Buffering Mechanism And Ground Experiment For Capturing Of Non-cooperative Satellite

Satellites could be broken down, off orbit or out of fuel after being sent into space. So all countries around the world are finding out ways to capture those satellites and figuring out problems. Those satellites can be divided into two types: cooperative satellites and non-cooperative satellites. Non-cooperative satellites need particular docking mechanism as they are not designed to be captured. In capturing a free-flying satellite in space, there is always possibility that the satellite may bounce off from a space robot, and/or that the satellite may be damaged due to hard collision. In order to avoid such a situation, soft contact utilizing active compliance control and/or passive mechanical compliance is of great interest.First, buffering mechanism can move in 5-DOF. It has axial direction and radial direction buffering. It also has balance part to compensate gravity. Due to the axial deviation between capturing mechanism and nozzle, buffering mechanism has 8 group of disc springs around the axle to solve this problem. FEA software is used to analysis the ultimate strength of buffering mechanism.Second, dynamical model of docking of non-cooperative satellite is built by analyzing the linear spring-dashpot model. A transform matrix is proposed to get the force of impact between two satellites. Also the principle of virtual power is used to analysis the dynamic progress of the capturing.Third, the main parameters of buffering mechanism, including stiffness and damping, are designed by analyzing the simplified one-dimensional model of dynamical model. Simulation software is used to simulate the progress of capturing of non-cooperative satellite.Final, the thesis designs a ground experiment to test buffering mechanism. The buffering mechanism, equipped to the end of docking mechanism, is pushing by a ground-based robotic arm and the experiment is set on the air-floating test bed. Different initial situations are set to be compared with. The result, buffering mechanism can reduce the force of docking, is proved to be the same as designed.