|
| ||
|
|
||
Bounded Disturbances (bounded + disturbance)
Selected AbstractsDirect adaptive control for non-linear uncertain systems with exogenous disturbancesINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 2 2002Wassim M. Haddad Abstract A direct adaptive non-linear control framework for multivariable non-linear uncertain systems with exogenous bounded disturbances is developed. The adaptive non-linear controller addresses adaptive stabilization, disturbance rejection and adaptive tracking. The proposed framework is Lyapunov-based and guarantees partial asymptotic stability of the closed-loop system; that is, asymptotic stability with respect to part of the closed-loop system states associated with the plant. In the case of bounded energy L2 disturbances the proposed approach guarantees a non-expansivity constraint on the closed-loop input,output map. Finally, several illustrative numerical examples are provided to demonstrate the efficacy of the proposed approach. Copyright © 2002 John Wiley & Sons, Ltd. [source] Disturbance attenuation by output feedback for linear systems subject to actuator saturationINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 2 2009Fen Wu Abstract In this paper, we study the problem of disturbance attenuation by output feedback for linear systems subject to actuator saturation. A nonlinear output feedback, expressed in the form of a quasi-linear parameter-varying system with state-dependent scheduling parameter, is constructed that leads to the attenuation of the effect of the disturbance on the output of the system. The level of disturbance attenuation is measured in terms of the restricted ,2 gain and the restricted ,2,,, gain over a class of bounded disturbances. Copyright © 2008 John Wiley & Sons, Ltd. [source] Robust observation and identification of nDOF Lagrangian systemsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 9 2007David I. Rosas Almeida Abstract A procedure to design a global exponentially stable, second-order, sliding-mode observer for nDOF Lagrangian systems is presented. The observer converges to the system state in spite of the existence of bounded disturbances or parameter uncertainties affecting the system dynamics. The generation of sliding modes permits the identification of disturbances using the equivalent output injection which, under some circumstances, can also be used to identify the system parameters via a continuous version of the last-square method. The proposed methodology is illustrated with some numerical examples and experiments. Copyright © 2006 John Wiley & Sons, Ltd. [source] ,2 -Stabilization of continuous-time linear systems with saturating actuatorsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 18 2006E. B. Castelan Abstract This paper addresses the problem of controlling a linear system subject to actuator saturations and to ,2 -bounded disturbances. Linear matrix inequality (LMI) conditions are proposed to design a state feedback gain in order to satisfy the closed-loop input-to-state stability (ISS) and the closed-loop finite gain ,2 stability. By considering a quadratic candidate Lyapunov function, two particular tools are used to derive the LMI conditions: a modified sector condition, which encompasses the classical sector-nonlinearity condition considered in some previous works, and Finsler's Lemma, which allows to derive stabilization conditions which are adapted to treat multiple objective control optimization problems in a potentially less conservative framework. Copyright © 2006 John Wiley & Sons, Ltd. [source] Adaptive robust stabilization of dynamic nonholonomic chained systemsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 3 2001S. S. Ge In this article, the stabilization problem is investigated for dynamic nonholonomic systems with unknown inertia parameters and disturbances. First, to facilitate control system design, the nonholonomic kinematic subsystem is transformed into a skew-symmetric form and the properties of the overall systems are discussed. Then, a robust adaptive controller is presented in which adaptive control techniques are used to compensate for the parametric uncertainties and sliding mode control is used to suppress the bounded disturbances. The controller guarantees the outputs of the dynamic subsystem (the inputs to the kinematic subsystem) to track some bounded auxiliary signals which subsequently drive the kinematic subsystem to the origin. In addition, it can also be shown all the signals in the closed loop are bounded. Simulation studies on the control of a unicycle wheeled mobile robot are used to show the effectiveness of the proposed scheme. © 2001 John Wiley & Sons, Inc. [source] Robust tracking control design for uncertain robotic systems with persistent bounded disturbancesASIAN JOURNAL OF CONTROL, Issue 4 2008Chung-Shi Tseng Abstract In this study, a robust nonlinear L, - gain tracking control design for uncertain robotic systems is proposed under persistent bounded disturbances. The design objective is that the peak of the tracking error in time domain must be as small as possible under persistent bounded disturbances. Since the nonlinear L, - gain optimal tracking control cannot be solved directly, the nonlinear L, - gain optimal tracking problem is transformed into a nonlinear L, - gain tracking problem by given a prescribed disturbance attenuation level for the L, - gain tracking performance. To guarantee that the L, - gain tracking performance can be achieved for the uncertain robotic systems, a sliding-mode scheme is introduced to eliminate the effect of the parameter uncertainties. By virtue of the skew-symmetric property of the robotic systems, sufficient conditions are developed for solving the robust L, - gain tracking control problems in terms of an algebraic equation instead of a differential equation. The proposed method is simple and the algebraic equation can be solved analytically. Therefore, the proposed robust L, - gain tracking control scheme is suitable for practical control design of uncertain robotic systems. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] | ||||||||||