摘要:

Artificial potential fields and artificial force fields are widely used in robotics for path planning and collision avoidance, both for robot manipulators and for mobile robots. Despite intensive research in designing suitable artificial potential fields, little attention has been devoted to tracking control for following the gradient of an artificial potential field. However, good tracking control is vital for successful application of the artificial potential field method in order to guarantee safe operation of the robot. In this paper, we extend previous results on a sliding mode control strategy to include actuator dynamics and non-holonomic motion constraints of mobile robots into the gradient tracking control algorithm.

ISSN:0020-7179    

DOI:10.1080/00207179608921850

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper describes a study related to the testing and validation of a neural-network based approach for the problem of actuator failure detection and identification following battle damage to an aircraft control surface. Online learning neural architectures, trained with the Extended Back-Propagation algorithm, have been tested under nonlinear conditions in the presence of sensor noise. In addition, a parametric study has been conducted that addresses the selection of ‘near optimal’ neural architectures for online state estimation purposes. The Failure Detect-ability/False Alarm Rate ratio problem has also been considered in this study. The testing of the approach is illustrated through typical highly nonlinear dynamic simulations of a high performance aircraft.

ISSN:0020-7179    

DOI:10.1080/00207179608921851

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A large class of discrete linear repetitive processes, termed discrete non-unit memory, can be interpreted as two-dimensional systems with the state-space model structure developed by Roesser. This paper shows that the criteria for stability along the pass of these repetitive processes is equivalent to BIBO stability for two-dimensional systems described by the Roesser model. The interplay of ideas between these two disciplines should greatly assist in the development of a coherent feedback control and systems theory for repetitive processes. Here, this new result is used to develop Lyapunov equations for discrete linear repetitive processes, which then yield new insight into their fundamental dynamic behaviour.

ISSN:0020-7179    

DOI:10.1080/00207179608921852

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Chaotic systems are characterized by the local divergence of nearby orbits in state-space. This provokes a sensitive dependence on initial conditions and, in turn, drastically limits the accuracy of long-term predictions. This has important implications in the filtering of data generated by such systems. In the present paper, the use of global smoothers for chaotic data is investigated. The ultimate objective is to be able to identify dynamically valid models from smoothed data when the identification from the original noisy data has completely failed. The objective is to produce identified models that faithfully reproduce the dynamical invariants of the original system, such as the geometry of the attractors in state-space, the largest Lyapunov exponent, fractal dimensions and Poincaré sections. Numerical examples are included, which illustrate the main points of the paper.

ISSN:0020-7179    

DOI:10.1080/00207179608921853

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A particular form of the YJBK parametrization is used to address the generalizedH∞control problem. It consists of using, as an intermediate stabilizing controller, the solution of an underlying generalized LQG control problem. This provides a direct link between the two solutions. In fact, when the YJBK free parameter falls to zero the two controllers become identical.

ISSN:0020-7179    

DOI:10.1080/00207179608921854

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A solution is presented to the H∞optimal deconvolution filtering, smoothing and prediction problems for multivariable, discrete, linear signal processing problems. A weighted H∞cost-function is minimized where the dynamic weighting function can be chosen for robustness improvement. The signal and noise sources can be correlated and signal channel dynamics can be included in the system model. A brief example is presented to demonstrate the approach.

ISSN:0020-7179    

DOI:10.1080/00207179608921855

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In the design of feedback control systems for linear multivariable plants, insisting on the elimination of coupling in closed-loop is often achieved at the expense of an increase in the multiplicity of infinite and non-minimum phase zeros beyond those of the plant plant. This behaviour is known as the ‘cost of decoupling’ since these additional zeros are manifested in the time domain by increased rise times and undershoots in step responses. Using partially decoupling controllers, however, it is always possible to obtain closed-loop systems with precisely the same number of infinite and non-minimum phase zeros as the plant, albeit at the expense of a restricted form of transient coupling. This paper uses a generalization of the interactor matrix to generate a class of partially decoupling controllers for square, stable plants in which diagonal decoupling arises as a special case, thereby permitting the designer to trade off speed of response versus the severity of transient interaction.

ISSN:0020-7179    

DOI:10.1080/00207179608921856

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Stochastic linear systems subject to time-varying parameter uncertainties affecting both system dynamics and noise statistics are considered. A linear filter is used to estimate a linear combination of the states of the system. When the filter is given, the stabilizing solution of a suitable Riccati equation is shown to yield an upper bound for the covariance of the estimator error. The main problem addressed in the paper is the design of an ‘optimal robust filter’ that minimizes such a covariance bound. Necessary conditions are given for the existence of an optimal reduced-order robust filter as well as necessary and sufficient conditions for the full-order case. The computation of the optimal filter calls for the solution of a Riccati equation that generalizes the standard Riccati equation for the Kalman filtering problem. A numerical example is provided in which the new filter is compared with both the Kalman andH∞-filters.

ISSN:0020-7179    

DOI:10.1080/00207179608921857

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper we show that many problems of multivariable stability margin optimization can be reduced to a spectral tangential interpolation problem of Nevanlinna-Pick type, where the interpolating transfer matrices are bounded not in infinity norm but in spectral radius. This equivalence is established via conformal mappings. Necessary and sufficient conditions for the existence of solutions to the spectral interpolation problem are given in terms of the positivity of an associated Nevanlinna-Pick matrix. We conclude by applying this approach to solve a multivariable gain margin problem.

ISSN:0020-7179    

DOI:10.1080/00207179608921858

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Decentralized stabilization and control schemes for large-scale power systems are presented in this paper. The interconnections between the subsystems are assumed to be unknown, but bounded. The control design for the first scheme utilizes the knowledge of the bounds on the interconnections between the subsystems, whereas this information is not required in the second control design due to its adaptive nature. These schemes are applied to a power system with two generators and an infinite bus connected through a network of transformers and transmission lines. Simulation studies for unknown interconnections arising due to faults and subsequent line switchings in the transmission network are carried out. The studies not only illustrate the simplicity of the developed controls, but also validate the fact that connective stability and robust performance is maintained for unknown interconnection topology using these schemes.

ISSN:0020-7179    

DOI:10.1080/00207179608921859

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor