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Extensive studies of off-road non-pneumatic tires (NPTs) were conducted for light and heavy equipment due to their advantages over conventional pneumatic tires in terms of low rolling resistance, thus no need for air pressure maintenance. Finite element (FE) simulations of NPT contact pressure, contact shear stress, vertical stiffness, von mises stress, and rolling resistance were performed using ABAQUS software in a series of vertical loads to simulate tire models of three different spokes geometries on unpaved soil to verify NPT performance under different conditions. The spokes geometries were hexagonal (honeycomb) spoke, hexagonal re-entrant (Lattice) spoke and spoke with curvature called spoke pairs. It was found that the rolling resistance of the honeycomb structure has the lowest value, while the contact shear stress and contact pressure were the highest.

In this paper, a fuzzy-PID controller is applied in a half vehicle active suspension system to enhance vibration levels of vehicle chassis and passenger seat. The fuzzy-PID controller consists of fuzzy and PID connecting in a series manner, the fuzzy output is considered as the PID input. Genetic Algorithm (GA) is selected to tune controller parameters to obtain optimal values that minimize the objective function. The equations of motion of five-degrees-of-freedom active half-vehicle suspension system are derived and simulated using Matlab/Simulink software. Double bumps and random road excitations are used to study the performance of suspension systems including bounce and pitch motion. The performance of the active suspension system using optimized fuzzy-PID controller is compared with conventional passive to show the efficiency of the proposed active suspension system.