i. mohammadzaman

In this paper, the robust gain-scheduled state-feedback controller problem is studied for uncertain linear parameter-varying systems whose state-space representations are the linear combination of the uncertain time-varying parameters including time-invariant parametric uncertainties (TIPU). It is supposed that these uncertainties are bounded by the given intervals and cannot be pulled out as an uncertain block. It is considered a serious challenge because the exact information about the plant dynamics cannot be extracted from the uncertain time-varying parameters. This is while; the gain-scheduled controllers need to have the exact information about the plant dynamics to satisfy the desired control purposes. To handle this challenge, we introduce a state-feedback gain, which is formed by a set of the new scheduling parameters and a secondary time-varying term. The stabilization conditions are obtained in terms of the linear matrix inequalities (LMIs). The effectiveness of the proposed method is shown using an example.

This paper investigates fixed-time nonsingular terminal sliding mode control of second-order nonlinear systems in the presence of matched and mismatched disturbances. Using estimation of the mismatched disturbance estimated by a fixed-time disturbance observer, a novel nonlinear dynamic sliding surface is designed. This estimation is utilized in designing a completely novel nonlinear dynamics sliding surface whereby the fixed-time convergence of the sliding motion is guaranteed in spite of mismatched disturbance. The convergence time of the closed-loop system including disturbance observer and control system is guaranteed to be uniform with respect to initial conditions. Moreover, the proposed controller avoids chattering phenomenon by producing a continuous control signal.

In this paper, a gain-scheduled three loop autopilot is designed for a pursuit system which can guarantee the mixed H_2/H_∞ performance and time domain constraints. The gain-scheduled autopilot problem is converted into a static state feedback control for a Linear Parameter Varying (LPV) system and then a control method is proposed by following the Linear Matrix Inequalities (LMIs) approach to satisfy the mixed H_2/H_∞ performance with regional pole placement constraints without any constraints on system matrices. The final gain-scheduled controller is obtained by the interpolation of the finite number of fixed controllers in every vertex, guaranteeing the stability and performance of the LPV system. The simulation results demonstrate the efficiency of the proposed method for the three loop autopilot design.