SEM image of Draper Labs Tuning Fork Gyroscope.

Polysilicon Stress

Vibration Suppression

Magnetic MEMS Microphone

MEMS Gyroscope

Thin Film MEMS Actuators

Soft Material Robotics

Nano-imprinting of Silk Biopolymers

Shear Stress Sensors for CMP

Home

WARNING: This page contains pdf files of articles that may be covered by copyright. You may browse the articles at your convenience, in the same spirit as you may read a journal or a proceedings article in a public library. Retrieving, copying, or distributing these files may violate copyright protection laws.

Thin Film Composite MEMS Actuators

We are developing MEMS actuators based around shape memory alloy (SMA) microwires or bimetallic strips in an elastomeric structure. The ultimate goal is to use these soft actuator patches for actuation of an all-soft-material robot under development with collaborators. We are working on fabrication, modeling, design, and testing of these devices. Students: Minchul Shin, ME PhD student, Alex Brindle, ME Undergrad, Aaron Gerratt, ME Undergrad, Peter Fallon, ME Undergrad, Brian Keirstead, ME Masters of Science student.

Two photographs of the thin film actuator devices.

Soft Material Robotics

We are working with a team of researchers at Tufts to construct, model, and demonstrate all-soft-material robots. The project has a biomimetic bent; we look to caterpillars for inspiration. However, we have been branching out from this starting point to a wide array of structures, actuation schemes, and control strategies. The project involves systems engineering, manufacturing, and computational modeling. Students: Alex Brindle, ME Undergraduate, Brian Kierstead, ME Masters of Science

Photograph of one soft robot design, molded out of a silicone elastomer, with shape memory alloy actuators.

Rapid Hot Embossing of Silk Biopolymers

With collaborators from the Biomedical Engineering department, we are working on developing tools and methodologies for rapid nanoscale hot embossing of silk fibroin biopolymer thin films. The project includes construction of custom hot embossing apparatus, process characterization, and evaluation of the optical properties of the embossed thin films. A microscale heater array is also under development for rapid, programmable thermal writing on silk thin films. Postdoctoral Researchers: James Vlahakis, PhD, Caprice Gray, PhD Students: Ethan Mandelup, ME Undergraduate

SEM and AFM images of nano-imprinted silk thin films.

Stress Sensors for Chemimechanical Polishing (CMP)

We are developing MEMS stress sensors to measure the interaction forces between the polishing pad and wafer during CMP processing. This will include both fluid shear stresses and direct solid-solid contact between pad asperities and the wafer surface. Floating element sensors and polymer micropost sensors are being pursued. The project is being conducted with industry and academic partners from around the country. Students: Minchul Shin, ME PhD students, Andrew Mueller, ME Masters of Science student, Douglas Gauthier, ME Masters of Science student.

SEM images of PDMS post-in-well sensors developed at Tufts by Andrew Mueller and Robert White.

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.

Return to the top level page.