Tiltrotor Control Law Design for Rotor Loads Alleviation Using Modern Control Techniques

A weighted least-squares eigenstructure assignment technique and a balanced singular value Linear Quadratic Gaussian with Loop Transfer Recovery (LQG/LTR) technique are used to develop rotor loads alleviation control laws for the V-22 Osprey aircraft. These techniques were applied to alleviate rotor yoke chord loads as part of a comprehensive Bell-Boeing structural loads limiting control law design effort. The control laws developed using these modern control techniques reduce precession generated rotor aerodynamic moments while allowing the pilot to exploit the maneuverability and agility of the tiltrotor configuration. Robustness to feedback sensor failures is ensured through a model following port limiting architecture derived using low order estimation techniques. Analysis and design of the rotor loads alleviation control laws using linear and nonlinear aircraft math models and piloted simulation is discussed.