Modelling, vibration analysis and feedback control of a piezoelectric forceps actuator

Abstract

A piezoelectric forceps actuator (PFA) is developed for potential use in minimally invasive surgery, biological cell diagnosis and semiconductor industrial applications. This article is concerned with modelling, vibration analysis and boundary feedback control of the actuator. In the development, the PFA is viewed as a slightly-curved beam laminated with piezoelectric layers. By generalised Hamilton's principle, the dynamic governing equations of the actuator are derived. The PFA control system that consists of the piezoelectric composite curved beam, a sensor and control logic is formulated by using distributed transfer functions. With the transfer function formulation, the natural frequencies, mode shapes and frequency response of the actuator are then predicted and a stabilising boundary feedback control law is developed. In addition, a characteristic performance analysis of the PFA is conducted, to relate the system parameters and multimorph configuration to the natural frequencies, damping and piezoelectric moment of the PFA. The theoretical predictions by the actuator model are verified in experiments.