Research On Resisting Disturbance Control Technology Of Small-size Unmanned Helicopter

The small-size unmanned helicopter is an underactuated,strong nonlinear,strong coupled,uncertain model system.In the process of flight,the small-size unmanned helicopter is sensitive to external interference and also has poor anti-interference ability.Especially when the disturbance causes a large change in the attitude angle in a short time,the disturbance may lead to saturation of the actuator,which is one of the main reasons for the deterioration of the control system performance.So,in order to improve the anti-interference ability of the unmanned helicopter and avoid the actuator saturation,this paper adopts the auto disturbance rejection control and anti-windup control.Firstly,according to the helicopter kinematics principle,dynamics principle,navigation theory and rudder model,we establish the dynamic model of six degree of freedom,according to the helicopter control principle,we establish a four channel,internal and external loop controller.The two parts forme a flight control simulation system of small-size unmanned helicopter based on PID.Secondly,in order to solve actuator saturation problem,we analyze the amplitude range of saturation,and add a negative feedback to the original control input link to compose anti-windup controller.The theory analysis of transformed controller reveals that the essence of anti windup control is to add a lead correction link.The simulation results in matlab/simulink show that the control performance of the anti windup controller is superior to the traditional PID control when the attitude angle varies greatly.In order to improve the ability of anti disturbance,an auto disturbance rejection controller is proposed,and we build an auto disturbance rejection controller(ADRC)for small-size unmanned helicopter.The theoretical analysis shows that the ADRC can realize the estimation and elimination of the internal uncertainty coupling and external disturbances in the system.We design the attitude tracking experiment,the height control experiment,the anti disturbance experiment in the matlab/simulink simulation system.The simulation results further verify the correctness of the theoretical analysis,and the stability and robustness of the proposed method are significantly improved compared with the PID controller.Finally,based on Trex 550 helicopter platform and stm32f4 hardware platform,the ADRC algorithm and anti saturation algorithm are realized in the flight control board using C language and keil cross compiler environment.The experiment results show that the precision of attitude control and position control of small unmanned helicopter has been greatly improved.