Research On ADRC And Finite-time Attitude Control Of Two-degree-of-freedom Unmanned Helicopter

UAV have attracted widespread attention due to their short revisit cycle,high flexibility,and fast maneuvering speed.It has become more and more important in the fields of national defense,urban management,agriculture,geology,meteorology,electric power,rescue and disaster relief,video shooting and other industries.Attitude control technology for drones has been extensively studied.In the actual flight environment,the UAV system has complexity and uncertainty.A major challenge of high-performance attitude control of unmanned aerial vehicle(UAV)is that the mathematical models of UAVs are always not accurately built and they are often disturbed by external disturbances.Taking up this challenge,to improve the performance and quality of UAV attitude control,chapter 2 takes two-degree-of-freedom unmanned helicopters as the research object,and studies the flight attitude control of pitch and yaw.A high-performance and easily operated control method is designed-a nonlinear adaptive disturbance rejection control method based on a nonlinear extended state observer.The key idea of this method is online estimating the "total disturbance",which is composed by unmodeled system dynamics and external disturbance at first,and then compensate it in the feedback control.We develop a nonlinear design in ESO and feedback control.The stability and convergence of the closed-loop control system are strictly proved,and the effectiveness of the control method is theoretically guaranteed.The simulation compares the linear adaptive disturbance rejection control,adaptive disturbance rejection control with time-varying parameters,the nonlinear adaptive disturbance rejection control proposed in this paper and improved sliding mode control.The numerical results show the method proposed in this paper is better among the four controls when the measurement output is disturbed by noise.To improve the control accuracy and convergence speed of the UAV system when the model is accurately known,chapter 3 design a finite time state observer,and a finite time output feedback controller based on the finite time observer.We study the finite-time output feedback stabilization of a two-degree-of-freedom unmanned helicopter linear system.The finite-time convergence of the closed-loop control system are strictly proved.The simulation shows the state of the control system tends to zero after a finite time under no-noise and noisy,thus verifying the effectiveness of the proposed control scheme.