Research On Control Of Spacecraft In Low-impact Separation

As the key component in the spacecraft, separation device directly affects thecompletion of the mission, therefore obtains increasing attention. The loading oftraditional fire separation device is huge, leading to a potential impact on spacecraft.In order to solve this problem, a new type of separation device is in need, whichowns the advantages of small separation loading, large load bearing, less requiredenergy as well as a controllability in separation speed. Taking the mobile platform asthe research object, the thesis designs a new type of pneumatic separation andunlocking device and study the controllability in the process of separation.First, with the knowledge of mechanics, the satellite platform, together with thesmall satellite’s orbit dynamics equation which is relative to the inertial coordinatesystem is established. Under the guidance of the Lagrange equation, the satelliteplatform’s attitude dynamic equation with flexible components and its kinematicequation are deduced, laying a foundation for subsequent controller design.In accordance with technique, the new pneumatic separation and unlockingdevice is designed, the mathematical model of new separation equipment deducedand the separation speed controller devised. On this basis, the influence of theseparation device’s design parameters on the separation process is studied. Theinfluence, of the impact load produced by separation mechanism, on satelliteplatform’s orbital movement is analyzed. The influence, of the impact momentgenerated by separation mechanism’s decentralization and the flexibility of solarpanels, on satellite platform’s attitude dynamic movement is explored.Based on the Lyapunov stability theorem, PD controller and sliding modevariable structure controller are designed respectively. The attitude stability and thecontrol precision of the two controllers are compared when the mobile platformmeets the impact load. The strain rate feedback compensator is designed according to the coupling influence between the flexible vibration of solar panels and theplatform.At last, the simulation is conducted on the separation control system throughsimulation software. Meanwhile, a mathematic model of the pyrotechnically actuatedseparation device is established. The simulation results demonstrate that comparedwith the pyrotechnically actuated separation device, the separation device in thisthesis generates smaller impact load, the satellite attitude controller meeting adequatedemands and stars keeping higher control accuracy as well as attitude stability. In themeantime, the improvement on control system’s dynamic characteristics generatedby the active vibration suppression is proved in the thesis...