A simple system for helicopter Individual-Blade-Control and its application to lag damping augmentation

A new, advanced type of active control for helicopters and its application to a system for blade lag damping augmentation is described. The system, based on previously developed M.I.T. Individual-Blade-Control hardware, employs blade-mounted accelerometers to sense blade lag motion and feeds back rate information to increase the damping of the first lag mode. A linear model of the blade and control system dynamics is used to give guidance in the design process as well as to aid in analysis of experimental results. System performance in wind tunnel tests is described, and evidence is given of the system's ability to provide substantial additional damping to blade lag motion.