摘要:

State-space solutions to a discrete-timeℋ∞problem are given. For a given number γ>0we give a characterization of all controllers such that theℋ ∞norm of the closed-loop transfer function is less than γ The approach taken is based on the solution of two Riccati equations using the stable deflating subspace of a symplectic pencil. This ensures that no unnecessary assumptions on the ‘A’ matrix on the realization of the transfer function are needed. While the results are the direct analogues of those in the continuous time, the state-space derivation is considerably more difficult.

ISSN:0020-7179    

DOI:10.1080/00207179108934198

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A new coordination strategy for hierarchical optimizing control is presented, Unlike the price coordination method this approach is not a primal and dual method and its convergence behaviour does not depend on the feature of the saddle point of the problem lagrangian. Compared with the price coordination method, this approach has two advantages. Firstly, its applicability conditions are easier to satisfy and secondly, its convergence behaviour is more desirable in terms of convergence rate and insensitivity of the hessian structure of the problem. A variable augmentation technique is employed to increase the flexibility of the iterative gain selection and to improve further the convergence behaviour of the method. Optimality and convergence analysis are provided for each different version of the algorithm presented. A comparative study between different versions of the algorithm presented and a single iterative integrated system optimization and parameter estimation (ISOPE) method with global feedback is also provided using computer simulation.

ISSN:0020-7179    

DOI:10.1080/00207179108934199

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We present a numerical procedure to compute non-singular, time-optimal solutions for non-linear systems that are linear in the control and have fixed initial and final states and bounded control. Part of our procedure is a new numerically computable test that determines whether bang-bang solutions satisfy Pontryagin's minimum principle. This test reveals the new important fact that, for non-linear systems, with linear control and dimension n, the probability that a bang-bang solution with more than n - 1 switches satisfies Pontryagin's Mini mum Principle is almost zero. Using a parameter optimization procedure we search for bang-bang solutions with up to n - 1 switches which transfer the system from the initial to the final state. If no controls with up to n - 1 switches can be found to satisfy Pontryagin's Minimum Principle the problem is very likely singular. We apply our procedure to the time-optimal control problem for rigid manipulators where friction may be included in the dynamics. We will demon strate that some solutions mentioned in the literature to satisfy Pontryagin's minimum principle do not. A class of time-optimal control problems turns out to be singular. To solve these problems we propose and demonstrate the method of control parametrization.

ISSN:0020-7179    

DOI:10.1080/00207179108934200

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We consider a design of decentralized control for a class of interconnected non-linear dynamical systems having uncertainty. This uncertainty is (possibly fast) time-varying, and it may appear in each system as uncertain parameter and input disturbance. It also may appear in the interconnections. No statistical information about the uncertainty is imposed; only its possible bound is assumed to be known. The two control schemes proposed here, namely the linear and the non-linear, take the bounds of the interconnections into account. The use of the non-linear control requires more assumptions than the use of linear control. In applications where these assumptions are met, the designers have both controls at their disposal, and depending on the particular application, one may be preferable to the other.

ISSN:0020-7179    

DOI:10.1080/00207179108934201

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

When a discrele-event systemPconsists of several subsystemsP1,...,Pnwhich operate concurrently, a natural approach to the supervisory control problem is to synthesize a ‘local’ controllerSi, for each subsystemPi, and operate the individually controlled subsystemsSi/Piconcurrently. Such an approach is called concurrent supervisory control and is closely related to decentralized supervisory control as studied by Cieslaket al. (1988) and Lin and Wonham (1988). In the present paper simple and easily computable conditions are developed which guarantee that concurrent supervisory control can achieve the optimal behaviour achievable by a global supervisor. To achieve this, two specific concurrent control strategies are introduced.

ISSN:0020-7179    

DOI:10.1080/00207179108934202

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The problem of inducing convergent quasi-sliding regimes on smooth state-space surfaces of non-linear single-input single output discrete-time controlled systems is addressed in full generality. A suitable extension of the notion of relative degree is used in establishing the most salient features of quasi-sliding motions in non-linearly controlled systems. Several examples are given.

ISSN:0020-7179    

DOI:10.1080/00207179108934203

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Worst-casel1identification is studied for BIBO stable linear shift-invariant systems. It is shown that the Chebyshev identification method when used with Galois input designs satisfies a certain robust convergence property and providesl1model error bounds in worst-case identification of BIBO stable systems with a uniformly bounded noise set-up. The robust identification methodology developed is compatible with the modelling requirements of modern robust control design.

ISSN:0020-7179    

DOI:10.1080/00207179108934204

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In a conventional rule based fuzzy control system, the rules are of the following form: if (condition) then (action), and all rules are essentially in a random order. The number of rules increases exponentially as the number of the system variables, on which the fuzzy rules are based, is increased. In this paper, the rules are structured in a hierarchical way so that the total number of rules will be a linear function of the system variables. The hierarchical fuzzy control algorithm developed in this paper is applied to control the feedwater flow to a steam generator of a power plant. The simulation results show that the hierarchical fuzzy controller yields superior performance over the conventional PID controller.

ISSN:0020-7179    

DOI:10.1080/00207179108934205

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The performance of deadbeat control systems is addressed. Analysis of conventional deadbeat control (CDC) reveals that, in addition to deadbeat tracking performance, other system properties, such as robustness and noise immunity, may need improvement. A model reference deadbeat control (MRDC) is proposed to remedy such deficiencies of CDC systems. Several examples are given to show that the MRDC scheme is better than the CDC scheme in attaining good transient response, noise immunity and robustness if a suitable reference model is selected.

ISSN:0020-7179    

DOI:10.1080/00207179108934206

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The smoothing problem for discrete-time gaussian reciprocal processes is examined. For this class of process, the smoother takes the form of a second-order two-point boundary-value nearest-neighbour model. This smoother is non-causal, but admits causal implementations which extend the two-filter and Rauch-Tung-Striebel smoothing formulae of Gauss-Markov processes. A multi-rate implementation based on a block cyclic reduction method is also described.

ISSN:0020-7179    

DOI:10.1080/00207179108934207

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor