This research comprises an experimental and analytical investigation of semi active dampers, a special class of nonlinear, controllable damping actuators for vibration isolation and disturbance rejection applications. The potential application areas for semi active damping technology include rotating and impact machinery, manipulators, bearing dampers, vehicle suspensions, prosthetics, space structures, and reaction mass devices. Dampers can be one of three types, active, passive, or semi active. The first is characterized by power input devices activated by a feedback signal and by power dissipation, the second by power dissipation only, and the third by power dissipation but also by some of the same active features as the active damper. Preliminary studies show that the semi active class performs nearly as well as the more complex, more expensive, higher power, and higher response time fully active dampers. The research is a three phase effort, including a theoretical analysis of the nonlinear dynamics of the damper actuator, the development of control concepts for various vibration applications of this class of dampers, and design, fabrication and study of a prototype damper.
