Dynamic characterization and modification of dynamic properties of a micro scanner

Abstract

Micro electro mechanical systems (MEMS) are used in many application areas in different disciplines and took their place among the most promising technologies. The performance of such systems is primarily related to their dynamical characteristics. This study presents the dynamic characterization techniques that are used to identify the modal parameters of a MEMS device and the methods that can be implemented to change its dynamic response. An electrostatic scanner is chosen as the case study to demonstrate the developed methodologies. Initially, the micro scanner is characterized using experimental modal analysis techniques to obtain frequency response function, modal damping, resonance frequencies, and mode shapes. Then, velocity and position feedback control loops are implemented to the scanner system to alter the damping and stiffness characteristics. A closed-loop Simulink model of the scanner is developed to verify the experimental measurements. Several curve fitting methods are used in order to have an accurate representation of the scanner system. Using the model, the influence of both position and velocity feedback on the effective damping, resonance frequency and the transient behavior of the scanner is investigated. The stability limits of the scanner under velocity feedback are also studied via numerical simulations. Based on the experimental and simulation results, the methodology developed in this study proves itself to be very efficient to alter the dynamical characteristics of the MEMS structures and it can be easily adapted to other MEMS applications.