On the vibration control using a piezoelectric actuator and a negative capacitor adjusted by a microprocessor

The design and realization of an adaptive vibration isolation system based on a method to control the effective elastic stiffness of piezoelectric materials are presented in this paper. In this system, the vibration isolation effect is achieved by absorption of vibrations transmitted through a multi-stack piezoelectric actuator connected to an active analog circuit that behaves as a negative capacitor. The problem of a high sensitivity of the system to the proper adjustment of the negative capacitor and a deterioration of the vibration isolation efficiency in changing operational conditions are analyzed. A method for the self-adjustment of the system by appending an additional digital control circuit to the negative capacitor is implemented. The transmissibility of vibrations through the piezoelectric actuator was measured in different control regimes.