Quadrotor Flight Control Based On Improved Active Disturbance Rejection Control Technology

Quadrotor UAV has been generally utilized in the military and civilian area because of its sensitive response,small size,low price and ability to take off and land in almost any situation.However,due to the specificity of the utilization of quadrotor UAV,it is trouble to model accurate and efficient control system due to the influence of unknown destabilization.Since the theory of auto disturbance rejection control(ADRC)technology was proposed,it has been widely applied to the quadrotor UAV because it can effectively control the indefinite system with nonlinear,time-varying and unknown interference.At the same time,as the core of ADRC,extended state observer(ESO)can take stock of the sum destabilization of the system,and its operation mechanism has been analyzed and improved by researchers.However,most scientific researchers improve the characteristics according to the selection of nonlinear error function and parameter setting of ESO,but few of them improve its structure.Therefore,This thesis text analyzes the ADRC in view of the deviation theory and finds that the ESO has problems such as high steady-state error and difficult parameter selection.Contrapose these problems,the structural error correction transformation is carried out,and the improved ADRC is designed and applied to the control system design of quadrotor UAV.This text mainly carries out the following aspects of research.Firstly,The kinetic model of the quadrotor UAV is established.This paper analyzes the structure and flight principle of quadrotor UAV and makes reasonable assumptions according to the actual situation.Then,according to Euler dynamics and the motion theorem of mass core,the dynamic model is deduced and the dynamic equation is obtained.For the sake of settle the trouble of underactuated dynamic model of the quadrotor UAV,the virtual variables were introduced and mathematical methods were used to change the model of it into a fully actuated model,and the position loop and attitude loop were led out.Secondly,Aiming at the model characteristics and control strategy of the quadrotor UAV.Taking the second order nonlinear system as an example,the ADRC means is expounded.The rationale and composition of ADRC are recommended,and the functions of tracking differentiator(TD),(ESO),nonlinear states feed-back(NLSEF)and disturbance compensation are introduced in detail.Then,by analyzing ESO from deviation theory,it is found that the traditional ESO has some problems,such as high steady-state error,difficult parameter selection and so on.The structure error is corrected and an improved ESO is designed.Thirdly,The attitude regulate of quadrotor UAV is discussed.The control system is divided into four channels,and the ameliorative ADRC is used to control the system.The design of the controller is deduced with the example of roll channel.The emulation validation of the controller is implemented from attitude tracking,hovering,external force and wind disturbance test.The simulation results show that the observation accuracy of the ameliorative ESO is better than that of the traditional ESO in the autonomous control of the quadrotor UAV.Finally,According to the different control requirements of the inner and outer rings of the quadrotor UAV,the backstepping controller is used for the position control system with high static error requirements,and the parameter regulates is utilized to decrease the position control error.The ameliorative ADRC is used for the attitude control system with high anti interference capability and high rapidity requirements,so that the real-time attitude can accurately and quickly keep up with the desired attitude.The quadrotor UAV is realized by designing different controllers in the inside and outside ring tracking of the trajectory.