My team was funded by a NASA SBIR to integrate tactile feedback into the space gloves, and in the process built the first haptic impedance matcher, a new tool to optimize size, weight, and power in a tactile feedback system. My role was to develop the impedance matcher and perform mechanical design.
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The Flagsuit LLC EVA glove was used as the integration platform for the system
Design
Analytical Modeling / CAD / Prototyping
I helped create the mount and grounding system used to hold the linear resonant actuators and transmit vibrations to the glove. To do this, I designed parts in Solidworks, 3D printed them, and sewed grounding loops onto them.
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Mechanical model used to optimize the parameters of the Impedance Adapter
Modeling
Mechanical models / Optimization / MATLAB
I constructed a mass-spring-damper model of the system, and synthesized the skin model from a variety of previously published models and data. I found parameters for the impedance adapter by running an optimization in MATLAB, and performed a sensitivity analysis on the result to guide design choices.
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Measurement of the motion of users' skin when vibrated by a vibration motor alone (control) and by a vibration motor coupled to an impedance adapter (IA #1 and #2)
Testing
I designed tests and ran human subject testing to collect objective data and perceptual results. Tests demonstrated a 4x increase in skin vibration with an impedance adapter, closely matching model predictions and approaching optimal energy transfer conditions.
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Tactors we built for the project integrated into the Flagsuit space glove
The project delivered a set of space gloves that integrated vibrotactile feedback and hand tracking to be used as part of a augmented reality interface. The system demonstrated 99% accuracy in pressured studies of text entry, and the optimization mechanism demonstrated power reductions of 66%.