SAFETY GUIDED DESIGN BASED ON STAMP/STPA FOR MANNED VEHICLE IN CONCEPT DESIGN PHASE

摘要

In manned vehicles, such as the Soyuz and the SpacernShuttle, the crew and computer system cooperate tornsucceed in returning to the earth. While computersrnincrease the functionality of system, they also increase therncomplexity of the interaction between the controllersrn(human and computer) and the target dynamics. In somerncases, the complexity can produce a serious accident. Tornprevent such losses, traditional hazard analysis such asrnFTA has been applied to system development, however itrncan be used after creating a detailed system because itrnfocuses on detailed component failures. As a result, it'srnmore difficult to eliminate hazard cause early in thernprocess when it is most feasible.rnSTAMP/STPA is a new hazard analysis that can bernapplied from the early development phase, with thernanalysis being refined as more detailed decisions are made.rnIn essence, the analysis and design decisions arernintertwined and go hand-in-hand. We have appliedrnSTAMP/STPA to a concept design of a new JAXArnmanned vehicle and tried safety guided design of thernvehicle. As a result of this trial, it has been shown thatrnSTAMP/STPA can be accepted easily by systemrnengineers and the design has been made morernsophisticated from a safety viewpoint. The result alsornshows that the consequences of human errors on systemrnsafety can be analysed in the early development phase andrnthe system designed to prevent them. Finally, the paperrnwill discuss an effective way to harmonize this safetyrnguided design approach with system engineering processrnbased on the result of this experience in this project.