ABSTRACT
Semi-active (SA) suspensions are those which otherwise passively generated damping or spring forces modulated according to a parameter tuning policy with only a small amount of control effort. This chapter presents the theoretical concepts for SA suspensions’ design and implementation, followed by an overview of developments and control techniques. It reviews some related practical developments ranging from vehicle suspensions to civil and aerospace structures. Vibration isolation suspensions and vibration absorbers are quoted in the literature as the two most commonly used techniques for such utilization. In vibration isolation either the source of vibration is isolated from the system of concern. Semi-active suspension addresses the limitations by effectively integrating a tuning control scheme with tunable passive devices. SA suspensions can achieve most of the performance characteristics of fully active systems, thus allowing for a wide class of applications. A common and very effective way to reduce transient and steady-state vibration is to change the amount of damping in the SA suspension.
