A rotational actuator based on the piezoelectric bimorph

With the advancing of reflectarray antenna technology, a rotational actuator is desired to enable the beam scanning capability. The anticipated characteristics of this actuator include small volume, low energy consumption, easy to control, fast response, high reliability, and etc. The actuator developed by this study is composed of bimorphs and micro-gears. It can rotate clockwise and counterclockwise alternately by varying the applied voltage. The most prominent advantage of this actuator is that it only requires feed forward control which is easy to implement. It doesn't need feedback control, as other actuators do, with no accumulative errors for its positioning application. This study has optimized the geometry of this actuator using the multi-physics coupling finite element method (FEM) software. The components of this actuator have been fabricated by micro-electric-mechanical-system (MEMS) fabrication process and precise machining technology. Glass fiber reinforced composited (GFRC) and Lead Zirconium Titanate (PZT) materials are used to fabricate the bimorph. The copper and stainless steel are used to fabricate the housing and gear, respectively. Several actuators have been assembled and tested to investigate the characteristics of this actuator. A test set up has been developed to measure the relationship between the rotation angle and the applied voltage. A fast camera has been employed to experimentally assess the response time, repeatability, stability and etc. Finally, the experimental results are correlated with the analysis results.