Toward Intelligent System Health Monitoring for NASA Robonaut JUYI PARK Center for Intelligent Systems Vanderbilt University Nashville, TN 37235-0131 USA STEVEN C. FERGUSON NILANJAN SARKAR KAZUHIKO KAWAMURA Center for Intelligent Systems, Vanderbilt University Nashville, TN 37235 USA BILL BLUETHMANN ROB AMBROSE KEN ALDER Automation, Robotics and Simulation Division, NASA Johnson Space Center Houston, TX 77058 USA Abstract—This paper presents an intelligent system health monitoring technique for a humanoid robot, Robonaut, which was developed at JSC to be used in space. Robonaut’s lower level controller publishes sensor information through NDDS, network middleware, and Self Agent analyzes the data to monitor the status of the robot. A hierarchical system health monitoring (SHM) technique is developed. As a base level of the SHM, a nonlinear model-based observer and a fuzzy logic framework are developed to detect faults and identify the fault source in the robot. Keywords – Robonaut, Self agent, System health monitoring, Fault detection and identification, Model based fault detector, Fuzzy logic 1. Introduction Like most humanoid robots, Robonaut is a complex electromechanical system comprised of many sensors and actuators. Overall task performance of such a system depends greatly on the proper functioning of its components. Despite the best design and maintenance practices, it is unlikely that such a complex system will be immune to random system faults. Any fault that may occur in the system may adversely affect