Self-tuning of position feedback and velocity feedback of active vibration isolation system with 6 DOFs

Active Vibration Isolation Systems (AVIS), which are composed of position feedback loop and velocity feedback loop, are widely used in IC equipments and high precision metrology devices to achieve high vibration isolation performance and maintain position stability. However, the performance of AVIS is always affected by both position feedback loop and velocity feedback loop. Traditionally, the control parameters of the velocity loop and feedback loop are determined in sequence. But theses tuning procedures are time-consuming and the performance of AVIS greatly depends on operator's experience. Further more, AVIS controlled with these parameters can not attain the best performance. In this paper, we propose a self-tuning procedure for the AVIS with velocity feedback and position feedback, which aims at optimal damping of AVIS with Sky-hook. As the structure coupling is weak in six orthogonal coordinates, the self-tuning procedure is realized in three steps: calculation of the decoupling matrix, identification of the structure parameters based on the dynamic model of the AVIS, optimization of the feedback controller by minimizing the vibration of payload. A simulation and an experiment are implemented to verify the self-tuning method and the performance of AVIS.