The Role of Dynamic Models in Cartesian Force Control of Manipulators

Abstract

Dynamic models are as important in Cartesian force control as they are in position control. A variety of Cartesian force control schemes are examined, comprising some that do incorporate a dynamic model into the control loop (resolved acceleration force control, operational space method, and impedance control) and some that do not (hybrid control and stiffness control). Stability analyses and experimental imple mentations are presented that demonstrate not only that using a dynamic model leads to more accurate control, but also that not using a model can in certain cases make force control unstable. Experiments on the MIT Serial Link Direct Drive Arm show that resolved acceleration force control is stable and accurate in producing force steps and sinusoidal force responses and in complying to sinusoidal position dis turbances.