Research On The Optimization Of Test Sequence Generation Method For CTCS-3 Level Train Control On-board Equipment

In recent years,Chinese railway has been developing at a high speed,and along with the introduction of Chinese train control system(CTCS),China’s railroad has been moving towards the goal of high speed,high density and high comfort operation.high-speed railroad.The on-board equipment is the main body of the CTCS-3 level train control system,which has an extremely important role in ensuring the safety of train operation and improving the efficiency of train operation,and the CTCS-3 level train control on-board equipment,as a typical safety-critical system,must be strictly tested before it is put into use.Relevant statistics show that testing can reduce the economic loss caused by system design defects by33% and discover potential problems and errors in the system,which is extremely important to ensure the correctness of the system.The test cases and test sequences of CTCS-3 level train control system are mostly written by experts manually,which are problematic in terms of completeness,correctness,redundancy and coverage,and also require huge human,material and financial resources,resulting in a lot of wasted resources and long test cycles.Based on the above problems,this paper mainly carries out the following studies.(1)Firstly,the overall structure and working principle of CTCS-3 level column-controlled on-board equipment are described in detail,the definition of Colored Petri Net(CPN),the concept and classification of test methods,the definition and design principles of test cases and test sequences are introduced,and the overall test strategy of this paper is elaborated.(2)Secondly,the test case generation method for CTCS-3 level train control on-board equipment is studied.The model-based test method can describe the complex state and behavior of the system and automatically generate test cases based on the generation of formal models to obtain specific test data,so the on-board equipment test cases are automatically generated using the model-based test method.The test cases are then concatenated according to certain rules to generate optimized test sequences for actual field testing or laboratory simulation testing.In this paper,CPN is used as a formal modeling tool to automatically generate test cases using the in-vehicle device registration and startup scenario as an example.Finally,16 test cases are generated,which contain all the information required for testing and satisfy the test conditions.(3)Thirdly,once again,the CTCS-3 level train-controlled on-board equipment test sequence generation method is studied.the logic of CTCS-3 level train-controlled on-board equipment system is complex and involves many functional scenarios.since the working modes of on-board equipment can be transformed into each other,thus generating an on-board equipment mode transformation directed graph,the on-board equipment test sequence optimization problem is transformed into a traveling salesman problem(The problem is then solved by using Modified Ant Colony Optimization(M-ACO)to generate 10 optimized test sequences of in-vehicle equipment,which meet the requirement of minimum repetition of test cases on the basis of full coverage of test cases.The test case coverage is guaranteed to meet the requirement of minimum repetition of test cases.(4)Finally,the test generation software is developed,and the test cases and test sequences generated by the software are imported into the in-vehicle device simulation test platform for verification.The test generation software is developed based on the VS platform,which can automatically generate test cases and test sequences to meet the requirements and convert them into a standard extensible markup language(XML)format that can be directly imported into the simulation platform.The test process of the train-controlled on-board equipment simulation test platform is divided into four main steps,namely test preparation,test process,test analysis and test results.Finally,the generated test sequences are imported into the simulation platform for verification,and it can be observed that the simulation platform interface train runs normally and the communication between the modules is correct,which proves the correctness of the CTCS-3 level train control on-board equipment test cases and test sequences generated in this paper.