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Control Theory and Applications, IEE Proceedings -

Issue 3 • Date May 1996

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Displaying Results 1 - 13 of 13
  • Optimal entire eigenstructure assignment of discrete-time linear systems

    Publication Year: 1996 , Page(s): 301 - 304
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    An improved method which assigns the closed-loop eigenvalues of a discrete-time linear system in desired preselected stable locations and which simultaneously selects those eigenvectors which satisfy a quadratic cost criterion with suitable weighting matrices is presented. The optimal feedback gain-matrix is determined without solving the algebraic matrix Riccati equation. The proposed explicit solution of the Riccati equation is feasible for both real and complex closed-loop stable eigenvalues View full abstract»

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  • Control of rigid robot manipulators via combination of adaptive sliding mode control and compensated inverse dynamics approach

    Publication Year: 1996 , Page(s): 283 - 288
    Cited by:  Papers (7)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (380 KB)  

    A new output tracking control method for rigid robot manipulators is developed via the combination of adaptive sliding mode control and the compensated inverse dynamics approach. The innovative compensated inverse dynamics approach is applied to rigid robot systems and no estimation of the inertia matrix, which avoids the inverse problem of the time-varying inertia matrix, is involved. The adaptive sliding mode control scheme is used to take into account the unknown but bounded parameter uncertainties and external disturbances. The performance of the proposed control method is demonstrated by simulation View full abstract»

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  • Theory of state covariance assignment for linear single-input systems

    Publication Year: 1996 , Page(s): 289 - 295
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    An alternative method for state covariance assignment for a general class of linear single-input systems is proposed. New formulas for both discrete and continuous systems are presented based on the inverse solutions of Lyapunov equations. These formulas are similar to the equations for pole placement. The set of all assignable covariance matrices to a single-input system is also characterised. Techniques for constructing these matrices are also described View full abstract»

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  • New sufficient condition for robust root clustering of linear state space models with structured uncertainty

    Publication Year: 1996 , Page(s): 244 - 246
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (300 KB)  

    A new sufficient condition is proposed for robust root clustering in an arbitrary subregion of the complex plane for both linear continuous time and linear discrete time uncertain systems. The systems are described by state space models with structured parameter uncertainty. Explicit bounds on uncertain parameters are derived to guarantee root clustering inside any specified region which may be demanded by stability and performance robustness. Illustrative examples show that the results of the proposed method can be much less conservative compared with the results of existing methods View full abstract»

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  • Neuro-adaptive hybrid controller for robot-manipulator tracking control

    Publication Year: 1996 , Page(s): 270 - 275
    Cited by:  Papers (15)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    The paper is concerned with the design of a hybrid controller structure, consisting of the adaptive control law and a neural-network-based learning scheme for adaptation of time-varying controller parameters. The target error vector for weight adaptation of the neural networks is derived using the Lyapunov-function approach. The global stability of the closed-loop feedback system is guaranteed, provided the structure of the robot-manipulator dynamics model is exact. Generalisation of the controller over the desired trajectory space has been established using an online weight-learning scheme. Model learning, using a priori knowledge of a robot arm model, has been shown to improve tracking accuracy. The proposed control scheme has been implemented using both MLN and RBF networks. Faster convergence, better generalisation and superior tracking accuracy have been achieved in the case of the RBF network View full abstract»

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  • Stability of zeros of sampled system with fractional order hold

    Publication Year: 1996 , Page(s): 296 - 300
    Cited by:  Papers (19)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    The paper deals with the stability of zeros of sampled-systems that are composed of a fractional-order hold, a continuous-time plant and a sampler in cascade. The stability conditions of the limiting zeros for sufficiently small or large sampling periods are derived. It is also shown that one can determine the range of the sampling period for stable zeros of the sampled system by calculating an analytical form of a criterion under a lowpass assumption on a continuous plant View full abstract»

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  • Use of multilayer feedforward neural networks in identification and control of Wiener model

    Publication Year: 1996 , Page(s): 255 - 258
    Cited by:  Papers (12)  |  Patents (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (368 KB)  

    The problem of identification and control of a Wiener model is studied. The proposed identification model uses a hybrid model consisting of a linear autoregressive moving average model in cascade with a multilayer feedforward neural network. A two-step procedure is proposed to estimate the linear and nonlinear parts separately. Control of the Wiener model can be achieved by inserting the inverse of the static nonlinearity in the appropriate loop locations. Simulation results illustrate the performance of the proposed method View full abstract»

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  • Fuzzy neural networks and application to the FBC process

    Publication Year: 1996 , Page(s): 259 - 269
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (900 KB)  

    Implementation of fuzzy systems using multilayer perceptron artificial neural networks is considered, and detailed equations for training the network are derived. Models for the fluidised bed nitrogen emissions are created using linear regression, multilayer perceptron neural networks, and fuzzy neural networks to illustrate and compare the behaviour of the algorithms View full abstract»

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  • Satellite attitude control via sliding mode with perturbation estimation

    Publication Year: 1996 , Page(s): 276 - 282
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (600 KB)  

    The conventional sliding-mode control (SMC) technique requires that the perturbation upper bounds are known a priori to achieve a robust control process. This requirement creates some difficulties, at the least causing the controller to be over-conservative. A recently introduced sliding mode control with perturbation estimation (SMCPE) philosophy removes this condition and replaces it with a continuous perturbation estimation process. It is shown that, for precise state measurements and high-speed control-loop closures, SMCPE manifests much smaller tracking errors than those of SMC. So far nonlinear systems in canonical form have been studied, and in the present paper the domain of application of SMCPE is extended to a more general class. For this extension, an I/O linearisation technique is utilised first, and then the SMCPE steps are followed for an output tracking control. Simulation results prove the strength of the technique for a satellite attitude control problem View full abstract»

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  • Model reduction with time delay combining the least-squares method with the genetic algorithm

    Publication Year: 1996 , Page(s): 247 - 254
    Cited by:  Papers (11)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    The paper proposes a novel method of model reduction with time delay for single-input, single-output systems combining the linear least-squares (LS) method with the genetic algorithm (GA). The denominator parameters and time delay of the reduced-order model are coded into binary bit strings and searched by the GA, while the numerator parameters are calculated by the LS method for each of candidates of the denominator parameters and time delay. Thus, all the best parameters and time delay of the reduced-order model can be obtained by repeating genetic operations of strings. The performance of the proposed method is shown by two numerical examples View full abstract»

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  • Parameterisation of observers for time delay systems and its application in observer design

    Publication Year: 1996 , Page(s): 225 - 232
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    The paper addresses the design of observers for systems with time delay. A factorisation approach is used to parameterise all observers for such systems. The necessary and sufficient condition of existence for observers is obtained. Based on the results in the parameterisation of observers, the estimation error dynamics is also parametrised. A design example is given to illustrate the proposed parameterisation procedure View full abstract»

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  • H2 robust digital vector control for the induction machine

    Publication Year: 1996 , Page(s): 237 - 243
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (500 KB)  

    Using a discrete time-variant state-space model for the induction machine, the authors consider the plant variations as being uncertainties represented by polytopes. In addition, an alternative scheme of vector control is proposed for digital control of the induction machine. This scheme involves treatment of the machine equations in state space and the acquisition of a robust state-feedback gain by an H2 convex optimisation method View full abstract»

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  • Robust stability for perturbed large-scale time-delay systems

    Publication Year: 1996 , Page(s): 233 - 236
    Cited by:  Papers (8)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    A robust stability criterion for perturbed large-scale time-delay systems with delay dependence is presented. The properties of a matrix measure and a comparison theorem are used in the formulation. The robust stability criterion obtained eliminates the need to solve the complex Lyapunov equation and can be used to estimate the size of the delay time for which stability is guaranteed. An example is given to illustrate the proposed method View full abstract»

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