Smart Aerodynamic Surface for a Typical Military Aircraft Using Shape Memory Elements

This work pertains to the development effort involved in the deployment of an additional winglike aerodynamic surface referred to as a "mousche" for the naval version of a typical military aircraft. The mousche is attached to the forebody of the naval aircraft. It is deployed only during landing (and retracted at all other times) in order to improve the landing characteristics of the aircraft on the aircraft carrier. The mousche is designed and constructed out of carbon-fiber-reinforced plastic to withstand the full load and is deployed using the actuator bank containing the arrays of shape memory alloy elements. The shape memory alloy actuator bank moves a distance of 15 mm while generating a net actuator force of over 2000 kg. This force is used to deploy the additional aerodynamic surface measuring 790 x 215 x 32 mm against a simulated lift and drag load acting simultaneously, i.e., a resultant lift load of 331.6 kg and a drag load of 33.16 kg acting at the center of gravity of the mousche. The shape memory alloy bank consists of 138 wires of about 1 mm in diameter and 650 mm in length. The actuation of these 138 wires is electronically and mechanically synchronized. The mousche has been analyzed using finite element method codes for the combined lift and drag load. Experimental and analysis values have matched well. The electronics circuit assembly of the smart actuator drive electronics that powers the shape memory alloy actuator bank has been designed and developed in the form of mother- and daughterboards. Each daughterboard has six miniaturized dc-dc converters, and the required power and control signals are routed to the motherboard. The smart actuator drive electronics have been integrated to carry out the full load test. The National Instruments 6009 data acquisition module along with graphical user interface software LabVIEW are used to conduct the experiments and to effect the closed-loop position control of the mousche.