Research On The Ground Dynamic Model And Simulation Of Wheeled UAV

The ground taxiing of unmanned aerial vehicle(UAV) is one of important phases in flight. In the process of ground taxiing, the gear and tire interact with ground to produce the ground forces,combined with the asymmetric structure, runway conditions and environmental factors, lead to UAV drift phenomenon during taxiing on the runway. Hence study the ground maneuver characteristics of unmanned aerial vehicle(UAV), build the ground model and trajectory bias rectification. It is quite significant to research the ground maneuver characteristics of UAV in guiding its taxing.Firstly, the relationship between friction coefficient and impact factor is analyzed, based on the study of the friction coefficient between the tires and the runway in the process of takeoff and landing.The longitudinal and lateral friction coefficient is calculated through the Pacejka magic formula. The nonlinear formula based on tire slip rate is used for calculating longitudinal friction coefficient, and the nonlinear empirical formula based on tire side-slip angle is utilized for lateral friction coefficient.This provides calculation method and basis for the establishment of tire model and solving the friction.Secondly, the quality- spring- damping model of gear and tire is established to obtain the amount and speed of compression in the stop and run process of aircraft. A double quality- spring- damping model is obtained combine with the gear and tire model. In addition, the ground model is built by analyzing ground movement characteristics of UAV, which lay a foundation for the simulations and control law design.Finally, Aircraft braking system model is set up and control law of main wheel differential brake is designed. The takeoff and landing performance of UAV is verified through different simulation results. The validity and efficiency of proposed methods can be proved.