Semi-active Control of Isolation System with Variable Friction

Semi-active Control of Isolation System with Variable Friction

Many researches have shown that a passive isolation system can effectively reduce seismic responses of structures. Passive isolation systems are simple and reliable but it is not adaptive under excitations different from the design one. For this reason, an active isolation system can be implemented to make an isolation system be adaptive. But there is another disadvantage in active isolation system, that is, it needs much energy for the actuator. The semi-active isolation system is a compromise between passive and active one. The piezoelectric smart isolation system(PSIS) composes of an isolation stage and a piezoelectric friction damper(PFD). In this research, a simple control law is proposed. The control force, which is the normal force of PFD, is proportional to the exponent power of the absolute velocity of isolation platform. It is simple, and full-state feedback is not required. From numerical simulation, the proposed control law is found to be more effective and efficient than passive isolation system.