Hybrid model-based force/position control: theory and experimental verification

Abstract

Force/position control is a relatively young and rapidly developing branch of robotics. Its practical implementation faces many difficulties due to inherent process complexity. Despite this, the majority of contributions in this field use the classic approach to force control, i.e. single-loop PID control. In this paper, two model-based control structures are proposed, yielding much better results of force control as compared to the classic approach, to be achieved. These are two-loop model-following control (MFC) structures that guarantee interesting disturbance suppression behaviour by an additional degree of freedom. Tests carried out with a Manutec r2 manipulator with six degrees of freedom have shown clear advantages of the control structures under study.