Structure dependence of the output performances of a self-deformation driving (SDD) piezoelectric actuator

Abstract

Pre-loading the driving compliant mechanism is an effective method to improve the self-locking ability of the parasitic motion principle (PMP) piezoelectric actuators, but it may also change the motion mode from the normal PMP to the self-deformation driving (SDD). When the self-deformation is distributed along the whole driving compliant mechanism, the structure design and analysis would be difficult. To facilitate the design and analysis of SDD piezoelectric actuators, following our previous study, an additional flexible hinge was introduced to the lever-amplification compliant mechanism, and thus the self-deformation would be concentrated in the introduced flexible hinge. The maximum one-step displacement of the proposed SDD piezoelectric actuator was analyzed by pseudo-rigid-body method, and the effects of the radius of the introduced right-circular flexible hinge on its compliance were theoretically analyzed. Output performances of the SDD actuator under various radiuses were characterized by experiments. The results showed that the introduced flexible hinge could not only increase the peak motion speed but also increase the adjustable initial gap, i.e. reducing the assembly requirements. Furthermore, when reducing the initial gap to be over the one corresponding to the peak motion speed, the backward motion would become remarkable; however, it would also bring an important advantage, improving the self-locking ability (also the loading capability). These results are expected to provide useful information for the design and application of SDD piezoelectric actuators.