Nonlinear Dynamic Inversion Autopilot Design for an Air Defense System with Aerodynamic and Thrust Vector Control

Bıyıklı, Rabiya
The study proposes complete attitude and acceleration autopilots in all three channels of a highly agile air defense missile by utilizing a subcategory of nonlinear feedback linearization methods Nonlinear Dynamic Inversion (NDI). The autopilot design includes cross-coupling effects enabling bank-to-turn (BTT) maneuvers and a rarely touched topic of control in the boost phase with hybrid control which consists of both aerodynamic fin control and thrust vector control. This piece of work suggests solutions to exclusive challenges of a system, such as non-minimum phase characteristics and mechanical coupling, which can also be referred to as the integrated mechanic design of TVC jet vanes and aerodynamic fins. A physically inspired solution to a non-minimum phase of a tail-controlled system is offered by performing output redefinition on the center of percussion of the missile. A cascaded two-loop structure is established with the fast loop inside and the slower loop outside. The thesis further analyses these designs with certain commands to create a highly coupled environment. In addition, the effects of uncertainties observed on the system with a selection of realistic uncertainty levels on parameters. Moreover, a realistic guided scenario in a 6-DOF simulation environment with the implementation of realistic sensor models and available feedbacks in real life for such air defense systems is inspected.


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Citation Formats
R. Bıyıklı, “Nonlinear Dynamic Inversion Autopilot Design for an Air Defense System with Aerodynamic and Thrust Vector Control,” M.S. - Master of Science, Middle East Technical University, 2022.