Cushion Characteristics Of Soft Landing On Mars With Omni-directional And Multi-chamber Airbag

Soft landing of the probe is one of the key technologies in the exploration ofMars. The control system and the precise instruments inside the probe are protectedonly when there is a landing buffer system making their peak load less than the limitresistance. The impact energy is mainly absorbed through the ways of airbag, landingleg, deformation of structure and recoil rocket. As a commonly used bufferingtechnique on soft landing of spacecrafts, the cushioning airbag can significantlyreduce the landing impact of the Lander with the advantages of good adaptability,high buffer efficiency and wide range of landing speed et.This thesis mainly investigated the cushion characteristics of soft landing onMars with omni-directional and multi-chamber airbag using numerical calculation andexperimental methods. The omni-directional airbag buffering system made referencesto the Mars Pathfinder. We mainly have done the following work:(1) It is validated that our method of airbag modeling based on the non-linearfinite element code LS-DYNA can effectively simulate the issues of airbag impact.The simulation result is in good agreement with the experimental result. The result isthe curve of acceleration of mass center of the drop hammer versus time respectivelyderived from simulation calculation using LS-DYNA and the impact experiment.(2) The accuracy of the finite element model of the soft landing system withomni-directional and multi-chamber airbag was verified. The results of the simulationanalysis of soft landing process conform the expectations that the landing system willexperience a energy decay process of several times of touchdown, bouncing androllover. After the simulation analysis, an experiment is carried out. The peak valueof the acceleration of mass center of the probe between simulation and experiment isalmost equal.(3) The cushion characteristic of omni-directional and multi-chamber airbag isstudied based on the rational design conditions. Influences of the characteristics oflanding surface, the landing direction, the initial airbag pressure, the airbag diameter,the diaphragm inner hole diameter and vent diameter on cushion properties areanalyzed. Based on the conclusions, a group of design parameters meeting bufferrequirements are got. The results can be used to guide the design of omni-directionaland multi-chamber airbag landing system.