Showing papers by "Shaikh Faruque Ali published in 2010"

Piezoelectric energy harvesting with parametric uncertainty

Abstract: The design and analysis of energy harvesting devices is becoming increasing important in recent years. Most of the literature has focused on the deterministic analysis of these systems and the problem of uncertain parameters has received less attention. Energy harvesting devices exhibit parametric uncertainty due to errors in measurement, errors in modelling and variability in the parameters during manufacture. This paper investigates the effect of parametric uncertainty in the mechanical system on the harvested power, and derives approximate explicit formulae for the optimal electrical parameters that maximize the mean harvested power. The maximum of the mean harvested power decreases with increasing uncertainty, and the optimal frequency at which the maximum mean power occurs shifts. The effect of the parameter variance on the optimal electrical time constant and optimal coupling coefficient are reported. Monte Carlo based simulation results are used to further analyse the system under parametric uncertainty.

An approximate modeling of 1d transient heat transfer in a gray participating medium

Abstract: Transient combined radiative and conductive heat transfer is very crucial for glass thermoforming industry. Real time control of the process is presently under consideration for better glass manufacture with less defects. Solution of transient combined radiative and conductive heat transfer in glass requires the solution of radiative transfer equation, which usually takes hours to converge using latest finite volume codes. This paper formulates a polynomial approximation of the radiative part for real time applications. A state space model of the transient conductive and radiative heat transfer is presented. All the states of the model is shown to be observable with measurement only at one surface. The method is faster and takes few seconds to reach steady state with little deviation from the finite element solution. Formulation of the discretization is shown for one dimensional gray medium. Numerical simulation is presented for a case close to glass thermoforming with different radiative sources. A comparison with finite element solutions is also presented and it demonstrates the efficiency of this numerical tool.

Semi-Active Structural Control Using MR Dampers

Abstract: Semiactive control using MR dampers begins with a model development that can describe the dampers' hysteretic characters properly and control algorithms that consider the nonlinear damper voltage to force map. This book develops an efficient MR damper model from experiments. Further an intelligent optimal fuzzy logic control, a nonlinear integral backstepping and a dynamic inversion control algorithms are developed in connection to MR dampers. Experiments and benchmark applications are presented for the control algorithms. The book is with recent research as goal. It can be used as a reference for structural control courses. The applications shown here are benchmark and practical. Which make this book very useful to industry and academia. Moreover, Chapter 2 forms the backbone of this book, providing a broad literature review on structural control and will be useful to every reader. Every chapter has an introduction which covers a wide range of literature specific to that chapter. New nonlinear control algorithms viz. integral backstopping and dynamic inversion are developed and various applications are shown which will benefit many researchers in structural control.