SEM image of Draper Labs Tuning Fork Gyroscope.

Polysilicon Stress

Vibration Suppression

Magnetic MEMS Microphone

MEMS Gyroscope

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Comparison of Techniques for Polysilicon Residual Stress Measurements

Experimental work comparing wafer curvature measurements, micro-rotating structures, buckling microstructures, and vibrating microstructures for the measurement of residual stresses in thin polysilicon films. Student: Andrew Mueller, ME Masters of Science student.

SEM images of surface-micromachined polysilicon structures developed at Tufts by Andrew Mueller and Robert White. Fabrication was conducted partly at the MIT Microsystems Technology Laboratory and the University of Michigan Nanofabrication Facility.

Mueller, A., and White, R. D. "Residual stress variation in polysilicon thin films", in Proceedings of the 2006 American Society of Mechanical Engineering International Mechanical Engineering Congress and Exposition, IMECE2006.

Active Vibration Cancellation for Essential Tremor

Essential tremor is a motion disorder which can make it difficult for some people to perform manual operations such as writing, eating, or applying makeup. The goal of this project is to design a feedback control system with an electromagnetic inertial actuator to actively cancel essential tremor. The control system must autotune to deal with variation of the plant properties over time. Both computational and experimental systems are being examined. Collaborator: Ken Kaiser, Draper Labs . Student: Nicholas Stone, ME Masters of Science.

Block diagram of the system model and controller.

Stone, N., Kaiser, K., and White, R. D. "Autotuning of a PID controller for an active vibration suppression device for the treatment of Essential Tremor", Proceedings of the 2006 American Society of Mechanical Engineering International Mechanical Engineering Congress and Exposition, IMECE2006.

Design of a Permanent Magnet MEMS Microphone

Development of a novel design for a MEMS microphone based on magnetic sensing. Fabrication should be relatively simple with fewer steps and easier material systems that piezoelectric sensing or capacitive sensing, but sensitivities appear to be comparable. Student: Liam Kelly, ME Masters of Engineering (graduated).

CAD rendering of the magnetic microphone design.

Shock and Vibration Effects on MEMS Gyroscopes

Prof. White's Master's thesis was conducted at Draper Laboratories and MIT in Cambridge, Massachusetts. I worked in the MEMS test lab, where we dealt mainly with micromechanical inertial sensors. My thesis was concerned with vibration and impact testing of Draper's MEMS Tuning-Fork Gyroscope.

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