摘要:

A predictive form of generator excitation control is proposed which has the potential of providing consistent and significantly improved performance characteristics over those of conventional schemes. The basic principle of the proposed form of control is presented. The performance capabilities are demonstrated via simulation studies on a test system and compared with those of a conventional automatic voltage regulator (AVR).

ISSN:0020-7179    

DOI:10.1080/00207179508921940

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper considers the problem of estimating the signal waveforms from the noisy data obtained with an array of receiving sensors. The maximum likelihood (ML) waveform estimate, derived under the assumption that the signals are deterministic, is compared with the minimum mean-square-error linear (MMSEL) estimate, derived under the assumption of stochastic signals. When the signals are assumed to be random, the MMSEL estimate has, by construction, a smaller MSE than the ML estimate. A ridge-type extension of the MMSEL estimate is shown to still possess smaller MSE than the ML estimate, under a reasonable condition, even if the signals are assumed to be deterministic. A numerical study provides more quantitative insights into the performance of several waveform estimators, including those mentioned above.

ISSN:0020-7179    

DOI:10.1080/00207179508921941

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Repetitive, or multipass, processes are a class of two-dimensional (2D) systems characterized by a recursive action over a finite fixed duration—the pass length. On each sweep, or pass, through the dynamics an output—the pass profile—is produced which acts as a forcing function on, and hence contributes to, the next pass profile. The basic unique control problem is that the output sequence can contain oscillations which increase in amplitude from pass to pass. Differential processes are a sub-class which have well defined structural links with standard linear systems. Previous work has used these links to develop computationally feasible stability tests which can be implemented using only standard linear systems tests. This paper reports the first significant results on the theoretical basis of output feedback based control schemes. The major result is a return difference theory for these schemes.

ISSN:0020-7179    

DOI:10.1080/00207179508921942

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

The generalizedH2optimal control problem for a linear time-invariant system is one in which the conventionalH2norm is replaced by an operator norm. The closed-loop system is described in terms of a mapping between the space of time-domain input disturbances inL2and the space of time-domain regulated outputs inL∞. A minimum of this norm is then sought over all stabilizing controllers. It is shown that optimal controllers for such problems have the structure of a Kalman filter with estimated state feedback, where the feedback gains are obtained from the solution to a weighted LQR problem. A computational algorithm is presented to determine the weights in this LQR problem, and examples are given which demonstrate various problems which may arise in obtaining the optimal weights. In particular, it is shown that the generalizedH2problem may involve the solution to a singular LQR problem.

ISSN:0020-7179    

DOI:10.1080/00207179508921943

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper presents results concerning the identification of a class of nonlinear systems. The main result of the paper gives the approximation power of a parametrized linearization family constructed from a given nonlinear system. The identification procedure derived from this approximation theory consists of constructing a parametrized linearization family from a set of input-output measurements of a given nonlinear system along a given trajectory. This paper utilizes related work on control-oriented system identification. Simulation results are included to support the theoretical development.

ISSN:0020-7179    

DOI:10.1080/00207179508921944

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper, we present a knowledge-based approach to dead-time estimation suitable for process control systems. The approach is based on the use of relay feedback, and a self-contained module for dead-time estimation is developed which is based on suitable heuristics derived and analysed in the paper. Knowledge-based techniques are adopted and this development forms a module of a larger project for development of an intelligent process control system. The paper also includes the results of real-time experiments to estimate the dead-time of a pilot scale coupled-tanks system.

ISSN:0020-7179    

DOI:10.1080/00207179508921945

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A recursive algorithm which maps a general class of nonlinear rational model, defined as the ratio of two polynomial functions, into the frequency domain is derived using the harmonic expansion method. The new algorithm provides, for the first time, a direct analytic map from the time domain rational model parameters to the higher-order frequency response functions. Complex nonlinear time domain behaviours can be analysed and interpreted in the frequency domain, and simulated examples are included to illustrate the concepts involved.

ISSN:0020-7179    

DOI:10.1080/00207179508921946

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper presents robustness properties of the Kalman filter and the associated LQG/LTR method for linear time-invariant systems having delays in both the state and the output. A circle condition relating to the return difference matrix associated with the Kalman filter is derived. Using this circle condition, it is shown that the Kalman filter guarantees (1/2, ∞) gain margin and ±60°phase margin, which are the same as those for non-delay systems. However, it is shown that, even for minimum phase plants, the LQG/LTR method cannot recover the target loop transfer function. Instead, an upper bound on the recovery error is obtained by using an upper bound of the solution of the Kalman filter Riccati equations. Finally, some dual properties between output-delayed systems and input-delayed systems are exploited.

ISSN:0020-7179    

DOI:10.1080/00207179508921947

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper describes an effective algorithm for solving ill-conditioned Sylvester or Lyapunov equations. These equations can be solved by conventional methods for ill-conditioned linear systems. However, such methods are not efficient since they require on the order ofn6arithmetic operations on ordern2data. For these ill-conditioned matrix equations, an implicit deflation algorithm is proposed to implement a certain SVD-based minimum norm least-squares approximate solution. The method is practical since it relies only on the ability to solve a Sylvester or Lyapunov equation. Certain practical details are also discussed.

ISSN:0020-7179    

DOI:10.1080/00207179508921948

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper, we propose a simplified linearization technique for control of hybrid step motors that is based on a tracking approach. Our controller consists of a current tracking controller and a torque controller. In particular, our torque controller contains a function which can be chosen freely under some constraints imposed by the physical limitation in stator currents. Any controller that can make the generated torque of a hybrid step motor linear to the torque command can always be represented by our torque controller with a specific choice of the free function. As an example for optimal choices of the free function, we present a method of determining the free function that gives minimal power loss due to stator resistance. We also present a method of obtaining the full dynamic model of a hybrid step motor. Prior works consider the special cases when the torque component due to variable reluctance is negligible or sinusoidal. Our results in this paper can be applied equally well to these special cases.

ISSN:0020-7179    

DOI:10.1080/00207179508921949

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor