Observer based friction compensation in robot control

Feed forward friction compensation is carried out based on the LuGre friction model. An observer observes the undetectable presliding displacement and low speed. Friction parameters and linearized robot parameters are identified according to an adaptive stratagem. A PD + feed forward robust control law is employed to ensure three kinds of stable results of the robot system. Proof is given for the stability of the system. The friction compensation enhanced the performance at low velocity. Simulation results verified the efficiency of the method.