A hybrid haptic device for wide-ranged force reflection and improved transparency

This paper is concerned with the transparency improvement of a 1-DOF (degree-of-freedom) hybrid haptic device with the wide-ranged haptic reflection. The hybrid haptic device is actuated by the combination of an active actuator and a passive one. A noble hybrid concept for the haptic device is proposed for two purposes; one is to improve the transparency of the haptic device by compensating friction components qualitatively and quantitatively, and the other is to reflect the wide-ranged force or torque in large workspace. In the proposed hybrid actuation, the passive actuator is used as the main source of the reflective output, since it has the passivity property in nature so that the safety in interaction and the stability in haptic control can be concurrently guaranteed. The active actuator, which is active in nature, is used either for compensating back-driven components in the haptic system or for providing additional outputs in the haptic reflection larger than the maximum capacity of the passive actuator.