Research On Preventive Maintenance Strategy For Hydraulic System Of Platform Fire Fighting Vehicle

As the core force of emergency rescue,platform fire fighting vehicle plays an important role in urban firefighting,rescue and disaster relief.With the rapid development of cities,urban planning is becoming more and more complicated and high-rise buildings are becoming more and more dense.As a result,the frequency of urban fires is getting higher and higher and the difficulty of rescue is increasing.In order to ensure the reliability of platform fire fighting vehicle in the rescue work,the minimum maintenance cost and the maximum availability are the starting point of this topic and the preventive maintenance is carried out in the absence of work.In this paper,the hydraulic system of platform fire fighting vehicle is taken as the research object,and the reliability analysis of the hydraulic system for luffing,rotating and leveling is carried out.The preventive maintenance model for hydraulic system of platform fire fighting vehicle is established,and the NSGA-II algorithm is improved according to the constraint functions.Finally,a preventive maintenance model solving software is established on the MATLAB GUI based on the improved NSGA-II algorithm.The main work and content of this thesis are as follows:(1)Analyze the hydraulic system for luffing,rotating and leveling,collect the corresponding fault events and fault data,apply the dynamic fault tree theory to establish corresponding dynamic fault trees,qualitatively and quantitatively analyze the dynamic fault trees.After analysis,the minimum cut sequence set and the corresponding reliability evaluation index are finally obtained,which provide data for the establishment of the preventive maintenance model.(2)In view of the characteristics of platform fire fighting vehicle,the non-periodic preventive maintenance strategy is adopted,and the concept of age reduction factor and equivalent service life are introduced to describe the actual system state after preventive maintenance.Taking the average maintenance cost and availability as the objective functions,and the total working time and reliability as constraint functions,a hydraulic maintenance preventive maintenance model for platform fire fighting vehicle is established.(3)According to the characteristic of the multi-objective function,the Pareto solution set is used as the optimal solution set of the model.According to the equality and inequality constraints,three aspects are improved: improve the initialization link of the algorithm,so that its initial variable value can satisfy the equality constraint;After the algorithm performs selection,crossover and mutation,take the average of the difference value to adjust the value of each variable;Insert the inequality constraint judgment function into the initialization,crossover and mutation of the program to judge whether the solution set of each link satisfies the inequality constraint.(4)Aiming at solving the maintenance model of platform fire fighting vehicle hydraulic system in this paper,a set of solution software is designed,which mainly includes startup interface,preventive maintenance model parameter setting interface,algorithm parameter setting interface and result reading interface.Finally,by inputting the model parameters and algorithm parameters in the software,the model of preventive maintenance is solved and the solution results are analyzed.