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A kind of launching platform driven by two permanent magnet synchronous motor (PMSM) motors which is used to launch kinetic load to hit the target, always faces strong parameter uncertainties and strong external disturbance such as the air current impulsion, which would degrade their tracking accuracy greatly. In this paper, an adaptive robust nonlinear controller is proposed for high-accuracy motion control of the launching platform, in which the adaption law is designed to estimate the unknown coupling coefficients of torque disturbance and feed-forward cancellation technique is used to compensate the coupling torque disturbance and some other constant disturbances. In addition, a nonlinear robust feedback term is designed to inhibit the influence of the parameter estimation error and the other model uncertainty to stabilise the closed-loop system. Considering that some system states are immeasurable due to cost-reduction, volume/weight limitations and structure restriction or heavy measurement noise is usually associated with the measurements, which may also deteriorate the achievable performance of full-state feedback controllers; a high-order sliding-mode observer is used to estimate the unmeasured system states, and it is synthesised with the adaptive robust controller via feed-forward cancellation method. The intermediary virtual control law and the final control law are derived by integrating the backstepping method. Furthermore, the controller theoretically guarantees a prescribed tracking transient performance and final tracking accuracy while achieving asymptotic tracking performance in the presence of parametric uncertainties only, which is very important for high-accuracy tracking control of launching platform. Extensive comparative experimental results are obtained to verify the high performance nature of the proposed control strategy. [ABSTRACT FROM AUTHOR]

In view of the reduced low-frequency oscillation damping effect caused by inaccurate modeling of the power system due to various uncertainties, a Youla parameterization robust control strategy considering system uncertainties is proposed in this article. First, the uncertainties of the measurement error and parameter estimation are described by the perturbation matrix, and the convex polytopic model is utilized to describe uncertainties caused by variation of the operating point. Then, by solving theH2/H∞inequalities, the Youla parameterization matrix is gained. Finally, the output error of the actual system to the nominal system is introduced to the output feedback control link via the Youla parameterization matrix. Thus, tracking control of the output error can be realized, as well asH2/H∞robust control of the system. Simulation results show that the proposed method is immune to internal and external uncertainties. Compared with control methods without considering uncertainties, the proposed method is capable of damping low-frequency oscillation faster and more effectively with better robust performance. [ABSTRACT FROM AUTHOR]