Posted on 02/09/2004 9:09:13 PM PST by BenLurkin
EDWARDS AFB - Someday, aircraft will be able to learn from past experiences and apply that knowledge to make changes in the way they fly. The first steps to that science fiction-like notion are under way at NASA's Dryden Flight Research Center at Edwards Air Force Base.
"We're edging ever so slowly towards somewhat living, breathing, thinking vehicles of the future," said John Carter, Dryden program manager for intelligent flight controls. "We expect someday almost all vehicles will have some aspect of learning software."
An early version of such a system made a flight test last summer on a specially outfitted F-15. The system consists of two forms of unique software: one calculates what is needed to stabilize the aircraft in real time and the second uses a neural net to create an aerodynamic model of the aircraft from the real-time data.
"Essentially, the aircraft was building its own wind tunnel model while it's flying," Carter said.
Previously, engineers took flight test data back to their desks and calculated the mathematical models needed to predict the aircraft's behavior. Now, that process is done by the computer on board the airplane.
In last summer's test flight, the new system compressed this modeling process to once every second. "It was a big compression and a big accomplishment," Carter said.
Although the system performed well on its trial run, it is not developed enough to turn over control of the airplane, he said. Engineers are taking the test results into a simulator to improve its accuracy in reproducing flight conditions. By moving the data collected and manipulated by the computer and neural net directly into the simulator, engineers can get it to be as close to real-world conditions as possible.
The intelligent flight control software determines the optimum flight control qualities based on the current conditions. This feature can be used for damage control, allowing the pilot to safely land a damaged aircraft.
If something changes while the aircraft is in flight, the intelligent flight control system automatically will recalculate its aerodynamic model and make the necessary adjustments to most closely meet that model.
Such a system also could be useful in flying autonomous unmanned vehicles, allowing them to self-correct in flight to meet changing conditions. "What it really gives us is robustness in a way we never had it before," Carter said.
The software can make real-time adjustments to the flight controls without the pilot ever even knowing it is happening.
Last summer's test was the first step in the process. The program flew the same regime more than once to see if the neural net was learning the models. Later this year, the program intends to test the neural net system in real-time damage adjustments.
During the flight test, the F-15's existing digital controls will be programmed to simulate a failure. The neural net system will be engaged to recover in real time.
The benefit of software capable of learning is it should be able to correct for problems it has never seen before by making changes to meet the optimum model already created.
All previous adaptive systems have relied on pre-programmed fixes, which makes them of little use for unforeseen problems. The intelligent flight control system adjusts to get the right aerodynamics, regardless of the problem.
This ability can be effective with prototype vehicles in which the aerodynamics are not well-known. Because the system learns on its own, it does not need the aerodynamics pre-programmed.
The auto-adjusting feature of these intelligent flight controls also may be used for more efficient flight. For example, the system could automatically make minute corrections required to minimize drag in changing conditions.
Another potential application could be to protect commercial aircraft from terrorist attack by using it for damage control, Carter said. Such a system also would help reduce pilot workload to the absolute minimum, he said.
The intelligent flight control system also can be used in conjunction with propulsion control, using the power of the engines' thrust to help control the aircraft.
Aircraft of the future likely will employ surface and propulsion control to most efficiently control the aircraft and recover from damage in flight, Carter said.
"We're using these automatic systems to try to add robustness to vehicles of the future, so you're getting the maximum protection and resistance to things that change in flight," Carter said. With the ongoing research at Dryden, "we are just now taking the first very small steps into this realm. We're at the very beginning of this. We're just trying to get this all to work for the very first time."
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.