Search results for "robust control."
showing 10 items of 78 documents
Robust fault detection filter design for a class of linear systems with mixed time-varying delays and nonlinear perturbations
2009
In this note, the problem of robust fault detection filter (RFDF) design for a class of linear systems subjected to some nonlinear perturbations and mixed neutral and discrete time-varying delays is investigated based on an H ∞ performance condition. By introducing a descriptor technique, using Lyapunov-Krasovskii functional and a suitable change of variables, new required sufficient conditions are established in terms of delay-dependent linear matrix inequalities (LMIs) to synthesize the residual generation scheme. Based on Luenberger type observers, the explicit expression of the filters is derived for the fault such that both asymptotic stability and a prescribed level of disturbance att…
Identification and Robust Control of a Quadratic DC/DC Boost Converter by Hammerstein Model
2015
This paper deals with the theoretical framework definition and the experimental application of the Hammerstein (HM) identification and related robust control technique to a quadratic dc/dc single-switch boost (Q-boost) converter. A set of fourth-order transfer functions (TFs) has been identified with the Hammerstein approach, on the basis of a pseudorandom-binary-sequence (PRBS) excitation signal. The set of identified TFs has been then used to design a suitable robust control technique, able to properly deal with the converter parameter uncertainty and load variations. The proposed approach has been tested in numerical simulation and validated experimentally on a suitably developed test se…
Finite Alphabet Control of Logistic Networks with Discrete Uncertainty
2014
We consider logistic networks in which the control and disturbance inputs take values in finite sets. We derive a necessary and sufficient condition for the existence of robustly control invariant (hyperbox) sets. We show that a stronger version of this condition is sufficient to guarantee robust global attractivity, and we construct a counterexample demonstrating that it is not necessary. Being constructive, our proofs of sufficiency allow us to extract the corresponding robust control laws and to establish the invariance of certain sets. Finally, we highlight parallels between our results and existing results in the literature, and we conclude our study with two simple illustrative exampl…
Robust motion control of nonlinear quadrotor model with wind disturbance observer
2021
This paper focuses on robust wind disturbance rejection for nonlinear quadrotor models. By leveraging on nonlinear unknown observer theory, it proposes a nonlinear dynamic filter that, using sensors already on-board the aircraft, can estimate in real-time wind gust signals in the three dimensions. The wind disturbance is then treated as input to the PD controller for a quick and robust flight pathway in presence of disturbances. With this scheme, the wind disturbance can be precisely estimated online and compensated in real-time. Hence, the quadrotor can successfully reach its desired attitude and position. To show the effective and desired performance of the method, simulation results are …
Robust stability and stabilization of uncertain T-S fuzzy systems with time-varying delay: An input-output approach
2013
An input-output approach to the stability and stabilization of uncertain Takagi-Sugeno (T-S) fuzzy systems with time-varying delay is proposed in this paper. The time-varying parameter uncertainties are assumed to be norm-bounded, and the delay is intervally time varying. A novel method is employed to approximate the time-varying delay, based on which the considered system is transformed into a feedback interconnection form. The new formulation of the system is comprised of a forward subsystem with constant time delay and a feedback subsystem embedding the uncertainties. By applying the scaled small-gain theorem to the converted system, less conservative stability and stabilization criteria…
Robust optimality of linear saturated control in uncertain linear network flows
2008
We propose a novel approach that, given a linear saturated feedback control policy, asks for the objective function that makes robust optimal such a policy. The approach is specialized to a linear network flow system with unknown but bounded demand and politopic bounds on controlled flows. All results are derived via the Hamilton-Jacobi-Isaacs and viscosity theory.
ROBUST CONTROL STRATEGIES FOR MULTI—INVENTORY SYSTEMS WITH AVERAGE FLOW CONSTRAINTS
2006
Abstract In this paper we consider multi—inventory systems in presence of uncertain demand. We assume that i) demand is unknown but bounded in an assigned compact set and ii) the control inputs (controlled flows) are subject to assigned constraints. Given a long—term average demand, we select a nominal flow that feeds such a demand. In this context, we are interested in a control strategy that meets at each time all possible current demands and achieves the nominal flow in the average. We provide necessary and sufficient conditions for such a strategy to exist and we characterize the set of achievable flows. Such conditions are based on linear programming and thus they are constructive. In …
Robust control in uncertain multi-inventory systems and consensus problems
2008
Abstract We consider a continuous time linear multi–inventory system with unknown demands bounded within ellipsoids and controls bounded within polytopes. We address the problem of ∈-stabilizing the inventory since this implies some reduction of the inventory costs. The main results are certain conditions under which ∈-stabilizability is possible through a saturated linear state feedback control. The idea of this approach is similar to the consensus problem solution for a network of continuous time dynamic agents, where each agent evolves according to a first order dynamics has bounded control and it is subject to unknown but bounded disturbances. In this context, we derive conditions under…
Robust control of a Hammerstein model of DC/DC converters
2007
This paper deals with the robust control of a Hammerstein mathematical model of DC/DC converters, consisting of the nonlinear static characteristics of the converter followed by one of a few number of linear time- invariant models which describe the converter in the useful working range. One of these models is assumed as the nominal model of the system and the remaining models are used for describing the model uncertainty. Nominal behaviour is assured using H-2 optimal control method, Robust stability and behaviour are assured by imposing H-infin specifications. The closed loop control system consisting of the converter Hammerstein model and the robust controller is analyzed by means of sim…
Robust H∞ synchronization of a hyper-chaotic system with disturbance input
2013
Abstract This paper concerns the robust control problems on the synchronization of a hyper-chaotic system with disturbance input. Using an appropriate Lyapunov function, we design the multi-dimensional and the single-dimensional robust H ∞ synchronization controllers in terms of linear matrix inequalities for the application in practical engineering. Corresponding theoretical derivations are given subsequently. Finally, some numerical simulations are provided to demonstrate the effectiveness of the proposed techniques.