Rapid Soft Fault Recovery

Empirical and analytic simulation studies of “rapid recovery” from soft faults have been activities, at the Langley Research Center (LaRC) at NASA, supporting the evolution of a systems integration facility where failure emulation testing could be performed (particularly on digital electronic technology-based systems). In the relatively recent past, the closed-loop performance of a Rapid Recoverable Computer (RRC) was studied. This computer, which hosted an autoland control law application program, together with a personal computer running a model (aero characteristics, sensors and actuators) of the B737 airplane, is identified as the Recoverable Computer System (RCS). The performance of the RCS rollback scheme for recovery from soft faults in ideal conditions, as well as in harsh Electromagnetic Environment (EME) conditions (possibly induced by lightning EME, etc.) was assessed. An RCS characterization study was performed using 1) an existing MATLAB SIMULINK model of the B737 autoland control law augmented with capability to simulate fault injection, as well as recovery methods, 2) a software package running on a PC to handle the communication of data and commands between the RCS and the flight simulation, and 3) empirical tests in the EME test facility.