STATIC SHAPE CONTROL FOR ADAPTIVE WINGS

A theoretical method was developed, and experimentally validated, to c ontrol the static shape of flexible structures by employing internal t ranslational actuators. A finite element model of the structure, witho ut the actuators present, is employed to obtain the multiple-input, mu ltiple-output control-system gain matrices for actuator-load control a s well as actuator-displacement control. The method is applied to the quasistatic problem of maintaining an optimum-wing cross section durin g various transonic-cruise flight conditions to obtain significant red uctions in the shock-induced drag. Only small, potentially achievable, adaptive modifications to the profile are required. The adaptive-wing concept employs actuators as truss elements of active ribs to reshape the wing cross section by deforming the structure. Finite element ana lyses of an adaptive-rib model verify the controlled-structure theory. Experiments on the model were conducted, and arbitrarily selected def ormed shapes were accurately achieved.