Notification:
We are currently experiencing intermittent issues impacting performance. We apologize for the inconvenience.
By Topic

Control Theory and Applications, IEE Proceedings -

Issue 1 • Date Jan 2000

Filter Results

Displaying Results 1 - 15 of 15
  • Root distribution of delta-operator formulated polynomials

    Publication Year: 2000 , Page(s): 1 - 12
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (428 KB)  

    Owing to its superior performance in high-speed signal processing/control, work on delta-operator based discrete time system implementations have attracted considerable attention. Stability and performance of such a system is closely related to the root distribution of its characteristic equation with respect to a certain `shifted' circle in the complex plane; the underlying sampling time determines its centre and radius. An algorithm that checks root distribution of a given polynomial with respect to this stability boundary is proposed. It is based on a scaled version of the well known Marden-Jury table that determines root distribution with respect to the unit circle in the complex plane; this is the stability boundary corresponding to discrete time systems that are implemented using the more conventional shift operator. The Marden-Jury table offers several additional advantages that are not all present in other available algorithms applicable to shift operator based polynomials. The proposed algorithm possesses all these properties, and the scaling scheme used ensures improved numerical accuracy and the existence of a limiting form View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the internal dynamics of flexible manipulators based on symmetric dichotomy

    Publication Year: 2000 , Page(s): 59 - 70
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    The symmetric acausal/causal dichotomy for the linearised stable internal dynamics of a class of flexible manipulators is studied. Computational issues, including the convergence of the iterative computation scheme and the symmetry computation of the desired internal dynamic trajectory, are addressed and the implication of the noncausal invertibility on tip trajectory planning is investigated. To explore the potential advantages offered by the inversion-based trajectory tracking control, it is highly desirable to have an internal dynamic model in an acausal/causal decoupled form. Also, this acausal/causal dichotomy should be explicit to provide a clear insight into the internal dynamics. This should also be useful for efficient computation and be able to guide tip trajectory planning. The symmetric dichotomy based internal dynamic model is developed to achieve these desirable characteristics. Case studies are carried out to illustrate the validity of the symmetric dichotomy based model for the internal dynamics View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Parameter identification of continuous systems with multiple-input time delays via modulating functions

    Publication Year: 2000 , Page(s): 19 - 27
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    The identification of continuous systems with multiple-input delays is discussed. A batch algorithm for parametric identification of both multiple time delays and unknown parameters is proposed using the modulating function approach. If the unknown delay is expressed as a linear combination of a bank of known delays, it is proven that the distribution of the identified coefficients is a sampling centred on the unknown delays; the result is then extended to the multiple delay case. The modulating function method guarantees a continuous-time approach and robustness for a high value of noise-to-signal ratio. Simulation results are included to illustrate the proposed technique View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Bandwidth allocation scheme in CAN protocol

    Publication Year: 2000 , Page(s): 37 - 44
    Cited by:  Papers (14)  |  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    The CAN (controller area network) is a serial communication protocol for distributed real-time control and automation systems. Data generated from field devices in manufacturing automation and process control systems are classified into three categories: real-time event data, real-time control data and non-real-time data. These data share a common CAN medium. Unless the traffic of the CAN protocol is efficiently controlled performance of the real-time application systems interconnected into the CAN bus can be degraded. The paper proposes a bandwidth allocation algorithm that can be applicable to the CAN protocol. The bandwidth allocation algorithm not only satisfies the performance requirement of real-time application systems interconnected into the CAN but also fully utilises the bandwidth of the CAN. The bandwidth allocation algorithm introduced in the paper is validated using a simulation experiment View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Discretisation of two degree-of-freedom controller and system with state, input and output delays

    Publication Year: 2000 , Page(s): 87 - 96
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    An interpolation method for discretisation of a two degree-of-freedom analogue controller and system with state, input and output delays is presented. A Newton centre interpolation formula is used for discretisation of a continuous-time system with state, input and output delays. Also, a Newton backward extrapolation formula and Chebyshev quadrature formula are employed to carry out output-feedback digital redesign of a two degree-of-freedom controller for the delayed analogue system. The developed digital redesign method is then extended to perform discretisation of a Smith predictor for an input-delayed analogue system. The newly developed output-feedback state-matching digital redesign method provides an alternative methodology for indirect digital design of a continuous-time system with state, input and output delays View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Robust predictive control using tight sets of predicted states

    Publication Year: 2000 , Page(s): 13 - 18
    Cited by:  Papers (12)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    A predictive controller for constrained linear time-varying systems with polytopic uncertainty is presented. The algorithm minimises an upper bound on the predicted quadratic cost function with respect to the first few future control moves and a feedback gain that completes the description of the predicted input trajectory. The optimisation problem is shown to be a convex problem which can be formulated as a linear-matrix-inequality (LMI) problem. Constraints are handled by posing necessary and sufficient conditions on the first few future control moves and a sufficient condition on the moves thereafter; these conditions are formulated in terms of additional LMIs. The algorithm is shown to be asymptotically stable. An example illustrates the efficiency of the method View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Gain fusion algorithm for decentralised parallel Kalman filters

    Publication Year: 2000 , Page(s): 97 - 103
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (260 KB)  

    A new gain fusion algorithm is proposed for application to decentralised sensor systems. The proposed algorithm gives computer-efficient suboptimal estimation results, such that it reconstructs the global estimate and covariance from local Kalman filter gains and estimates without significant loss of accuracy. Compared to the conventional algorithm, the smaller communication requirement and the removal of the calculation requirement of inverse covariances make the proposed algorithm more suitable for real time applications. A numerical example shows that the proposed algorithm provides a convincing suboptimal decentralised algorithm. In addition, the proposed gain fusion algorithm can be easily extended to accommodate local Kalman filters with reduced order View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Stochastic stability of the continuous-time extended Kalman filter

    Publication Year: 2000 , Page(s): 45 - 52
    Cited by:  Papers (18)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    The error behaviour of the extended Kalman filter is analysed. It is proved that the estimation error remains bounded if the system satisfies a detectability condition and both the initial estimation error and the disturbing noise terms are small enough. Moreover, some selected cases with both bounded and unbounded estimation error are demonstrated by numerical simulations View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • LQG and GA solutions for active steering of railway vehicles

    Publication Year: 2000 , Page(s): 111 - 117
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (276 KB)  

    The paper presents control strategies for the active steering of solid axle railway vehicles using the linear quadratic Gaussian (LQG) method. The paper investigates the benefits of actively controlling and steering the wheelsets of a railway vehicle and studies what could be achieved when modern control techniques are used on the vehicles via mechatronic components. An optimal H2 controller is developed for the active steering and is fine-tuned using genetic algorithms. A Kalman filter is developed to provide the full state feedback required by the optimal control. The Kalman filter is formulated in such a way that it not only estimates all the vehicle states, but also calculates parameters such as curve radius and cant of the railway track on which the vehicle is travelling. Computer simulations are used in the study to assess the system performance with the control scheme proposed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Global stabilisation of input-saturated systems subject to L2 disturbances

    Publication Year: 2000 , Page(s): 53 - 58
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    Globally stable control of linear systems with input saturation subject to L2 disturbances is analysed. The well known results on disturbance-free systems are that nonlinear controls can ensure global stability, while linear time-invariant controls can only achieve semiglobal stabilisation. A linear control with a tuning parameter is proposed to achieve global stability of the systems even when they are subject to arbitrary L2 disturbances. The parameter is automatically tuned using a switch rule based on state measurement. The advantage over the existing algorithms is that no online solution of algebraic Riccati equations is needed. Control design of an armature-controlled DC servomotor is used to demonstrate the proposed algorithm, and simulation results are shown View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optimal position control of synchronous reluctance motor via totally invariant variable structure control

    Publication Year: 2000 , Page(s): 28 - 36
    Cited by:  Papers (11)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (396 KB)  

    An optimal control method is presented. The proposed controller is designed via combining classical state feedback control and variable structure control (VSC). This method fully matches the merits of the easy design of the linear quadratic (LQ) method and the strong robustness of the VSC. The presented optimal control method is demonstrated on a synchronous reluctance motor (SynRM). It is proved that the synchronous reluctance motor can be used in position control by the proposed method and the designed performance can be easily obtained regardless of the disturbance and uncertainty. A prototype PC-based SynRM control system is built to verify the validity of the proposed scheme View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Assignment of reduced sensitivity eigenstructure

    Publication Year: 2000 , Page(s): 104 - 110
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (300 KB)  

    The presented technique addresses the problem of maintaining the powerful design simplicity and visibility of eigenstructure assignment, while reducing closed-loop eigenstructure sensitivity to dominant parameter variations. The method results from consideration of the allowable eigenvector subspace as a complete description of the eigenstructure assignment problem. Variations in open-loop system dynamics can thus be visualised as movements of the closed-loop allowable subspace. If a nonlinear model is linearised about two operating points with intersecting subspaces, assignment from the intersection will yield the same closed-loop eigenstructure at both operating points. This hypothesis is proven, and the analysis extended to include the case of non-intersecting subspaces. This reduced subspace design method has been tested on an eighth-order helicopter model that exhibits significant nonlinearity when forward speed is varied. The results demonstrate a considerable reduction in variation of the closed-loop eigenstructure over conventional techniques View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Robust control for nonlinear similar composite systems with uncertain parameters

    Publication Year: 2000 , Page(s): 80 - 86
    Cited by:  Papers (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    Describes the similarity between two nonlinear control systems, shown in a large number of physical systems of interest in many engineering applications. By utilising similar information, robust controllers for large-scale nonlinear similar composite systems with uncertain parameters are proposed. The results obtained show that the similar structure of composite systems possesses a holographic property and can simplify the analysis and design of nonlinear systems View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Robust compensator design for exploiting existing control systems

    Publication Year: 2000 , Page(s): 71 - 79
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    Simple design methods are proposed for attaching compensators to improve the robustness of previously designed control systems in use. Robust model matching (RMM) is a practical approach to designing robust compensators. First, RMM is generalised and its standard design procedure is presented. Then, by considering the configuration of RMM, design methods for attachable robust compensators are suggested. The performance of the proposed method is then examined with laboratory experiments View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Survey of adaptive dual control methods

    Publication Year: 2000 , Page(s): 118 - 128
    Cited by:  Papers (19)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (492 KB)  

    A survey of adaptive dual control methods, elaborated from the early 1960s until the present, is given. The development of dual control methods is considered in chronological order, taking into account its close interconnection with general progress in adaptive control theory and applications. Detailed classifications of stochastic adaptive control methods and dual control methods are presented. The properties of a neutral control system and the nature of the dual effect in adaptive control systems are described. The historical stages of the development of the theory and applications of dual control are reviewed View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.