Research On Characteristics Of Shimmy And Deviation Correction Of UAV Taxiing With Four Wheels

The UAV is affected by both aerodynamic and ground forces at its taxiing stage.When taxiing in a high speed,it's easy for it to be disturbed and get posture changed.In order to keep the UAV taxiing steadily on the ground,we need to research the problem of its ground dynamics in detail.In this paper,a certain four point landing gear UAV is taken as the research object,and the problems of the front wheel shimmy,the problems of deviation correction with braking and deviation correction with steering and the comprehensive deviation correction are studied in detail.Firstly the shimmy dynamics model was built to reflect the true state of motion.And tire deformation,bumper pillar deformation and rigid body aircraft motion are taken into account.Then the front wheel dynamic shimmy analysis is carried out.The influence of landing gear parameters and aircraft body parameters on shimmy is analyzed.And then the shimmy of two front wheels and the fuselage is studied according to the difference of the way the two front wheels are disturbed.A detailed study on UAV taxiing movement is carried out.Its movement model is simplified and analyzed.And the whole aircraft taxiing dynamics model which includes the tire model,buffer model and aircraft body model is built,which can calculate and analysis the load and response of the UAV when taxiing.According to the problems of deviation when taxiing,the control system model of deviation correction with braking and deviation correction with steering are furtherly established.The simulation of deviation correction with braking and deviation correction with steering for different deviation conditions is conducted to verify the feasibility of the deviation correction system.Finally,the two kinds of way of deviation correction are reasonably distributed according to the distribution coefficient of deviation correction instruction,and the simulation of comprehensive deviation correction is conducted,and the response of comprehensive deviation correction is compared with the response of single deviation correction,which verifies the advantage of comprehensive deviation correction control system.The research methods and the conclusion of this paper plays an important reference role on the study of UAV taxiing with four wheels.