Optimal large-angle attitude control of rigid spacecraft by momentum transfer

Abstract

The optimal large-angle reoriented manoeuvring control (OLRMC) of rigid spacecraft by three orthogonal momentum wheels with free final slewing time is investigated. The performance index to be minimised is defined as a combination of the time of manoeuvre and the integral squared sum of control torques. By utilising an iterative procedure, this control problem is formulated and solved as a constrained nonlinear programming (NLP) one. In this novel method, the count of control steps is fixed initially and the sampling period is treated as a variable in the optimisation process. An approach to find the initial feasible solutions of the NLP problem is also proposed. Since initial feasible solutions can be found easily, the optimisation process of the NLP problem can be started from different points to find the large-angle rest-to-rest manoeuvre of the rigid spacecraft between two attitudes. To show the feasibility of the proposed method, simulation results are included.