Nonlinear Flight Control Using Forebody Tangential Blowing

Abstract

A novel nonlinear approach is presented to designing aircraft control laws based on combining high-gain control and Lyapunov techniques. The approach is applied and demonstrated experimentally to control the lateraldirectional dynamics of an aircraft at high angle of attack using forebody tangential blowing (FTB). FTB is a pneumatic device that modie es the vortical e ow over the forebody. The modie ed vortical e ow in turn creates roll and yaw moments for control characterized by highly nonlinear and uncertain input/output characteristics. The control approach presented here robustly inverts these characteristics and enables the exploitation of the full FTB efe ciency. The control approach is applicable in general to nonlinear systems which are actuated by a subsystem comprising uncertain static nonlinearities and linear dynamics.