Piezo actuators for active vibration control and isolation—principles and practical experiences

Piezoelectric actuators based on PZT ceramics are a widely used drive system and are also often used for active noise and vibration control applications. They offer high static and dynamic forces, are very stiff, allow high-frequency dynamic applications, and contain no moving parts. But they also have severe disadvantages: They are very sensitive to bending moments and pulling forces and have to be driven by electrical fields of some kV/mm to obtain displacements of about 1%. The actuators have a high capacitance, which is a challenge for the power amplifiers, and the material exhibits hysteresis which shows up as nonlinearities. Based on these restrictions, different concepts for the application of piezo actuators for active vibration control and isolation systems are presented, and mechanical as well as electrical aspects are discussed. For a real life application, it was decided to use one of the concepts at an experimental stage. The design of this actuator system will be presented. Experimental results and experiences will be shown, including test stand results of the entire active vibration control system. The main problem proved to be with the nonlinearities of the actuator response, which are prohibitive for at least some applications.