M.S. Thesis Presentation by Priya Vallabh
Tuesday, July 9, 2002

(Dr. Wayne Book, advisor)

"Electrorheological Brake for Haptic Interface Systems"


This projects investigated the feasibility of using electrorheological (ER)
fluids in passive haptic braking devices. ER fluids are fluids that
experience a rapid and reversible change in apparent viscosity when
subjected to electric fields. A design methodology for designing brakes
with ER fluids was developed using available theoretical literature. Based
on this design methodology, a test ER brake was designed and built.
Extensive testing revealed that even though ER fluids exhibit Coulomb
friction type behavior, their fast response times would allow the output
torque of an ER brake to be precisely controlled, minimizing problems such
as stiction. Another phenomenon observed was an increase in shear stress as
strain rate tended to zero. The effect of this phenomenon on haptic braking
systems is important since haptic systems function at low speeds. This
phenomenon was thoroughly investigated and these results are presented. A
proposed design for a passive haptic interface system, utilizing ER brakes,
is also presented.