Performance analysis of a 2-link haptic device with electric brakes

Passive haptic devices have better stability than active ones, but usually have limited capability of haptic display. In this paper a 2-link passive haptic device equipped with electric brakes is discussed. Since passive devices cannot generate forces in all directions, determination of the region available for force reflection is important to their design and operation. This analysis can be done by a so-called force manipulability ellipsoid (FME). In some haptic applications, the endpoint of a device is required to move along a certain trajectory (e.g., the surface of a virtual wall) and haptic display plays a role of path guide. Performance of path guidance is also investigated in this research. Finally, guideline for the design of more efficient passive haptic devices is briefly discussed.