The design and characterization of a piezo-driven inchworm linear motor with a reduction-lever mechanism

A piezo-driven inchworm linear motor with a reduction lever mechanism has been designed and characterized. The inchworm motor consists of two clamping devices for gripping a moving shaft and one push-pull device operated by three piezoelectric stacks. To reduce positioning errors caused by control voltage fluctuations and to improve positioning accuracy, a reduction lever mechanism with a monolithic flexure structure is employed to the push-pull device. For the design analysis of the push-pull and clamping devices, their analytical models and equations were developed, by which the static characteristics were evaluated. The positioning performances of the inchworm motor assembled with the push-pull and clamping devices were experimentally characterized. The developed inchworm linear motor proved effective not only in performing a step movement of 1 nm up to 82.5 nm, with the step size optionally adjusted, but also in providing ultra high positioning accuracy.