Modeling of Piezo Stack Actuators and Their Application in Active Vibration Control

Abstract

This paper presents the vibration control of a highly simplified two degree of freedom model of a helicopter. The vibration control study has been performed using both active and passive vibration control schemes. In the case of active vibration control, the feedback mechanism affects the stiffness of the system; whereas in passive vibration control, the absorber mass affects the inertia of the system. The active control is achieved using a combination of piezo stack sensor and actuator mechanism. A finite element model for the piezo stack mechanism has been developed to obtain a relation between deformation, applied/induced potential and externally applied mechanical load. The results of this study indicate that inclusion of sensor and actuator units increases the natural frequency of the system due to increase in stiffness of the system. It is observed that in the case of active vibration control, the frequency response of acceleration of the system is highly sensitive to small variations in the magnitude of gain around its optimum value and insensitive to changes in excitation frequency; whereas in passive vibration control, the frequency response does not exhibit any significant change in the characteristics with respect to the variation in the absorber mass, while it is highly sensitive to changes in operating frequency.