摘要:

The active damping aspect is treated of the spacecraft control laboratory experiment (SCOLE). A continuum model, rather than a finite element model, is used. First, a group of rather weak sufficient conditions for strong stabilizability is presented. Structural passive damping is no longer required to be positive definite and, in fact, can even be zero, while strong stabilizability can still be achieved by active damping. Then, the mode excitation problem is studied for both linear and (saturating) nonlinear active damping. The popular notions of ‘characteristic equation’ and ‘root locus’ in feedback control are extended to our distributed parameter system, which is a feature of this work. The root locus provides an insight into the nature of active damping

ISSN:0020-7721    

DOI:10.1080/00207729308949585

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Current legislation on equipment reliability requires military contractors supplying materials to provide warranties specifically against product failure. Thus, we have a need to forecast accurately spare parts requirements. Our model differs from existing models for logistics planning in that we allow for the phenomenon of reliability growth. The model outputs include spares requirements at both the flightlines and at a central repair depot. The model can also be used to determine central depot starring requirements, based upon a specified system utilization

ISSN:0020-7721    

DOI:10.1080/00207729308949586

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The multi-modal optimization problem is considered. An automata model with improved learning schemes is proposed to solve the global optimization problem. The numerical simulation shows that the automata approach is better than the well-known gradient approach because the gradient approach is easily trapped inside the local optimal states. Theoretically, we prove that the automaton converges to the global optimum with a probability arbitrarily close to one. The simulation result also shows that our automata model converges faster than the existing models in the literature

ISSN:0020-7721    

DOI:10.1080/00207729308949587

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The aim of this paper is to present some results allowing positively invariant and asymptotically stable polyhedral sets to be determined for the linear singular discrete-time system ExK+1= AxK; the regular and singular cases of pencil (E, A) are considered. Necessary and sufficient algebraic conditions guaranteeing that some sets are positively invariant and asymptotically stable are given. Also discussed are some issues relating to the positive invariance of some domains and consistent initial conditions. Finally, as an application, the proposed results are used to determine a stability domain for a state feedback regulator with constraints on controls

ISSN:0020-7721    

DOI:10.1080/00207729308949588

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Sets of (characteristic) polynomials with uncoupled variations in odd and even coefficients arise when systems experience parameter variations. This paper derives frequency domain criteria for robust stability of polynomial sets with uncoupled variations in odd and even coefficients. The frequency domain criteria only require one frequency domain plot to check the robustness of polynomial sets with uncoupled variations in odd and even coefficients. Furthermore, the largest stable polynomial set can be graphically estimated from the same frequency domain plot

ISSN:0020-7721    

DOI:10.1080/00207729308949589

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Generalized predictive control (GPC)-type control algorithms traditionally derived in the polynomial domain are derived in this paper in the state-space domain, but following the polynomial approach due to Clarkeet al.(1987). Relations between the polynomial and state-space parameters are presented. Some possible state-space representations which were used earlier in different publications are discussed. The problem of deriving the GPC algorithm in the state-space domain is solved for the unrestricted case as well as for the case of restricted control and output horizons. Some properties of the state estimate for this problem are presented; in particular, two methods of Kalman filtering—optimal and asymptotic—are proposed. The solution is valid for any possible (minimal or non-minimal) state-space representation. Another approach to this problem is by the ‘dynamic programming method’ and solving the Riccati equation (Bitmeadet al.1990). This approach is also presented in this paper but the method differs from this earlier work and does not require extending the state dimension. Ultimately, certain features of the state-space approach are discussed, such as (a) the opportunity for straightforward analysis of the transient states produced by switching on the regulator, by changing the set-point or by changing the regulator parameters; (b) easy extension to the multidimensional case; and (c) the possibility of introducing nonlinearities into the model

ISSN:0020-7721    

DOI:10.1080/00207729308949590

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Exponential weighting of future tracking errors and control increments is employed for receding-horizon predictive control and seen to improve the dynamic behaviour of the closed-loop system. A sufficient condition for the asymptotic stability ofgeneralized predictive control(GPC) with these weightings is derived. The condition can be easily satisfied whereas the corresponding condition for GPC with constant weighting is highly restrictive. In the case ofconstrained receding-horizon predictive control(CRHPC), a prescribed degree of stability is obtained just as with infinite-horizon optimal control using the same type of weighting. This makes it possible to use a simplified CRHPC law with no weighting on the tracking error but which guarantees convergence to the set-point faster than a bounding exponential

ISSN:0020-7721    

DOI:10.1080/00207729308949591

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Material requirements planning of batch production in multi-stage manufacturing systems is discussed where component parts may have significant non-zero production or purchasing lead time. The presence of such lead time poses a synchronization problem for the rolling horizon planning of component part production in the system. The synchronization problem is analysed, discussed and modelled first for the case of assembly product structures where a component has a unique successor component. The analysis is then extended to the more complex case of general product structures where a component may have multiple successor components. The associated general structure multi-stage lot-sizing problem is then formulated as a mixed integer linear program first in terms of conventional stock, and then reformulated in terms of echelon stock. The echelon stock quantity of a component is its lead-time adjusted total system stock, counted both as a stand-alone component and as part of successor components. The echelon stock formulation permits the derivation of valid inequalities that can be used in an optimal solution method, and facilitates the development of a fast heuristic method for the capacitated problem

ISSN:0020-7721    

DOI:10.1080/00207729308949592

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A synthesis procedure is presented for designing discrete time-dependent stochastic control systems such that the given performance specifications are satisfied over a finite time horizon. The application of the proposed method is demonstrated in the control of two different time-varying plants with stochastic disturbances

ISSN:0020-7721    

DOI:10.1080/00207729308949593

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A general adaptive control scheme is presented for an unknown time invariant singular system of the form Ex(t + 1) = Ax(t) + Bu(t); y(t) = Cx(t). Owing to the non-causality of this kind of system, the identification of unknown parameters is re-considered and a new residual signal is constructed and used in the recursive calculations. A general design procedure is obtained that uses the identified parameters and includes two steps: (i) preliminary output feedback gain design in order to make the original system causal; (ii) adaptive control design for the causal system. It has been shown that any adaptive control algorithm can be combined with this scheme to obtain a globally stable closed-loop system. The design procedure is shown to perform well on a simulation of a third-order singular system

ISSN:0020-7721    

DOI:10.1080/00207729308949594

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor