Research And Application Of Gert Network Optimization Model For The Commercial Development Of Launch Vehicle

Development project of carrier rocket contains a large number of launch activities,which are highly dependent,uncertain and repetitive.Many activities can not be carried out successfully at one time.It needs repetitive feedback cycle and information exchange,which leads to the rework and iteration of activities,and increases the project cost and prolongs the launch cycle.The project managers usually want to obtain the minimum time limit and cost,the maximum benefit and value at the same time.Under such conditions,how to make full use of existing resources,save costs,improve the quality and successfully complete the commercial launch mission of launch vehicles is of great practical significance to improve the competitiveness of commercial launch services.In practical management,managers should first consider the commercial launch mission characteristics of launch vehicles,such as how to characterize complex project activities.Therefore,this paper extends the traditional GERT network analysis algorithm according to the relationship between the factors of the launch vehicle development project.We constructs the multi-stage and parallel GERT network diagram of the launch vehicle development project.Considering the future development expectation of the project,a comprehensive foreground value maximization optimization model is constructed based on the foreground theory.On the basis of project schedule description,multi-mission optimization for commercial launch of launch vehicles with uncertain completion time of project activities is carried out.In this paper,interval variables are used to characterize the uncertainty of each part of the activity time in the process of project planning,and a mathematical model of the change of completion probability caused by time and resource input is proposed.An optimization model of time planning and resource scheduling under the scenario of total completion time,resources and probability constraints is established to solve the inverse problem of project activity time.In practice,there are random overlap and random feedback of activities in the process of project development.Therefore,DSM and GERT network are combined to depict the random overlap and random feedback of activities in complex product development projects,and the calculating framework of project duration,cost and other indicators is established.This paper studies the time-resource optimal scheduling model and its calculation method under the uncertainty of the completion time of each activity in the project and the constraints of total project time,cost and quality.