References of "Jasim, Najah"
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See detailRobust adaptive control of spacecraft attitude systems with unknown dead zones of unknown bounds
Jasim, Ibrahim UL; Jasim, Najah

in Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering (2012), 226(7), 947-955

This paper addresses the problem of attitude control of a spacecraft when unknown dead zones of unknown bounds exist at the actuators. A robust adaptive controller with parameter update laws are designed ... [more ▼]

This paper addresses the problem of attitude control of a spacecraft when unknown dead zones of unknown bounds exist at the actuators. A robust adaptive controller with parameter update laws are designed for the spacecraft’s attitude and an asymptotically stable tracking performance is mathematically proven based on the proposed design. Numerical simulation results along with the theoretical proof show that the proposed control scheme can successfully stabilize the attitude of the spacecraft with the unknown actuator dead zones. [less ▲]

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See detailRobust Adaptive Pitch Control of Floating Wind Turbines
Jasim, Ibrahim UL; Jasim, Najah

in Journal of Energy and Power Engineering (2012), 6

In this paper, a modified sliding-mode adaptive controller is derived to achieve stability and output regulation for a class of dynamical systems represented by a non-homogeneous differential equation ... [more ▼]

In this paper, a modified sliding-mode adaptive controller is derived to achieve stability and output regulation for a class of dynamical systems represented by a non-homogeneous differential equation with unknown time-varying coefficients and unknown force function. In this scheme, the control law is constructed in terms of estimated values for the bounds of the unknown coefficients, where these values are continuously updated by adaptive laws to ensure asymptotic convergence to zero for the output function. The proposed controller is applied to solve the problem of pitch angle regulation for a floating wind turbine with dynamic uncertainty and external disturbances. Numerical simulations are performed to demonstrate the validity of the designed controller to achieve the desired pitch angle for the floating turbine’s body. [less ▲]

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See detailRobust Control Design for Spacecraft Attitude Systems with Unknown Dead Zone
Jasim, Ibrahim UL; Jasim, Najah

in 2011 IEEE International Conference on Control System, Computing and Engineering (2011, November)

In this paper, we consider the challenge of controlling inherently complicated nonlinear systems accompanied by input's hard nonlinearities characterized by unknown parameters. This challenge is addressed ... [more ▼]

In this paper, we consider the challenge of controlling inherently complicated nonlinear systems accompanied by input's hard nonlinearities characterized by unknown parameters. This challenge is addressed in this paper by considering the problem of controlling the attitude of a spacecraft when unknown dead zones exist at the actuators. The spacecraft's dynamics is described by the exact form of Euler's equations of motion, allowing for the case of large angle of rotations to be considered. We propose a control scheme that ensures the spacecraft's attitude to track time-varying maneuvers with an exponential tracking error convergence and robustness to actuator dead zones uncertainties. Numerical simulation results along with the theoretical proof show that the proposed control scheme can successfully stabilize the attitude of the spacecraft and achieve the desired tracking performance. [less ▲]

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See detailAdaptive Sliding Mode Control Design for a Class of Nonlinear Systems with Unknown Dead Zone of Unknown Bounds
Jasim, Ibrahim UL; Jasim, Najah

in Abstract book of 1st International Conference on Energy, Power, and Control (2010, December)

The control problem for a class of nonlinear systems that contain the coupling of unmeasured states and unknown parameters is addressed. The system actuation is assumed to suffer from unknown dead zone ... [more ▼]

The control problem for a class of nonlinear systems that contain the coupling of unmeasured states and unknown parameters is addressed. The system actuation is assumed to suffer from unknown dead zone nonlinearity. The parameters bounds of the unknown dead zone to be considered are unknown. Adaptive sliding mode controller, unmeasured states observer, and unknown parameters estimators are suggested such that global stability is achieved. Simulation for a single link mechanical system with unknown dead zone and friction torque is implemented for proving the efficacy of the suggested scheme. [less ▲]

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See detailStable Robust Adaptive Control of a Robotic Manipulator with Unknown Dead Zone and Friction Torques
Jasim, Ibrahim UL; Jasim, Najah

in World Academy of Science, Engineering and Technology (2010)

The problem of controlling a two link robotic manipulator, consisting of a rotating and a prismatic links, is addressed. The actuations of both links are assumed to have unknown dead zone nonlinearities ... [more ▼]

The problem of controlling a two link robotic manipulator, consisting of a rotating and a prismatic links, is addressed. The actuations of both links are assumed to have unknown dead zone nonlinearities and friction torques modeled by LuGre friction model. Because of the existence of the unknown dead zone and friction torque at the actuations, unknown parameters and unmeasured states would appear to be part of the overall system dynamics that need for estimation. Unmeasured states observer, unknown parameters estimators, and robust adaptive control laws have been derived such that closed loop global stability is achieved. Simulation results have been performed to show the efficacy of the suggested approach. [less ▲]

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