Uncertainty Analysis on the In-suit Respiration Mannequin Assembly (IRMA)

Le résumé fourni par la source

Traditional spacesuit carbon dioxide (CO2) washout testing relies on human test subjects, which introduces significant variability that complicates iterative design changes and model correlation. To address these challenges and advance the state-of-the-art for inspired CO2 washout assessment, NASA has been developing the In-suit Respiration Mannequin Assembly (IRMA). IRMA is a breathing mannequin that can be placed in spacesuits and replicate realistic and repeatable breathing profiles. To simulate the metabolic breathing of a human test subject across a range of metabolic rates, IRMA injects variable amounts of CO2 into simulated lungs, which are subsequently expired into the suit volume. Utilization of a mannequin instead of a suited test subject yields more repeatable breaths and provides a baseline to produce data for model correlation and comparison across different suit designs. To ensure the test data from IRMA is relevant and accurate, it is critical to assess the uncertainty of the system and identify potential issues in the design. IRMA incorporates multiple sensors for tracking humidity, CO2 concentration, flow rate, pressure, and temperature, which allows for control of injection rates and quantification of the relevant characteristics of each inhale and exhale. Every sensor possesses inherent error which must be considered when assessing the overall uncertainty of the key parameters computed using IRMA (inspired CO2, CO2 injection rate, and breathing characteristics). This work details an uncertainty analysis on IRMA. This started with calibration testing on each relevant sensor. Sensor data was then integrated into an uncertainty analysis using the Kline-McClintock and Monte Carlo Simulation methods to compute the expected uncertainty propagation on the final parameters. Ultimately, it was found that IRMA is able to effectively meet the goals of producing realistic breath profiles and measure inspired CO2.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.