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Upper Stage Guidance and Control with Fuzzy Logic
, M.Sc. Thesis Sharif University of Technology ; Asadiyan, Nima (Supervisor)
Abstract
In this thesis, fuzzy logic is used to suggest a simple algorithm in guidance and control suitable for upper stage decoupler transfer with finite and continuous thrust. It is attempted to improve injection accuracy utilizing classic guidance and control methods and fuzzy logic, while unpredictable errors exist. Orbital perturbations, uncertainties in thrust vector, and initial injection errors in parking orbit, are considered in order to actualize results. In this research, Lambert guidance, velocity to be gained, and fuzzy logics are used for upper stage guidance. Fuzzy-PD control is designed and applied into the upper stage. Final results show acceptable position errors and suitable fuel...
Closed-loop powered-coast-powered predictive guidance for spacecraft rendezvous with non-singular terminal sliding mode steering
, Article Acta Astronautica ; Volume 166 , 2020 , Pages 507-523 ; Ebrahimi, M ; Assadian, N ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
The present study aims to present a guidance algorithm based on the relative motion prediction for orbital rendezvous, in which a coast phase is allowed between two powered phases. In both powered phases, the solution of the Hill-Clohessy-Wiltshire equations is used to find the required state variables at each time instant. To track the required trajectory and compensate for any orbital perturbations and uncertainties, a non-singular terminal sliding mode method is utilized as the steering law. Then, the finite time convergence of the state variables is mathematically proved. In addition, the starting time of the second powered phase is adapted to perturbations and uncertainties by another...