Research On Modeling And Control Method Of Quadrotor System

Quadrotor aircraft is the most widely used small unmanned aerial vehicle at present.Various flight attitudes including vertical takeoff and landing can be achieved by changing the rotational speed of four symmetrically distributed rotors.This kind of aircraft has the characteristics of simple design structurersimple control and motion sensitivity.However,since the quadrotor system is an under-actuated system,the design of control system is difficult.The quadrotor control system includes attitude control loop,speed control loop,position control loop..Attitude control loop is the core inner loop of a quadrotor control system.Its stability and control performance are directly related to the operation efficiency of the whole system.How to design a stable and fast attitude controller is a hot issue in the current academic research.The research on attitude control algorithm for quadrotor system has important academic research value.On the basis of consulting a large number of academic papers,this paper has carried out in-depth research on the attitude control algorithm of quadrotor,which is as follows:1.Aiming at the attitude control problem of a quadrotor,an attitude controller with disturbance observer is designed by combining adaptive algorithm and backstepping sliding mode algorithm is presented.First,according to Lyapunov stability criterion,a backstepping sliding mode control law is designed,and an integral adaptive law is introduced to overcome the parameter disturbance of the model and the external disturbance of the system.For the uncertain disturbance of the system,the boundary problem of its disturbance value is often difficult to estimate.In this paper,a disturbance observer is designed.The real-time estimation of the unmeasurable disturbance is carried out,which improves the anti-jamming ability of the system.Finally,the simulation analysis is carried out on MATLAB/Simulink platform,which verifies that the controller designed in this paper has better robustness.2.Considering the MIMO characteristic of a quadrotor,an attitude controller based on model predictive control algorithm is designed.Predictive control algorithm has natural decoupling ability and can deal with the coupling effect between variables effectively.In this paper,a linear predictive control algorithm based on state space model is adopted.A linearization method is designed around each state point for the quadrotor nonlinear model.The model mismatch is reduced by retaining the coupling relationship between system parameters as much as possible.In order to ensure unbiased tracking,the model is incrementally extended,and the output information is added to the state,and the state feedback correction is carried out by Kalman filter algorithm.The parameter adjustment of the controller is flexible and simple,and it can match the computing ability of the current mainstream hardware platform.Finally,the validity of the algorithm is verified on MATLAB.3.According to the classical UAV system structure,the overall structure of the quadrotor aircraft is designed,including the selection and installation of the aircraft frame,power system and ground station command and control system,and finally the quadrotor aircraft experimental platform is built.Then the classical cascade PID controller is designed to realize the overall control of the aircraft,including the outer loop position control and the attitude inner loop control.Finally.the flight test is carried out on the physical platform.The experimental platform built by the test can achieve good operation and meet the control effect.It can provide a physical platform for subsequent advanced algorithm verification.