An Electrothermomechanical Lumped Element Model of an Electrothermal Bimorph Actuator

TitleAn Electrothermomechanical Lumped Element Model of an Electrothermal Bimorph Actuator
Publication TypeJournal Article
Year of Publication2008
AuthorsTodd, S., and H. Xie
JournalJournal of Microelectromechanical Systems
Pagination213 - 225
Date Published02/2008
KeywordsBimorph, electrothermal modeling, electrothermomechanical modeling, lumped element modeling, micromirror, thermal actuator, thermomechanical modeling.

This paper reports a simple electrothermomechanical lumped element model (ETM-LEM) that describes the behavior of an electrothermal bimorph actuator. The ETM-LEM is developed by integrating an electrothermal LEM of a heater with a thermomechanical LEM of a bimorph actuator. This new LEM uses only one power source in both the electrical and thermal domains. The LEM provides a simple and accurate way of relating the output mechanical response of a bimorph actuator to the electrical inputs. The model shows that the tip angular rotation of the bimorph actuator is linearly proportional to its average temperature change. The LEM predicts a linear relationship between both the average temperature change and bimorph tip angular rotation versus voltage when operated above a certain voltage. The LEM is used to predict the rotation angle of a fabricated electrothermal bimorph micromirror in response to the electrical inputs and produces results that agree with finite element model simulations and experimental data within 15% for all measured parameters.

Short TitleJ. Microelectromech. Syst.