A novel stick-slip piezoelectric actuator based on a triangular compliant driving mechanism

There is a growing demand for positioning actuators with a higher resolution, accuracy, speed, and driving force. Various piezoelectric actuators have been proposed to meet these requirements; however, they all have inherent limitations. This paper presents a novel high-performance piezoelectric actuator that can overcome the limitations of existing designs. It is based on the stick-slip actuation principle and makes use of coupling motions of the proposed triangular driving mechanism to generate a clamping action during the 'stick' phase and a releasing action during the 'slip' phase. Unlike existing driving mechanisms based on similar principles, the proposed actuator can employ its unique structure to amplify the clamping force and the related driving force by using a large design triangular angle. Apart from its superior performance in driving force, it is interestingly found that its driving speed performance also improves when the design angle is increased. Finite-element analysis and experiments are carried out to justify the superior performance of the proposed actuator. In comparison with existing actuator prototypes based on similar principles, a prototype of the proposed actuator, even driven with a lower input voltage, achieves an 11 times larger driving load and a 3 times higher free-load driving speed.