Structural Modal Control and Gust Load Alleviation for a SensorCraft Concept

SensorCraft is an Air Force Research Lab (AFRL) concept for a high flying vehicle that will be capable of providing greatly increased Intelligence, Surveillance, and Reconnaissance (ISR) capabilities. Part of the technology SensorCraft will require is high aerodynamic and structural efficiency to accomplish its mission goal of long range and sustained presence. To achieve a long loiter time, it will have a light weight structure with a high aspect ratio wing that carries much of the fuel mass. Hence, the structural modes will be in the same frequency range as the rigid body modes and will be strongly coupled with them. Wing stresses will need to be reduced and the gust load contribution will need to be minimized to keep the structural bending loads low along the span of the wing. This paper documents the results of a wind tunnel test at NASA Langley in the Transonic Dynamics Tunnel of a gust load alleviation system for a SensorCraft concept. The wing was fixed to the wall of the tunnel and the 4 trailing edge and 1 leading edge control effectors were used to simultaneously control first and second bending as well as control the pitching moment at the balance attachment.