Exploration Systems Health Management Laboratory

In today’s environment of building and advancing the technology of autonomous space exploration hardware, health management technologies are needed to monitor the hardware to assess system performance degradation, as well as, detect anomalies or access the probability of a future anomaly, any of which can affect not only mission success but crew safety as well.

The Exploration Systems Health Management Laboratory (ESHML) was built to assist in the development and testing of Health Management Algorithm technologies on flight-like hardware in relevant aerospace systems such as propulsion, cryogenic fluid or electrical power systems. Promising algorithms, tested on desktop computer systems are transferred to the ESHML in order to evaluate and characterize their performance as well as advance their Technology Readiness Level for eventual use on manned or unmanned exploration vehicles.

The ESHML contains two real-time target systems. The first is a flight-like unit containing a 333 Mhz PowerPC 750, 128 Mb RAM, a SCSI drive and serial and Ethernet communications. The unit is booted from a VxWorks real-time kernel and algorithms of interest are compiled and downloaded to the target through WindRiver’s Tornado Interface software. NASA generated code can be linked in and used to collect data on algorithm characteristics such as CPU utilization or memory usage. The PowerPC 750 was chosen for use in the Propulsion IVHM Technology Experiment (PITEX) since it was to be used on the X-34 and is still representative of the class of CPUs used on current exploration vehicles.

The second system is called the Portable Health-Management Algorithm Test (PHALT) System and uses Simulink/xPC software from the Mathworks Inc. to develop real-time executable code which can then be tied into a relevant exploration vehicle testbed such as an Electrical Power System (as seen to the right). The PHALT System components consist of a laptop with the Mathworks software installed which serves as the development host and a rack-mountable industrial PC which serves as the real-time target. The target PC can obtain data from one of five sources: a Simulink model, test data playback, a 64-channel data acquisition card, a two-port CAN bus card, or the Ethernet. The PHALT system currently simulates a variety of failures–fail open, fail closed, fail to zero, drifts, noise and intermittent failures. These failures can be superimposed onto testbed data prior to it being analyzed by the health management algorithms. A diagram of a generic Simulink model, used on the PHALT System is shown below.

Publications

Balaban, E., Maul, W., et al: “Transient Region Coverage in the Propulsion IVHM Technology Experiment”, 2004 International MultiConference in Computer Science and Computer Engineering, June 2004.

Chicatelli, A.; Maul, W.; and Fulton, C.: “Propulsion IVHM Technology Experiment”, NASA/CR 2006-214238.

Maul, William A; et al: “Addressing the Real-World Challenges in the Development of Propulsion IVHM Technology Experiment (PITEX)”, NASA/CR 2005-213422 and AIAA-2004-6361.

Maul, William A.; Melcher, Kevin J.; Chicatelli, Amy K; and Sowers, T. Shane: “Sensor Data Qualification for Autonomous Operation of Space Systems”, FS-06-07 (NASA/TM-2006-214475), American Association for Artificial Intelligence 2006 Fall Symposium Series, November 2006.

Melcher, Kevin J.; Fulton, Christopher E;, Sowers, Thomas S.; Maul, William A.: “Development and Application of a Portable Health Algorithms Test (PHALT) System”, 54th Joint Army-Navy-NASA-Air Force (JANNAF) Propulsion Meeting, May 2007.

Meyer, C.; Cannon, H.; et al: “X-34 Main Propulsion System Design and Operation”, AiAA/ASME/SAE/ASEE Joint Propulsion Conference, July, 1998

Meyer, C.; Cannon, H.; et al: “Propulsion IVHM Technology Experiment Overview”, 2003 IEEE Aerospace Conference.

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last updated: 2.29.08