Design And Implementation Of Auxiliary Visualization System For Astronaut Control Of Serving Aircraft

The on-orbit service technology based on the small extravehicular serving aircraft is of great significance in the research of the efficient and stable on-orbit operation of the spacecraft.When the astronaut in the cabin controls the serving aircraft to serve the space station,on-orbit service should ensure not only the high efficiency of the mission,but also the safety of spacecraft and astronauts.It is necessary to design a visual system for auxiliary operation,which can realize the modeling of the complex space environment and the relative motion of the spacecraft.For the relative motion of spacecrafts at close range,it is necessary to provide early warning of collision in time,and form a visual system with high sense of reality,immersion and interaction.For the above reasons,this paper has done the following work:(1)Relative motion modeling of serving aircraft and space station.The space coordinate system involved and its transformation are introduced to make sure of the absolute orbit of the space station and the nominal orbit of the serving aircraft relative to the space station,such as separation/evacuation,diversion/hover,rendezvous and docking,etc.The relative motion of the spacecraft is modeled by the kinetic C-W equation and the relative motion state is calculated according to the initial conditions.(2)Collision detection algorithm for complex structures.The collision detection of complex structure model is introduced,which focuses on the theoretical basis of convex collision correlation,the preprocessing of complex model and the calculation of the distance between convex bodies based on improved GJK algorithm,to achieve real-time collision detection of relative motion between spacecraft and improve the real-time collision detection.(3)Based on the relative motion and collision detection algorithm of spacecraft,the on-orbit service of the International Space Station is selected for simulation.The programming based on C++,OSG network,multi thread,and dynamic link library is used to achieve the system development.And the natural celestial bodies,such as the sun,the earth and the moon,and the artificial satellites,such as the space station,and the serving aircraft,are built in the space virtual environment using OSG's extended OSGEarth.Good human-computer interface is provided,which includes viewpoint switching,text display controlling,etc.through the operation of mouse and keyboard.Scene is driven by geographic information data,3D model data,real-time measurement and control data or simulation data,and network transmission data,etc.The relative motion of the serving aircraft to the space station is simulated to monitor the relative position in real time and carry out collision detection.Collision warning information is displayed in the form of collision mesh surrounding sphere,text information,and sound,which ensures the high efficiency and safety of mission during the astronauts operating the serving aircraft.