Ultrareliable fault-tolerant control systemsIt is demonstrated that fault-tolerant computer systems, such as on the Shuttles, based on redundant, independent operation are a viable alternative in fault tolerant system designs. The ultrareliable fault-tolerant control system (UFTCS) was developed and tested in laboratory simulations of an UH-1H helicopter. UFTCS includes asymptotically stable independent control elements in a parallel, cross-linked system environment. Static redundancy provides the fault tolerance. A polling is performed among the computers, with results allowing for time-delay channel variations with tight bounds. When compared with the laboratory and actual flight data for the helicopter, the probability of a fault was, for the first 10 hr of flight given a quintuple computer redundancy, found to be 1 in 290 billion. Two weeks of untended Space Station operations would experience a fault probability of 1 in 24 million. Techniques for avoiding channel divergence problems are identified.
Document ID
19850035686
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Webster, L. D. (NASA Ames Research Center Moffett Field, CA, United States)
Slykhouse, R. A. (NASA Ames Research Center Moffett Field, CA, United States)
Booth, L. A., Jr. (NASA Ames Research Center Moffett Field, CA, United States)
Carson, T. M. (NASA Ames Research Center Moffett Field, CA, United States)
Davis, G. J. (NASA Ames Research Center Moffett Field, CA, United States)
Howard, J. C. (NASA Ames Research Center Moffett Field, CA, United States)