Dynamometer Control with Resonance Suppression Beyond Antiresonance
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Solution Overview
Problem
The existing test systems face limitations in improving the reproducibility and control responsiveness due to an antiresonance point in the transfer function from the higher-order command signal to the dynamometer revolution speed, restricting the control response to frequencies below half the antiresonance frequency, and often cannot accommodate a revolution detector due to test piece restrictions.
Innovation Solution
A test system incorporating a dynamometer coupled with a test piece via a fastening shaft, an inverter, speed sensor, and a dynamometer control device that includes a response model, feedforward controller, and speed controller to generate torque current commands, along with a resonance suppressing controller to manage mechanical resonance and prevent excessive load on the fastening shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple feedback controller is used in the dynamometer control device, then the device complexity is reduced, but the control response frequency is restricted to at most 1/2 of the antiresonance point frequency
Solution Approach 1:
The control device is segmented into multiple independent functional modules: feedforward controller (generates torque command from speed command), response model (predicts dynamometer response), feedback controller (corrects deviations), and resonance suppressing controller (mitigates mechanical resonance). Each module operates independently with its own transfer function, allowing the system to achieve high response frequency without increasing overall device complexity.
2Speed
If the control frequency is increased beyond half the antiresonance point frequency, then the control response improves, but mechanical resonance occurs causing excessive load on the fastening shaft
Solution Approach 1:
The resonance suppressing controller acts as an intermediary between the feedforward controller and the dynamometer. It receives the torque current command signal, processes it through a resonance suppressing transfer function that cancels out resonant frequencies, and outputs a corrected signal. This intermediary component eliminates mechanical resonance and excessive load on the fastening shaft while allowing high control response frequency to be maintained.
3Speed
If a revolution detector is attached to the test piece to eliminate antiresonance frequency issues, then control response improves, but the test piece restrictions prevent attachment
Solution Approach 1:
The patent replaces the mechanical measurement approach (revolution detector attached to test piece) with an electrical control approach. Instead of mechanically measuring test piece speed and using that for control, the system uses the feedforward controller and response model to electrically compute the required torque command signal, achieving high response frequency without any mechanical attachment to the test piece.
Data Source
AI summary
This test system comprises: a dynamometer connected to a test piece W; an inverter for supplying electric power to the dynamometer; an encoder for generating a speed detection signal N corresponding to a rotational speed of the dynamometer; and a dynamometer control device 6 for generating a torque current command signal DYref. The dynamometer control device 6 comprises: a response model 61 that receives a higher-order speed command signal Nr and outputs a model speed command signal Nr′; a feedforward controller 62 that receives the higher-order speed command signal Nr and outputs a feedforward input uff; and a speed controller 64 that generates the torque current command signal DYref on the basis of a feedback input ufb generated on the basis of a deviation e between the model speed command signal Nr′ and the speed detection signal N, and the feedforward input uff.