摘要:

Control system experiments are described that were carried out on flexible structure facilities at the Jet Propulsion Laboratory (JPL) and the Wright-Patterson Air Force Base (WPAFB). The feedback controllers were designed using the technique of weighted gap optimization to increase structural damping and achieve robust control.

ISSN:0020-7179    

DOI:10.1080/00207179308922987

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Worst-case identification in H∞is considered in the situation in which corrupted frequency response measurements are available at an arbitrary set of frequencies. Two new classes of algorithms are presented: one yields polynomial models directly, the other is a two-stage algorithm producing rational models. Each has improved convergence rates for the class of exponentially stable discrete-time systems (with errors typically O(ϵ)+ O(Δr) for arbitrarily large r, where ϵ is the noise level and Δ is the maximum spacing between identification points). A numerical example is given.

ISSN:0020-7179    

DOI:10.1080/00207179308922988

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A new general state-space representation for causal and anticausal discrete-time systems is introduced. Some of its properties related to systems and network theory concepts are developed. The relation to the descriptor form state-space representation is also explained. Applications are given to show the usefulness of the new representation.

ISSN:0020-7179    

DOI:10.1080/00207179308922989

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper presents a model reference adaptive control system (MRACS) which does not depend on the degree of the plant when the plant is the continuous-time periodically linear time varying (LTV) system.A prioriinformation is only the relative degree and the time-varying period. The controller has adjustable scalar functions. The optimal functions of these are estimated directly, synchronizing with the time-varying period of the plant by adaptive laws. The main contribution of this paper is that the computational burden of the adaptive law for the direct function estimation is reduced. It is accomplished with the maximum normalized error evaluation typed adaptive law. The design method and the global stability analysis of the proposed system are shown and a simple numerical simulation result is indicated to verify the viability of the proposed system.

ISSN:0020-7179    

DOI:10.1080/00207179308922990

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The discrete-time linear positive and quasilinear monotone systems are considered. The set of initial points is restricted to be the cone of non-negative vectors. The input belongs to the cone of non-positive vectors. The necessary and sufficient conditions of null-controllability for linear systems are obtained. The conditions are sufficient for quasilinear systems.

ISSN:0020-7179    

DOI:10.1080/00207179308922991

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Controlling a collection of linear multiple input systems with a single linear state feedback controller is considered. A straightforward numerical procedure, which is based on the minimization of a weighted sum of the quadratic performance indices of the systems is presented. In this method the performance of the closed loop systems, rather than simultaneous stabilization, is the primary consideration. The proposed procedure is computationally efficient and since only an unconstrained minimization problem must be solved, it is also simple to implement. The resulting controllers are found to be effective at rapidly stabilizing each member of the collection of systems. Furthermore, through the choice of the quadratic performance index, it is possible to limit the size of the feedback controller by changing a single user specified parameter and thus ensure that the control action is not excessive. Two examples are used to illustrate and to test the procedure.

ISSN:0020-7179    

DOI:10.1080/00207179308922992

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The Nyquist plot, which maps the loop transfer function along a Nyquist contour, has been used for studying the stability of control systems. However, if a controller with an integral mode is used or if the process transfer function contains purely imaginary poles, a closed Nyquist plot can only be constructed by using some asymptotical properties of the system loop transfer function. This fact makes it difficult to apply the Nyquist plot to MIMO systems, where such asymptotic properties are not readily clear and readable. In such cases justification of stability based on the Nyquist plot of the original loop transfer function is not easy. In order to resolve this difficulty, this paper describes a new Nyquist test. This test is characterized by its use of a normalized Nyquist plot, which facilitates determining encirclements of the plot around the critical point.

ISSN:0020-7179    

DOI:10.1080/00207179308922993

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An optimal controller combining the optimal pole placement technique and the dominant energy mode concept for the automatic generation control of power systems is presented in this paper. Firstly, based on the physical reasoning about the power plant to be controlled, the weighting matrix is roughly selected and the optimal feedback gain vector is found. Then the weighting matrix and thus the feedback gain are sequentially modified to let the dominant energy eigenvalues of the closed-loop system be placed in the desired region. A technique for determining the dominant energy eigenvalues of MIMO systems is proposed. Improper eigenvalue placement can be avoided, and very good control performance can be obtained. The proposed method is applied to design an automatic generation controller for an interconnected thermal power system. The simulation results indicate that very good dynamic responses of the area frequency deviations and tie-line power deviation are achieved.

ISSN:0020-7179    

DOI:10.1080/00207179308922994

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In control system design, specifications are commonly given in terms of log-magnitude quantities (i.e. decibels). This description induces a multiplicative or relative error criterion for plant model reduction. Techniques from the theory of additive Hankel norm approximation and spectral factorization are synthesized to produce a multiplicative approximant of a possibly unstable or non-square plant. It is shown that the reduced-order model preserves the unstable poles and right half-plane zeros of the original system. Explicit state-space formulae are provided for the construction of the reduced-order model and its error properties are discussed. The method is illustrated by a numerical example.

ISSN:0020-7179    

DOI:10.1080/00207179308922995

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Output injection feedback is a special kind of pole-positioning mechanism whereby linear combinations of the output measurements are fed directly into the plant's state. Using this mechanism, arbitrary closed-loop pole assignment can be achieved so long as the plant is completely observable. In the event that output injection feedback is not possible, a dual-observer-based compensator can be used to realize the pole-positioning effect of output injection. In this paper, we consider discrete-time systems and derive the equivalent dual-observer-based compensator, herein termed a single-rate input compensator. Further, we explore the concept of multirate input sampling and show that a multirate input compensator (employing multirate sampling of the plant input) of dimension much smaller than that of the single-rate input compensator (employing single-rate input sampling of the plant input) can be designed. Necessary and sufficient conditions for the existence of both types of compensators are found. Design procedures for constructing these compensators are also outlined.

ISSN:0020-7179    

DOI:10.1080/00207179308922996

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor