Fault tolerant control for vertical tail damaged Aircraft in final approach with switching LQR controller

This paper mainly focus on the fault tolerant control issue of vertical tail damaged aircrafts during landing process in final approach. A damage indicator is used to describe the damage degree of the vertical tail and rudder. Based on the damage indicator, the nonlinear relationship between the damage degree indicator and corresponding aerodynamic stability derivatives is fully considered. Nonlinear relationship between rudder derivative, vertical tail derivative and damage indicator in different low Mach number situations were studied. Furthermore, a modified state space feedback controller with variable element linear quadratic regulator (LQR) is proposed for changing objective between different control variables in different stages of final approach.