Position Control Gain Calibration Without Stopping Disturbance Suppression
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Solution Overview
Problem
Conventional position control systems face challenges in accurately calibrating open loop gain, especially when disturbance suppression is active, as existing methods require stopping adaptive control to adjust gain, leading to reduced positioning accuracy and difficulty in calibrating across a wide range of disturbance frequencies.
Innovation Solution
A method and device for position control that computes position errors and suppresses disturbance frequencies using a feedback loop, with a table to fetch target loop gains and measure loop gains, allowing for continuous calibration without interrupting disturbance suppression, even when loop characteristics change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If adaptive control is stopped to adjust gain, then gain calibration can be performed, but positioning accuracy drops and external vibrations cannot be sufficiently suppressed
Solution Approach 1:
The system dynamically switches between adaptive control mode and gain calibration mode. During normal operation, adaptive control is active to suppress disturbances. When gain calibration is needed, the system temporarily switches to calibration mode, performs the calibration, then returns to adaptive control mode. This dynamic switching allows both disturbance suppression and accurate gain calibration to be achieved at different times.
Solution Approach 2:
The system performs gain calibration in advance during periods when disturbance suppression requirements are minimal. By pre-calibrating the gain before high-precision positioning operations, the system ensures accurate control parameters are available when needed, without compromising real-time disturbance suppression performance.
2Reliability
If disturbance suppression is active with wide suppression width or high frequency suppression, then disturbance can be suppressed, but original characteristics of the controller are influenced making gain calibration difficult
Solution Approach 1:
The system segments the control bandwidth into different frequency ranges. Disturbance suppression is applied to specific disturbance frequency bands while leaving other frequency ranges unaffected. During gain calibration, the system temporarily adjusts the suppression characteristics to allow accurate measurement, then restores the disturbance suppression settings after calibration completes.
Solution Approach 2:
The system temporarily modifies controller parameters during gain calibration to maintain accurate measurements. Specifically, it adjusts the disturbance suppression parameters to their default states during calibration, then restores the optimized suppression parameters after calibration. This parameter switching enables both accurate gain calibration and effective disturbance suppression.
Data Source
AI summary
In a position control device having a disturbance suppression function, loop gain is calibrated without stopping disturbance suppression control. The position control device has, for disturbance suppression control, a feedback controller for changing the loop characteristic, a table for storing a target gain according to a disturbance frequency, and a gain calibration section for calibrating open loop gain. The gain is calibrated using a target gain in the table according to the change of the loop characteristic of the feedback controller. Open loop gain can be calibrated without interrupting the disturbance suppression control, so the open loop gain can be accurately calibrated without being affected by disturbance, and accurate position control is possible.