Research On Control Technology Of Quadrotor UAV With Wind-Sand Environment

In this paper,we present a strategy for accurate trajectory tracking control of a quadrotor with unknown disturbances.To guarantee that the tracking errors of all system state variables converge to zero in finite-time and eliminate the chattering phenomenon caused by the switching control action,a control strategy that combines linear prediction model of disturbances and fuzzy sliding mode control(SMC)based on Logical Framework with Side Conditions(LFSC)is designed.In this paper,the traditional sliding mode control algorithm,the traditional fuzzy sliding mode control algorithm,LFSC control algorithm and wind-sand two-phase flow are studied respectively.The chattering phenomenon generated by the sliding mode control algorithm is eliminated,which lays a foundation for improving the control performance of the quadrotor UAV in the future.In this paper,the reason of chattering phenomenon of sliding mode algorithm and the necessity of reducing chattering are explained.In order to research the chattering phenomenon of input quadrotor caused by the sliding mode control algorithm,the traditional sliding mode control algorithm and the traditional fuzzy sliding mode control algorithm are simulated and analyzed by establishing the simulation model of the quadrotor.Simulation experiments show that the traditional SMC algorithm and the traditional fuzzy SMC(FSMC)algorithm have the problem of chattering,which makes the SMC method hard to apply in practice.In addition,improving the accuracy and robustness of the control system is very important for the flight of the quadrotor in complex external environment.Therefore,the LFSC method is proposed.In this paper,LFSC is applied for both position and attitude tracking of the quadrotor.Firstly,a linear prediction method is devised to the effects of minimize external disturbances.Secondly,new fuzzy law is implemented to eliminate the chattering phenomenon.In addition,the stabilities of two subsystems are demonstrated by Lyapunov theory,respectively.Simulation results demonstrate that the proposed LFSC scheme can guarantee that the tracking errors of all system state variables converge to zero in finite-time and the highfrequency chattering phenomenon caused by the switching control action does not appear using the proposed LFSC scheme.Besides,simulation results and comprehensive comparisons demonstrate the superior performance and robustness of the proposed LFSC scheme in the case of external disturbances.In this paper,the finite element model of the quadrotor is established to explore the disturbance characteristics of the quadrotor under the complex condition of wind-sand two-phase flow.In this paper,different initial flow velocity,different particle diameter and different particle concentration of two-phase wind sand flow were simulated and analyzed.The simulation results demonstrate that the interference force and torque of the quadrotor are related to the particle concentration and the initial airflow velocity,and have nothing to do with the particle diameter.The larger the initial flow is,the larger the interference force and torque are.The higher the particle concentration,the larger the interference force and torque are.The situation that has the greatest influence on the disturbance force and torque of the quadrotor is selected to verify the proposed LFSC algorithm.The simulation reaults shows that the proposed LFSC control algorithm can maintain good robustness of the quadrotor with the complex environment of two-phase wind and sand flow.In order to verify the practical application of the proposed LFSC algorithm,a software test platform for the quadrotor is built,and the actual flight test is carried out.The results confirmed the effectiveness and feasibility of the proposed LFSC algorithm.It provides a strong theoretical basis for the design of the control system of the quadrotor against the two-phase flow of wind and sand.The paper provides an important reference for the control performance and robustness of the quadrotor system in the complex environment and the deeper exploration of the control system design of the quadrotor.