Research On Fault Injection Of Safety Critical Software In Railway Signal System

ABSTRACT:To ensure the safe and efficient operation of trains, the safety critical software in railway signal system adopts fail-safe to design security functions. Because the fault is a combination of various events and has certain delitescence, it is difficult for traditional testing methods to simulate all the faults prevented by security design when authenticating the system safety. The fault injection test is able to realize system security testing by ejecting faults into target system to accelerate its invalidation. The software fault injection has become a hot research topic for its positive features in low cost, safety, and multiple-mode injection. However, due to the complexities of faults and target system, and other problems, there is no general testing tools for software fault injection.This paper presents the security testing method of software fault injection and utilizes it in the safety critical software system in railway vehicle on-board safety computer to conduct detailed research on this system and design a fault injection system. Then based on this fault injection system, this paper proposes a fast developing method by the combination of the LabVIEW graphic programme and the Visual C++ dynamic debugging facility, designs and accomplishes a'Software Fault Injection Simulation Testing Platform of Vehicle On-board Triple Module Redundancy Safety Computer Safety Critical Software System'. Through a simulating computer, this platform can support the parallel and synchronous operation of software and information exchange in three safety mainframe computers, and accomplishes static and dynamic fault injection testing on target system. In addition, this platform is able to complete automatic testing by importing XML scripts, and locate faults by dynamic debugging. Finally, the main functions of this simulation testing platform is authenticated in experiments and promoted as a reliable security testing tool to the safety critical software in vehicle on-board safety computer. The simulation testing platform which is researched and developed in this paper, achieves an excellent performance when tested in practical systems, and provides valuable experience and theoretical reference for the development of other security testing tools of safety critical software system in railway signal system.