Modelisation et commande robuste d'helicoptere

This memory deals with the modeling and the robust control of helicopter. Obtaining a mathematical model of helicopter system with a single main rotor that includes rigid, hinge restrained rotor blades with flap, and lag, degrees of freedom due to a combination of the aerodynamic, inertia, and mass loads is the object of modeling part. The model allows several hinge sequences and two offsets in the hinges. The aerodynamic loads are calculated by the blade element method. No analysis of aero elasticity is employed and the blades are supposed to be rigid. The download and the inflow follow the Pitt/Peters' dynamic model. Model trim and linearization are described and can be applied to a subset of the model in the rotating or no rotating coordinate frame. Two different mathematical models of helicopter are used one for linear dynamics and other for nonlinear dynamics. The inflow effects are accounted for by using a three state nonlinear dynamic inflow model. The analytical linear model was developed on the nonlinear model including the fuselage rigid body, the main rotor with flapping dynamics, the tail rotor and an atmospheric model. The analytical linear model has 22 states, including nine states of the rigid body, nine states of flapping and inflow dynamics. and four for the swashplate actuator dynamics. The configuration of helicopter used in this research is UH-60A (Black Hawk) of Sikorsky. transport helicopter with four blades articulated rotor.; In this memory, a robust control system design procedure is developed. The design procedure is based on Hinfinity mixed sensitivity formulation or loop-shaping approach, and recent theoretical developments that enable the synthesis of a robust controller with fixed or dynamic structure. To this end, Hinfinity form is discussed, a procedure for computing pre and/or post compensators is developed, and the Hinfinity cost function is modified to include specifications on the transfer matrix from references to controlled outputs. Fore flight controllers were designed for the linear model of UH-60A (Black Hawk) helicopter: two on Hinfinity mixed sensitivity approach, one on loop-shaping method and one on linear quadratic regulator and Hinfinity approach.