Adaptive Control of Robot Manipulators in Constrained Motion

Adaptive motion and force control of manipulators in constrained motion in the presence of parametric uncertainties both in the robot and contact surfaces is solved in this paper. A new constrained dynamic model is obtained to account for the effect of contact surface friction. An adaptive law is suggested with unknown parameters updated by both motion and force tracking errors to guarantee asymptotic motion and force tracking without any persistent excitation condition to be satisfied. The suggested controller includes a expected PI type force feedback control structure with a low proportional (P) force feedback gain. Acausality problem is analyzed by a quasi-static method to show that allowable proportional force feedback gain is severely limited in implementation. With a slight modification to the updating law, the controller also possesses robustness to bounded measurement noise and disturbances.