A nonlinear control of an QZS isolator with flexures based on a lyapunov function

Abstract

This paper presents an active control method for a quasi-zero stiffness (QZS) isolator using flexures based on a Lyapunov function. First, shown is a dynamic model of an active QZS isolator having indirect horizontal actuation. In the model, the control force is applied along the horizontal direction to compensate for vertical vibrations. Next, a nonlinear control algorithm for the active isolator is developed based on a Lyapunov function. Simulation of the active isolator model which consists of passive QZS isolators, sensors and actuator dynamic models is done to study the effects of control tuning gain on the system performances. In order to verify the active isolation performances, developed is an experimental model including an active QZS isolator, an exciter device and various sensors. Finally, experiments for such as impulse disturbance rejection and transmissibility are performed and the results show that the indirect horizontal actuation by the active QZS isolator using flexure attenuates impulse disturbance as well as isolates the base vibration effectively.