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Control Theory and Applications, IEE Proceedings -

Issue 6 • Date Nov. 2006

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Displaying Results 1 - 15 of 15
  • Development and experimental evaluation of a fixed-gain nonlinear control for a low-cost pneumatic actuator

    Publication Year: 2006 , Page(s): 629 - 640
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (571 KB)  

    A practical, easy-to-implement and accurate fixed-gain nonlinear position controller for a typical low-cost industrial pneumatic actuator is developed and evaluated experimentally. The positioning system comprises an inexpensive 5-port three-way proportional control valve with flow deadband, and a double-rod actuator exhibiting significant dry friction. Quantitative feedback theory is used first to systematically design a robust proportional-integral (PI) control law that minimises variations in the dynamic response of the actuator over a wide range of operating conditions and in the presence of uncertainty in the system parameters. Nonlinear modifications, which condition the integral part of the designed PI control law, are then implemented in a step-by-step fashion to further improve closed-loop performance by reducing overshoot and negating the effects of the control valve deadband and actuator friction. Experimental results clearly illustrating the effectiveness of the positioning system for a number of tracking and regulating tasks are presented View full abstract»

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  • Robust stabilisation and passivity of nonlinear systems with structural uncertainty

    Publication Year: 2006 , Page(s): 641 - 646
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (211 KB)  

    Robust stabilisation and passivity of general nonlinear systems with structural uncertainty is considered. On the basis of the theory of passive systems, it is verified that under some conditions passivity implies zero-state detectability and that passivity can result in robust stabilisation of the general nonlinear system with structural uncertainty. A smooth-state feedback law is constructed with the solution of an equation. The effectiveness of the proposed technique will be tested via simulations View full abstract»

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  • Adaptive fuzzy CMAC control for a class of nonlinear systems with smooth compensation

    Publication Year: 2006 , Page(s): 647 - 657
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    Adaptive fuzzy cerebellar model articulation controller (CMAC) schemes are proposed to solve the tracking problem for a class of nonlinear systems. The proposed method provides a simple control architecture that merges CMAC and fuzzy logic, so that the complicated structure and the input space dimension in CMAC can be simplified. Adaptive laws are developed to tune all of the control gains online, thereby accommodating the uncertainty of nonlinear systems without any learning phase. In particular, smooth compensation is adopted to overcome the chattering problem associated with conventional switching compensation. By Lyapunov stability analysis, it is guaranteed that all of the closed-loop signals are bounded and the tracking errors converge exponentially to a residual set whose size can be adjusted by changing the design parameters. Simulation results for its applications to three examples are presented to demonstrate the performance of the proposed methodology View full abstract»

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  • Guaranteed cost control of linear systems over networks with state and input quantisations

    Publication Year: 2006 , Page(s): 658 - 664
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (151 KB)  

    The guaranteed cost control design for linear systems connected over a common digital communication network is addressed. A new model is proposed that takes into consideration the effect of both the quantisation levels and the network conditions. A control design criterion is derived on the basis of the Lyapunov functional method and the idea of the cone complementary linearisation algorithm. A numerical example is given to show the application of the method proposed View full abstract»

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  • Less conservative D-stability test for polytopic systems using linearly parameter-dependent lyapunov functions

    Publication Year: 2006 , Page(s): 665 - 670
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (123 KB)  

    The robust Dscr-stability of linear systems with polytopic uncertainty is studied. It provides a new stability test that is less conservative than the existing ones based on linearly parameter-dependent Lyapunov functions. The present criterion is in terms of linear matrix inequalities formulated by the vertices of the matrix polytope. Numerical examples are given to show the less conservativeness of the result View full abstract»

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  • PI auto-tuning during a single transient

    Publication Year: 2006 , Page(s): 671 - 683
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (543 KB)  

    A certain adaptive PI tuner operates by injecting variable-frequency sinewaves at the PI's set-point. Its initialisation requires: (a) a stable preliminary controller, (b) reasonable values (correct within a factor of about 3) of the first probing frequency omega0 and of the plant's gain |Gp(jomega0)|, and (c) an effective choice of the adaptive gain Ka for rapid tuning. The challenge is to prime the parameters of both the PI and the adaptive algorithm during an open-loop starting transient, using data obtained before the output attains its set-point, and then to complete the tuning for a short period while under closed-loop control. A relevant parameter is Tm , the time for the plant's impulse response to attain its maximum (or equivalently the time for a maximum slope of the step-response s(t)), and a simple estimator of Tm is described. One of three generic plant models is adopted according to the relative position of Tm within the primary experimental time [T1...T 2], and it is shown how initialisation depends on the chosen model. The described approach is shown to be effective for a range of plants View full abstract»

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  • Stability analysis for a class of switched large-scale time-delay systems via time-switched method

    Publication Year: 2006 , Page(s): 684 - 688
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (115 KB)  

    One new criterion of delay-independent stability for the switched time-delay large-scale system is deduced by employing a time-switched method and the comparison theorem. The total activation time ratio of the switching law can be determined to guarantee that the switched time-delay system is exponentially stable with stability margin lambda. One example is exploited to illustrate the proposed schemes View full abstract»

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  • Delay-dependent robust stabilisation of discrete-time systems with time-varying delay

    Publication Year: 2006 , Page(s): 689 - 702
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (199 KB)  

    The stability of discrete systems with time-varying delay is considered. New delay-dependent stability criteria are devised, which are dependent on the minimum and maximum delay bounds. An initial analysis leads to a criterion depending on an inequality involving certain matrices that can be freely chosen. By carefully choosing them to reflect the appropriate relationship between states at differing times, a stricter criterion is thereby obtained. Furthermore, new results for delay-dependent robust stabilisation of uncertain systems with time-varying delay are provided on the basis of a linear matrix inequality (LMI) framework. As the conditions obtained for the existence of admissible controllers are not expressed using strict LMI conditions, a cone complementary linearisation procedure is used to find suitable controllers. Finally, the results obtained, including the stability analysis, static output-feedback stabilisation and dynamic output feedback stabilisation are further extended to discrete time-delay systems having uncertain but norm-bounded parameters. Numerical examples demonstrate the validity of the approach proposed View full abstract»

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  • Stability analysis and control of non-standard nonlinear singularly perturbed system

    Publication Year: 2006 , Page(s): 703 - 708
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (172 KB)  

    Stability analysis and control of a non-standard nonlinear singularly perturbed system are studied. A non-standard form in which linear and nonlinear parts coexist is considered and a transformation using linear parts is suggested. On the basis of this transformation, the non-standard form is changed into a quasi-standard form, which is similar to a standard form. For the transformed system, the stability conditions under which the system is exponentially stable for the sufficiently small perturbation parameter epsi are found. Using this analysis, a stabilising controller is designed. The practical aspects of the scheme proposed are illustrated through the control of a series DC motor View full abstract»

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  • Robust adaptive deadzone compensation of DC servo system

    Publication Year: 2006 , Page(s): 709 - 713
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (140 KB)  

    Deadzone in DC servo system is often poorly known and it can severely limit system performance. A robust adaptive deadzone compensation scheme is presented for general DC servo system with deadzone of unknown width. The tuning algorithms were rigorously shown to guarantee small tracking errors as well as bounded deadzone parameter estimates using Lyapunov stability. The other prominent feature of the controller is that it can deal with the uncertainty in both inertial and friction parameters. The simulation results are presented to demonstrate its efficacy View full abstract»

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  • Analogue realisation of fractional-order integrator, differentiator and fractional PI/spl lambda/D/spl mu/ controller

    Publication Year: 2006 , Page(s): 714 - 720
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (173 KB)  

    The fractional-order differentiator sm, integrator s -m (0<m<1) and the fractional PIlambdaD mu controller are studied. A very simple method, useful in system and control theory, which consists of approximating, for a given frequency band, these fractional-order operators by a rational function, is presented. Simple analogue circuits that can serve as analogue fractional-order integrator and fractional-order differentiator are also obtained. A rational function and an analogue circuit realisation of the fractional PIlambdaDmu controller are also derived. Illustrative examples are presented to show the usefulness of the method View full abstract»

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  • Multirate interacting multiple model particle filter for terrain-based ground target tracking

    Publication Year: 2006 , Page(s): 721 - 731
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (301 KB)  

    Ground target tracking is a nonlinear filtering problem when it incorporates terrain and road constraints into system modelling and uses polar coordinate sensing. Furthermore, when tracking ground manoeuvring targets with an interacting multiple model approach, a non-Gaussian problem exists because of an inherent mixing operation. A multirate interacting multiple model particle filter (MRIMM-PF) is presented to effectively solve the problem of nonlinear and non-Gaussian tracking, with an emphasis on computational savings. The sample subset of each mode is updated at a different rate and mode switches are performed according to a Markov chain at a low rate. For a fixed number of samples, simulation results show that the MRIMM-PF significantly reduces computational costs, with comparable tracking performance to multiple model particle filter View full abstract»

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  • Feedback linearisation of uncertain nonlinear systems with time delay

    Publication Year: 2006 , Page(s): 732 - 736
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (124 KB)  

    A control scheme for a class of feedback linearisable nonlinear systems with uncertainty and time delay is proposed. Using the adaptive sliding mode control based on the reduction method, a controller compensating the uncertainty and time delay is introduced. Specifically, the delay-dependent stability analysis for the considered system is presented View full abstract»

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  • Design of sliding mode control for nonlinear stochastic systems subject to actuator nonlinearity

    Publication Year: 2006 , Page(s): 737 - 744
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    Sliding mode control for a class of nonlinear Ito stochastic systems with sector nonlinearities and deadzones is concerned. The unmatched nonlinear uncertainties may appear in both the system state and stochastic perturbation. By utilising stochastic Lyapunov theory, sufficient conditions are derived via linear matrix inequalities such that the sliding motion is globally asymptotically stable in probability despite nonlinear uncertainties and actuator nonlinearities. It has been shown that the reachability of the specified switching surface can be ensured. An example illustrating the present method is provided View full abstract»

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  • Discrete fuzzy control of time-delay affine takagi-sugeno fuzzy models with H/spl infin/ constraint

    Publication Year: 2006 , Page(s): 745 - 752
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (163 KB)  

    Takagi-Sugeno (T-S) fuzzy models play an important role in nonlinear control because they can be used to approximate nonlinear systems. Also, for the affine T-S fuzzy models, the local linear sub-system properties can be easily related to the physics of the controlled nonlinear system. This is one advantage of the affine T-S fuzzy models relative to the homogeneous T-S fuzzy models. In the literature, however, most authors have focused on the homogeneous T-S fuzzy models and only a few have considered the affine T-S fuzzy models. Moreover, it is known that time delays exist in physical systems. To date, there has been no study to consider the time-delay effects in the analysis of affine T-S fuzzy models. Therefore the parallel distributed compensation-based Hinfin fuzzy control problem for the discrete time-delay affine T-S fuzzy model is now presented. An iterative linear matrix inequality algorithm is used to solve the bilinear matrix inequality problems. Finally, numerical simulation for a time-delayed nonlinear truck-trailer system is given to show an application of the present approach View full abstract»

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