摘要:

Concerns the on-line evaluation of an auto-tuning optimal PID automatic voltage regulator for a synchronous generator. The design of the regulator is performed directly on a non-linear laboratory model turbogenerator, using optimization techniques, and the control strategy combines automatic voltage regulation with the functions of a power system stabilizer. The PID and stabilizing signal parameters are optimized on-line in real time, using a search procedure, with linear quadratic performance index, and only impulse responses of the system are required. Appropriate hardward and software systems have been developed, and the regulator has been extensively tested on a micromachine. Results obtained for long-term operation show that the controller can provide good performance during varying operating conditions, with a wide range of disturbances. The results have been compared with those obtained under the same operating conditions using a conventional automatic voltage regulator and stabilizer.

ISSN:0020-7179    

DOI:10.1080/00207179108953647

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The relationship is explored between the SISO open-loop and closed-loop system structures associated with the use of stable minimum-phase controllers in the face of unrestricted plant uncertainty. All types of plant structure and uncertainty, including arbitrary numbers of right half-plane poles and zeros, are considered in a progressive manner within a Nyquist-Bode framework. In the face of increasingly severe types of plant uncertainty, it is shown why meeting closed-loop system performance objectives becomes increasingly difficult for such plants; there remains, however, a strict relationship between open-loop and closed-loop system structures.

ISSN:0020-7179    

DOI:10.1080/00207179108953648

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A theory of static state feedback for multivariable continuous-time non-linear systems is formulated. The theory applies to systems described by differential equations of the formẋ(t) = ƒ(x(t)u(t)). The basic objective is to design static feedback compensators which achieve the following properties: (a) the state-space trajectory of the closed-loop system is confined within a specified subspace, and (b) the closed-loop system is internally stable. An explicit method for designing such compensators is developed. The construction of the compensators involves only quantities directly derived from the given functionƒ.

ISSN:0020-7179    

DOI:10.1080/00207179108953649

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A discrete optimal control problem can always be treated as a conventional mathematical program but the dimension of the latter depens onN, the number of stages, and can, therefore, be forbiddingly high. In this paper we exploit the structure of the optimal control problem and present a version of a conventional sequential quadratic programming algorithm which merely requires, at each iteration, the solution ofNquadratic sub-problems of dimensionm(equal to that of the control) rather than the solution of one quadratic sub-problem of dimensionNmas required by the mathematical programming formulation.

ISSN:0020-7179    

DOI:10.1080/00207179108953650

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Some recent results on guardian maps and their application to generalized robust stability are reviewed and a characterization of the maximum stability range is obtained. This framework is then applied to the analysis of robust stability in several physically motivated examples.

ISSN:0020-7179    

DOI:10.1080/00207179108953651

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A technique is presented for analysing linear and bilinear discrete systems in terms of Walsh functions. The method replaces the solution of a dynamical difference equation with the solution of an algebraic equation. In the special case of a linear system, a numerically stable recursive technique is derived to solve this algebraic equation. The technique is illustrated with an example.

ISSN:0020-7179    

DOI:10.1080/00207179108953652

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The problem of the existence and structure of minimum-time control for multiple robot arms cooperatively handling a common object is addressed. The dynamical system is modeled by considering the arms as closed kinematic chains. The conditions of the existence of the time-optimal solution are verified by applying a Lyapunov approach and the concept of the feedback equivalence to linear systems. Furthermore, it is shown that the structure of the minimum-time control law for individual joint actuators requires that at least one of the actuators is always saturated on any finite time subinterval, while the rest of them are either saturated or singular, depending upon the motion configurations and robot parameters. Thus, it is suggested that totally-singular optimal control does not exist in this problem, but that partially-singular control may occur. This theoretical result should be able to provide insight into the dynamic characteristics of the multiple robot system, which can be valuable in the path planning and design specifications of the system.

ISSN:0020-7179    

DOI:10.1080/00207179108953653

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

A relationship between the higher-order frequency response functions of the Volterra series model and the well-known describing function representation for non-linear systems is derived. It is shown that a large class of generalized describing functions can be derived from the Volterra model and that this approach removes the restriction to specific inputs. The concept of a worst case transfer function is introduced, and examples are included to illustrate the results.

ISSN:0020-7179    

DOI:10.1080/00207179108953654

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The design of an optimal pumpage or recharge strategy for contaminated groundwater remediation is considered. The formulation of the control problem combines a two-dimensional Galerkin finite element simulation model of steady state groundwater flow and transient convective-dispersive transport with non-linearly constrained optimization algorithms. The ‘discrete gradients’ of the constraints are computed by the ‘discrete adjoint state method’ or by the solution of ‘discrete sensitivity equations’, according to the number of control parameters compared to the number of gradients to be computed. This technique is shown to be very efficient when used in conjunction with the ‘constrained variable metric method’ of Han, modified by Schittkowsky. Numerical experiments indicate that problems with up to fifty injection or extraction wells may be solved in a computer time equivalent to one or two hundred simulations of the state equations.

ISSN:0020-7179    

DOI:10.1080/00207179108953655

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

In this paper we consider several problems related to the robust stability of polynomials whose coefficients depend on real parameters. We first show that if these parameters appear linearly in the coefficients, the computation of the largest stability hypercube with a fixed centre does not require a frequency ‘sweep’. Its size can be determined by considering a finite set of frequencies. We also demonstrate that for some polynomials where the coefficients themselves are polynomials in the parameters, the determination of stability can be made in a manner that involves a single frequency sweep and where at each frequency a finite number of simple tests are carried out. The methods are based on the Nyquist theorem and ‘value set’ ideas, and the approach provides analytical solutions.

ISSN:0020-7179    

DOI:10.1080/00207179108953656

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor