A test subject runs in a zero gravity simulator on Earth in the Exercise Countermeasures Laboratory at Glenn Research Center, Cleveland. (NASA Photo)
› View Larger Image Dave Mitchell of Hoh Aeronautics doesn't have to be sold on the value of participating in Small Business Innovative Research agreements.
What began as a series of code under two SBIR agreements with the Air Force has been refined into an algorithm to detect pilot-induced oscillations, or PIO, with two SBIR agreements with Dryden. It now also is a commercially viable product used by The Boeing Company.
The Realtime Oscillation Verifier algorithm for detecting PIO, which Mitchell calls ROVER, uses control input and aircraft response to determine if a PIO is occurring. The phenomenon occurs when a pilot overcorrects for perceived changes from normal control of the aircraft.
As part of SBIR contracts with the Air Force at Wright-Patterson Air Force Base in Ohio, the ROVER was used to post process simulation and flight-time histories to look for PIO. It was not user-friendly and was a small part of the work performed on those contracts, Mitchell said. However, the idea showed promise and under Phase I and II SBIR agreements with Dryden – Tim Cox was the contracting officer – the ROVER was optimized.
"We improved the algorithms, worked out a logic structure, wrote new versions of the algorithms for its various uses and implemented the code in a Dryden simulator and a simulator at Hoh Aeronautics. We also performed piloted evaluations of ROVER as a PIO detection tool," he said.
That work has paid dividends.
"We have sold two copies of the executable code to Boeing for use on C-17 control law improvement and advanced transport aircraft control law development efforts," he added.
In addition, Mitchell worked with Dryden on a follow-on SBIR Phase III agreement earlier this year. Bruce Cogan, the project lead, worked with Air Force Test Pilot School personnel to see if research and software developed at Dryden could provide future aircraft designers with a better prediction tool. The tool is intended to accurately gauge how an aircraft would fly when a flight control surface is damaged and adaptive, or "intelligent," flight control software is used to compensate for the loss.
The ROVER was intended to identify PIOs within the unusual flight regimes the aircraft flew as a result of the in-fight simulations. Although there were no indications of PIOs during those research flights, Mitchell assisted with designing the experiment. The project represents the follow-on work that can be available through successful SBIR agreements and the partnerships that are developed through that work, Mitchell said.
Mitchell is pleased with the concept's development and he enjoys working with Dryden.
"It's been wonderful. I was a co-op at Dryden in the 1970s. I greatly enjoyed my time and I've had the chance to talk to others who have come along since I left. They are easy to work with [at Dryden] and very interested in the work. It's all positive," he said.
SBIR work has been good for Hoh beyond just the sale of a product.
"The SBIR did what it was intended to do – develop this product. We have had a few commercial sales of the product for flight test and for ground testing of new control laws. In both cases, it was not just a sale of a product, but also of our services with the analysis and interpretation of the results," he said.