Active Disturbance Rejection Controller Design Of Flight Control For Unmanned Helicopter

Helicopters are a unique aircraft that can take off and land vertically,fly at low altitudes,and hover in a position that is not available to traditional fixed-wing aircraft,which makes helicopters a wide range of applications.But the system of helicopter with the characteristic of six degrees of freedom,non-linearity,coupling,and strong external interference,It is a difficult task that it can autonomous flight,so we need to design a good control system for unmanned helicopter with strong robustness.Computer simulation is also a popular method,which can reduce the time and cost of designing flight control system.The main contents of this paper include the following aspects:First,setting up the unmanned helicopter model is the foundation.According to the kinetic and aerodynamic analysis of U8 unmanned helicopter,a small disturbance motion equation of unmanned helicopter is established,and the mathematical model of attitude channel is obtained.Through the method of mathematical transformation,the attitude channel is transformed form a high-order system into second-order system.Second,unmanned helicopter autonomous flight,attitude control is the key.In order to improve the accuracy,robustness and stability of unmanned helicopter attitude control,this paper uses the emerging technology of active disturbance rejection control(ADRC).The double closed-loops control structure is used to realize the autonomous flight control of the unmanned helicopter.The inner loop uses the active disturbance rejection controller to control the attitude and the outer loop uses the improved nonlinear PID controller.Based on the in-depth analysis of the theory of active disturbance rejection control,it is pointed out that the active disturbance rejection control technique has a good decoupling characteristic for the coupling system,which can decouple unmanned helicopter pitch,yaw,roll and height channel.With flexible selection of state variables turn this channel into independent second-order systems,on this basis,for each channel design of the active disturbance rejection control controller,and PID controller control effect to do comparison.The simulation results show that the active disturbance rejection control controller has good attitude stabilization control effect,strong anti-interference ability and good robustness.Finally,the three-dimensional model of unmanned helicopter and the virtual world of flight are established by using the 3D animation technology in Matlab.The flight control system of unmanned helicopter is connected with the virtual world to construct the trajectory tracking control of the unmanned helicopter.The whole trajectory contain: Take off first,thenbegin to climb smoothly,and finally into a highly stable level forward flight The simulation results show that the designed flight control system has the advantages of with simple control algorithm,strong robustness and strong anti-interference ability,and has good control effect,which can be used to control the trajectory of the pre-set trajectory.The 3D animation technology can visually show the whole take-off process,which simplifies the process of observing fly states,understanding and analysis of many complicated information in the system,and plays a good role in the design of the control system.