Robust Motion/Force Control of Holonomic Constrainted Nonholonomic Mobile Manipulators using Hybrid Joints

In this paper, robust force/motion control strategies are presented for mobile manipulators under both holonomic and nonholonomic constraints in the presence of uncertainties and disturbances. Robust controls are proposed based on a simplified dynamic model, the defined reference signals and the mixed tracking errors. The proposed control strategies guarantee that the system motion converges to the desired manifold with prescribed performance. Constraint force control is developed, which does not utilize force feedback control but is based on the passivity of hybrid joint. Experiment results validate not only the states of the system asymptotically converge to the desired trajectory but also the constraint force asymptotically converges to the desired force