Adaptive Control And Fault Tolerant Of Quadrotor Unmanned Aerial Vehicles

The quadrotor, as one kind of Micro Unmanned Aerial Vehicles (UAVs), has recently gainedgreat interest in both military and civil applications, and how to develop a reliable control algorithmto guarantee a stable autonomous flight has become crucial. However, due to strong turbulence,birds and other unpredictable factors, the flight qualities and security may be affected and evendegraded. Therefore, control not only in normal operation conditions but also in the presence offaults or failures is crucial and necessary for UAVs.This paper focuses on the control and fault tolerant of the quadrotor system and severalalgorithms are designed based on adaptive theory. Various simulations are carried out to analyze theeffectiveness of the proposed algorithms. The main work and contributions are as follows: firstly,the kinematics and dynamics equations of the system are analyzed and the mathematical model withsix degree of freedom is established. Secondly, a nonlinear mode of Quadrotor is decoupled into adouble-loop and multi-subsystems control structure, and an integral term is introduced to thenonlinear backstepping controller, dealing with the mode uncertainty caused by simplification; then,an attitude model is established based on the quaternions, and a model reference adaptivebackstepping control method is proposed, in order to control the quadrotor in the presence ofparameters uncertainty and unknown disturbance. Subsequently, an adaptive fault tolerant algorithmbased on the backstepping approach is developed, in which the effects of actuator constant faults areconsidering as uncertainty of the system. At last, an adaptive fault tolerant scheme is proposed byestablishing actuators matrix and introducing a parameter estimator, and single fault and multiplefaults are both analyzed.