Dynamic analysis of a flexure-based mechanism for precision machining operation

This paper presents the dynamic modelling and performance evaluation methodologies of a flexure-base mechanism for ultra-precision grinding operations. The mechanical design of the mechanism is briefly described. A piezoelectric actuator is used to drive the moving platform. A flexure-based structure is utilized to guide the moving platform and to provide preload for the piezoelectric actuator. By simplifying the Hertzian contact as a linear spring and damping component, a bilinear dynamic model is developed to investigate the dynamic characteristics of the flexure-based mechanism. Based on the established model, the separation phenomenon of the moving platform from the piezoelectric actuator is analyzed. The influence of the control voltage on the maximum overshoot is also investigated. The slope and cycloidal command signals are used to reduce and/or avoid the overshoot of such flexure-based mechanism under step command signal actuation condition. The effects of the rising time of the command signals on the maximum overshoot and the settling time are studied.