Optimal Reconfiguration for Formation Flying Subject to Several Constraints
- Paper number
IAC-06-C1.P.4.02
- Author
Dr. Liu Jianfeng, Harbin Institute of Technology, China
- Coauthor
Dr. Siyuan Rong, Harbin Institute of Technology, China
- Coauthor
Dr. Naigang Cui, Harbin Institute of Technology, China
- Year
2006
- Abstract
Satellite formation flying is the placing of micro satellites into nearby orbits to form a cluster,these clusters of satellites usually work together to accomplish a mission,in recent years it has become a topic of significant interest in the aerospace engineering.Formation flying system has several benefits compared to the large single spacecraft system with equivalent missions,but is not limited to:low cost for launch and mass production,larger aperture size,greater launch flexibility,higher system reliability and easier expandability. In the present paper the problem with respect to reconfiguration for satellites flying in formation subject to several constraints of collision avoidance, final configuration,energy equalization and so on is addressed.Reconfiguration maneuvers is a challenging,can be required to transfer between one configuration and another,to make up for a satellite failure and to introduce new satellites in the formation.In this research a method for optimal formation reconfiguration is introduced in view of nonlinear programming technique which has seldom been applied to optimal reconfiguration for satellite formation flying.The cost function, constraints and their gradient are computed according to time interval discretized using N time nodes,at the same time the control sequence is generated by discretizing state and terminal constraints,these constraints are represented by a set of linear time-varying differential equations which describe the relative motion of each satellite with respect to a general elliptic or circular reference orbit which consider the disturbances coming from the non spherical Earth and air drag,the control strategy developed consists in checking if the real trajectory stays in the vicinity of the optimal one computed.When the error becomes greater than the predefined threshold a new optimization is carried on computing a new optimal control sequence,the iteration will not stop until those constraint equations are satisfied,thus further this method is based on finding a solution to the system of nonlinear equations that arise from the first order necessary conditions for an extremum of the nonlinear programming problem,the simulation results were be analyzed that demonstrated the good performance of the control strategy proposed for reconfiguration.In this way the real reconfiguration are made up by a series of optimal trajectories.The method proposed may be viable for future space mission.- Abstract document