摘要:

A sufficient condition is derived such that the closed-loop state delayed system is stable and guarantees a prescribedH∞norm bound of the closed-loop transfer matrix from the disturbance to the controlled output. Based on this derivation, a full-order observer-basedH∞controller for the stace delayed linear systems is constructed by solving two modified algebraic Riccati equations. The state feedbackH∞controller for the state delayed linear systems is also obtained by solving a modified algebraic Riccati equation. An illustrative example is given to show the applicability of the proposed approach.

ISSN:0020-7179    

DOI:10.1080/00207179608921613

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper investigatesH ∞ control design where the compensator is assumed to have immediate access to the command signal (usually denoted byW1) but not to the disturbance signal (denoted byW2). While the Doyle-Glover paradigm feeds only a plant outputYinto the compensator, in many industrial applications the command signal at timetcan be transmitted to the compensator at timetif there is any advantage to doing so. In this article we analyse both linear and nonlinear systems and find that the advantage of this control architecture is great. The results in this paper generalize those of Ballel al.(1993), Doyleet al.(1988) and Heltonel al.(1992). A necessary condition is given for the general nonlinear systems. These suggest formulas for controllers. For special cases such as when there is no disturbance signalW2or the system is linear, we have very satisfactory conclusions. In particular, for linear systems with uncertainty, we derive conditions for the solution of the robustH∞ control problem to exist.

ISSN:0020-7179    

DOI:10.1080/00207179608921614

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper investigates, by using the state-space approach, some basic properties and state feedback compensation problem ofn-dimensional discrete systems in the practical sense that the input and output signals of the systems are unbounded in, at most, one dimension. Notions of practical controllability, practical observability, practical stabilizability by state feedback and practical detectability are introduced and corresponding necessary and sufficient conditions are derived. Moreover, a connection between the state-space representation and doubly coprime matrix fractional description on the ring of practically stable rational functions is shown. The obtained results clarify that all then-dimensional problems considered in the practical sense are in fact equivalent to the corresponding problems ofnone-dimensional systems, hence can be essentially solved by using one-dimensional methods.

ISSN:0020-7179    

DOI:10.1080/00207179608921615

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper, decentralized stabilization of interconnected systems based on quasi-block diagonal dominance of transfer function matrices has been examined. Some previous results are refined and extended to the case where diagonal blocks are not necessarily square. It has been shown that the refined stability result leads to a necessary and sufficient condition for robust decentralized stability for a class of additively perturbed interconnected systems. Some design considerations for decentralized controllers are discussed.

ISSN:0020-7179    

DOI:10.1080/00207179608921616

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper, an adaptive model output following control utilizing almost strictly positive real (ASPR) characteristics of the plant is considered. The plant is said to be ASPR if there exists a static output feedback such that the resulting closed-loop transfer function is strictly positive real. A design scheme of an adaptive model output following control system having a simple structure is proposed for the ASPR plant. The ASPR condition imposes severe restrictions on the plant with relation to the practical application. However, we can construct an ASPR augmented plant, which is regarded as a virtually new controlled plant, by implementing a parallel feedforward compensator or pre-compensator on the plant. The design scheme of such compensators that make the non-ASPR plant virtually ASPR is proposed by taking plant uncertainties into consideration. As a result, the applicable class of the proposal can be expanded. The effectiveness of the proposed methods is confirmed through numerical simulations.

ISSN:0020-7179    

DOI:10.1080/00207179608921617

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Output tracking control of non-minimum phase systems is a highly challenging problem encountered in the control of flexible manipulators, space structures, and elsewhere. Classical inversion provides exact output tracking but leads to internal instability, while recent nonlinear regulation provides stable asymptotic tracking but admits large transient errors. As a first step to solve this problem, this paper addresses the stable inversion of non-minimum phase nonlinear systems. Using the notions of zero dynamics and stable/unstable manifolds, an invertibility condition is established for a class of systems. A stable but non-causal inverse is obtained offline that can be incorporated into a stabilizing controller for dead-beat output tracking. This inverse contrasts with the causal inverse proposed by Hirschorn where unstable zero dynamics result in unbounded inverse solutions. Our results reduce to those of Hirschorn for minimum phase systems, however. In a numerical example, the stable inverse has achieved much superior tracking performance as compared with that produced using nonlinear regulation.

ISSN:0020-7179    

DOI:10.1080/00207179608921618

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this work averaging methods are used to analyse the behaviour of an adaptive controller with slowly varying parameters. The incorporation of time varying parameters into a stability analysis of an adaptive controller leads to certain perturbation terms in the error system. The type of averaging results so far applied to adaptive control cannot deal with these perturbations. Thus, some new averaging theorems are needed. These results are known in the averaging literature. However, here a very simple proof technique has been found which gives finite and infinite interval averaging results under weaker conditions. The averaging analysis shows that, with regard to parameter tracking, the adaptive algorithm behaves like a first-order filter. It is also clear that successful tracking then requires knowledge of the true speed of parameter change.

ISSN:0020-7179    

DOI:10.1080/00207179608921619

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper examines the tracking/rfejection problem of an adaptive controller using the internal model principle. The major contributions are to establish the tracking/rejection properties of the controller and to relax the order restriction of the filters used in some existing continuous time adaptive systems. It is shown that, in the presence unmodelled dynamics and external disturbances, the controller can give a small 'in the mean’ tracking error after the establishment of global bounded-input bounded-output stability of the adaptive system. Perfect tracking/rejection of deterministic trajectories/disturbances can be achieved when the unmodelled dynamics disappear. For the implementation of the controller, no a priori knowledge on the modelling error is required. The adaptive scheme was also tested to be effective by simulation studies.

ISSN:0020-7179    

DOI:10.1080/00207179608921620

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper considers an adaptive minimal observer synthesis algorithm based upon a well-known model reference adaptive system strategy. This algorithm gives state and parameter estimation from output feedback alone for single input single output processes and results are presented which illustrate its excellent convergence properties.

ISSN:0020-7179    

DOI:10.1080/00207179608921621

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The paper presents a new design for a robust output observer and demonstrates that it can be used to detect sensor faults in uncertain systems with output disturbances. The time-domain design uses anl ∞ technique to minimize a norm of the estimation error. The estimation error forms a residual signal that is the basis for fault detection, fault isolation and disturbance rejection. The minimum detectable fault and the maximum non-detectable fault are introduced to quantify the sensitivity of the detection scheme at a given alarm threshold. These quantities are obtained as solutions to non-convex optimization problems.

ISSN:0020-7179    

DOI:10.1080/00207179608921622

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor