Robust indirect adaptive control of electromechanical servo systems with uncertain time-varying parameters.

This paper focuses on high-accuracy motion control for electromechanical servo systems with time-varying parameter estimation. A robust indirect adaptive controller based on a nonlinear X-swapping technique is proposed to achieve the online estimation of the time-varying parameters. The time-varying parametric uncertainties can be well compensated via the adaptive feedforward cancellation technique, and the residual model uncertainties are suppressed by a nonlinear robust control law. The Lyapunov-based stability analysis illustrates that the proposed method obtains a prescribed estimating result and an excellent asymptotic tracking performance. Extensive experimental results are acquired to affirm the applicability of the proposed control strategy. [ABSTRACT FROM AUTHOR]