Stability Control Of Quadrotor UAV Under Abrupt Disturbance And Parameter Uncertainty

Quadrotor Unmanned Aerial Vehicle(UAV)has been used in various fields,such as military reconnaissance,electric power inspection,agricultural plant protection and logistics delivery.Because quadrotor UAV is easily affected by external force,load change,actuator failure and other sudden changes in the process of mission,it is necessary to design a controller with good stability,high robustness and strong adaptability to control quadrotor UAV system.This paper focuses on the research of control algorithm for quadrotor UAV under sudden disturbance and system parameter uncertainty during flight.The main work is as follows:Firstly,the development and application of quadrotor UAV are described,and the sudden disturbances in the flight process of quadrotor UAV in various fields are analyzed.The control algorithm used by quadrotor UAV is introduced and the composition and flight principle of quadrotor UAV system are analyzed.Besides,based on the Newton-Euler equation,the dynamics models under the conditions of external disturbances,sudden mass changes and actuator failure are established.Secondly,a double closed-loop trajectory tracking control strategy based on sliding mode control is designed to solve the problem that the stability of quadrotor UAV system is affected by external disturbance and internal parameter uncertainty.The quadrotor UAV system is divided into two subsystems: position(outer loop)and attitude(inner loop).The adaptive nonsingular fast terminal sliding mode control algorithm is adopted in the attitude loop to make the attitude error converge to zero quickly in finite time.The outer loop controller is designed by using RBF neural network approximation function to any function and combining the strong robustness of sliding mode control algorithm.The control strategy ensures that the state variables of quadrotor UAV can quickly converge to the expected value under the condition of external disturbance and internal parameter uncertainty,so as to track the given trajectory stably.Thirdly,a fractional order sliding mode control algorithm based on the adaptive law was designed to solve the control problem that the total mass of the quadrotor UAV system was changed due to the sudden change of load.The mass and disturbance adaptive law is used to estimate the total mass and external disturbance of the system in real time.The fractional order sliding mode control algorithm is used to control the stability of the system when the load changes sharply.Meanwhile,the fractional order sliding mode reaching law is designed to further weaken the chattering caused by sliding mode control.Finally,an adaptive fuzzy integral sliding mode controller is designed to solve the control problem of actuator sudden failure of quadrotor UAV system.The fuzzy approximation principle is used to estimate the actuator and external disturbance of the quadrotor UAV system in real time,and the adaptive fuzzy integral sliding mode control algorithm is used to control the system,so as to ensure that the quadrotor UAV can track the desired trajectory stably after the actuator failure.