Record Details

Design And Analysis Of MEMS Angular Rate Sensors

Electronic Theses of Indian Institute of Science

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Field Value
 
Title Design And Analysis Of MEMS Angular Rate Sensors
 
Creator Patil, Nishad
 
Subject Microelectromechanical Systems
Detectors
Gyroscopes
Damping
Equivalent Circuit Model
Simulink Model
SABER Validation
Single Crystal Silicon (SCS) Gyroscope
MEMS Gyroscope
Guided Beam
Polysilicon Gyroscope
PolyMUMPS Fabrication
Electronic Engineering
 
Description Design and analysis of polysilicon and single crystal silicon gyroscopes have been carried out. Variations in suspension design have been explored. Designs that utilize in-plane and out-of-plane sensing are studied.
Damping plays an important role in determining the sense response. Reduction in damping directly affects sensor performance. The various damping mechanisms that are prevalent in gyroscopes are studied.

Perforations on the proof mass are observed to significantly reduce the damping in the device when operated in air. The effects of perforation geometry and density have been analyzed. The analysis results show that there is a two orders of magnitude reduction in damping of thick gyroscope structures with optimized perforation design.

Equivalent circuit lumped parameter models have been developed to analyze gyroscope performance. The simulation results of these models have been compared with results obtained from SABER, a MEMS specific system level design tool from Coventor-ware. The lumped parameter models are observed to produce faster simulation results with an accuracy comparable to that of Coventorware

Three gyroscopes specific to the PolyMUMPS fabrication process have been designed and their performance analyzed. Two of the designs sense motion out-of-plane and the other senses motion in-plane. Results of the simulation show that for a given damping, the gyro design with in-plane modes gives a resolution of 4◦/s. The out-of-plane gyroscopes have two variations in suspension. The hammock suspension resolves a rate of 25◦/s in a 200 Hz bandwidth while the design with folded beam suspension resolves a rate of 2◦/s in a 12 Hz bandwidth. A single crystal silicon in-plane gyroscope has been designed with vertical electrodes to sense Coriolis motion. This design gives an order of magnitude higher
capacitance change for a given rotation in comparison to conventional comb-finger design.

The effects of process induced residual stress on the characteristic frequencies of the polysilicon gyroscopes are also studied. The in-plane gyroscope is found to be robust to stress variations. Analysis results indicate that the tuning fork gyroscope with the hammock suspension is the most susceptible to compressive residual stress, with a significant drop in sensitivity at high stress values.
 
Publisher Indian Institute of Science
 
Contributor Pratap, Rudra
 
Date 2007-06-18T09:55:23Z
2007-06-18T09:55:23Z
2007-06-18T09:55:23Z
2006-06
 
Type Thesis
 
Identifier http://etd.iisc.ernet.in/handle/2005/291
 
Language en_US
 
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