Research On Condition-based Maintenance Method For On-board Equipment Of CTCS Based On Independent Increments Process

The on-board equipment of train control system is the core equipment to ensure the safe and efficient operation of the train,which has a complex structure,numerous failure modes and heavy maintenance tasks.Corrective maintenance and planned maintenance have gradually failed to meet the requirements of reliability and economy of on-board equipment.With sensors and condition monitoring technology,Condition-Based Maintenance(CBM)obtains real-time information of the equipment to diagnose and prognose the health status of the equipment.The optimal maintenance strategies of the equipment,which can effectively reduce the failure probability in operation and maintenance costs,can be formulated based on the diagnosis and prognosis results.The research on the key technologies of CBM in on-board equipment is of great significance to promote the practical application of CBM in on-board equipment.This thesis takes on-board equipment of train control system as the research object,and studies three key problems that need to be solved for CBM: the extraction of condition monitoring objects and parameters,the establishment of performance degradation model and the solution for optimal CBM strategy.The main research contents are as follows.(1)In order to determine the condition monitoring objects and parameters of on-board equipment,this thesis employs function-based failure mode and effect analysis to obtain the condition monitoring objects and parameters of on-board equipment at the function level;at the component level,the failure mode and effect analysis and risk analysis are implemented to obtain the maintenance significant items,followed by determining the maintenance prioritization of the maintenance significant items using the analytic hierarchy process and Monte Carlo simulation.(2)Aiming at the problem of establishing degradation models of on-board equipment,this thesis analyzes the performance degradation existing in the on-board equipment.Combined with the degradation characteristics of on-board equipment,the degradation models(Gamma process and Wiener process)based on independent increments process are used to describe the performance degradation of on-board equipment.(3)In order to solve the optimal CBM strategy model for on-board equipment,this thesis establishes the CBM strategy model under continuous monitoring and periodic monitoring,followed by solving the optimal maintenance strategy with the goal of minimum asymptotic unavailability and the goal of minimum maintenance cost rate respectively.Aiming at the shortcomings of the traditional iterative method to solve the optimal CBM strategy,this thesis proposes an optimal adaptive weight based particle swarm optimization algorithm to solve the optimal CBM strategy.Based on the life distribution of on-board equipment,this thesis uses Gamma process and Wiener process to simulate the degradation data of the on-board equipment.According to the simulation data,the maximum likelihood method is used to estimate the parameters,and a case study of CBM strategy about BTM and ATP-CU is explored.The simulation results show that the optimal preventive maintenance thresholds of BTM and ATP-CU under continuous condition monitoring are 78 and 92 respectively.Under periodic condition monitoring,the optimal monitoring interval of the BTM is 1124 days,the optimal preventive maintenance threshold is 78.05,and the optimal maintenance cost rate is 2.64 yuan/day;the optimal monitoring interval of the ATP-CU is 224 days,the optimal preventive maintenance threshold is 83.97,and the optimal maintenance cost rate is 21.02 yuan/day.By changing the maintenance cost parameters in the model,the change trend of the optimal value of monitoring interval of equipment,the threshold of preventive maintenance and the maintenance cost rate is consistent with the theory,which proves the effectiveness of the model theoretically.At the same time,the simulation results show that the optimal maintenance cost rate of BTM and ATP-CU under CBM is better than that when time based maintenance strategy is used,which further verifies the effectiveness of the CBM model.This thesis contains 43 figures,15 tables and 73 references.