On The Use of Eddy Current Brakes as Tunable, Fast Turn-On Viscous Dampers For Haptic Rendering

We describe the use of eddy current brakes as fast turn-on, tunable, linear dampers for haptic rendering using a prototype haptic device outfitted with eddy current brakes. We show that at the speeds typically required for haptic interaction, eddy-current-induced drag is proportional to velocity. We also show that a modulation rate of approximately 250 Hz can easily be achieved with off the shelf components. A method for decoupling the damping at the end effector is discussed. We discuss the results from haptic experiments for rendering viscosity, virtual walls and virtual friction. Experimental results show that the addition of programmable physical damping improves impedance and stability for rendering with negligible computational cost.