Abstract: For the on orbit stretching berthing refueling task, a bias loading elliptical helical pipeline configuration is proposed to solve the problem of additional force caused by synchronous extension of the refueling pipeline in the docking process. Firstly, the axial stiffness and stress mathematical expression of the pipeline are deduced, and the accuracy of the above two expressions is verified by finite element simulation and experiments. Then, the configuration optimization design based on the minimum axial stiffness is carried out for the elliptical helical pipeline and the other three applicable pipelines in the same design space. The optimal configuration and minimum additional force of the above four pipelines are obtained, and the complete design method of this kind of on orbit refueling pipeline is formed. Compared with the finite element simulation and experimental results, the relative errors of the derived mathematical expressions of the axial stiffness and stress of the pipeline are less than 5%, which can be used for the design and analysis of this kind of pipeline. Compared with the unbiased circular helical pipeline, the proposed bias loading elliptical helical pipeline reduces the additional force of the pipeline by about 83.5% during the docking process, which is more suitable for the on orbit berthing refueling task.

Key words: On orbit refueling, Elliptical helical pipeline, Axial stiffness, Optimization design, On orbit berthing