Numerical Simulation And Characteristics Analysis On Unfolding Process Of Flexible Spacecraft With Small Rocket

A flexible spacecraft is a lightweight spacecraft with a flexible fabric which can be extended and deformed.It relies on thrust of small solid rocket to complete the space release.During the unfolding process,large deformation of flexible body and collision between multiple rigid bodies occur.It can easily cause the vibration of the system structure,and affect the stability of the aircraft and attitude control accuracy.It even leads to unintended results such as yaw and instability of the aircraf.In order to obtain the dynamic characteristics of the spacecraft deployment process,it established a small solid rocket engine internal ballistic model,and obtained a small rocket thrust values.Based on the theory of rigid-flexible coupling dynamics,the unfolding process of spacecraft is simulated in RecurDyn(Multi-body dynamic analysis software).The dynamics characteristic of the spacecraft under different dose of ignition were analysed.At the same time,different nozzle bevel angle were discussed.The main research contents include the following:1.According to the axial deployment mechanism and radial deployment mechanism of the flexible spacecraft,the structural composition of the spacecraft is analyzed in detail.It plans the working flow of the flexible spacecraft.The working characteristics and design requirements of the spacecraft are summarized.2.According to the principle of solid rocket motor,a small solid rocket engine internal ballistic model including ignition process was established.The fourth-order Runge-Kutta method was used to calculate the internal ballistic process.The internal ballistic pressure and thrust data of the small solid rocket were obtained.It analysed the work characteristics of the small solid rocket.The accuracy of the calculation model was verified by comparing the calculation results with the experimental data.3.Based on the basic theory of software RecurDyn,a multi-rigid body model of flexible spacecraft is established.The motion process of the radial deployment process is obtained through simulation calculation.The dynamic characteristics of the radial expansion process basing on a pure rigid mechanism are analyzed.4.Using the flexible body technology of the multi-body dynamics software RecurDyn,based on the rigid-flexible coupling dynamics principle,a dynamic model of the axial deployment process of a spacecraft with a flexible canopy was established and implemented in the multi-body dynamics software RecurDyn.The establishment of a physical model such as constraint application,contact setting,and external force application was used to simulate the process of axial deployment of a flexible spacecraft.The dynamic characteristics of the flexible spacecraft were analyzed in detail.5.In order to investigate the flexible effect of the flexible canopy on the system,the axial deployment process of the spacecraft including the canopy and the uncovered canopy was comparatively analyzed.For that the proportion of the ignition charge is large in small solid rocket,various motion parameters changes of the flexible spacecraft are analyzed on the different ignition charge.For the selection of the angle arrangement of rocket nozzles,the working characteristics and changing rules of flexible space vehicles with different nozzle angles are analyzed.It is not only provides theoretical guidance for the optimization design and attitude stabilization of small flexible spacecraft,but also provides experience and help for practical projects.