On March 11, 2010, a team consisting of members of the NASA Ames Diagnostics & Prognostics Group, the NASA Dryden Flight Research Center, and the US Air Force successfully conducted a baseline test flight of the Flyable Electro-mechanical Actuator (FLEA) test stand on a C-17 Globemaster III aircraft. The test stand, built in collaboration with students and faculty of the California Polytechnic State University (Cal Poly), is designed to provide a platform for inexpensive, quick-turnaround testing of prognostic health management algorithms in realistic flight environments. The C-17 Globemaster III flight was a culmination of a year and a half of design and development and was preceded by a series of ground tests, both in the ADAPT Lab at NASA Ames and at NASA Dryden.
During the flight, the team accomplished the target goals of control verification, data acquisition, and signal processing systems performance, along with collecting baseline data on healthy actuators and demonstrating flight safety of the experimental equipment. For most of the flight, the FLEA emulated motion of one of the elevator actuators in real time with some additional pre-recorded profiles being executed for the purpose of a comparison with laboratory data. All of the hardware and software modules operated as expected and allowed for data collection in various flight regimes and system configurations. The flight also provided the team with valuable insight into ways of improving the system for subsequent flights. The collected data are currently being analyzed and used for further development of diagnostic and prognostic algorithms.
BACKGROUND: Electro-mechanical actuators (EMA) are gradually replacing the more traditional hydraulic actuators in the new generation of fly-by-wire aircraft and spacecraft. Their quick adoption, however, is being hindered by the lack of performance data in relevant environments and uncertainty about whether some of the more critical fault modes can be detected and mitigated in time to ensure safety. The objective of this work is to develop prognostic health management algorithms that will help ensure EMA safety. In order to validate such algorithms, an EMA test stand has been designed and built through a partnership between NASA Ames and California Polytechnic State University. Unlike current laboratory stands typically weighing thousands of pounds, this test stand is portable enough to be easily placed into a standard equipment rack on board a wide variety of aircraft. The stand, once fully functional, will allow testing of EMA health management technologies in realistic flight environments, and thus substantially increase their Technology Readiness Level – all without the expense of dedicated flights, as the stand is designed to function as a non-intrusive secondary payload. No aircraft modifications are required, and experiments can be performed during any available flight opportunity, such as pilot proficiency flights, ferry flights, or flights dedicated to other projects. Motion and load profiles are derived from the corresponding real-time values for one of the aircraft’s control surfaces (by interfacing with the aircraft data bus).
TEAM: Ames - Edward Balaban, Kai Goebel, Sriram Narasimhan, Ann Patterson-Hine, Indranil Roychoudhury, and Abhinav Saxena; Dryden - David Berger, Michael Delaney, Mark Dickerson, Ross Hathaway, and Michael Venti
COLLABORATORS: Cal Poly - Sarah Harding, Frank Owen, Michael Koopmans (now Oregon State University), Austin Lawrence, Catlin Mattheis (Oregon State University), Irem Tumer
NASA PROGRAM FUNDING: Integrated Vehicle Health Management (IVHM) Program, ARMD, and AVSP
Contact: Edward Balaban