Distributed dynamics approximation through lumping and fuzzy clustering : reliability and validity issues

This paper presents a fuzzy reasoning based approach for modeling the distributed dynamics of a parallel flow heat exchanger. Distributed-parameter and lumped-parameter models of the heat exchanger are first derived. The validity of such model representations is discussed and limitations regarding their use for practical purposes are presented. The alternative modeling approach presented in this work aims at developing a moderately complex model with interpretable structure for the parallel flow heat exchanger which is the main component of a pilot thermal plant. The proposed multivariable fuzzy rule-based model achieves simultaneous prediction of the air and water temperatures. The experimental study conducted on the real plant shows the performance of the fuzzy model in capturing the key dynamical properties of the physical plant over a wide operating range and under varying dynamics. Copyright © (2011) by International Operational Modal Analysis Conference (IOMAC) All rights reserve

On lyapunov stability of interconnected nonlinear systems : recursive integration methodology

This paper evolved from an endeavor to construct a Lyapunov function of interconnected nonlinear systems described by ordinary differential equations. This construction is an intractable problem and crucial part of the design when applied to problems of high dimension with intricate structure. The design obtained is applicable if the system under investigation is a generalization of the strict feedback form and whose dependency graphs satisfies the decomposition into lower triangular form. This design is mainly developed for moderated nonlinear continuous time dynamical systems. However, as we show in the example, it is emphasized that the present results can be extended to discontinuous systems provided they can be approximated by smooth modifications. A key step in our approach which based on back integrating procedure is to decompose the interconnected system into subsystems using graph theoretic decomposition. In the proposed methodology, the postulated Lyapunov function is obtained by backward integration the composite system trajectory. This novel approach leads straightforward and by one shot methods to both Lyapunov function of the composite system and its time derivative. A practical example is presented to illustrate the effectiveness of the result

A constructive methodology of Lyapunov function of composite systems with nonlinear interconnection term

For composite systems with a coarse decomposition it is usually more difficult to find a suitable Lyapunov function for the sub-systems that may no longer be of low order, and provides computational and analytical difficulties. In this paper, we present a constructive methodology of Lyapunov function in the case of coarse decomposition to analyze stability of the origin for a general class of nonlinear composite systems expressed in state variables as n first-order nonlinear differential equations. We need to find a storage function to be used as Lyapunov function. A family of this design can be constructed by recursive procedure of a different version of the same basic step: the augmentation by one equation at each step. The present results make use of graph-theoretic decomposition techniques in which the composite systems lead to a sequence of coarser subsystems. Finally, an example is given to illustrate the constructive methodology propose

Stability of interconnected systems under structural perturbation : decomposition- aggregation approach

In this paper, the decomposition-aggregation method is used to carry out connective stability criteria for general linear composite system via aggregation. The large scale system is decomposed into a number of subsystems. By associating directed graphs with dynamic systems in an essential way, we define the relation between system structure and stability in the sense of Lyapunov. The stability criteria is then associated with the stability and system matrices of subsystems as well as those interconnected terms among subsystems using the concepts of vector differential inequalities and vector Lyapunov functions. Then, we show that the stability of each subsystem and stability of the aggregate model imply connective stability of the overall system. An example is reported, showing the efficiency of the proposed techniqu

A combined IQG/LTR and fuzzy logic strategy for the improved control of a drum-type boiler-turbine plant

This paper addresses the design of a fuzzy control system with a fuzzy controller and a fuzzy estimator for a fossil-fuelled drum-type boiler-turbine unit. The fuzzy control method is based on a dynamic Takagi-Sugeno (TS) fuzzy model which has been developed in Habbi et al. [Automatica 39 (2003) 1213] for the nonlinear steam power plant. In the design procedure, a dynamics augmentation is first suggested and a dynamic fuzzy augmented system is determined to deal with the non-minimum phase behaviour of the plant. The global fuzzy control system is designed from a local concept viewpoint using the optimal control theory. To assess the performance of the proposed optimal fuzzy controller, simulations under various operation conditions including actuators saturation are performed over a wide operating range of the physical plan

A dspace dsp control platform for v/f controlled induction motor drive and parameters identification

This paper presents a full digital implementation of open loop and closed loop Volt-per-Hertz (V/F) Controlled Induction Motor Drive with dSPACE DS 1104 Hardware/Software and Matlab/Simulink environment for educational purpose. A feature of this environment is a simple user interface, which requires a basic knowledge of Matlab/Simulink for designing the controller and motor parameter identification. Advances in Computer, Communication, Control and Automation Advances in Computer, Communication, Control and Automation Look Inside Other actions Export citation About this Book Reprints and Permissions Add to Papers Share Share this content on Facebook Share this content on Twitter Share this content on LinkedI

Experimental results of sensorless rotor field oriented control using MRAS

This work deals with design and implementation of sensorless rotor field oriented control using model reference adaptive system (MRAS) of induction motor (IM) drives. SVPWM, using an injected Zero-Sequence Signal (ZSS), is used for controlling the motor. Proportional Integral Controllers with antiwindup are designed. A 3Kw, 3-phase, 50Hz, 1420rpm, induction motor and a dSPACE DS1104 hardware/software are used to carry out the control application. The experimental results show the effectiveness and the limitation of the control metho