Robust Nonlinear Close Formation Control of Multiple Fixed-Wing Aircraft
Qingrui Zhang, Hugh H. T. Liu
Abstract
This paper investigates robust nonlinear control for close formation flight of multiple fixed-wing aircraft. It aims to achieve precise position control in general flight operation under the aerodynamic impact induced by the trailing vortices of leader aircraft. One crucial concern is the boundedness of position errors subject to uncertainties and disturbances to be regulated with accuracy. This paper develops a robust nonlinear control algorithm to fulfill precise close formation-tracking control. The proposed control algorithm consists of baseline control laws and disturbance observers. The baseline control laws are employed to stabilize the nonlinear dynamics of close formation flight, whereas the disturbance observers are introduced to compensate system uncertainties and formation-related aerodynamic disturbances. The position control performance can be guaranteed within the desired boundedness to harvest enough drag reduction for a follower aircraft in close formation using the proposed design. The effectiveness of the proposed design is demonstrated via the numerical simulation of the close formation flight of two fixed-wing aircraft.