摘要:

Advances in the technology of complex control systems demand high-speed and reliable communications between the individual components and subsystems for decision making and control. This can be accomplished by integrated communication and control systems which use asynchronous time-division-multiplexed networks. Unfortunately, these networks introduce randomly varying distributed delays as a result of time-division multiplexing. A predictor-controller algorithm has been developed with the objective of mitigating the detrimental effects of the network-induced delays that are distributed between the sensor(s), controller and actuator(s) within a control loop. This paper presents the implementation and verification of the above delay compensation algorithm. Performance of the delay compensator has been experimentally verified on an IEEE 802.4 network testbed for velocity control of a d.c. servomotor.

ISSN:0020-7179    

DOI:10.1080/00207179408923135

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We combine recently proposed adaptive nonlinear controllers with two types of observer-based identifiers. The controllers guarantee an input-to-state stability property with respect toθ˜andθ˜and the observer-based identifiers independently guarantee boundedness ofθ˜. A stability enhancement in the observer is crucial in establishing stability properties.

ISSN:0020-7179    

DOI:10.1080/00207179408923136

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Singular (J, J')-lossless factorization for strictly proper functions is studied. The method of infinite zero compensation derived by Copeland and Safonov is used to extend the results of Kimura to singular systems. Since (J, J')-lossless factorization contains both inner–outer factorization and Wiener–Hopf spectral factorization as special cases, the results obtained here unify previous results on singular factorization problems.

ISSN:0020-7179    

DOI:10.1080/00207179408923137

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The decomposition-aggregation method is used to carry out the transient stability analysis of anN-machine power system (the transfer conductances are included). The system is decomposed using either pair-wise or triple-wise decompositions. Elements of the system aggregation matrix are obtained by applying a new majorization procedure. In this procedure, the whole space is divided into a number of subspaces, each of them involving a number of system state variables. For every subspace, the majorization is carried out considering only positive interactions. In this way, the proposed majorization procedure can decrease the number of interactions to be majorized simultaneously, and produce a system aggregation matrix with weaker off-diagonal elements. Two power systems, with three and seven machines, are used as numerical examples. An estimate of the asymptotic stability domain of the seven-machine system is determined. It is found that the developed majorization procedure can lead to a considerable reduction of the conservativeness of the decomposition-aggregation method.

ISSN:0020-7179    

DOI:10.1080/00207179408923138

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

For a SISO, linear and time-invariant plant, with one real parameter uncertainty and one complex fictitious perturbation representing performance uncertainty, the structured singular value, μδ˜(M), is calculated. Thenμ—Kiteration can be used to design aμ-optimal controller. A simple design example is considered. The results are compared with those obtained for the same system with the real parameter modelled as a complex perturbation. This illustrates the conservatism that can be introduced by treating real uncertainty as complex uncertainty.

ISSN:0020-7179    

DOI:10.1080/00207179408923139

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A general structure detection and parameter estimation algorithm is derived for the identification of nonlinear systems that can be approximated by a stochastic nonlinear rational model defined as the ratio of two polynomial expansions of past inputs, outputs and noise sequences. The algorithm includes an intelligent structure detection module that learns the structure of the model from the input/output data. Simulation results are included to illustrate the application of the new algorithm.

ISSN:0020-7179    

DOI:10.1080/00207179408923140

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A nonlinear state-space model representing the robot dynamics and containing a disturbance term due to gravitational loading is presented. An adaptive model-following control problem satisfying the matching conditions is formulated using a suitable linear time-invariant reference model. The control input is designed to have two components: a non-adaptive linear component to do the task of model-following and a nonlinear unit-vector component based on hyperstability theory to do the adaptive task. An additional integral feedback term is further added and then the overall asymptotic hyperstability is established. Simulation experiments on the first three joints of a PUMA 560 robot manipulator have indicated the potential of our design approach.

ISSN:0020-7179    

DOI:10.1080/00207179408923141

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A new optimal stochastic control problem is posed. The criterion is to maximize the mean-time-between-failures criterion given a certain reference value. It is shown that this control problem is closely related both to the problem of minimizing the variance of the signal—minimum variance control — and to the problem of minimizing the so-called upcrossing probability—minimum upcrossing control. It is made plausible that the upcrossing probability is a better approximating criterion to minimize than the variance criterion. The problem of minimizing the upcrossing probability can be thought of as finding optimal weighting-matrices in an LQG-problem. The new controller is compared with the minimum variance controller for a first-order process. It is seen that the new controller causes a lower upcrossing probability and a larger mean time between failures. The improvement in the example is up to about 25%. This makes it possible to choose the reference value closer to the critical level without causing smaller mean time between failures. Further, it seen that the control signal is more well behaved.

ISSN:0020-7179    

DOI:10.1080/00207179408923142

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The problem of using an ‘identification tool box’ for the design of ‘grey-box’ models for nonlinear dynamic objects is non-trivial. The design is an interactive process, and it is not given aprioriin what order to execute the various subtasks that the tool box supports what design parameters to manipulate and how to interpret the intermediate results. The difficulties are enhanced when the uncertainty of the designer'sa-prioriinformation and the quality of the experiment are such that a model contains other stochastic elements than measurement error.

ISSN:0020-7179    

DOI:10.1080/00207179408923143

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Methods are presented for the synthesis of simple centralized and decentralized memoryless feedback controllers that guarantee asymptotic stability of uncertain time-delay systems and uncertain interconnected time-delay systems, respectively. The methods allow the controllers to be synthesized using simple formulae. Numerical examples are given to illustrate the results.

ISSN:0020-7179    

DOI:10.1080/00207179408923144

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor