Actuator Inertia Compensation Using Q-Axis Current Derivative
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Solution Overview
Problem
Existing control systems for robots require additional sensors like acceleration sensors for inertia compensation, which complicates the configuration and lacks sufficient responsiveness.
Innovation Solution
A control system that calculates an inertia compensation command value based on the derivative of the q-axis current of the actuator, eliminating the need for additional sensors and using feedforward control for improved responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional sensors such as acceleration sensors are used for inertia compensation, then inertia compensation performance is improved, but device complexity and cost increase
Solution Approach 1:
The system uses the actuator's own q-axis current signal to perform inertia compensation without requiring external sensors. The differentiation unit processes the existing current signal to generate the inertia compensation command, making the system self-sufficient and eliminating additional hardware components.
Solution Approach 2:
The patent introduces a differentiation unit as an intermediary component that processes the q-axis current signal to extract acceleration information. This intermediary transforms the existing electrical signal into a form suitable for inertia compensation, replacing the need for physical acceleration sensors.
2Measurement precision
If feedback control with acceleration sensor is used for inertia compensation, then compensation accuracy is improved, but responsiveness deteriorates
Solution Approach 1:
The system performs preliminary differentiation of the q-axis current signal to predict acceleration trends before they fully manifest. By processing the current signal through the differentiation unit in advance, the system proactively generates compensation commands that anticipate inertial effects, improving responsiveness while maintaining accuracy.
Solution Approach 2:
The patent replaces the mechanical sensor-based measurement system with an electrical signal processing approach. Instead of using physical acceleration sensors that introduce measurement delays, the system uses electrical differentiation of the current signal, which provides faster and more responsive acceleration estimation.
3Reliability
If machine learning is used for inertia compensation, then compensation performance is improved, but device complexity and computational requirements increase
Solution Approach 1:
The patent changes the approach from complex machine learning models to a simple mathematical differentiation operation. By transforming the problem from pattern recognition to signal differentiation, the system achieves effective inertia compensation through straightforward parameter processing rather than complex computational algorithms.
Solution Approach 2:
The system extracts only the essential acceleration information needed for inertia compensation by differentiating the q-axis current signal. This extraction approach removes unnecessary complexity of machine learning while retaining the critical dynamic information required for effective compensation.
Data Source
AI summary
A control system includes: a torque command generator configured to generate a torque command value for an actuator; an inertia compensation calculator configured to calculate an inertia compensation command value based on a derivative of a q-axis current of the actuator, and a drive command calculator configured to calculate a drive command value by adding the torque command value generated by the torque command generator to the inertia compensation command value calculated by the inertia compensation calculator, and output the drive command value to the actuator.