Fly-By-Feel Systems Represent The Next Revolution In Aircraft Controls
A “fly-by-feel” system could measure the aerodynamic forces directly on aircraft surfaces and use that information in a physics-based adaptive flight controls system to increase maneuverability, safety and fuel efficiency.
As a step in that direction, Dryden researcher Marty Brenner was selected to receive a NASA Innovation Fund award for a project that would begin investigation of components that could be used in such a system. Brenner envisions state-of-the-art sensors that could be candidates for wind-tunnel or flight-test applications and determine guidelines for further development.
In fact, Brenner also received more good news on June 22, when it was announced he had been chosen for an Aeronautics Research Mission Directorate Seedling Fund award for his Fly-By-Feel research. The new award builds on Innovation Fund awards he received previously, but the new funding will subsidize work concentrated on modeling controls.
NASA is interested in the fly-by-feel concept to meet its goals for increased fuel efficiency and improved reliability and ride quality through managing gusts and flutter (vibration on aircraft surfaces) suppression and load alleviation.
Brenner looked at the materials and process needed to fabricate state-of-the-art sensors and transduction mechanisms to see which might work best for the challenges of a fly-by-feel system. Additionally, a number of available sensors were tested for potential use.
The research was successful and future work could include testing other transduction mechanisms to identify the best fit for the concept, as well as selecting a sensor array for wind-tunnel tests and then for flight research, to track key aerodynamic information and develop a real-time signal-processing algorithm for the new sensor array.
“The hot film sensors can be put on an aircraft right away and then the additional sensors could be added later,” Brenner said.
The research has promise, he said.
“Fly-by-feel is geared toward designing airplanes and control systems with distributed sensing. It puts distributed sensing in the aircraft design and helps meet challenges with flight control. As part of the design of the structure and a complement for how the control system is going to be designed, using the distributed design for multi-objective problems can maximize aero-structure performance,” Brenner said.
Arun Mangalam, president of Tao of Systems Integrated of Hampton, Va., is a partner in the research. His company developed the hot film sensors and the Distributed Aerodynamic Sensing and Processing, or DASP, toolbox on which Brenner has been principal investigator (see lead story).
“This allows you to really look at the aerostructure-design space,” Mangalam said.
The fly-by-feel concept could enable a vehicle to autonomously react to changes in aerodynamic and structural conditions through the use of distributed sensors that don’t just obtain sensor information as it is happening, but also convert it into aerodynamic coefficients that can be used for flight control, Brenner explained. Also of importance is the fact that knowledge of aerodynamic loads across the span of the wing and flight-control surfaces enables a controller to redistribute the loads for optimum performance.
Accurate real-time aerodynamic load and moment sensors also could enable a number of revolutionary capabilities across a wide speed range, including but not limited to shorter takeoff and landing, safe and reliable supersonic operation and larger passenger and cargo capacity. Fly-by-feel also has the potential of becoming one of the key new technologies to opening the door not only to aeronautics, but also to monitoring the health and increasing the range and endurance of future planetary exploration vehicles.
Though the concept of fly-by-feel has a number of steps that must be validated before it is fully proven, Brenner said he will continue to take steps today to ensure that technologies of tomorrow will be ready when they are needed.