Serhat Obuz

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In this paper, a tracking controller is developed for a class of nonlinear systems subject to time delay in the control input, uncertainties in the dynamic model, and additive disturbances. The control development is based on a novel predictor–like method to address the time delay in the control input. Lyapunov based stability analysis is used to prove(More)
A robust controller is developed for uncertain, second-order nonlinear systems subject to simultaneous unknown, time-varying state delays and known, time-varying input delays in addition to additive, sufficiently smooth disturbances. An integral term composed of previous control values facilitates a delay-free open-loop error system and the development of(More)
Previous results have shown experimental evidence that the muscle response to neuromuscular electrical stimulation (NMES) is delayed; the time lag is often referred to as electromechanical delay. NMES closed-loop control methods have been developed to compensate for a known constant input delay. However, as a muscle fatigues, this delay increases. This(More)
In the present work, a control method is developed to yield lower limb tracking with neuromuscular electrical stimulation (NMES), despite an unknown time-varying input delay intrinsic to NMES, uncertain nonlinear dynamics, and additive bounded disturbances. A novel filtered tracking error signal is designed to obtain a delay-free control expression in the(More)
A decentralized controller is designed for leader-based synchronization of communication-delayed networked agents. The agents have heterogeneous dynamics modeled by uncertain, nonlinear Euler-Lagrange equations of motion affected by heterogeneous, unknown, exogenous disturbances. The developed controller requires only one-hop (delayed) communication from(More)
In this paper, a tracking controller is developed for a class of nonlinear systems subject to time delay in the control input, uncertainties in the dynamic model, and additive disturbances. The control development is based on a novel predictor–like method to address the time delay in the control input. Lyapunov based stability analysis is used to prove(More)