Production-Line Robot Learning Control for Vibration Suppression
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Solution Overview
Problem
High-speed robot operations in production lines often result in vibrations at the robot's distal end due to insufficient rigidity, leading to incorrect operation or damage to objects, necessitating slower speeds and stopping the production line for learning, which reduces efficiency and causes losses.
Innovation Solution
A robot control system equipped with a sensor for detecting actual positions and a control device that adjusts operation-speed change rates within vibration allowance conditions, allowing for learning control to suppress vibrations and maintain high-speed operations without damaging objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the robot operation speed is increased to improve production efficiency, then productivity increases, but vibrations at the distal end of the robot increase causing incorrect operation or damage to objects
Solution Approach 1:
The system performs preliminary learning control by detecting vibrations during robot operation and calculating compensation amounts in advance. The learning control part accumulates vibration data and computes compensation values before actual high-speed operation, allowing the robot to operate at high speeds without causing damage to objects.
Solution Approach 2:
The system attaches sensors to the distal end of the robot to detect actual vibrations during operation. This feedback information is fed back to the learning control part, which calculates compensation amounts based on the detected vibrations, enabling continuous optimization of vibration suppression while maintaining high-speed operation.
2Loss of time
If learning control is conducted at high operation speed to reduce takt time, then learning time decreases, but vibrations exceed allowance requiring additional learning at lower speed
Solution Approach 1:
The system dynamically adjusts the operation speed during learning control based on detected vibrations. The learning control part monitors vibration levels in real-time and adapts the operation speed accordingly, allowing high-speed learning when vibrations are within allowance and automatically reducing speed when vibrations exceed thresholds, thus optimizing learning time while ensuring reliability.
3Object-affected harmful factors
If the production line is stopped for learning without objects to prevent vibrations from damaging objects, then object safety is ensured, but production efficiency decreases due to reduced operating rate
Solution Approach 1:
The system enables the robot to perform learning control autonomously during production line operation with objects present. The learning control part uses the actual objects in the production line as learning targets, eliminating the need to stop the production line or remove objects. This self-service approach allows simultaneous production and learning, maintaining high operating rates while ensuring object safety through real-time vibration monitoring and compensation.
Data Source
AI summary
A control device includes a learning control part in which a difference is calculated between a target position and an actual position of a portion detected based on a sensor, and an operation-speed change rate is increased or reduced several times within a maximum value of the operation-speed change rate set for increasing or reducing the operation speed of a robot mechanism unit and within allowance conditions of vibrations occurring at the portion to be controlled; meanwhile, learning is repeated to calculate an updated compensation amount based on the difference and a previous compensation amount previously calculated for suppressing vibrations at each operation-speed change rate, and a convergent compensation amount and a convergent operation-speed change rate are stored after convergence of the compensation amount and the operation-speed change rate.