Research On Ground Modeling Of Tricyle Landing Gear UAV

The force is very complex for the UAV when it is on the ground. It's dynamic characteristics is different from flying in the air. So it is important to build a accuracy ground model, to imitate the ground dynamic characteristics of the UAV, and provide a real simulation environment to satisfy the requirements of the ground simulation verification, in order to guarantee the safety for UAV landing.In this paper, we choose a certain type of a front three point landing gear UAV as the object.When finished analyzing the dynamic characteristics of UAV during its taxiing process, we treated landing gear buffer as a spring damper system. According to the relationship between the compressive strength of the landing gear and the support force of the wheel, we built the mechanical model of landing gear. After the relationship between the friction coefficient and the slip ratio of the wheel was analyzed, and according to the characteristics of UAV ground lateral movement, we have divided the lateral movement into low and high speed roll stage. For low speed sliding surface friction, it can strong ability to counteract the external disturbance, so according to force and torque balance mechanism, the mechanism of three wheel side force distribution was designed, and then the dynamic model of the UAV ground motion at low speed was built. Considering the UAV aerodynamic effect of high speed sliding and its ground friction significantly weakened, a model among the lateral friction force lateral stiffness and sideslip angle of the wheel was built. The model realized the ground dynamics simulation of the sample UAV at high speed.After modeling the ground motion of the sample UAV, according to the front wheel deflection and rear wheel brake mechanism of the two types of deviation, the dynamic model among the ground friction deflection angle of front wheel and the brake combining moment was built. The model simulate the force change process of the front wheel deflection and rear wheel brake deviation of the sample UAV when it's on ground.After finishing analysis the dynamic of the UAV taxiing process, according to the Newtonian dynamics and kinematics theory of inertia space, a ground dynamics model of the UAV was built. The simulation results show that the model is accurately to simulate the dynamic characteristics of UAV.The model is correct and useful, it satisfy the needs of simulation verification.