Nonlinear robust adaptive precision motion control of motor servo systems with unknown actuator backlash compensation.

In this article, the problem of high precision motion control for motor servo systems with modeling uncertainties and unknown actuator backlash is addressed. The combination of synthesized adaptive laws and continuous nonlinear robust term handles parameter uncertainties and system disturbances. The adaptive technique updates the unknown parameters of actuator backlash in real time and the backlash inverse function eliminates the backlash effect. Meanwhile, the designed controller without knowing the range of the disturbance upper bound but automatically estimates through the adaptive law, which improves the engineering practicability. Finally, the theoretical analysis proves the perfect asymptotic stability of the presented controller even with unmodeled disturbances and unknown actuator backlash. Extensive comparative experiments reveal the superiority of the presented method. • A nonlinear robust adaptive controller is proposed for motor servo system with unknown actuator backlash. • The unknown upper bound of unmodeled disturbances can be updated by adaptive laws online. • Excellent asymptotic output tracking performance is achieved with the proposed controller. • The effectiveness of the proposed controller is verified by comparative experimental results. [ABSTRACT FROM AUTHOR]