The development of automobile suspension systems has been evolved due to benefit from simulation tools and co- evolution of electronics and microprocessor control to get the most efficient and appropriate suspension system for cars and vehicles. Suspension systems are generally classified into passive, semi- active, or active. This classification depending on the amount of external power required for the system to perform its function. A traditional passive system comprised of springs and dampers. Semi-active suspensions use spring and controlled damper, the damper consumes small amounts of energy to adjust the damping level. Active suspensions have a controllable force actuator powered from an external energy source. Active suspension systems can potentially generate any desired force and so are much more flexible than conventional passive systems. This Project starts with concise survey and discussion of related topics of automobile suspension designs and controls. A mathematical model of the active hydro-pneumatic suspension for dynamic simulation in Simulink is introduced. The design and characterization of the computer controlled suspension test-rig, road profile and excitations are explained. Finally the a PID controller is designed and tuned for optimized performance under various road conditions are performed in SIMULINK.