nima maleki

This paper investigates the performance of a predictor-based  H_∞controller applied to a first-order DC motor system under significant input-time delays. Alongside the proposed predictor-based H_∞ controller, an LQR controller has been implemented to serve as a benchmark for effectively comparing and evaluating the performance of the proposed method. This study specifically focuses on scenarios involving time delays exceeding one second and external disturbances such as constant, sinusoidal, and stochastic disruptions. The proposed controller employs a robust memory-state feedback mechanism to ensure closed-loop stability and minimize the impact of disturbances. Using Linear Matrix Inequality (LMI) conditions, the controller compensates for input delays of up to five seconds while guaranteeing disturbance attenuation. A delay-dependent Lyapunov stability analysis is conducted to validate the proposed approach. Comprehensive simulation results and evaluations based on key performance metrics, such as settling time and overshoot, indicate that the predictor-based H_∞  controller outperforms both the open-loop configuration and the LQR controller. Notably, the proposed approach achieves a reduced overshoot, a faster transient response, and superior disturbance attenuation compared to the LQR method. Furthermore, this controller significantly enhances the overall system robustness and control precision in scenarios with prolonged delays. The predictor-based H_∞ controller suggests an innovative solution for mitigating the effects of long input delays in DC motor systems, thereby overcoming a pivotal challenge in robust control.

In this paper, the possibility of use of p-Xylylenediamine (PXDA) as a new amine in CO2 absorption process is inspected. Also, data regarding CO2 solubility in PXDA at pressures of 8-500 kPa, concentrations of 2 to 5 mol/L and temperatures of 313 to 353 K were obtained by experiment. The response surface methodology (RSM) was used to model CO2 solubility in amine solution. Moreover, the results illustrated the good accuracy of the mode (R2=0.9708). The 3D charts obtained from the model have shown that CO2 loading has an inverse relation with temperature and concentration and a direct relation with pressure. The simultaneous effect of temperature and pressure on CO2 loading indicates that, at low pressures, an increase in temperature has limited impact on CO2 loading, but at higher pressures, this effect is more pronounced. For ability test of PXDA in absorption of CO2, this solution compares with MEA. Finally, the results indicate that PXDA in both concentrations have more 45% CO2 loading, 44% absorption rate, 50% net cyclic capacity, and about 35% further resistance again oxygen.