الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The goal of this research is to study experimentally the main characteristics of the Hydro-Pneumatic suspension system therefore; a test rig including the twin-accumulator system is built. Furthermore, both damping and the stiffness characteristics of the Hydro-Pneumatic suspension system were measured using a sinusoidal displacement excitation as a system input. The experimental work was extended to include the dynamic performance representing the ride comfort and road handling when the hydro-pneumatic suspension system was used based on a quarter vehicle model test rig.
Additionally, this research is primarily studying the behavior of the twin-accumulator suspension over the conventional suspension system focusing on ride quality behavior and road holding. Therefore, a dynamic model of passive and twin-accumulator suspension system for a quarter model was constructed. MATLAB Simulink environment was used to develop the suspension system models and thus, the simulation was applied with two different road disturbances, namely, step input and random input to disturb the suspension system. The optimum solution was obtained numerically by utilizing a multi-objective evolutionary strategy algorithm and employing a cost function that seeks to minimize the RMS value of the body acceleration, the suspension displacement as well as the dynamic tire load. Moreover, in this work, an active suspension system with PI controller was presented in order to improve the suspension performance criteria. The simulation results of passive, optimized twin accumulator suspension and active suspension system consisted of body displacement, wheel deflection; vehicle body acceleration, suspension travel and dynamic tire load were compared and analyzed.
Results show that the twin-accumulator suspension system gives worthwhile improvements in ride behavior compared with the passive suspension. Finally, it can be observed that the performance of body displacement and wheel displacement can be improved by using the proposed PI controller.