Composite Momentum-based Observers for the Estimation of External Force on Robot Manipulators

Abstract

This paper investigates the estimation of external force on robot manipulators. The issue is of great importance for the safety of human-robot collaborative tasks and for the human-robot interactive tasks. However, the estimation of external force using model-based approach suffers from model uncertainties and disturbances. It also requires a quick estimate when detecting a collision. To satisfy both fast convergence and robustness, composite observers are newly proposed, which is composed of sliding mode observers and polynomial observers based on momentum state. Through their complementary roles, a composite observer achieves improved performance in safety and estimation. The simulation results show the effectiveness and validity of the proposed composite momentum-based observers.