A novel active vibration isolator applied for micro-gyro by array of deposited electrodes

Micro-gyroscopes are usually driven into resonance so that the sensitivity and resolution can be enhanced. However, if any substantial vibration of the gyroscope base, over which the seismic proof mass is seated, was present, then the preset resonant frequency would be altered and the performances of the gyroscopes could be much degraded. In this paper, an innovative three degree-of-freedom (DOF) isolation system is proposed to attenuate the undesirable vibrations caused by the ambient environments. The mathematic model of the proposed 3-DOF micro-machined isolation system is established and analyzed such that the transfer function of transmissibility is obtained. The pull-in instability and associated pull-in voltage for the actuators of the isolation system are numerically unveiled so that the interval of the applied voltage to generate the electrostatic control force can be set to ensure the stability of the suspension system. In addition, a fuzzy logic proportion and derivative (PD) controller is synthesized for disturbance rejection. Five sensing electrodes, in cooperation with the isolator, are used to provide the feedback signals of the relative displacements of the proof mass with respect to the base, i.e., pitch, yaw and lateral linear displacement. Ten tuning electrodes are utilized to generate the required electrostatic forces to preserve the seismic proof mass from external disturbance. In comparison with the traditional PD action, the proposed fuzzy logic PD control strategy is verified by intensive simulations to illustrate its superior vibration isolation capability.