Motion/force control of uncertain acatastatic nonholonomic mechanical systems via sliding modes

The position/force control of Lagrangian mechanical systems with acatastatic nonholonomic constraints is addressed in this paper. The main feature of this paper is that control strategy is developed at the dynamic level and can deal with model uncertainties in the mechanical systems. This is achieved by decomposing the system into two cascaded subsystems: a kinematic system with drift and a lower dimensional system which retains the mechanical system structure. It is shown that the proposed control law guarantees simultaneously the stabilization of the position to an equilibrium point and constraint force tracking in the presence of parameter modeling uncertainties