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Zero Dynamics (zero + dynamics)
Selected AbstractsNonlinear reference tracking control of a gas turbine with load torque estimationINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 8 2008B. Pongrácz Abstract Input,output linearization-based adaptive reference tracking control of a low-power gas turbine model is presented in this paper. The gas turbine is described by a third-order nonlinear input-affine state-space model, where the manipulable input is the fuel mass flowrate and the controlled output is the rotational speed. The stability of the one-dimensional zero dynamics of the controlled plant is investigated via phase diagrams. The input,output linearizing feedback is extended with a load torque estimator algorithm resulting in an adaptive feedback scheme. The tuning of controller parameters is performed considering three main design goals: appropriate settling time, robustness against environmental disturbances and model parameter uncertainties, and avoiding the saturation of the actuator. Simulations show that the closed-loop system is robust with respect to the variations in uncertain model and environ-mental parameters and its performance satisfies the defined requirements. Copyright © 2007 John Wiley & Sons, Ltd. [source] Explicit constructions of global stabilization and nonlinear H, control laws for a class of nonminimum phase nonlinear multivariable systemsINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 12 2008Weiyao Lan Abstract This paper investigates a global stabilization problem and a nonlinear H, control problem for a class of nonminimum phase nonlinear multivariable systems. To avoid the complicated recursive design procedure, an asymptotic time-scale and eigenstructure assignment method is adopted to construct the control laws for the stabilization problem and the nonlinear H, control problem. A sufficient solvability condition is established onthe unstable zero dynamics of the system for global stabilization problem and nonlinear H, control problem, respectively. Moreover, based on the sufficient solvability condition, an upper bound of the achievable L2 -gain is estimated for the nonlinear H, control problem. Copyright © 2007 John Wiley & Sons, Ltd. [source] Boundedness in Lurie system with stiffening nonlinearitiesINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 6 2008Abdallah Ben Abdallah Abstract In this paper, we deal with the problem of boundedness of solutions in single-input single-output Lurie system. We prove the boundedness of solutions from the stability of zero dynamics under a restriction on the nonlinearity. The linear block is supposed to be of relative degree one or two, stabilizable by high-gain output feedback and not necessary minimum phase. The nonlinearity is required to have the stiffening property. Copyright © 2007 John Wiley & Sons, Ltd. [source] Nonlinear Control VIA Generalized Feedback Linearization Using Neural NetworksASIAN JOURNAL OF CONTROL, Issue 2 2001Graham C. Goodwin ABSTRACT A novel approach to nonlinear control, called Generalized Feedback Linearization (GFL), is presented. This new strategy overcomes one important drawback of the well known Feedback Linearization strategy, in the sense that it is able to handle a broader class of nonlinear systems, namely those having unstable zero dynamics. It is shown that the use of a nonlinear predictor for the system output is a key feature in the derivation of the control strategy. For certain types of systems this predictor can be found as a nonlinear function of the system input and output, allowing an output feedback control solution. The use of Artificial Neural Networks (ANN) to directly parameterize the predictor of the controlled variable when an explicit model for the system is not available, is investigated via computer simulations. This approach is based on the functional approximation capability of multi layer ANN. [source] | ||||||||||