Performance of V-Shaped Electrothermal Silicon Microactuator and Its Application
|Course||Mechanical Design and Theory|
|Keywords||MEMS V-shaped Electrothermal Microactuator Silicon Flexure Hinge Silicon Microgripper|
Microactuator is an important part of Micro Electro Mechanical Systems, which used as the drive and executing unit. The function of microactuator includes of energy conversion, motion and force transmission and system message response. In this paper, V-shaped electrothermal silicon microactuator is researched including design, model building, performance analysis, experimental testing and the application.Different V-shaped electrothermal actuators are designed and fabricated using the surface and bulk silicon micromachining process respectively. And the design experience is improved. Several testing methods of micro scale mechanical behavior parameters are established by test. Statical and dynamic performance parameters of the electrothermal actuator are acquired.Statical models of the microactuator are established via both strain energy method and force method separately, which got the same result. The stress-electric-thermal coupling model is deduced according to mechanics, electricity and thermodynamics. The calculations indicate that the force output is inverse proportional to the displacement output. The displacement output is proportional to the heat temperature. The unloaded displacement output is proportional to the span length of actuator beam, but is nonlinearly inverse proportional to the width of oblique beam. The unload displacement output indicate parabolic relation with the rake angle of beam, but is independed with thickness of beam. In addition, the unload displacement output has the quadratic relationship with the drive voltage.In order to research the difference between the working frequency and natural frequency, the flexural vibration mechanical model must be established. According to thermoelastic deflection of the V-shaped titled beam, the forth-factorially partial differentiation equation is used to describe the dynamic performance. Then the natural frequency and the mode of the actuator are obtained through analyzing of free vibration modal. Theoretical calculation results indicate that the natural frequency is proportional to the width of silicon beam, increased nonlinearly with the rake angle of oblique beam, and reduced nonlinearly with the length of silicon beam.The statical testing results of the actuator indicate that the resistance of silicon beam is a constant in the range of operation voltage. The tested unload displacement output is quadratic to the drive voltage. And the result is identical with theoretical analysis results. The power consumed by actuator increase nonlinearly with the rise displacement output. The testing force output also increase with the rise of voltage, and reduce proportionally with the displacement output. It is identical with theoretical results, too.