Structure and control strategy for a piezoelectric inchworm actuator equipped with MEMS ridges

Compared with conventional piezoelectric inchworm actuators (PIAs), which rely on a frictional mechanism to produce large stroke and force outputs, PIAs equipped with MEMS ridges can achieve much higher power density in small geometries through the interlocking of micro-ridges. This is promising for future adaptive space structure applications. However, from a practical perspective, achieving stable interlocking MEMS ridges remains challenging, and so an accurate structural assembly and effective control strategy are required. This paper presents an actuator with a simple structure, thus simplifying the assembly process and reducing assembly errors, and then designs a reasonable control strategy that compensates for hysteresis and the uncertain compression of the structure induced by acting against external loads of different stiffness. Finally, the stable interlocking of MEMS ridges is experimentally validated by measuring the significant improvement in PIA load capacity.