Enhancements to an Atmospheric Ascent Guidance Algorithm

Abstract

Enhancements to an advanced ascent guidance algorithm for rocket-powered launch vehicles are described. A general method has been developed for conveniently and efficiently handling the common case of (asymmetric) launch vehicles with unbalanced thrust and aerodynamic moments. The new part of this development concerns the treatment of endo-atmosperic flight. An alternative method for handing the transversality conditions has been developed that eliminates the need for a priori elimination of the constant multipliers that adjoin the terminal state constraints to the performance index. As a result, new constraints can be formulated and implemented with relative ease.The problem of bum-coast-bum trajectory optimization is treated using a modified multiple shooting technique.

Pseudospectral Model Predictive Control for Exo-atmospheric Guidance

“…However, for exo-atmospheric guidance, the PEG approach still remains as the basis for modification and improvement. Some of the researches on PEG include those of Rose M. Benjamin and David K. Gellar [11], Dukeman [12,13], Lu, P. et al [7,14,15], Lijun Zhang [16], etc. The methods of Lu, P. et al [7,14,15] consider complete ascent profile including coast phases.…”

“…However, the methods involve analytical multiple shooting method for guidance solution and require iterations. Dukeman [12,13] solved calculusof-variation two-point-boundary-value-problem starting from vertical rise till main engine cut-off. The proposed method does not involve iteration and is mathematically faster and robust.…”

Improvements to an analytical multiple-shooting approach for optimal burn-coast-burn ascent guidance

“…(3.17) involves a switching function S that determines when the vehicle is using full thrust or coasting [14,13,30].…”

“…Regarding rapid mission planning, and especially the ability for in flight mission changes, the robustness of the algorithm is of the highest importance. To this end, algorithm convergence is enhanced using a multiple-shooting formulation [24] adding two additional nodes to the numerical problem [13,15,30]. One node is placed at the end of first burn,…”

“…[12] to a free final time formulation in which coast arcs are optimized. In another recent effort, Dukeman and Calise [13] develops a numerical multiple-shooting algorithm and introduces alternate forms of the switching conditions which allow for more general terminal conditions. In similar works, Lu et.…”