Research On Attitude Control Algorithms Of Quadrotor

As a kind of the multi-rotor UAVs,the quadrotor is highly favored in the military and civilian fields for its advantages of strong mobility,high stability,simple operation,and vertical take-off and landing.The quadrotor is a strongly coupled,underactuated,nonlinear control system with six degrees of freedom and four control variables.To ensure that it can fly steadily,there are high requirements for all aspects of technology,and the design of the control method for the quadrotor flight attitude is the most important part of the entire flight control system.Therefore,the research on the attitude control algorithm has a very important significance for the rapid development of the quadrotor.In this paper,based on the analysis of its kinematics and dynamics characteristics,a dynamic model is established based on Newton-Mechanical equations.The control system is divided into two loops: the attitude angle and height channel are internal loops,and the planar channel x and y are external loops.Three different control algorithms were studied.The Simulink toolbox under MATLAB software was used to establish simulation models and their performance was compared through simulation experiments.Firstly,the controller design based on backstepping algorithm is studied.The results show that the stability,accuracy and anti-jamming capability of the controller need to be improved.Then,a backstepping adaptive control algorithm is studied,which is to add a corresponding adaptive law to the control system based on the backstepping method and to fuse the two algorithms.The results show that the improved backstepping adaptive algorithm has fast response,high stability,strong anti-interference ability,and has a certain degree of self-adaptability.Finally,the backstepping self-adaptive PID control algorithm is studied,which combines the backstepping adaptive algorithm with the classic PID algorithm.Unlike the algorithm fusion of scheme 2,this combination is a combination of different controllers.The outer loop controller is designed with the PID algorithm and the inner loop controller is designed with the backstepping adaptive algorithm.The results indicate that the backstepping adaptive PID control algorithm has very good control performance.Compared with the above two control algorithms,the backstepping self-adaptive PID control algorithm has better stability,faster response speed,stronger anti-interference ability and higher accuracy.This effectively validates the feasibility and effectiveness of this combined control algorithm.