Real-Time Sensor Validation, Signal Reconstruction, and Feature Detection for an RLV Propulsion Testbed

Amy L. JankovskyNASA Lewis Research CenterCleveland, OhioChristopher E. FultonAnalex CorporationCleveland, OhioMichael P. BinderWilliam A. Maul IIIClaudia M. MeyerNYMA CorporationCleveland, OhioAbstractA real-time system for validating sensor health has been developed in support of the reusablelaunch vehicle program. This system was designed for use in a propulsion testbed as part of an overalleffort to improve the safety, diagnostic capability, and cost of operation of the testbed. The sensorvalidation system was designed and developed at the NASA Lewis Research Center and integrated into apropulsion checkout and control system as part of an industry-NASA partnership, led by RockwellInternational for the Marshall Space Flight Center. The system includes modules for sensor validation,signal reconstruction, and feature detection and was designed to maximize portability to other applications.Review of test data from initial integration testing verified real-time operation and showed the system toperform correctly on both hard and soft sensor failure test cases. This paper discusses the design of thesensor validation and supporting modules developed at LeRC and reviews results obtained from initial testcases.IntroductionThe Reusable Launch Vehicle (RLV) program is a cooperative effort involving the United Statesgovernment and industry to achieve relatively inexpensive and reliable access to space. To attain thesegoals, innovative technologies are being developed and demonstrated. One such effort is the IntegratedPropulsion Technology Demonstrator (IPTD) at the NASA Marshall Space Flight Center. The IPTD is aground-based test facility developed by Rockwell International and NASA for the purpose ofdemonstrating and refining propulsion system technologies before they are tested in flight. One importantgoal of the RLV program is to improve operational efficiency by reducing the cost, time and number ofpersonnel required to prepare a space vehicle for launch, including between-flight maintenance. Automatedmonitoring of the propulsion system and associated ground support facilities, as well as detection anddiagnosis of anomalies before launch and during flight are all critical to improving operational efficiency.The portion of the IPTD program which integrates monitoring and diagnostics with control issues for thetest stand as well as the test article is the Propulsion Checkout and Control System (PCCS). lReal time determination of maintenance requirements is an important capability to achieve the fastturn around requirements of the RLV program. The PCCS was designed to demonstrate some technologiesthat will help achieve this goal. The overall PCCS system includes smart sensing techniques, model-baseddiagnostics, and automated control capabilities to operate the test article and provide maintenance and