Vibration analysis of piezo-actuated flexure-jointed mechanisms

Abstract

Piezoelectric (PZT) actuators are commonly employed to drive flexure-jointed mechanisms with a nanometer resolution. There are three issues related to piezoelectric actuators; hysteresis, creep and vibration. Although the first two problems have been studied widely, a little attention has been given to the vibration analysis of piezoelectric actuators and elastic (compliant) mechanisms they drive. When a piezoelectric actuator is coupled with an elastic system (e.g. a flexure-jointed mechanism), the effect of the resulting vibration on the accuracy of the piezo-actuated flexure-jointed mechanism is significant, and therefore, the vibration problem deserves a systematic investigation. In this paper, we report on vibration analysis of such systems, and the influence of the actuator and mechanism dynamics on the system accuracy through a numerical analysis. A flexure jointed Scott-Russell mechanism is considered as the mechanism driven by a piezoelectric actuator. This mechanism can be used not only to change the direction of a translation motion by 90° but also to be a mechanical displacement amplifier. Numerical results are provided to quantify the interaction between the actuator dynamics and the mechanism dynamics from vibration and positioning accuracy points of view. Further, the influence of the type of input signals on the positioning accuracy of the piezo-electric actuated flexure-jointed micromanipulation systems is elaborated with extensive numerical results.