A nonlinear dynamic model was derived for the torque generated by a
harmonic drive. Measurements were taken in two cases: locked-load, to approximate
low-speed operation, and free-load. Frequency response measurements, with
variable amplitudes, were taken as a means of approximating the uncertainty
model, and H-infinity controllers were subsequently designed. These proved
to be reliable and performed well. The models were also used to ``clean
up'' torque signals corrupted with periodic noise signals related in frequency
to some of the gear-related signals.