Low-thrust Orbit Transfer Using Suboptimal Model Predictive Staticprogramming(mpsp)

The optimal fuel or time is main goal of orbit transfer. Low-thrust orbit transfer trajectories is studied in this paper. The problem is tackled by implementing a fast and efficient control law called Model Predictive Static Programming(MPSP). This control technique borrows in great details, techniques from the well-known Model Predictive Programming(MPC) and Approximate Dynamic Programming(APC). It is a suitable control algorithm for nonlinear systems as it does not require the system dynamics to be linearized. Its convergence rate is also fast as the costate variable are made static and hence static optimization techniques can be applied to obtain a solution without the need to solve two-point boundary value problems while seeking optimal solutions indirectly. Moreover, since MPSP poses the desired conditions as a set of ?hard constraints?, the final accuracy level achieved is very high. MPSP control can further be applied as a reference control for already existing tracking controllers in a 2DoF configuration to handle unwanted output disturbance. This technique can be applied in any rendezvous scenario such as missile control, planet-to-planet orbit transfer etc. It has been applied here to the Earth-Mars low-thrust transfer and test cases with different terminal conditions are shown. Also, its characteristics in terms of accuracy, cost efficiency and rate of convergence are compared with other well established optimal control laws such as those derived from pseudospectral theory.