Research On Interlocking Software Modeling Based On UML And Simulation

Railway signal computer interlocking software is a type of safety-critical software. It implements the route control and ensures the traveling safety.In order to improve the safety and reliability of the interlocking software, the current interlocking system structure was analyzed, the unified modeling language (UML) was introduced, and the interlocking software system model was thus proposed. In addition, a simplified interlocking software system was designed on the basis of the model, and its simulation on uClinux validated the model.Research work in this thesis was focused on the followings:Firstly, the current interlocking system structure was designed based on the interlocking functional requirements, and then the software system structure was designed based on the available structure. A simplified interlocking software system was introduced.Secondly, the basic signal objects, including the signals, the points, the tracks and the routes, were described. The data structures of all the objects were designed and their states were analyzed.Thirdly, the base route process was modeled, and the state change of the route process was specified with the statechart diagram. The statechart diagram was combined with the finite state machine, and the delicated-granularity finite state machine was used to realize the route state change process.Fourthly, it was compared between the 6502 logic and the computer interlocking technological conditions counterpart in view of succession to some extent. The individual process of the base route process was discussed and every individual process was modeled from different respects.Finally, the developing platform was constructed. The porting of the interlocking application on uClinux was expatiated. The result indicated that the simplified interlocking software system ran steadily on uClinux.