Control System Aspects of an Analytical Investigation into Controlling the Structural Modes of Flexible Aircraft

Disturbing pilot accelerations and structural loads due to structural motion are areas of increasing concern, both to the pilots and designers of vehicles for low-altitude, high-speed missions. Such aeroelastic problems can be alleviated by a control system synthesized to effectively increase the damping ratio of the structural modes. The paper discusses the specifics of sensing, local force application, coupling, and adaptability of typical control systems, using the XB-70 as the basic study vehicle. It is shown that a relatively simple conventional control system can be designed to provide damping to the structure while adapting to flight condition variations continuously and guaranteeing phase and gain-stabilization of the structural modes.