Browsing by Subject "Saturation"

Now showing 1 - 4 of 4

Open Access
An anti-windup compensator for systems with time delay and integral action
(2017-08) Öztürk, Dilan
Being one of the most popular saturation compensator methods, anti-windup mechanism is commonly used in various control applications. The problems arising from the system nonlinearities are prone to change the behaviors of the system adversely in time such as performance degradation or instability. Anti-windup schemes including internal model structure with the robust compensator are crucial in terms of preserving the system stability and minimizing the tracking error when controller operates at the limits of the actuator. Saturation problem is further aggravated by the dead-time that appears frequently in the systems depending on processing of sensed signals or transferring control signals to plants. Smith predictor based controllers are e cient in the compensation of time delay, indeed the controller is designed by eliminating the delay element from the characteristic equation of the closed-loop system. We apply Smith predictor based controller design for the system incorporating time delay and integral action to achieve high performance sinusoidal tracking. This study extends an anti-windup scheme via Smith predictor based controller approach by redesigning the transfer functions within the anti-windup structure. We present simulation studies on the plant transfer function including time delay and integrator to illustrate that our extended structure successfully accomplish accurate tracking under the saturation nonlinearity.
Open Access
Extension of an Anti-windup Scheme for Systems with Time Delay and Integral Action
(Elsevier B.V., 2018) Öztürk, D.; Özbay, Hitay
This study extends a recent anti-windup scheme by using Smith predictor based controller approach and by redesigning the transfer functions within the anti-windup structure. We present simulation studies for a system including time delay and integrator to illustrate that our extended structure successfully accomplish accurate tracking under the saturation nonlinearity.
Open Access
Power saturation in standard and double-AR unfolded laser diode cavities
(IEEE, 2016) Peters, M. G.; Fily, A.; Rossin, V.; Demir, Abdullah
We report modeling and experimental results that demonstrate mechanisms limiting the output power of broad area semiconductor lasers. The modeling comprises numerical simulations of the laser cavity with evolution of non-uniform carrier density, photon density, temperature and index. We measure unfolded laser cavities to validate simulation methods and input parameters.
Open Access
Sorption of Cs+ and Ba2+ on magnesite
(Cambridge University Press, 1998) Shahwan, Talal; Süzer, Şefik; Erten, Hasan N.
Sorption behavior of Cs and Ba ions on magnesite was studied using the radiotracer method complemented by X-ray photoelectron spectroscopy. Cs and Ba were used as radiotracers. The sorption of Cs is seen to be temperature dependent, whereas Ba sorption is not much affected by temperature changes. It was found that Freundlich type isotherms provide an adequate description of the sorption process. The magnitude of the free energy of sorption are seen to be within the 8-16 kj/mol range. It can be remarked that the sorption of Cs and Ba on magnesite is a fast process suggesting an ion exchange type mechanism, mainly taking place at the surface of mineral particles.