Disturbance Rejection Of Coaxial Helicopter Micro Air Vehicle

Micro Aerial Vehicles(MAV)are subject to growing interests from researchers because of its search,rescue and reconnaissance missions in Atmospheric Boundary Layer(ABL)area which is below 1000 meters.But the flight safty and flight stability of MAVs are threatened by turbulences and gusts unsteady air field,because of complex topography and geomorphology,and then climate evironments.By the studies of MAVs' disturbance reject to enhance flight stability and flight safety of MAVs in the urban district,plateau and other complex terrain and complex weather conditions,which has important theoretical value and practical significance to achieve all-weather regional development of MAVs.For a long time,the disturbance rejection method study of MAVs in ABL area unsteady flow field is a hot and difficult point.To attenuate the disturbances of MAVs resulted from the unsteady flow field,this thesis is focus on disturbances rejection of coaxial helicopter MAV,explore the disturbance rejection method applied on MAVs.After that,bio-inertial reaction wheel and bio-windy reaction wheel are proposed.Besides,a new coaxial helicopter MAV,without stabilizer bar or swashplate,is presented based this reaction wheels.My studies proposed that the active disturbance rejection method of bio-reaction wheel could reject several standard disturbances.Besides that,the coaxial helicopter MAV with bio-reaction wheel could follow the alltitude instructions rapidly,which could enable the coaxial helicopter MAV control its flight direction correctly.The above works make contribution to all-weather flight of MAVs.The major work and creative contribution of this thesis are as follow:Firstly,passive disturbance rejections of stabilizer bar are proposed.Focus on disturbance rejection characteristics of stabilizer bar of coaxial helicopter MAV,the disturbance rejection characteristics in impulse disturbance,step disturbance,sine disturbance,and Gaussain disturbane and chirp disturbance of a hover coaxial helicopter MAV are proposed.The simulation results show that:1.The stabilizer bar could reject the impulse disturbance and step disturbance completely;2.The passive disturbance rejection of stabilizer bar could not reject the sine disturbance,Gaussain disturbane and chirp disturbance.Secondly,based on the disturbance rejection characteristics of stabilizer bar,the active disturbance rejection method of Manduca sexta is analysed.The application method of this method is studied.The scheme of electromagnetic pendulum,inertial reaction wheel and windy reaction wheel inspired by active disturbance rejection method of Manduca sexta are proposed.Experiment study shows that:1.The responsed frequency of electromagnetic pendulum designed could reach to 7Hz,but the weight and the size are not suitable for MAVs.2.The responsed frequency of inertial reaction wheel could reach to 10 Hz and then its weight and size are suitable for MAVs.Besides,it would not result in complex dynamic model to MAVs.Unfortunately,the output torque will disappear when its speed reach the limit.3.The responsed frequency of windy reaction wheel could reach to 10 Hz,and then its weight and size are suitable for MAVs.Besides,it would not result in complex dynamic model to MAVs.In addtion,it's not easy saturated because the output torque is involved with its speed.The study result shows that the inertial reaction wheel and windy reaction wheel could apply for disturbance rejection of MAVs.Finally,based on disturbance application of coaxial helicopter MAV,a novel coaxial helicoter MAV without stabilizer bar or swashplate is proposed and then the characteristics of disturbance rejection and attitude tracking are studied.This thesis derived the nonlinear and linear dynamic model of bio-reaction wheel coaxial helicopter MAV by the Langrange method.The compared simulation shows that while the attitude angle below 0.3 rad,the nonlinear model of the bio-reaction wheel coaxial helicopter MAV could be replaced by linear model.After that,the disturbance rejection characteristics of bio-reaction wheel coaxial helicopter MAV in impulse,step,sine,Gaussian and chirp disturbance by PID and LADRC control method.The simulation results show that:1.Several standard disturbance effected on the coaxial helicopter MAV could be rejected by bio-raection wheel.2.Compared by PID control,there is much better disturbance rejection characteristics for LADRC control.3.Duiring attitude tracking effected by disturbance,LADRC has the characteristics of fast response and no overshoot.