Stability and Performance of Haptic Displays: Theory and Experiments

In haptic simulation, a human operator kinesthetically explores a virtual environment. To achieve a virtual sense of touch, the human interacts with an active mechanical device, called a haptic display. This paper presents an approach to guarantee that this physical man-machine interface remains stable, while maximizing performance. The key element in ensuring stability is the virtual coupling network, an artificial link between the haptic display and the virtual environment. Considerations of structural flexibility in the haptic device are included in the derivation of design criteria for such networks. Solutions for both the impedance and admittance models of haptic interaction are included. Numerical and experimental results for a two degree-of-freedom haptic display demonstrate the effectiveness of the proposed approach in achieving performance and stability in haptic simulation.