Optimization of Directionally Attached Piezoelectric Actuators

A directionally attached piezoelectric (DAP) actuator is one method to control the twisting vibration of a plate with high authority. Although insuring proper performance for DAP actuators has been discussed in terms of the control law used, the optimization of the mechanical details of the actuator itself has received little attention. There is an interaction between the actuator and the controlled structure because more actuator material on the structure adds actuation power but also stiffens the structure. The effects of DAP actuator geometric parameters and material properties are explored in a systematic way for the case of a cantilever beam and it is shown that significant improvements in performance are possible. The material property study indicates that an optimum point exists whereby the weight and thus cost can be lowered while improving structure response by using a composite actuator. The actuator thickness, width, orientation angle, and offset from the clamped end have significant effects on structure response. In order of importance, the geometric parameters are: actuator thickness, orientation angle, width and offset. A study of the modal distribution for the structure shows that if the input disturbance that is to be suppressed is modally well characterized, the structure can be efficiently controlled by using more than one independent actuation voltage.