Static Motor Auto-Tuning Using Virtual Damping and Frequency Response
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Solution Overview
Problem
Existing static auto-tuning methods for electric motors are complex, calculation intensive, and costly, with limited accuracy and safety concerns due to unpredictable rotor displacement and speed response during tuning.
Innovation Solution
A less complex and less costly static auto-tuning system and method that uses a closed-loop feedback mechanism and a virtual damping coefficient to accurately determine inertia and friction coefficient values, enabling better control of motor operation through gain calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex signal processing algorithms like FFT are used to reduce noise effect, then measurement precision improves, but device complexity and cost increase due to requiring separate central processing units
Solution Approach 1:
The patent extracts and removes the complex FFT processing requirement from the system architecture. Instead of using a separate central processing unit for complex signal processing, the invention uses a simplified processing approach that achieves comparable noise reduction without the computational overhead, directly resolving the contradiction between measurement precision and device complexity
Solution Approach 2:
The patent replaces expensive, complex processing hardware (separate central processing unit) with a simpler, more cost-effective processing approach. The simplified algorithm achieves sufficient noise reduction for industrial applications without requiring high-performance computing resources, reducing system cost and complexity while maintaining adequate measurement precision
2Reliability
If static auto-tuning is used to avoid abrupt system movement, then reliability improves, but measurement precision deteriorates due to low signal-to-noise ratio at low speeds
Solution Approach 1:
The patent introduces dynamic elements into the static auto-tuning process by implementing a multi-frequency excitation approach. The system applies vibration torque at multiple frequencies and uses a simplified spectral analysis to extract system parameters, thereby improving measurement precision while maintaining the safety advantages of static tuning
Solution Approach 2:
The patent utilizes mechanical vibration principles by applying controlled vibration torque to the motor system during static auto-tuning. This vibration excitation generates measurable responses that improve the signal-to-noise ratio, enabling accurate parameter estimation without requiring high-speed movement or complex processing
3Measurement precision
If rotational auto-tuning is used for accurate parameter measurement, then measurement precision improves, but ease of operation worsens due to limited rotor displacement in robotic arms and AGVs
Solution Approach 1:
The patent inverts the conventional approach by performing auto-tuning in the static domain rather than requiring rotational movement. Instead of rotating the motor to measure parameters, the system applies vibration torque at standstill and extracts parameters from the vibrational response, making tuning feasible for robotic arms and AGVs with limited rotor displacement while maintaining measurement accuracy
Solution Approach 2:
The patent replaces the mechanical rotation-based measurement system with a vibration-based measurement system. By substituting rotational movement with controlled vibration and using simplified spectral analysis, the system achieves accurate parameter measurement without requiring the mechanical displacement that rotational auto-tuning demands
Data Source
AI summary
A static auto-tuning system and method for controlling operation of a motor in a system. A speed reference signal is generated resulting in a speed response of the motor. Closed-loop feedback magnifies the rotating friction effect to an observable level. Inertia and rotating friction coefficient values of the system are estimated based on the speed frequency response and a virtual damping coefficient. A fixed low frequency speed signal may result in a first frequency response function for determining virtual damping, and a variable frequency excitation signal may result in a second frequency response function for determining the inertia and rotating friction characteristics. Closed-loop gains are determined based on these characteristics. The excitation signal may be sampled and a peak value in each interval may be identified and stored to produce an envelope of peak values for determining the gain response. Operation of the motor is controlled using the determined gains.