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Nonlinear Uncertain Systems (nonlinear + uncertain_system)
Selected AbstractsAdaptive control for nonlinear uncertain systems with actuator amplitude and rate saturation constraintsINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 1 2009Alexander Leonessa Abstract A direct adaptive nonlinear tracking control framework for multivariable nonlinear uncertain systems with actuator amplitude and rate saturation constraints is developed. To guarantee asymptotic stability of the closed-loop tracking error dynamics in the face of amplitude and rate saturation constraints, the control signal to a given reference (governor or supervisor) system is modified to effectively robustify the error dynamics to the saturation constraints. Illustrative numerical examples are provided to demonstrate the efficacy of the proposed approach. Copyright © 2008 John Wiley & Sons, Ltd. [source] Finite-model adaptive control using an LS-like algorithm,INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 5 2007Hongbin Ma Abstract Adaptive control problem of a class of discrete-time nonlinear uncertain systems, of which the internal uncertainty can be characterized by a finite set of functions, is formulated and studied by using an least squares (LS)-like algorithm to design the feedback control law. For the finite-model adaptive control problem, this algorithm is proposed as an extension of counterpart of traditional LS algorithm. Stability in sense of pth mean for the closed-loop system is proved under a so-called linear growth assumption, which is shown to be necessary in general by a counter-example constructed in this paper. The main results have been also applied to parametric cases, which demonstrate how to bridge the non-parametric case and parametric case. Copyright © 2006 John Wiley & Sons, Ltd. [source] LMI optimization approach to robust H, observer design and static output feedback stabilization for discrete-time nonlinear uncertain systemsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 3 2009Masoud Abbaszadeh Abstract A new approach for the design of robust H, observers for a class of Lipschitz nonlinear systems with time-varying uncertainties is proposed based on linear matrix inequalities (LMIs). The admissible Lipschitz constant of the system and the disturbance attenuation level are maximized simultaneously through convex multiobjective optimization. The resulting H, observer guarantees asymptotic stability of the estimation error dynamics and is robust against nonlinear additive uncertainty and time-varying parametric uncertainties. Explicit norm-wise and element-wise bounds on the tolerable nonlinear uncertainty are derived. Also, a new method for the robust output feedback stabilization with H, performance for a class of uncertain nonlinear systems is proposed. Our solution is based on a noniterative LMI optimization and is less restrictive than the existing solutions. The bounds on the nonlinear uncertainty and multiobjective optimization obtained for the observer are also applicable to the proposed static output feedback stabilizing controller. Copyright © 2008 John Wiley & Sons, Ltd. [source] On an output-feedback stabilization problem with uncertainty in the relative degreeINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 7 2008Giorgio Bartolini Abstract This paper deals with an output-feedback finite-time control problem for a class of nonlinear uncertain systems whose relative degree is affected by an uncertain system parameter and is therefore unknown at the stage of control design. We show that an existing second-order sliding mode control algorithm can address successfully the control task of a finite-time output-feedback stabilization when the uncertain relative degree is equal to 1 or 2. We derive constructive tuning rules for the control parameters and show its effectiveness by using computer simulations. Copyright © 2007 John Wiley & Sons, Ltd. [source] Constrained robust sampled-data control for nonlinear uncertain systemsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 5 2002Li-Sheng Hu Abstract In industrial process control, computer control, which makes the closed-loop system a sampled-data one containing both continuous- and discrete-time signals, is widely used. In contrast with traditional approximation methods, sampled-data synthesis, a direct digital controller design procedure without approximation, has received increasing attention during the past few years. However, many of the existing results cannot be applied to sampled-data control design for the uncertain systems. In this paper, a result of robust asymptotic stability of sampled-data systems with constraints on the state is presented based on a result on practical stability for these systems. Then the robust sampled-data control for a class of uncertain nonlinear systems with constraints on the output is developed. The problem is formulated from vehicle steering control with constraint on the side slip angle of body. The result is described by some matrix inequalities which could be solved by an iterative algorithm based on the linear matrix inequality technique. Finally, a numerical example is presented to demonstrate the result. Copyright © 2002 John Wiley & Sons, Ltd. [source] Robust unscented Kalman filtering for nonlinear uncertain systemsASIAN JOURNAL OF CONTROL, Issue 3 2010K. Xiong Abstract A derivative-free robust Kalman filter algorithm is proposed for nonlinear uncertain systems. The unscented transform (UT) is adopted instead of the linearization technique to obtain the solution of the H, filter Riccati equation. A robust unscented Kalman filter (RUKF) is derived to guarantee an optimized upper bound on the estimation error covariance despite the model uncertainties and the approximation error of the UT. The proposed algorithm is applied to a satellite attitude determination system. Simulation results show that the RUKF is more effective than the unscented Kalman filter (UKF) in cases where alignment errors are present. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] | ||||||||||