Model-based control for nonprehensile manipulation of a two-rigid-link object by two cooperative arms

Robots are expected to come in direct contact with human at care facilities and/or homes soon. Motivated by the application of holding and/or transferring a patient applying a robot, this paper introduces the dynamic model, static analysis and control algorithm for nonprehensile manipulation of a two-rigid-link object applying two cooperative arms. Newton-Euler equations are applied for formulating the object dynamics while a visco-elastic model is applied for modeling the interaction between the object links and the arms. Static analysis specifying the equilibrium points based on the derived dynamical model is introduced. A PD controller with a disturbance observer is designed to control the object lifting-up motion. Static analysis as well as controlled object lifting-up motion simulation results is presented which show the validity of the proposed analysis and control algorithm.