Research On Parachute Opening Triggering Algorithms In Mars Entry Process

Mars is a planet that nearest the earth,it's an important object for human to exploration since long time ago.As the key process in Mars landing system,the parachute is the best means for deceleration that people all accepted,while it works in a environment that supersonic velocity,low density and low dynamic pressure,therefor choosing an appropriate opening time relate to the landing system's successful and failure.In this paper,under the background of Mars exploration,we study the entry of Mars landing system and parachute deployment control method and deceleration of parachute.First of all,based on the dynamic of parachute recovery system that in our country,the entry dynamic models of 3dof and 6dof are being established,using Mars atmosphere model and MER aerodynamic database,and the basic characteristics of process and the effect of Mars' s rotation are analysed.Secondly,self-adapt opening control method is achieved according to opening control method,and the effect of aerodynamic characteristic for the method is being researched.Then,introduce the deviations of atmosphere density,entry angle,axial-force coefficient,normal-force coefficient,pitching-moment coefficient,moment of inertia,and set a set of random trajectories to analyse the effect of opening point distribution during random trajectories using self-adaptive opening control method.What's more,a multi-body model is built to study the dynamic characteristic and the deceleration effect during steady descent,and test the applicability and dependability of the methods,and study the whole trajectory of entry,descent,landing process.This paper associates self-adapt opening control method with Mars entry process and parachute deceleration process,it can provide references to design,analysis and research on relative problems on Mars entry and parachute deceleration.