Movement Simulator Reference Filter for Sinusoidal Tracking
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Solution Overview
Problem
Movement simulators face significant attenuation and phase-shift issues when tracking high-frequency sinusoidal references, limiting their ability to accurately characterize components, as existing control systems are constrained by high-frequency dynamics and robustness requirements.
Innovation Solution
A control device with a reference filter and adaptive tracking mechanism, using a transfer function Rr(z−1)/Fr(z−1) to filter sinusoidal references and solve a Bezout equation for effective tracking, and recursive identification algorithms to estimate and compensate for residual attenuation and phase-shift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the cut-off frequency of the control loop is increased to improve tracking performance, then the ability to follow high-frequency sinusoidal references is improved, but the system becomes unstable due to unmodeled high-frequency dynamics
Solution Approach 1:
The patent segments the control problem by separating low-frequency tracking (handled by the robust controller) from high-frequency reference following (handled by the filter). The filter processes the reference signal to extract high-frequency components while the controller maintains stability, allowing the system to track high-frequency sinusoidal references without compromising stability.
Solution Approach 2:
The patent introduces a filter as an intermediary element between the reference signal and the controller. This filter acts as a mediator that shapes the reference signal to contain high-frequency components while maintaining compatibility with the controller's stability constraints, enabling accurate tracking without directly increasing the controller's cut-off frequency.
2Reliability
If a robust controller is designed to ensure stability against high-frequency dynamics, then system reliability is improved, but the cut-off frequency and tracking performance deteriorate
Solution Approach 1:
The patent divides the control architecture into two independent parts: a robust controller that ensures stability by ignoring high-frequency dynamics, and a filter that handles high-frequency reference signal processing. This segmentation allows each component to be optimized for its specific function without compromise.
Solution Approach 2:
The filter serves as an intermediary that preprocesses the reference signal before it reaches the robust controller. By filtering the reference signal to emphasize high-frequency components while maintaining stability compatibility, the mediator enables the robust controller to achieve both stability and high-frequency tracking performance.
3Measurement precision
If the movement simulator tracks high-frequency sinusoidal references, then measurement precision for component characterization is improved, but attenuation and phase-shift errors increase
Solution Approach 1:
The patent applies preliminary action by processing the reference signal through a filter before it is used for control. This preprocessing step anticipates and compensates for potential tracking errors by shaping the reference signal to account for system dynamics, thereby improving both measurement precision and tracking accuracy for high-frequency sinusoidal references.
Solution Approach 2:
The patent employs feedback mechanisms where the system continuously monitors its response to sinusoidal references and adjusts the filter parameters accordingly. This feedback loop enables real-time compensation for attenuation and phase-shift errors, maintaining high measurement precision and tracking accuracy across varying frequencies.
Data Source
AI summary
The control device of a movement simulator, between its input formed of a control signal and its output formed of a measured magnitude among its speed, its position and its acceleration, by a transfer function B(z−1)/A(z−1) includes a corrector synthesized from the modelling of the movement simulator and equivalent to a RST controller. The controller includes a reference input, a retro-action input whereon is applied the measured magnitude and an output producing the control signal. The transfer function between the reference input of the controller and the measured magnitude is H(z−1)/W(z−1). The device has a reference filter whose input is a sinusoidal reference signal c(t) at a frequency wc and applying at output a filtered reference signal on the reference input of the controller. The reference filter has a transfer function Rr(z−1)/Fr(z−1), whose denominator and numerator are adapted to ensure, for the frequency wc, effective tracking by the movement simulator of the sinusoidal reference.