Ensuring control integrity of critical systems subjected to electromagnetic disturbances: problem overview

An assessment process for verifying the control integrity of critical flight systems in adverse, as well as nominal, operating environments is currently under development at the NASA Langley Research Center. The assessment process involves a combination of analysis, simulation and tests, and it addresses: 1) closed-loop operation of the controller under test, 2) real-time dynamic detection of controller malfunctions, and 3) the resulting effects on the aircraft relative to the stage of flight, flight conditions, and required operational performance. Closed-loop high-intensity radiated fields (HIRF) effects experiments were performed on a fault tolerant flight control computer. This paper presents an overview of the problem of ensuring the integrity of critical control systems operating in harsh electromagnetic environments, and an approach for the assessment of these systems. A description of the closed-loop HIRF experiments and closed-loop effects on the simulated flight of the aircraft are also presented.