Research On Quadrotor Based On Sliding Mode Control

Quadrotor is a type of unmanned aerial vehicle(UAV)powered by four propellers to generate lift,It can be vertically lifted and can fixed-point hovering which is flexible and highly controllable.Due to the advantages,It has good practicability in military reconnaissance,disaster search and rescue,and aerial photography.The development prospects have important engineering significance and research value.Besides the quadrotor has characteristics of nonlinearity,underactuation,strong coupling,and sensitivity to interference.The establishment of mathematical models and controller design have become the focus of research.This paper analyzes the development status and research status of quadrotor.Based on previous work,the Qball-X4 UAV of this laboratory is used as the research object to perform modeling and control simulation.1.The physical modelling method was used to establish the mathematical model of the quadrotor.To solve the problem that the mathematical model is difficult to obtain due to the under-driving and strong coupling characteristics of the quadrotor,this paper firstly analyzed its structural characteristics and basic flight modes,including lift,hover,roll,pitch and yaw.Then the ground coordinate system and the body coordinate system were established to study the changes of the motion state under the two reference systems.Simultaneously,the quadrotor was regarded as a rigid body structure,and its movement was analyzed from the kinematics and dynamics angles to establish its nonlinear mathematical model.2.Study sliding mode control ideas and chattering suppression methods.Because of chattering problem in sliding mode control,it is difficult to apply it to quadrotor and other physical mechanical systems.This paper selects the spring mass damping system as the control object,and studies its Matlab/Simulink simulation experiment based on sliding mode controller.Then,the sliding mode control law is approximated and the simulation results show that the improved sliding mode control law can suppress the chattering problem and can be applied to controller construction of quadrotor.3.Construct quadrotor sliding mode controller.Aiming at the sensitivity of quadrotor susceptible to interference,a sliding mode control algorithm was introduced to enhance the system’s anti-jamming capability.A SMC law approximation method was used to construct a sliding rotor controller for a quadrotor,In MATLAB/Simulink simulation,the results of the system’s response speed,position overshoot,and callback time are analyzed.The results verify the effectiveness of the sliding mode controller.4.The Qball-X4 quadrotor drone was tested in an experimental platform.The test verifies the correctness of the establishment of quadrotor model and the effectiveness of trajectory tracking.