Wireless sensor and actuator networks: Enabling the nervous system of the active aircraft

The ever increasing volume of air transport necessitates new technologies to be adopted by the flight industry to fulfill the requirements of safety, security, affordability, and environmental friendliness while still meeting the growing demand. What we need to achieve this goal is a new type of aircraft cruise control, interconnecting all the onboard active control systems and making more accurate control decisions than is currently possible, thus improving overall flight efficiency. Active Aircraft envisions such a nervous system of distributed wireless sensor and actuator network components, enabling the early detection of potential problems and quick, accurate reactions to these. As part of this vision, WSANs deployed on aircraft wings help reduce aerodynamic drag and significantly reduce fuel consumption. In this article we first describe this conceptual change in aircraft control technology. We then introduce a WSAN application to reduce skin friction drag and a network topology to enable it. In our application WSANs form virtual flap arrays on the wings to measure the skin friction in real time and to react using synthetic jet actuators, which suck and expel air on the wing to reduce the friction. The Active Aircraft vision imposes stringent performance requirements on the underlying WSAN communication algorithms. The medium access control and routing protocols, in particular, must meet the quality of service criteria set by active control applications. Thus, we also present the application characteristics of Active Aircraft and raise the issue of design considerations with regard to the communication protocols.