Phased-array piezoelectric actuators using a buckling mechanism having large displacement amplification and nonlinear stiffness

Novel designs of an array of piezoelectric stack actuators using a unique buckling mechanism are presented in this paper. Multiple PZT actuator units with high gain displacement amplification mechanisms are arranged in parallel with spatial phase differences. Having an inherent kinematic singularity, the buckling mechanism provides not only an extremely high gain of displacement amplification, but also varying stiffness and nonlinear force-displacement characteristics. The phased array PZT actuator exploits this nonlinearity for gaining a large output displacement as well as for combining multiple PZT stacks in parallel without conflicting with each other. Three specific designs of arrayed buckling actuators are presented. The aggregate output force-displacement relationship is analyzed and its profile is shaped with respect to spatial phase differences and nonlinear stiffness and force characteristics of individual PZT buckling actuator units.