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The impact of random perturbations on resonant motions in nonlinear oscillatory systems is studied. It is shown that the reliability of resonant systems can be associated with stable motions within a small near resonant domain (effect of "capture in resonance"). The model of near resonant motions in stochastic systems is given, and asymptotic analysis of this model is developed. It is demonstrated...
In this paper, we present a brief review of the various definitions on passivity of nonlinear systems and positive real transfer functions. The relationships between the definitions are clarified and illustrated with examples. Furthermore we review the stability of the feedback interconnection of passive systems to relax the assumptions on the plant to be controlled. In particular we present a version...
The popular Generalised Predictive Control (GPC) algorithm is used to derive a discrete-time nonlinear predictive controller for muscle relaxant anaesthesia, in a Wiener structure form, and which exhibits strong nonlinearities as well as varying dead-time and dynamics due to patient-to-patient variability. The proposed controller minimises the GPC quadratic performance index taking into account the...
The process of assessing the compartmental nature of a system under analysis involves a number of different professional skills. The first basic question is: given an experiment, i.e. an input-output sequence, and suppose there is no error in the data, is the result compatible with the compartmental assumption? In this paper, a step toward the solution of this fundamental problem is reported by proving...
This paper considers the design of vibration absorbers for multi degree of freedom vibrating systems. Similarities between absorber design and control problems are pointed out and an approach is presented to solve the absorber design problem by a technique that is similar to loopshaping technique used in control system design. A criterion for selecting the collocated sensor and actuator locations...
This paper presents a method of designing the state feedback which place the closed-loop poles of a given uncertain system inside some region. The Lévy-Hadamard and Bendixson theorems have been used to derive algebraic relations which set bounds on the real and imaginary parts of the eigenvalues of the closed-loop system matrix. This helps in placing the closed-loop poles in a specified region, either...
In this paper a roadway controller is designed, analyzed and simulated for single automated highway lane which consists of vehicles equipped by cruise controllers keeping the desired safety distance which is made to depend on the following vehicle velocity. Main results of the paper are the following. Macroscopic traffic flow model for mean speed evolution which takes into account command speed generated...
In the control of linear systems with non-symmetrical input constraints, larger domains of initialisation can be obtained by allowing slow initial dynamics of the system in closed-loop, and making it faster during its evolution. The positive invariance concept application leads to a piecewise linear constrained control using non-symmetrical nested polyhedral sets.
The problem of H∞ optimal control for the plant consisting from two-mass and non-linear spring is considered in the paper. Till now two mass problem (benchmark problem) was considered for linear cases only. The novelty our work is generalisation of this problem (using the describing function method) for non-linear cases. The H∞ control theory is firstly adapted to cope with non-linear plants. To this...
In this paper a new factorization of discrete nonlinear systems is presented. This factorization is based on the star-product, an operation corresponding to the linear connection of systems. Finally some applications to system analysis and feedback design are provided.
In this paper, the problem of stabilizing the class of nonholonomic systems in chained form is solved by means of a quasi-continuous output feedback and invariant manifold technique. To this end, we assume that only the first and the last state variables are measurable. The proposed controller yields exponential stability in a large domain, while avoiding a discontinuity surface at the initial time...
Optimal budgetary policies for the period 1995 to 2000 are calculated for Austria within the framework of a problem of quantitative economic policy. An intertemporal objective function is minimized subject to the constraints of a macroeconometric model. Exogenous variables of the model are forecast by time series methods. Using the optimum control algorithm OPTCON, approximately optimal policies are...
We consider the minimum variance adaptive control problem for a discrete nonlinear plant. The uncertainty is described by Hölder class of functions. We prove information inequalities which provide asymptotic minimax lower bounds for mean-square control error. The bounds are shown to be tight for the case of Gaussian disturbances.
We study the problem of observing the state of continuous nonlinear descriptor systems in quasilinear form and present an idea how to construct a state observer. Our approach is based on rewriting the descriptor system as an equivalent system of explicit differential equations on a restricted manifold. Afterwards the restrictions are replaced by measurement equations. Thus an observer can be constructed...
The aim of this paper is to solve the disturbance rejection problem for linear systems modelled by bond graph. A graphical characterization of the infinite structure is proposed in terms of input-output causal paths in the associated bond graph model. Then we derive directly on the bond graph model necessary and sufficient conditions for the solvability of the disturbance rejection problem.
In this paper a predictive control algorithm for nonlinear discrete-time systems is presented. Starting from a state-space model, conditions for the asymptotic tracking of constant reference signals in a neighbourhood of a given equilibrium are first derived. Then it is shown that the system under control can be locally described in terms of a suitable NARX (Nonlinear ARX) model, which can be identified...
The paper deals with the output stabilization problem for nonlinear feedback systems with unmodelled functional block. The processes of the unmodelled block are assumed to be unmeasurable in general case. The infinite dimensional system case is considered. The problem solution is related to the generalized H∞-control problem, for which the solution existence criteria are established. These criteria...
In this paper a new method for driving a switching power amplifier by use of sigma delta modulation is proposed. After an explanation of the principles of sigma delta modulation the digital control concept is presented. The conventional solution by means of both, digital to analogue conversion and pulse width modulation is replaced by a pure digital one. A digitally implemented sigma delta modulator...
We present definitions of feedback stabilizability and detectability that are weaker than those previously appearing in the literature. Stabilizability and detectability (in this sense) are sufficient to ensure an equivalence between internal and external stability for well-posed systems. Furthermore, stabilizability and detectability are shown to be preserved under feedback (and other) connections...
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