Robust adaptive friction compensation in servo-drives using position measurement only

Friction compensation via position measurement only in servo-drives is considered in this paper. A robust nonlinear adaptive controller is designed which uses only the motor position (i.e., the output) for feedback and does not require knowledge of electromechanical system parameters, such as parameters in the friction model, rotor inertia, etc. Moreover, the proposed controller can reject any bounded unknown disturbance. The reduced-order Lunberger observer is introduced and an observer-based backstepping procedure is carried out. Simulation results are depicted to show the performance of the advocated controller.