Modeling a Novel MEMS Gyroscope Nilgoon Zarei Prof. John Jones Prof. Albert Leung 8-May- 2012

Background & Introduction Theory Comsol Design Simulation Results Overview Background & Introduction Theory Comsol Design Simulation Results Prototype Fabrication and Design steps Conclusion Future Work Reference

Introduction Thermal gyroscope What is a gyroscope? Gyroscope is a sensor which monitors rotation. Two categories: Conventional gyroscope Fiber Optic Gyroscope Ring Laser Gyroscope 2. MEMS gyroscope Capacitor gyroscope Thermal gyroscope

Advantage of MEMS Gyroscope Lower cost Lower weight Higher sensitivity Wider range of application Aerospace, spacecraft & satellites Military Cell phone and cameras Automobile industry

No proof mass Advantage of Thermal MEMS Gyroscope No mechanical stress No wearing Higher sensitivity Lowest cost Disadvantage: Acceleration signal will produce significant impact on output signal

Theory and background Fundamental operating principle of the Thermal Gyroscope is the Coriolis Force [1] 2010 NSERC USRA, Albert Leung Warm air bubble travels from one heater to the other. With a fixed gyro, the bubble travels in a straight line. With rotation, the air bubble will deviate towards one of the sensors.

Initial gyro design Oscillating flow + Output signal Heater 1 - Variable resistors detect hot air deflection resulting from Coriolis Effect

Simulation results Find ΔT in two cases, rotation and non-rotation, then calculate their difference.

Simulation results θ Sensor Results depends on θ

New Gyro design Hot sensor 1 Oscillating flow Hot sensor 2 In this design we don’t have heaters To reduce the impact of buoyancy force

Output signal and rotation relation Linear relation between ω and output signal

θ

Fabrication process of building Thermal gyro Pt OX Si

Fabrication process of building Thermal gyro Pt OX Si

Fabrication process of building Thermal gyro Pt OX Si

Fabrication process of building Thermal gyro Pt OX Si

Fabrication process of building Thermal gyro Sensor resistance : 4.8K Ω Heater resistance : 600K Ω Devised mask

Experimental Work Pump Output signal

Conclusion : Operation of thermal gyro demonstrated Force convection model based on heater sensor, is a reliable model It is possible to monitor rotation independent from θ We have fabricated a sensor and run experimental work to confirm simulation results

Future work Continuing the experimental work Building a rotary stage for experimenting rotation

References A.M. Leung, A Low-Cost Thermal MEMS Gyroscope, Hilton Head Workshop 2010: A Solid-State Sensors, Actuators and Microsystems Workshop, pp 364-367, Hilton Head Island, South Carolina, USA, June 6-10, 2010. Design and Analysis of a Micromachined Gyroscope 8251-33: SPIE Conference, San Francisco, California, USA, 2011

Thank you