ABSTRACT
This chapter discusses optimal semi-active control design methods. In active control, the freedom to apply arbitrary control forces to the structure makes it a powerful tool for suppressing structural vibration. Even if an active control law is designed as a stabilizing one, it is not inherently stable. Semi-active control is a well known strategy that uses semi-active dampers for improving stability of dynamical systems. The chapter deals with a state space model for semi-active controlled plants, corresponding control constraints and the clipped optimal control approach. It deals with three optimal semi-active control problems, which are addressed theoretically and demonstrated numerically. Clipped optimal control is a heuristic approach, in which the controller design is usually done by some known optimal method that ignores the actuator's constraints.
