Multilateral haptic system stability analysis: The effect of activity or passivity of terminations via a series-shunt approach

Haptic teleoperation and haptic interaction systems can be modeled as multi-port networks. In this context, bilateral or trilateral haptic systems stability has been analyzed in the literature by using their two-port or three-port network models. Traditionally, such stability criteria assume that operators and environments (collectively, terminations) of the multilateral haptic systemare passive but otherwise arbitrary. However, recent research has shown that such an assumption can be inaccurate or too conservative as far as the human operator in a robotic system is concerned. In order not to jeopardize the haptic system stability when a termination is active or sacrifice system performance when a termination is strictly passive, we need a stability analysis approach that can take into account the degree of passivity (or lack thereof) of each termination. In response to this need, we have developed an approach based on series-shunt decomposition of the termination impedance model. Experimental validation of the theoretical stability criteria are performed involving active operators and environment for both bilateral and trilateral teleoperation.