An Innovative Stepping Piezoelectric Actuator Driven by Friction Differential Force: Design, Modeling, and Experimental Evaluation

In this article, an innovative stepping piezoelectric actuator driven by friction differential force was proposed. The differential piezoelectric actuator consists of three parallel shafts (two driving shafts and one guiding shaft), two of which can move axially under the action of piezoelectric stacks. Specific voltage signals were used to excite sequential movement of the driving shafts, thereby generating a frictional force difference on a mover. The friction differential force can be used to push the mover to move in a stepping manner along the guiding shaft, which eliminates the adverse effect of the clamping mechanism and reduces parasitic displacement. The primary load-bearing component was analyzed using the finite element method and the operational principle of the differential piezoelectric actuator was clarified by constructing a dynamic model. A prototype was manufactured, and an experimental platform was established. The experimental findings demonstrated that the differential actuator attained a resolution of 36 nm and a peak velocity of 1.019 mm/s. Under a consistent driving voltage of 150 V and a driving frequency of 1 Hz, the maximum load capacity was measured to be 300 N. Moreover, the parasitic displacement observed in the differential actuator prototype was ±0.119 μm.