USING PETRI NETS FOR SAFETY ANALYSIS OF UNMANNED METRO SYSTEM

Abstract In unmanned transportation systems, the certification of the control/command equipments is a technical process based on rigourous methods taking into account precise and detailed objectives. In France, for a number of new automated transport systems, INRETS has been in charge of this certification process as an authorized body, appointed by the Ministry of Transport. Such process intends to assess that the system design satisfies initially defined safety objectives. INRETS-CRESTA has developed a tool based on Petri nets and a methodology for applying this tool. The principle is to examine and eventually to complete the safety study achieved by the constructor, by coupling and simulating a functional model with environment model. In this paper we describe how this tool is used to specify safety functions and to demonstrate their safety. This method is illustrated by an example of application to the VAL automated system.