Nonlinear decoupling for position and force control of constrained robots with flexible joints

A nonlinear decoupling and linearizing feedback control for force-controlled robots with constrained end-effector motion is considered. A general method is presented which assures an exact feedback linearization for both rigid and flexible joint robots, as the joint flexibility can cause instability of robot control. The application of the developed control laws produces a set of decoupled linear subsystems, corresponding to the position/velocity constraint space and contact force constraint space. The implementation of this method is demonstrated for the case of a two-link robot with the end-effector constrained to move along a rough plane