least one direction. The method includes moving the manipulator and the tool according to the program instructions until one of the target points is reached.