Integration of Wake Impact Alleviation Control System into Control System Architecture of Modern Fly-by-Wire Aircraft

Abstract

Wake vortices can represent a serious disturbance for encountering aircraft because they can cause sudden, unexpected aircraft reactions like strong rolling motions. This paper presents a control system, called Online Wake Identification and Impact Alleviation (OWIDIA), which has the particular purpose to alleviate these wake-induced aircraft reactions and is applied in addition to the regular flight control laws of the aircraft. The OWIDIA system uses the information of an airborne forward-looking Doppler lidar sensor about the wake vortex wind velocities in front of the aircraft. On the basis of these measurements, an online wake identification algorithm characterizes a potential wake vortex and a control module determines the control surface deflections that countervail the wake-induced aircraft response. The present paper shows the undesired interactions that can occur when combining the OWIDIA system with the basic control laws of the aircraft and demonstrates how these interactions can be prevented.