Modeling And Controller Design Of Small Unmanned Helicopter Based On System Identification

According to small unmanned helicopter has unique characteristics such as low altitude flight and ready to take off and landing at any time, it has been widely used in military and civil applications.As helicopter is a nonlinear, strong coupling,complex aircraft and the common helicopter is very easy to be affected by change of temperature, wind and other environmental factors during the process of flight, so there are a lot of problems in set a ideal unmanned helicopter flight control system. Firstly, the helicopter itself is nonlinear and high complexity, so it is difficult to establish a complete mechanism model. Secondly, the instability of the helicopter leads to the input reaction is very sensitive, and it need to join the high frequency feedback signal to keep stable. Thirdly, while the helicopter in the flight process of horizontal and vertical coupling, the pitch yaw coupling is serious, which increased the difficulty to design the controller. At last, the helicopter flight process couple with high risk, which affects the safety of flight experiments.In view of the characteristics of the small unmanned helicopter, this paper based on the helicopter flight dynamics to build the mechanism model. While depth analysis the inside of a small unmanned helicopter mechanics and motion equation,the original function structure model of each input and output channels of the small unmanned helicopter is obtained. This paper based on CIFER system identification method and the original transfer function structure model, An improved method of system identification is proposed and the least square method is applied to search the state space model of minimum cost function, then the speed of convergence of the cost function is accelerated. By comparing the simulation results, improved identification method enhance the accuracy of system identification, so as to build a better transfer function model of small unmanned helicopter.In this paper, by using the auto disturbance rejection control(ADRC) method to establish a control system of a small unmanned helicopter, the controller of the unmanned helicopter in pitch channel, yaw channel, roll channel and height channel are designed, so as to its performance can overcome a variety of disturbance factorsin the flight test. Then the identification effect of the model can be better used in engineering practice.In this paper, Simulink platform of MATLAB has been used in the flight control system for simulation experiments. The platform was used to establish the transfer function structure model to carry out the simulation test. The auto disturbance and the traditional PID controller were added to rejection the ADRC controller in the model. And the above two controllers’ anti-jamming performance were compared. The simulation results show that the ADRC controller compare to the traditional PID controller has better effect in anti-jamming. Moreover, it shows that ADRC controller has practicability and high effectiveness.