Highly Efficient Piezoelectric Actuators for Active Vibration Control Enrico L. Colla, Ganesh Suyal, Sandrine Gentil, and Nava Setter Ceramics Laboratory, Swiss Federal Institute of Technology, 1015 Lausanne, Switzerland ABSTRACT An high performance / inexpensive diskbender actuator was produced by combining efficient design and fabrication methods and a new technique to operate these actuators was developed and tested, which can enhance the displacement and force capabilities by almost a factor of 2 by using the same maximal driving voltage. The properties of these actuators are intermediate between those of standard bimorphs, used for very large displacements but providing rather small forces, and those of low voltage stack multilayers, which provide quite large forces but are generally heavier, larger and expensive for equivalent displacements. The absence of any external mechanical amplification mechanism and their geometry make these actuators particularly suitable for active vibration damping applications within buildings affected by perturbations of hundreds of μm or for noise control by emission of controlled sound in antiphase. The class of displacement/force, which can be obtained with suitably dimensioned actuators, provides sufficient high motion even for the lower audio frequency region (400-1500 Hz). In order to lower the driving voltages, multilayer diskbenders were also fabricated with the same technique. The number of layers does not influence the actuator displacement and force properties but the increased capacity of the actuator may require sophisticated driving amplifiers. INTRODUCTION During the last 30 years a growing number of perturbations consisting of vibrations and noise produced by many human activities, are substantially affecting our environment. An emblematic example is the load of noise pollution for people leaving in regions close to large airports or large noisy industrial plants. The suppression of those perturbations appears therefore to be an important technological challenge of our time. Recent advancements such as the availability of high-power and low-cost computing, smart materials, and advanced control techniques have led to a growing use of active vibration control systems to suppress perturbations, in both, new applications with severe requirements, or even to replace passive systems. The latter are generally clumsy, heavy and with poor damping performances because unable to adapt or retune to changing disturbances or structural characteristics over time [1, 2]. The implication of active control is that desirable performance characteristics can be achieved through flexible and clever strategies, whereby actuators excite the structure based on the response of the structure to noise as measured by sensors. An active vibration control system consists of a set of actuators and sensors coupled by a controller. The sensors detect the amplitude and phase of the incoming external perturbations and the control manipulates the signal from the sensor and outputs the suitable driving commands to the actuators, which in turn influence the mechanical response of the system. Mat. Res. Soc. Symp. Proc. Vol. 785 © 2004 Materials Research Society D1.5.1