Dynamometer Control for High Inertia Resonance
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Solution Overview
Problem
Existing dynamometer systems face instability issues due to insufficient consideration of load inertia, leading to resonance phenomena and difficulty in achieving stable speed control, especially with higher inertia moments.
Innovation Solution
A dynamometer system that includes a control device with a shaft-torque-detection-compensation unit and a disturbance observer compensation unit, which corrects torque-current-command values by filtering resonance frequencies and accounting for overall inertia, enabling stable speed and position control across the entire frequency domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the control response is raised to improve speed control performance, then the response speed improves, but instability phenomena such as hatching and divergence occur due to resonance characteristics of the mechanical system
Solution Approach 1:
The patent detects resonance frequencies using a torque meter and intentionally generates counter-phase vibration commands at these frequencies to cancel out the resonance effects. This converts the harmful resonance phenomenon into a controllable and compensatable effect, allowing high-speed control without instability.
Solution Approach 2:
The system continuously monitors the mechanical system's response through the torque meter and encoder, detects resonance conditions, and adjusts the vibration commands in real-time. This closed-loop feedback mechanism enables the system to maintain stability while operating at high response speeds by dynamically compensating for resonance effects.
2Weight of moving object
If the inertia of the load is great, then the load capacity increases, but the tendency toward instability and resonance becomes remarkable
Solution Approach 1:
The patent utilizes controlled mechanical vibrations at detected resonance frequencies to actively counteract the adverse effects of high inertia. By generating vibrations that are phase-opposed to the resonance vibrations, the system cancels out the destabilizing effects of high load inertia, enabling stable control even with heavy loads.
Solution Approach 2:
The system dynamically changes control parameters including vibration frequency and amplitude based on the detected resonance characteristics and load conditions. This allows the controller to adapt to varying inertia levels and maintain optimal stability margins across different operating conditions.
Data Source
AI summary
Provided is a dynamometer system capable of stable speed control and position control even in instances of large load inertia. A speed-control device (6C) in a dynamometer system is provided with: a speed-control-circuit unit (61A) for calculating a torque-current-command value (T2) on the basis of an angular-velocity-command value (ωref) and the angular velocity (ωM) of the dynamometer; a disturbance-observer-compensation unit (63C) for correcting the torque-current-command value by subtracting a disturbance observer (Tobs) from the torque-current-command value (T2); and a shaft-torque-detection-compensation unit (62A) for correcting the torque-current-command value by adding a shaft-torque-detection-compensation amount (Tsh_K), which is obtained by multiplying a filter transfer function (GBPF) and a control gain (K1) by a shaft-torque-detection value (Tsh), to a torque-current-command value (T1). Therein, the filter transfer function (GBPF) has only the resonance frequency and vicinity thereof for mechanical systems comprising load devices and dynamometers set as a passband.