摘要:

Following on from a rationalized presentation of algorithms for integrated system optimization and parameter estimation, four forms of the algorithm are applied to a mixing process which is controlled from within a distributed computer control system. It is seen that three of the algorithms produce, as expected, the process optimum despite using an unfaithful process model. The performance of the various algorithms is compared and suggestions are made as to the most appropriate application of the algorithms in on-line optimization.

ISSN:0020-7721    

DOI:10.1080/00207729308949483

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The conditions of controllability and observability are given in the frequency domain for discrete-time infinite-dimensional systems. The conditions of stabilizability and detectability are also investigated. Moreover, preservation of those system properties after discretization are discussed.

ISSN:0020-7721    

DOI:10.1080/00207729308949484

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

When we use the usual digital control scheme, unstable zeros appear in the discrete-time system due to the existence of limiting zeros even though the continuous-time system has no unstable zeros. We show that two-delay output control systems and two-delay input control systems have no finite zeros in the case where the continuous-time infinite-dimensional systems are generated by analytic semigroups.

ISSN:0020-7721    

DOI:10.1080/00207729308949485

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Two ordering policies for a complex system with age-dependent minimal repair and two types of lead times are considered. Introducing costs due to ordering, repairs, shortage and holding, the expected cost per unit time is derived in the long run as a criterion of optimality and the optimum ordering policies found by minimizing that cost. We show that, under certain conditions, there exists a finite and unique optimum policy. Various special cases are discussed.

ISSN:0020-7721    

DOI:10.1080/00207729308949486

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Based on the stabilizability of a nominal system (i.e. a system in the absence of uncertainty), by making use of the Lyapunov stability criterion and combining with the algebraic Riccati equation, a new approach for designing a robust linear state feedback controller for uncertain linear dynamical systems is presented. Using this approach, the BIBO stability of uncertain linear dynamical systems is also discussed, Some analytical methods and the Bellman-Gronwall inequality are employed to investigate the robust stabilization conditions on the feedback controller. The main features of this approach are that no matching condition about uncertainty is needed and the uncertain systems can be asymptotically stabilized. An example is given to demonstrate the validity of our results.

ISSN:0020-7721    

DOI:10.1080/00207729308949487

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A class of dynamic system is discussed where its uncertainty can be described as a lumped model, called lumped uncertainty, and the lumped uncertainty is cone-bounded for the state variables. We first propose a simple adaptation law for the boundary of uncertainty. Then based on this adaptive boundary, variable structure control is presented to render uncertain dynamic systems asymptotically stable. When the parameter adaptation has been completed, the system trajectory is constrained by the prescribed switching surface of the sliding mode. We apply the proposed method to a variable length pendulum as an example in numerical simulations. Simulation has shown its effectiveness in the control of a class of uncertain dynamic systems.

ISSN:0020-7721    

DOI:10.1080/00207729308949488

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A new technique for decoupling controller design is proposed. A reference model representing the desired closed-loop dynamic behaviour is chosen. A quadratic performance index is used to measure both coupling and tracking errors in the closed-loop system. The system state equation is organized in incremental canonical form. The optimal decoupling control law is obtained by minimizing the performance index. This algorithm has been applied to a paper machine headbox control system. The performance of the system under different conditions is satisfactory.

ISSN:0020-7721    

DOI:10.1080/00207729308949489

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Fuzzy controllers can be made to adapt to changing process and environment dynamics. One methodology to adapt the initial knowledge base to changing operating conditions is presented. The membership functions associated with the process controller output are adjusted in response to future or past performance of the feedback control system. A linearized process model is identified on-line and is used to predict the future performance of the controller. This performance index is used to adapt the controller as long as the identified process model is statistically reliable. If the process model is considered unreliable then an index related to the past performance of the controller is used to make the adjustments.

ISSN:0020-7721    

DOI:10.1080/00207729308949490

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A two level adaptive controller for the control of a high speed robot is proposed. Dynamic interaction effects of the robot system are eliminated by applying a centralized adaptive multivariable decoupler. Decentralized adaptive PID controllers stabilize and eliminate the static positioning errors of the robot system. No prior knowledge of robot dynamics is required for this scheme. Output transients caused by sensitivity to the system parameter variations is reducible by adjusting the gain constants of the decoupler. Computation load for the implementation of the decoupler is minimal due to its direct nature, The effectiveness of the scheme is demonstrated by simulation results in high speed repetitive motion trackings and load change conditions.

ISSN:0020-7721    

DOI:10.1080/00207729308949491

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The process of social reproduction gives rise to processes of exchange and distribution, whenever ultimate consumption does not occur within the production unit. Suitable choices of allocating social output between consumption and investment bring about alternative paths of accumulation that together with the prevailing institutional arrangements generate alternative distributional paths. One can express preferences between alternative accumulation paths and these preferences can be given numerical values. Whatever the choice one makes there are always capital costs involved in running an action and meeting a policy target as well as political and social costs of diverting resources to an alternative choice at the expense of others. Social costs are also known as shadow prices which reflect the fact that in general they cannot be observed directly as for instance market prices. The purpose of this study is to illustrate based on a model drawn from our current research how one can use stochastic analysis and control theory to recast these mentioned allocation problems in the framework of stochastic optimization aimed at obtaining optimality conditions and accounting prices in the form of adjoint variables. Thereby, we find a method of assessing the action at issue and gain interesting insights into the qualitative behaviour of random accumulation from the highly neglected perspective of accounting prices.

ISSN:0020-7721    

DOI:10.1080/00207729308949492

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor