M.Sc Thesis

M.Sc StudentDov Ofir
SubjectOptimal Trajectories and Optimal Guidance for Maneuvering
DepartmentDepartment of Aerospace Engineering
Supervisors PROF. Yoseph Ben-Asher
PROF. Isaac Yaesh
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


A closed-loop guidance system for extending rocket range or auto-correcting rocket trajectory is presented. In this research we propose using Pseudo Spectral methods for finding open-loop guidance and trajectories, and designing closed-loop guidance by using the Neighboring Extremals (NE) method. This method finds the optimal neighboring solutions by linearizing the governing (state and co-state) equations. For large deviations from the nominal trajectory this linearization is not sufficiently accurate. A novel approach is proposed whereby a Fuzzy Logic method is employed. The combination of the Fuzzy logic with NE is termed "Fuzzy Neighboring Externals". Fusing neighboring-extremals and fuzzy control concepts in order to deal with large uncertainties and external disturbances develops a new sub-optimal rocket guidance methodology. The methodology is shown to produce near-optimal implementable closed-loop guidance for maneuvering rockets. Simulations of a case study demonstrate performance under large uncertainties.