ISSN:0020-7179    

DOI:10.1080/00207179408923109

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A decoupled wide envelope lateral/directional axes control design is presented for a supermanoeuvrable version of an F-18 aircraft. A control structure is developed that separates gain scheduling issues from aircraft performance issues. Flight condition dependent state and control effectiveness variations are accounted for by an inner loop controller designed using eigenstructure assignment. Structured singular value synthesis is used to design an implicit model following outer loop controller that addresses flying qualities performance specifications. A control selector is designed that generates lateral/directional aerodynamic and thrust vectoring commands from generalized control inputs of roll and yaw acceleration. Flying qualities and robustness analyses show that the control system performs well despite neglected dynamics and system uncertainties. Nonlinear simulations are presented showing excellent decoupling of roll and yaw responses.

ISSN:0020-7179    

DOI:10.1080/00207179408923110

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Integral control of large-scale systems implies coordination of activities by information exchange via communication networks. Usually these networks are shared with other users. Thus traffic conditions in the network may introduce time-varying random delays in the control loop with adverse effects on its performance and stability. Hence, the control must be designed to compensate for these delays. Recent work in modelling integrated control and communication systems has shown that the communication specific phenomena inducing random communication delays (such as multirate sampling, vacant sampling and message rejection) may be encompassed by finite-dimensional linear discrete-time models, provided that the plant and the controller are linear and time invariant. Existing approaches to the design of integrated control systems rely on conservative stability tests, because onlysufficientstability conditions were found for systems with random time-varying delays. In this paper,necessary and sufficientconditions are found for zero-state mean-square exponential stability of the considered class of control systems. Numerical tests for zero-state stability are outlined and illustrated by a simple example. Finally, the results are also demonstrated on specific hardware, a multiprocessor real-time control network which has been recently developed.

ISSN:0020-7179    

DOI:10.1080/00207179408923111

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A prerequisite for the feasibility of the technique of observer-based fault detection and isolation (FDI) in dynamic systems is a satisfactory robustness with respect to modelling uncertainties. This paper surveys the most relevant methods to increase the robustness in both the stage of residual generation and residual evaluation. Among these methods are the generalized observer scheme, the robust parity space check, the unknown input andH∞observer scheme, the decorrelation filter, and the concept of adaptive threshold selection. It is pointed out that the unknown input observer concept, which provides perfect decoupling from the modelling errors or its optimal approximation with the aid ofH∞techniques, constitutes a general framework of robust residual generation that generalizes and unifies numerous other approaches, among them the parity space and detection filter approach. It is further shown that this FDI method can even be applied to a certain class of nonlinear systems.

ISSN:0020-7179    

DOI:10.1080/00207179408923112

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The nature of the attraction of the solution of the time-invariant matrix Riccati differential equation towards the stabilizing solution of the algebraic Riccati equation is studied. This is done on an explicit formula for the solution when the system is stabilizable and the hamiltonian matrix has no eigenvalues on the imaginary axis. Various aspects of this convergence are analysed by displaying explicit mechanisms of attraction, and connections are made with the literature. The analysis ultimately shows the exponential nature of the convergence of the solution of the Riccati differential equation and of the related finite horizon LQ-optimal state and control trajectories as the horizon recedes. Computable characteristics are given which can be used to estimate the quality of approximating the solution of a large finite-horizon LQ problem by the solution of an infinite-horizon LQ problem.

ISSN:0020-7179    

DOI:10.1080/00207179408923113

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The known theories of transformations between polynomial matrices are extended to the case of rational matrices. Specifically, Ω-equivalence between rational matrices having possibly different dimensions is defined, and this has the property of preserving the zero structure of rational matrices in the region Ω ⊆C∪ {∞}Some implications of this new equivalence transformation for linear system theory are also provided.

ISSN:0020-7179    

DOI:10.1080/00207179408923114

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Sufficient conditions for the stability of time-varying discrete interval systems are presented. The spectral radius of the maximum absolute matrix of all interval matrices is employed as opposed to utilizing the matrix norm or Lyapunov theorem. For special cases, our result becomes a necessary and sufficient condition for stability. Furthermore, the proposed conditions are inclusive of the previous results of stability of time-invariant interval systems.

ISSN:0020-7179    

DOI:10.1080/00207179408923115

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Elementary state-space concepts are used to derive a transparent solution to theH∞control problem on an infinite horizon. The main contribution of this solution is a novel representation of suboptimal controllers in terms of a pair of parametric Riccati equations with a coupling constraint. Unlike the classical parametrization in terms of linear fractional transformation, this state-space representation has a homogeneous Riccati formulation which should help to make the most of the suboptimal controller diversity. Potential applications include the design of reduced-order controllers and, more generally, the selection of suboptimal controllers to meet or optimize additional constraints.

ISSN:0020-7179    

DOI:10.1080/00207179408923116

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Criteria are presented that ensure that all zeros of a discrete system are inside the unit disc when a continuous-time plant with a time delay is sampled by use of a zero-order hold. A necessary and sufficient condition developed in this paper is a natural extension of the results for the case with no time delays. This paper also derives sufficient conditions for stable discrete zeros in terms of the coefficients of a continuous-time transfer function. They guarantee that all the sampled zeros stay inside the unit disc as long as the sampling period is selected to satisfy a simple relation.

ISSN:0020-7179    

DOI:10.1080/00207179408923117

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The detection and diagnosis of changes in stationary dynamical systems via statistical methods and using input design to improve detection performance are discussed. A cumulative sum test to detect a change towards one of several hypotheses is obtained by exploiting connections with the sequential probability ratio test. For input design, the objectives are taken to be to decrease the detection time and, at the same time, to ensure a tolerable false alarm rate. Both off-line auxiliary inputs and on-line generation of the input signal by a linear output feedback are considered. The problem is first introduced for the two-hypotheses case and then the design techniques are extended to the general multiple-hypotheses case.

ISSN:0020-7179    

DOI:10.1080/00207179408923118

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor