Multibody Dynamics And Experiments Of Parafoil System

Traditional parachute airdrop systems represented by circular parachute,has been unable to meet the requirements of rapid and accurate delivery in modern warfare.Parafoil with its good gliding and handling performance has become a hotspot of precision airdrop system.However the flexible and large deformation characteristics of the parafoil also bring nonlinear and unstable aerodynamic characteristics,and complex problems of added mass.There are obvious relative motion between canopy and payload,parafoil system must be treated as a mutibody system.Besides,because of the flexibility of the parafoil,the installation and data acquisition of the sensor on the parafoil is difficult,and enough and accurate experiment data can hardly obtained.The flight dynamics for parafoil system was studied.The mutibody dynamics method is used,and theory and practice are combined,aimed at a high fidelity dynamic model of parafoil system.And the dynamic model is applied to the simulation of airdrop process and personel landing fall.First of all,according to the material object and airdrop experiment of small parafoil platform,the parametric model of parafoil system is establised.The mass and geometric characteristics of parafoil system are in a detailed and full description with right amount of key parameters.The parametric model is one of important basis of aerodynamic calculation,dynamic modeling and simulation,and three dimensional visualization.Second of all,with the assumption of rigid canopy,a CFD numerical simulation method is used to study the aerodynamic characteristics of the two-dimensional airfoil and three-dimensional canopy,and the effect of canopy bulge is selective analysed.The polynominal type aerodynamic model of canopy and simplified aerodynamic model of the suspension lines,risers and payload are establised,which provide the original aerodynamic data for the subsecquent dynamics simulation.Third of all,considering the relative movement of parafoil system,a 18-dof dynamic model is established using quasi-coordinate method.Based on different assumptions,the relative motion is simplified accordingly,and a 9-dof and a 6-dof dynamics model are established.The motion characteristics and wind effects are analysed base on 18-dof and 9-dof dynamic model.At the same time,the airdrop experiment of small parafoil platform is conducted.A airdrop scheme based on parachute tower is selected and a measurement scheme is designed on the purpose of parameters identification,in which the selection of measurement and the selection and arrangement of the sensors are considered.And a detailed experimental scheme including post division,experimental flow and plan instruction is formulated.The scheme of small parafoil platform and experiment measurement are verified,which can be the foundation of subsequent work,including the revision of the theoretical model and parameter identification of parafoil system.Finally,based on VC++ integrated development,Unity 3D engine and virtual reality technology,a integrated simulation platform of parafoil system is developed.The airdrop process of parafoil and personnel parafoil landing fall process are simulated respectively based on 9-dof and 6-dof dynamic model,and a prototype simulation trainning system of parafoil landing fall has been built.The research work of this paper can provide a reference for the optimum design,dynamic modeling,airdrop experiment,the design of ground station,the simulation training of parafoil landing fall and other related issues.