טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentNadler Ron
SubjectVirtual-Formation Control Laws for Maintenance and
Reconfiguration of Satellite Formation
DepartmentDepartment of Aerospace Engineering
Supervisor Professor Emeritus Mauricio Guelman


Abstract

Spacecraft Formation Flying is an innovative concept referring to the coordinated operation of satellites flying in a particular pattern while maintaining precise, time-varying, relative states. The scientific mission is set for the entire formation as for a virtual platform. The Formation Flight concept incorporates unique challenges among which is the development of control architectures. In this thesis an autonomous translation control algorithm is designed for the maintenance and reconfiguration of formation flying missions in Earth’s gravitational field. The research deals with the overall translation control problem of the formation flying concept which comprises the decentralized (local) orbit keeping control problem and the higher level, coordination control problem of the satellite motions. The algorithm is based on a novel dynamic formation modeling called the “virtual formation” and on multi-level, closed loop control architecture. The design integrates decentralized individual orbit control and formation coordination control while allowing for on-line tradeoff weighting between the absolute and the relative translational modes of motion of the satellites. The tradeoff is determined according to the formation flight strategy (maintenance, reconfiguration, formation acquisition, or altering the coordination method). The realization of the algorithm is based on linear feedback control systems. Linear Quadratic formulation is used to determine the optimal maneuvers for formation maintenance and reconfiguration. The algorithm enables to dynamically combine between maintaining formation configuration coherency and flying the formation, as a virtual platform, on some desired orbit. The performance of the proposed algorithm is demonstrated through non-linear simulations of formations in LEO and GEO.