On the Distinction between Active and Passive Reaction in Grasp Stability Analysis

Stability analysis for multi-fingered robotic grasping is often formalized as the problem of answering the following questions: can the hand exert contact forces on the object either without a net resultant wrench (thus loading the contacts while creating purely internal forces) or in order to counterbalance an external disturbance (by applying an equal and opposite wrench). However, some of the most commonly used methods for performing this analysis do not distinguish between active torque generation and passive resistance at the joints (and, in fact, many commonly used methods disregard the actuation mechanism entirely). In this study, we introduce an analysis framework constructed to capture such differences, and present evidence showing that this is an important distinction to make when assessing the stability of a grasp employing some of the most commonly used actuation mechanisms.