Development of external orifice semi active suspension system (EOSASS) for armored vehicle

Suspension system considered as the most important component that defines the handling and ride performance of an armored vehicle. A good suspension system provides a reliable damping force in order to maintain a good contact between the vehicle‘s tires and road surface. Commonly, the suspension system installed in current armored vehicle
is passive type suspension system where it produces a constant damping value. Therefore, the armored vehicle shows a poor performance in term of handling and ride performance
during off-road condition due to the suspension system could not varies it damping values with extreme road conditions. In order to overcome this problem, a new suspension system design known as External Orifice Semi Active Suspension System (EOSASS) is proposed. In this design, the existing passive damper was modified by combining with an additional hydraulic unit. The hydraulic unit is designed to control the orifice area of the suspension system during extension and compression stages using DC motor. This enables the damping value to be controlled and varied depending on the road conditions and handling maneuver. The experimental characterizations on force-velocity and forcedisplacement behaviors of EOSASS prototype were conducted using Instron Testing system. Then, the behavior of EOSASS is modeled by Adaptive Neuro-Fuzzy Inference System (ANFIS) interpolation technique. The model is then validated with the behavior
of EOSASS obtained from the experimental data. The performance of the ANFIS interpolation model then evaluated through force tracking control simulation to investigate the performance of the developed model. Next, a seven degree of freedom (DOF) vehicle ride model developed using MATLAB/Simulink as a plant for inner and outer loop controllers to evaluate the vehicle’s dynamic response by applying the proposed control strategies. The inner loop consists of ANFIS interpolation model of EOSASS that actuated by DC motor. Hybrid control comprising Skyhook and PID controller utilized for outer loop control strategies. In the meantime, the seven (7) DOF ride model with control strategies then optimized by Particle Swarm Optimization (PSO) technique in order to provide an optimum parameter to the proposed control strategies. The vehicle dynamic response such as body, pitch and roll acceleration responses that optimized by PSO exhibits the most outstanding performance compared to nonoptimized hybrid control strategies, PID control strategies and passive system.