Design And Implementation Of A Fire-Alarm System In High-Speed Train

With the development of economy and improvement of scientific level in our country,high-speed train has been an absolutely necessary vehicle in our life.High-speed train brings convenience to people,but it brings much security risk to people at the same time too,and fire is one of the most serious risk.Fire alarm system in high-speed train has stricter requirements than ordinary fire alarm system,because in high-speed train,miss alarm would lead more people to death and false alarm would cause train to stop,so it is of great significance to design reliable fire alarm system for high-speed train.In the first,the power supply circuit,storage circuit and so on that included in system hardware circuit are designed in this paper,according to the actual demand of high-speed train.In order to solve the problem that it is difficult to supply power for fire detector in train's cabin,a interface circuit of two-line bus which has ability to detect repeat address fault is designed in this paper.The interface circuit not only supply the stable communication between controller and fire detector,but also can supply power for fire detector in the distance,which can greatly reduce the difficulty of installing this fire alarm system in high-speed train.What's more,the interface circuit can detect many detector faults like address repeat,sensor lost,sensitivity too low and so on,improving the maintainability of fire alarm system.Then,the software of high-speed train fire alarm system was designed in this paper,including the driver of fire detector,the driver of EEPROM,reliability of system and the like.When designing the reliability of system,in order to solve the problem that using single-threshold judgement rule is less effective,a dynamicthreshold-follow algorithm based on interference frequency and a fire judging algorithm based on combining moving window filtering with fuzzy processing are proposed.The dynamic-threshold-follow algorithm based on interference frequency improves the adaptability of fire alarm system to environment,and the judging algorithm based on combining moving window filtering with fuzzy processing provides a reliable fire judgement rule.The cooperation of two algorithms can not only insure the sensitivity but also enhance the anti-interference capability of fire alarm system.In the paper,a simulation tool TINA-TI which is based on SPICE engine is used to simulate the interface circuit of two-line bus.The result of simulation is identical to the result of theoretical analysis,indicating the interface circuit proposed in this paper can better implement the communication function between controller and detection node.At the same time,a simulation using MATLAB about system reliability is finished in this paper,and the result of the simulation prove that the reliability algorithm proposed in this paper has a high sensitivity and a good anti-interference capability.In the end,a testbed is established to experimentally verify the high-speed train fire alarm system.The result of experiment indicates that this fire alarm system can stably and reliably monitor the fire of high-speed train and ensure the safety of passengers in the train.