Electrical and Electronic Engineering - Research Publications

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    Data Monitoring Sensor Network for Big Net Research Testbed
    Rao, AS ; Izadi, D ; Tellis, RF ; Ekanayake, SW ; Pathirana, PN ; Marusic, S ; Palaniswami, M ; Gubbi, J ; Law, YW (IEEE, 2009-01-01)
    Equipped with recent advances in electronics and communication, wireless sensor networks gained a rapid development to provide reliable information with higher Quality of Service (QoS) at lower costs. This paper presents a real-time tracking system developed as a part of the ISSNIP BigNet Testbed project. Here a GPS receiver was used to acquire position information of mobile nodes and GSM technology was used as the data communication media. Moreover, Google map based data visualization software was developed to locate the mobile nodes via Internet. This system can be used to accommodate various sensors, such as temperature, pressure, pH etc., and monitor the status of the nodes.
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    Control oriented modeling of turbocharged (TC) spark ignition (SI) engine
    Sharma, R ; Nesic, D ; Manzie, C (SAE International, 2009-01-01)
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    Model Reduction of Automotive Engines using Perturbation Theory
    Sharma, R ; Nesic, D ; Manzie, C (IEEE, 2009-01-01)
    In this paper, a new constructive and versatile procedure to systematically reduce the order of control oriented engine models is presented. The technique is governed by the identification of time scale separation within the dynamics of various engine state variables and hence makes extensive use of the perturbation theory. On the basis of the dynamic characteristics and the geometry of engines, two methods for model reduction are proposed. Method 1 involves collective use of the regular and singular perturbation theories to eliminate temperature dynamics and approximate them with their quasi-steady state values, while Method 2 deals with the elimination of fast pressures. The result is a library of engine models which are associated with each other on a sound theoretical basis and simultaneously allow sufficient flexibility in terms of the reduced order modeling of a variety of engines. Different assumptions under which this model reduction is justified are presented and their implications are discussed.
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    On stability properties of nonlinear time-varying systems by semi-definite time-varying Lyapunov can
    Wang, ZM ; Tan, Y ; Wang, G ; Nesic, D (IFAC, 2008-12-01)
    Stability properties (uniform stability/uniform asymptotic stability) of nonlinear time-varying systems are explored using positive semi-definite time-varying Lyapunov candidates whose derivative along trajectories is either non-positive or negative semi-definite. Once these positive semi-definite time-varying Lyapunov candidates are available, conditional stability properties on some specific sets can be used to ensure stability properties ( unform stability and unform asymptotic stability) of nonlinear time-varying systems.
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    Dynamic Practical Stabilization of Sampled-data Linear Distributed Parameter Systems
    Tan, Y ; Trelat, E ; Chitour, Y ; Nesic, D (IEEE, 2009-01-01)
    In this paper, dynamic practical stability properties of infinite-dimensional sampled-data systems are discussed. A family of finite-dimensional discrete-time controllers are first designed to uniformly exponentially stabilize numerical approximate models that are obtained from space and time discretization. Sufficient conditions are provided to ensure that these controllers can be used to drive trajectories of infinite-dimensional sampled-data systems to a neighborhood of the origin by properly tuning the sampling period, space and time discretization parameters and choosing an appropriate filtering process for initial conditions.
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    Nonlinear Gain l2 Stability of Nonlinear Feedback Systems with Quantized Measurements
    KAMENEVA, T ; NESIC, D (IEEE - Institute of Electrical and Electronic Engineers, 2008)
    In this paper we address the stabilization problem of the nonlinear feedback systems with quantized measurements in the presence of bounded disturbances. Building on an approach applied in [Liberzon, Neˇsi´c, 2004] to the linear time-invariant systems with quantized feedback, we extend the results of [Kameneva, Neˇsi´c, 2008] to the quantized control systems with nonlinear dynamics. Using the time-sampled scheme proposed in [Liberzon, Neˇsi´c, 2004] and later used in [Kameneva, Neˇsi´c, 2008], we show that the nonlinear gain l2 stability is achievable for the nonlinear systems with quantized feedback.
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    Uniform stability of sets for difference inclusions under summability criteria
    Teel, AR ; Nesic, D ; Loria, A ; Panteley, E (IEEE, 2009)
    We present equivalent characterizations of uniform global exponential stability and uniform global asymptotic stability of arbitrary closed not necessarily compact sets for nonlinear difference inclusions. Our conditions are established in the form of summability criteria that do not require the knowledge of a Lyapunov function.
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    Networked and Quantized Control Systems with Communication Delays
    Heemels, WPMH ; Nesic, D ; Teel, AR ; van de Wouw, N (IEEE, 2009)
    There are many communication imperfections in networked control systems (NCSs) such as varying sampling/transmission intervals, varying delays, possible packet loss, communication constraints and quantization effects. Most of the available literature on NCSs focuses on only some of these phenomena, while ignoring the others, although recently some papers appeared that consider at least three of these phenomena. In one paper time-varying delays, time-varying transmission intervals and communication constraints are considered, while in an other time-varying transmission intervals, communication constraints and quantization effects are studied. As both approaches are based on the same underlying hybrid modeling framework, it will be shown here that the models can be combined in a unifying hybrid model including the five mentioned network phenomena under some restrictions. On the basis of this model, stability will be analyzed of the closed-loop system in which the controller is obtained using an emulation approach. The analysis provides tradeoffs between the maximally allowable transmission interval (MATI), the maximally allowable delay (MAD) and the quantization parameters, while still guaranteeing closed-loop stability.
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    On mismatch between initializations at coder/decoder in quantized control
    Kameneva, T ; Nesic, D (Elsevier BV, 2008-12-01)
    This paper analyzes the stability of linear systems with quantized feedback in the presence of a mismatch between the initial conditions at the coder and decoder. We show that using the scheme proposed in Liberzon, Nesic (2007) it is possible to achieve global exponential stability of linear systems with quantized feedback when the coder and decoder are initialized at different initial conditions.