Abstract
With the improvement of the performance of optical equipment carried by on-orbit spacecraft, the requirements of vibration isolation are increasing. Passive isolation platforms are widely used, but the ability to suppress the low-frequency deterministic vibration disturbance is limited, especially near the system’s natural frequency. Therefore, an active vibration control strategy is proposed to improve passive isolation performance. In this paper, a Youla parameterized adaptive active vibration control system is introduced to improve the isolation performance of a piezo-actuated active–passive isolation structure. A linear quadratic Gaussian (LQG) central controller is first designed to shape the band-limited local loop of the closed-loop system. Then, the central controller is augmented into a Youla parameterized adaptive regulator with the recursive least square adaptive algorithm, and the Youla parameters (Q parameters) can be adjusted online to the desired value to suppress the unknown and time-varying multifrequency deterministic vibration disturbance. In the experiment, the residual vibration with respect to the combination of multiple frequencies is effectively suppressed by more than 20 dB on average, and a quick response time of less than 0.3 s is achieved when the deterministic residual vibration changes suddenly over time. The experimental results illustrate that the proposed adaptive active vibration control system can effectively suppress the low-frequency deterministic residual vibration.
Highlights
With the improvement of the performance of optical equipment carried by on-orbit spacecraft, the requirement of vibration isolation on the space instrument platform is increasing in the space microgravity environment
The Youla parameterized controller is formulated by augmenting the central controller with the Q parameter based on the internal model principle (IMP), and the adaptive algorithm is developed to online tune the free Q parameter according to the variable residual vibration
It cannot ignore the fact that the deterministic residual vibration has unknown or time-varying characteristics, so that the adaptive algorithm is developed to tune θ online and converges to the target parameter, the system achieves the elimination of the unknown multifrequency or time-varying deterministic residual vibration
Summary
With the improvement of the performance of optical equipment carried by on-orbit spacecraft, the requirement of vibration isolation on the space instrument platform is increasing in the space microgravity environment. This paper will focus on the design of an adaptive active control system for the single-axis isolation structure, which can be used to suppress the low-frequency unknown deterministic residual vibration with multifrequency and time-varying characteristics. An adaptive feedback control system is designed for the unknown vibration disturbance suppression of a lathe system in Reference [15], in which an adaptive algorithm is introduced to adjust the feedback controller in real time according to the unknown residual acceleration feedback signal. The adaptive algorithm can be introduced to adjust the free parameter Q of the resulting parameterized controller online according to the vibration disturbance, so the unknown or time-varying deterministic vibration disturbance will be gradually eliminated.
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