Discrete-event And Continuous Mixed Simulation Of Space Station Operational Tactical Standard And Fault Plan

China will operate her own space station in about 2020.In order to ensure that the station operates normally and missions can be operated successfully,the planner should make different levels of planning for the various on-orbit missions,including the strategic plan(long-term),the tactical plan(mid-term)and the execution plan(short-term),and simulate and evaluate the obtained plans to make sure it reasonable and feasible.This dissertation studies the modeling and evaluating of the the tactical plan of the space station operations.The major achievements are summarized as follows.The DEVS(Discrete EVent Specification)model of the space station operation system is constructed.According to the characteristics of the operational process of the station,the model frameworks of the task scheduling layer,the astronaut execution layer and the equipment system layer are divided,and the corresponding attribute models according to the task events,astronauts and materials are also abstracted.Based on the discrete event system specification,the atomic models of control center,astronaut system,spacecraft system,space station subsystem and on-orbit material reserving management system are established,and then the coupling model of the whole station operating system is established.A mixed simulation method combing discrete and continuous processes for the standard tactical space station operational plan is proposed.Based on the characteristics of the tactical space station operation plan,the characteristics of discrete-event and continuous mixed simulation for tactical plan are analyzed.By using the simulation method of event scheduling in discrete event simulation,combining with clock-advance method,a dual timeline hybrid simulation engine is designed and the simulation flow of the standard plan is developed.Meanwhile,the plan evaluation system for the feasibility analysis and performance evaluation of the standard plan is constructed.The proposed method is tested by a tactical space station operational plan with the duration of 2 years,and the results show that the proposed method can provide valuable references for the plan verification.A discrete-event and continuous mixed simulation method for the tactical space station operational plan considering fault events is proposed.In order to clarify the effect of fault events on the operation of space station,the causes of spacecraft launch delay events and astronauts' threat events from the perspective of uncertainty of incident occurrence time are analyzed,and the corresponding emergency strategy and process are designed.The fault event probability model used in fault simulation is built.Based on the hybrid simulation engine,the simulation flow of the fault plan is designed,and the statistical evaluation system of the fault plan based on the classical statistical theory is put forward.The feasibility of the method is investigated by the tactical space station operational plan with the duration of 2 years and considering random factors,and the results show that this method can provide a valuable reference for the improvement and adjustment of the plan.The optimization method of simulation experiment for the fault plan based on variance reduction is constructed.According to the characteristics of the simulation of the space station operational tactical fault plan,and based on relationship between the data confidence interval and the simulation number of times in the same confidence level,a simulation experiment method of determining the number of times is designed based on the sequential program method.Based on the variance reduction technique,the experimental method is optimized to improve the precision of statistical results and efficiency of the experiment.The test results demonstrate the effectiveness of the proposed method.The propotype simulation software of space station operational tactical plan is developed.Based on the theoretical model and method of space station operational tactical plan,the prototype system software of the space station operational tactical plan is developed,which would lay the foundation for the engineering application of the method.Based on the tactical operation of the Chinese space station,this dissertation studies the standard plan simulation method,the fault plan simulation method considering random factors,and the experiment design of simulation,and then develops the propotype simulation software.The proposed methods and the obtained results can provide references to the operation of the Chinese space station.