Jon Morris

An architecture for intelligent systems based on smart sensors

Based on requirements for a next-generation rocket test facility, elements of a prototype IRTF have been implemented. A key component is distributed smart sensor elements integrated using a knowledgeware environment. One of the specific goals is to imbue sensors with the intelligence needed to perform self-diagnosis of health and to participate in a hierarchy of health determination at sensor, process, and system levels. The preliminary results provide the basis for future advanced development and validation using rocket test facilities at Stennis Space Center (SSC) 1. We have identified issues important to further development of health-enabled networks, which should be of interest to others working with smart sensors and intelligent health management systems.

Integrated System Health Management (ISHM) for Test Stand and J-2X Engine: Core Implementation

ISHM capability enables a system to detect anomalies, determine causes and effects, and predict future anomalies. It provides advice to improve operations based on health status, and includes user interfaces for integrated awareness of the health of the system. NASA Stennis Space Center (SSC), NASA Ames Research Center (ARC), and Pratt & Whitney Rocketdyne (PWR) are currently implementing a core ISHM capability that encompasses the A1 Test Stand and the J-2X Engine. The implementation incorporates all aspects of ISHM; from anomaly detection (e.g. leaks) to root-cause-analysis based on failure modes and effects analysis (FMEA), to a user interface for an integrated visualization of the health of the system (Test Stand and Engine). The implementation provides a low functional capability level (FCL) in that it is populated with few algorithms and approaches for anomaly detection, and root-cause trees from a limited FMEA effort. However, it is a demonstration of a credible ISHM capability, and it is inherently designed for continuous and systematic augmentation of the capability. The paper describes all aspects of the current implementation, and on-going activity leading to a pilot capability that could potentially support the J-2X test program.

A Road Map for Integrated Systems Health Management

Integrated systems health management (ISHM) is one of several approaches to building automated diagnostic and prognostic systems. We describe a unique architecture for ISHM along with other key technology elements such as Smart Sensors complying with the IEEE 1451.x family of standards, and user interaction methods. Technology readiness levels (TRL) and functional capability levels (FCL) are useful metrics for evaluating the readiness of each contributing technology and identifying those technologies that need further development.

Smart sensor demonstration payload

This paper discusses smart sensors which are a critical element to monitoring, control, and evaluation processes as needed to support ground based testing for rocket engine test. Sensor applications involve tens to thousands of sensors; their reliable performance is critical to achieve overall system goals. These system engineering trade-offs include the familiar constraints of power, signal conditioning, cabling, reliability, and mass, and now include considerations such as spectrum allocation and interference for wireless sensors.

One summer at NASA's John C. Stennis Space Center

The test stands at SSC are enormous structures, each with several hundred - even thousands - of sensors. With such a high sensor count and variety it is incredibly difficult to do anything useful with the influx of data in real time beyond recording it for future examination. However, it would be ideal if the test controller could not only view all of the data in an intuitive and information rich environment but also have the complementary sensor data fused together to provide more robust information. Enter the integrated intelligent health management system (IIHMS). The IIHMS is a collection of smart sensors, each aware of the local process they are measuring, controlled by an expert system with a global view of the entire system. The long-range goal is to develop an expert system to provide the test controller with a fully immersed environment in which to monitor the condition of every system component and receive advice on anomalies and proper courses of action. The IIHMS is now termed intelligent system health management (ISHM). Dave was assigned the hardware design of a smart temperature sensor that would form the foundation layer of the IIHMS; Don was responsible for the firmware that would add the intelligence to Daves hardware by enabling it to monitor the health (i.e., quality) of the sensor and the quality of measurements in real time; Jon was left the task of designing the link between the smart sensor and the expert system. This work discusses the summer experience of the authors at SSC.