the paper presents an efficient scheme for a Nonlinear PID (NPID) controller to improve the dynamic response of the Electric Vehicle (EV). The objective of the proposed controller is to track accurately the reference speed selected by the driver of the EV. A MATLAB/Simulink model is established and validated for the considered EV to study the system performance. The proposed NPID controller has been investigated by comparing it with the traditional PID controller. The optimal parameters of Both the NPID and PID controllers were obtained using the Harmony Search (HS) optimization technique based on a cost function. The desired rise time, settling time, steady-state error, and overshoot have been taken into account in the cost function. Two tests were performed, the first test was implemented at fixed reference speed while the second one was carried out at a staircase command of reference speed. The simulation results can be summarized as follows: in the first test, the NPID controller reaches the steady-state speed at 38.12 seconds while the PID controller stabilizes at 44.68 seconds. Moreover, the NPID controller has a 0.5% steady-state error however, the PID controller has a 4% steady-state error. Besides, the second test shows that the NPID controller can decrease the root mean square of error by 30.1% compared to the PID controller. Lastly, the proposed NPID controller can enhance EV performance significantly.
Authors: F. Deifalla Ahmed , mousa eslam , yehia dina , abdelrahman amr 
Published: November 2023

Two-way shear failure of slabs is a sudden one, which has catastrophic outcomes. Slabs with large spans may be subjected to in-plane tensile forces due to thermal or earthquake loading. There is a lack of agreement between various design codes regarding the significance of in-plane tensile forces on the two-way shear strength. Two-way shear failure of slabs is a sudden one, which has catastrophic outcomes. Slabs with large dimensions may be subjected to in-plane tensile forces due to restraint or earthquake loading. There is a lack of agreement between various design codes regarding the significance of in-plane tensile forces on the two-way shear strength. The purpose of this study is to explore, propose a simplified two-way shear strength model, which includes the effect of in-plane tensile forces on the strength. A review for the experimental investigations, existing models, design codes for two-way shear of slabs is presented, with emphasis on in-plane tensile forces. The loading method used in the current experimental testing is misleading, where the two-way shear and the in-plane forces are independent. A comparative study was conducted between the existing formula and design codes for this case. The comparison between different codes with the experimental results show that the new proposed Eurocode design code was found to be the most accurate one. However, it did not include the effect of the in-plane tensile forces in a physically sound manner. In addition, more full testing of concrete slabs under combined two-way shear and tensile forces are required to refine this existing two-way shear design code provisions or develop new formulas or mechanical models.