Flight control in a windshear via nonlinear Hinfinity methods

The design of the control of an aircraft encountering wind shear after takeoff is treated as a problem of minimizing the H_infinity gain between the wind shear and the vertical acceleration of the aircraft. The method of nonlinear H_infinity control is used to design the control law. For the reason of robustness, no information or assumptions about wind shear structure or intensity are used in the design of the controller. The approximate solution of the Hamilton-Jacobi-Isaacs equation is used to design a nonlinear controller to improve the performance. Simulations under both linear and nonlinear controllers are carried out. The performance of the aircraft is good and the angle of attack is smooth.