This paper presents a study of control method for Xi'an-Lingtong freeway by using optimal control theory of large scale systems. An accurate non-linear discrete dynamic traffic flow model is described in the paper...
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This paper presents a study of control method for Xi'an-Lingtong freeway by using optimal control theory of large scale systems. An accurate non-linear discrete dynamic traffic flow model is described in the paper, unknown parameters for the traffic flow model are identified according to the data collected from the freeway. A three layer hierarchical control method for Xi'an-Lingtong freeway is proposed based on the traffic flow model. Finally, a simulation of Xi'an-Lingtong freeway control system is studied and the simulation result is satisfied.
Let P be a convex set of real polynomials. Consideration is given to the question of when there exists a real polynomial b(s), or, more generally, a real transfer function b(s), such that p(s)/b(s) is strictly positiv...
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Let P be a convex set of real polynomials. Consideration is given to the question of when there exists a real polynomial b(s), or, more generally, a real transfer function b(s), such that p(s)/b(s) is strictly positive real for all p(s) in P. Necessary and sufficient conditions are found for the transfer function case, and when the degree of the polynomials in P is restricted, such conditions are also found for the polynomial b(s) case. Closely related results are also obtained for a z-transform version of the problem. The results have application in adaptive systems.< >
Robust Schur stability conditions are obtained for polynomials of orders two to five. For n=2 and 3, the conditions obtained are related to stability of the corner points, while for n=4 and 5, the conditions are relat...
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Robust Schur stability conditions are obtained for polynomials of orders two to five. For n=2 and 3, the conditions obtained are related to stability of the corner points, while for n=4 and 5, the conditions are related to stability of corner and possible supplementary points. The number of points increases substantially as the polynomial order increases. The obtained results are of importance in the robust design of controlsystems. The difficulty in extending the approach to higher-order polynomials is discussed. Special cases for such extensions are mentioned. Further applications of the results obtained may be of use in the stability study of two-dimensional systems. Some examples for the application of the stability conditions are given and, in particular, the two counterexamples presented in the literature are discussed.
This paper presents general frequency domain criteria for the robust stability of systems with parametric uncertainities. The criteria are applied to the robust stability verification of LTI systems with or without ti...
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This paper presents general frequency domain criteria for the robust stability of systems with parametric uncertainities. The criteria are applied to the robust stability verification of LTI systems with or without time delays and of LTI systems operating under possibly nonlinear passive feedback.
An on-line scheme to fault detection in adaptive controlsystems is proposed by introducing Kullbaek Discrimination Information (KDI) as a detection index. When a physical parameter change due to a failure has occurre...
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An on-line scheme to fault detection in adaptive controlsystems is proposed by introducing Kullbaek Discrimination Information (KDI) as a detection index. When a physical parameter change due to a failure has occurred in a system under adaptive control, the failure effect will hardly be visible in the output performance because of the adaptation mechanism. Such a parameter change is also difficult to detect by monitoring the regulator parameters, which are determined by a recursive identification based on the direct approach. Since the failure effect is reflected as a change in the predictor model used for the adaptive control design, the fault detection leads to a model discrimination problem. It has been shown that the KDI can be used as an effective distortion measure for the model discrimination and the index can be applied in a modified form to detect a fault on-line. Simulation studies on a second order damped oscillatory system have been carried out to demonstrate the efficiency of the method.
The estimation of sinusoidal frequencies by the overdetermined Yule-Walker (OYW) Method is considered. An explicit expression is derived for the asymptotic covariance matrix of the estimation errors. The effect of inc...
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The estimation of sinusoidal frequencies by the overdetermined Yule-Walker (OYW) Method is considered. An explicit expression is derived for the asymptotic covariance matrix of the estimation errors. The effect of increasing the number of Yule-Walker equations on estimation accuracy is analyzed. The asymptotic estimation accuracy of the OYW method is compared to the best achievable accuracy corresponding to the Cramér-Rao bound
An effective algorithm for the calculation of stability regions in the plane of two control parameters is proposed. The algorithm is suitable for small computers. In comparison with the classical technique, the derive...
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An effective algorithm for the calculation of stability regions in the plane of two control parameters is proposed. The algorithm is suitable for small computers. In comparison with the classical technique, the derived algorithm requires fewer manual calculations. The program and its short characteristic equation is included. Utilization of the program is illustrated on an example of an automatically controlled power system having a ‘forced’ excitation system.
The paper considers robust stability properties for Schur polynomials of the form f(z) = Σi=0 nan-izi By plotting coefficient variations in planes defined by variable pairs ai, an-i for each i and requiring in each s...
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The paper considers robust stability properties for Schur polynomials of the form f(z) = Σi=0 nan-izi By plotting coefficient variations in planes defined by variable pairs ai, an-i for each i and requiring in each such plane the region of obtained coefficients to be bounded by lines of slope 45°, 90° and 135°, we show that stability for all polynomials defined by comer points is necessary and sufficient for stability of all polynomials defined by any points in the region. Using this idea, one can construct several necessity and differing sufficiency conditions for the stability of polynomials where each ai can vary independently in an interval [ai, a- i]. As the sufficiency conditions become closer to necessity conditions the number of distinct polynomials for which stability has to be tested increases.
Models and model quality are prime concerns for most design issues in control and systems analysis. The success of a simulation study hinges upon the reliability of the model used. In this contribution we discuss how ...
Models and model quality are prime concerns for most design issues in control and systems analysis. The success of a simulation study hinges upon the reliability of the model used. In this contribution we discuss how to build mathematical models that given certain constraints, are of optimum quality for a prespecified (simulation) application. We then take into account the influence of both bias errors and random errors on the model. It turns our that for a fairly broad class of identification methods in the prediction error family, the optimal choices of design variables can be given in an explicit form.
A three step method for obtaining nearly maximum likelihood ARMA spectral estimates is presented. The computational complexity of the algorithm is comparable to Yule-Walker methods, but the method gives asymptotically...
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A three step method for obtaining nearly maximum likelihood ARMA spectral estimates is presented. The computational complexity of the algorithm is comparable to Yule-Walker methods, but the method gives asymptotically efficient estimates. The implementation of the algorithm is discussed, and numerical examples are presented to illustrate its performance.
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