Rendering Virtual Inertia in Haptic Interfaces: Analysis and Limitations

Virtual environments designed for haptic applications are usually rendered as a combination of spring and damper elements. The resulting haptic experience can be greatly enhanced by also adding virtual inertia, for example when interacting with mobile virtual objects. This paper analyzes the impact of implementing virtual inertia on haptic rendering stability. It describes the methodology followed to identify the physical inertia of a mechanism, to derive the acceleration from position, and the implications of this process on stability. Main results show how digital filtering and internal flexibility of the device affect the expected uncoupled stability region.