Motor Controller with Imperfect Position Integrator
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Solution Overview
Problem
Existing motor controllers face challenges in achieving error-less control, particularly in maintaining a position error close to zero, as they often result in significant overshoot and vibration due to the incorporation of integrators in control loops, which complicates gain adjustments and stability.
Innovation Solution
A motor controller configuration incorporating both position and speed integrators with imperfect integration in the position controller and perfect integration in the speed controller, along with feed-forward control mechanisms, to reduce overshoot and position errors by balancing gains and compensating for viscous friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If integrators are incorporated in control loops to achieve error-less control, then position error can be reduced close to zero, but significant overshoot and vibration occur
Solution Approach 1:
The patent applies parameter changes by using different integration methods for position and speed control loops. The position controller uses imperfect integration with a leakage term that exponentially decays the integrated error, while the speed controller uses perfect integration. This differential parameter approach allows the system to achieve error-less control without excessive overshoot and vibration, resolving the contradiction between position precision and system stability.
2Measurement precision
If integrators are incorporated in control loops to achieve error-less control, then position error can be reduced close to zero, but gain adjustments become complicated
Solution Approach 1:
The patent segments the control system into two distinct control loops with different integration characteristics: a position control loop using imperfect integration and a speed control loop using perfect integration. This segmentation allows each loop to be tuned independently with appropriate gain settings, simplifying the overall gain adjustment process while achieving error-less control.
3Measurement precision
If integrators are incorporated in control loops to achieve error-less control, then position error can be reduced close to zero, but vibration occurs
Solution Approach 1:
The patent changes the integration parameter in the position control loop by introducing a leakage term that prevents the integrator from accumulating error indefinitely. This imperfect integration approach eliminates the vibration caused by perfect integration while maintaining the ability to reduce position error close to zero, thus resolving the contradiction between precision and vibration suppression.
Data Source
AI summary
A motor controller to control a motor includes a position controller, a speed controller, a first integrator, and a second integrator. The position controller is configured to generate a speed command based on a position error between a position command and a motor position. The speed controller is configured to generate a torque command to be input to the motor based on a speed error between the speed command and a motor speed. The first integrator is configured to calculate an integral value of the position error to be added to the position error. The second integrator is configured to calculate an integral value of the speed error to be added to the speed error.