Position Control Apparatus for Low-Frequency Vibration Suppression
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Solution Overview
Problem
Existing position control systems for machine tools face challenges in accurately detecting low-frequency vibrations and require significant memory and time for calculation, leading to reduced responsiveness and excessive gain margins due to noise interference and inefficient parameter updates.
Innovation Solution
A position control apparatus with an aging corrector that detects constant vibrations by analyzing the position command and driven member position, calculates vibration periods and amplitudes, and adjusts control parameters to suppress low-frequency vibrations without large memory or time consumption, while minimizing responsiveness reduction and excessive gain margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If vibration detection and parameter update calculations are performed continuously with high precision, then measurement precision and reliability improve, but loss of time and productivity deteriorate due to excessive calculation time and memory usage
Solution Approach 1:
The patent applies partial action by performing vibration detection and parameter updates only when necessary (when constant vibration is detected) rather than continuously. The control parameter update is triggered selectively based on vibration detection results, reducing unnecessary calculations while maintaining precision when needed.
Solution Approach 2:
The patent extracts the essential vibration detection function from continuous monitoring by using specific detection criteria (constant vibration detection based on position command and driven member position). This extraction allows precise vibration detection without requiring continuous full-system analysis, reducing calculation time.
2Reliability
If control parameters are updated frequently to suppress vibrations, then stability and reliability improve, but productivity deteriorates due to reduced system responsiveness
Solution Approach 1:
The patent implements periodic action by updating control parameters only at specific intervals when constant vibration is detected, rather than continuously. The parameter update occurs periodically based on vibration occurrence, maintaining stability while preserving system responsiveness during normal operation.
Solution Approach 2:
The patent applies dynamics by making the control parameter update frequency adaptive rather than fixed. The parameter update rate dynamically adjusts based on actual vibration conditions - updating only when constant vibration is detected, thus maintaining reliability when needed while preserving productivity during normal states.
3Manufacturing precision
If high gain values are set in speed loop and position loop to reduce position error, then manufacturing precision improves, but stability deteriorates due to excessive gain margins and reduced responsiveness
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting control parameters (such as gain values) based on detected vibration conditions. When constant vibration is detected, parameters are modified to suppress vibration, while maintaining higher precision-oriented parameters during normal operation, thus resolving the contradiction between precision and stability.
Solution Approach 2:
The patent implements feedback by using vibration detection results (based on position command and driven member position feedback) to trigger parameter updates. This feedback mechanism allows the system to automatically adjust parameters to maintain both precision and stability, updating control parameters only when vibration feedback indicates a problem.
Data Source
AI summary
A position control apparatus is configured to perform full-closed control for controlling the position of a driven member. The position control apparatus includes a vibration period and amplitude detector that detects a vibration period and a vibration amplitude included in a difference value between the position command value and the driven member position detection value. The position control apparatus also includes a constant vibration detector that outputs, as a vibration period of the constant vibration, a vibration period obtained while the driven member is not in an acceleration/deceleration state and the vibration period and the vibration amplitude detected by the vibration period and amplitude detector are equal to or greater than a vibration period threshold value and a vibration amplitude threshold value, respectively. The position control apparatus also includes a control parameter changer that changes the control parameter based on the vibration period output from the constant vibration detector.