Factors in development of semi-active suspension for ground vehicles

The suspension system of a ground vehicle is responsible for ride comfort and for isolation of the chassis from the road disturbances. The performance of suspension system is crucial for the health of equipment and personnel onboard. The suspension system consists of a spring and a damper. The spring deforms to the road undulations and thereby reduces acceleration level in the chassis. The mass of the vehicle suspended with the spring exhibits a tendency towards sustained oscillations. The role of the damper is to decay and arrest the oscillations of the spring-mass system. A large level of damping reduces the effectiveness of the spring and may lead to increased acceleration in the chassis. A low level of damping makes the suspension system vulnerable to resonance. These conflicting requirements suggest that by suitably varying the damping, ride comfort can be improved substantially. Such systems, wherein, the damping is variable are called as semi-active suspension. This has been subject matter of a great interest because, it offers a substantial improvement in ride comfort with inexpensive hardware and requires low power. This paper consolidates the factors to be considered for development of semi-active suspension for ground vehicles and highlights the underlying technical challenges.