Ahmed H. El-Shaer

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This paper deals with servo control of SISO nonlinear systems driven by piezoelectric actuators operating in highly uncertain conditions. A proportional-integral (PI) Luenberger observer-based controller is systematically designed to achieve accurate tracking performance, enforce desired closed loop dynamics, as well as robust disturbance rejection in the(More)
This paper presents a two-degree-of-freedom controller structure for electric power steering systems. The controller is synthesized using a hybrid linear matrix inequality and genetic algorithms optimization. Robust stability is studied for both sector-bounded and passive uncertainties resulting in a system of linear matrix inequalities (LMIs) and a linear(More)
This paper presents an approach employing disturbance observers to enhance the performance inverse-based hysteresis compensation based on the Prandtl-Ishlinskii model. A disturbance observer (DOB) is designed to improve the closed loop robust tracking performance in the presence of plant dynamics uncertainty and hysteresis nonlinearities. Simulation results(More)
This study presents a scaled-bilateral telemanipulation system for magnetic-based control of paramagnetic microparticles. This bilateral control system consists of a haptic device (master-robot) and an electromagnetic system with four orthogonal electromagnetic coils. The electromagnetic system generates magnetic field gradients to control the motion of the(More)
This paper is concerned with the stability and synthesis of fixed structure controllers satisfying robust multi-objective H<inf>2</inf>/H<inf>&#x221E;</inf> performance for systems involving human-in-the-loop actuation. Closed loop robust stability conditions are studied for both sector-bounded and passive uncertainties. An iterative algorithm comprised of(More)
This paper is concerned with synthesis of static output feedback (SOF) control satisfying multi-objective performance criteria. Closed loop robust stability is studied for both sector-bounded and passive uncertainties. Given an initially stabilizing SOF gain K<sub>o</sub>, an estimate of the set of stabilizing gains is obtained using Monte Carlo based(More)
In this paper, a nonlinear axially moving string with the Kelvin-Voigt damping is considered. It is proved that the string is stable, i.e., its transversal displacement converges to zero when the axial speed of the string is less than a certain critical value. The proof is established by showing that a Lyapunov function corresponding to the string decays to(More)
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