A Variable Impedance Control Strategy for Object Manipulation Considering Non–Rigid Grasp

Abstract

This paper presents a novel control strategy for the compensation of the slippage effect during non-rigidly grasped object manipulation. A detailed dynamic model of the interconnected system composed of the robotic manipulator, the object and the internal forces and torques induced by the slippage effect is provided. Next, we design a model-based variable impedance control scheme, in order to achieve simultaneously zero convergence for the trajectory tracking error and the slippage velocity of the object. The desired damping and stiffness matrices are formulated online, by taking into account the measurement of the slippage velocity on the contact. A formal Lyapunov-based analysis guarantees the stability and convergence properties of the resulting control scheme. A set of extensive simulation studies clarifies the proposed method and verifies its efficacy.