Design And Analysis Of New Configuration Running System Of Unmanned Vehicle Platform

With the complex battlefield environment in the future,the high-intensity maneuverability,wide-area adaptability and rapid deployment capability make great demands on the ground unmanned vehicle platform.The unmanned vechles are designed to drive at high speed and across complex obstacles,such as mountains,hills,urban ruins and deserts.It is accessible to areas where conventional vehicles are difficult to reach.As the "torso" of the ground unmanned vechle,the running system is the key component determining the road adaptability,off-road capability,load capacity and stability.After investigating the development status of ground unmanned platforms at home and abroad,this paper studies the high-mobility unmanned ground vehicle platform with excellent performance in various countries,and absorbing their advantages and disadvantages.Finally,a innovative running systom is developed based on the "three-variable" mechanisms.Which means variable-wheelbase,variable-track and variable chassis height mechanisms.This paper mainly analyzes the theoretical and simulation of variable-wheelbase and variable chassis height,proposing a vehicle dynamics control systom with the help of variable-wheelbase and vehicle attitude adjustment,to improve vehicle handling stability and obstacle-crossing capability.The mathematical modeling of vehicle dynamics based on the magic formula,which uses multiple variables that affect vehicle handling stability as inputs to the mathematical model.In terms of the influence of the active variable-wheelbase mechanism on the driving characteristics of vehicle,various aspects are analyzed,including the dynamic/static load distribution Under different tyre sliding conditions,the lateral and longitudinal forces and the vehicle yaw moment are affected.Otherwise,the overturning moment and the change in the center-axle affect the forces and moments in all directions of the tyre.Under the extreme driving conditions of the innovative running systom,the analysis results can provide a theoretical basis for the "three-variable" mechanisms controlling,to enhance the vehicle handling stability to a certain extent.The unmanned vehicle s’ appeal for high maneuverability usually quantifies the ability to obstacle-overcoming as technical indicators of trench-crossing and step-overcoming.Before the method realization and theoretical analysis of vehicle high-mobility,the theoretical analysis of the influence of variable-wheelbase on vehicle dynamics is carried out,which provides a theoretical basis for the obstacle analysis.In term of the special conditions of trench-crossing and step-overcoming,based on the method of variable wheelbase and vehicle attitude adjustment,the corresponding control strategies are proposed respectively.The control strategy of the obstacle-overcoming is divided into eight steps.It is assumed that the vehicle move at a very low speed.The theoretical analysis of each step can be approximated as a static force analysis,to study the difficulty of the entire obstacle-crossing.The dynamics simulation software(Adams)was utilized to verify the feasibility of control strategy of obstacle-overcoming based on the “three-variable” mechanisms.Finally,the finite element analysis are carried out mainly for the key components in the innovative running system,including double-cross arms and hydro-pneumatic springs.The finite element analysis is mainly for the double-cross arms.Firstly,under two special conditions of static dropping and low-speed striking,the vehicle dynamic simulations are carried out in the Adams software.The peak loads at the joint of each component are measured in the simulation results.These peak loads are used as the load inputs for the finite element analysis of each key component.Through mathematical modeling and simulation analyzing in the finite element analysis software,the displacement cloud map and the stress cloud map of each component are solved,to check and optimize the strength of mechanical structure.