Analyzing and simulation of MEMS in VHDL-AMS based on reduced-order FE models

This paper deals with the computer-aided generation of reduced-order macromodels (ROMs) for system level simulation using VHDL-AMS. The focus is thereby set on the application of ROMs in system simulation. It also gives an survey of our approach of reduced-order modeling. VHDL-AMS is used to describe microelectromechanical systems based on lumped and rigid bodies for several years. But such models often have a limited accuracy if the system contains flexible bodies or nonhomogeneous electrical fields. Methods of reduced-order modeling of linear systems to increase the system model accuracy are also available for some years. The work presented in this paper combines the advantages of reduced-order modeling and VHDL-AMS system level simulation, whereas our approach of reduced-order modeling is able to handle nonlinear systems too. The application of ROMs on system level and their export to VHDL-AMS have been demonstrated by two surface micromachined vibration sensor arrays which are intended for wear state recognition. Additionally, a new approach called "multi architecture modeling" has been applied which simplifies the integration of macromodels into the system. As a result of this work, we are able to simulate certain classes of nonlinear ROMs with an error less than 1% compared with the finite-element method simulation. Also, simulation time of ROMs is shorter than simulation time of models based on lumped and rigid bodies.