Study On Skid Steering System Of Multi-axle Light ATV

Currently,because of the seriously shortage of the light mechanization equipment which could adapt to complex border geographical environment,the priority way to perform a task is walking in frontier.In this way,the mobility is slow,and the comprehensive fighting capacity is low.A kind of vehicle with high mobility capacity in complex non-road area is urgently needed.In abroad,several kinds of multi-axle light ATV had been developed and equipped,and most of them is equipped with skid steering system.There is a big difference between the theory of skid steering and theory of traditional steering for wheeled vehicles,and a complete system theory of the skid steering system has not been established yet.Many problems occurs during the usage in practice,like steering difficulty,poor handling stability,damageable steering brake,and high fuel consumption,etc.This paper completed the design of skid steering system of multi-axle light ATV,the research of tire mechanical characteristics during skid steering,the analysis of lateral dynamics of skid steering vehicle,the bench verification test and road test of skid steering.The fundamental theory and technical system on skid steering of multi-axle light ATV has been established,and is of great importance to the development of vehicle technology.First,the steering system of multi-axle light ATV is designed.The user requirement is analyzed by using the QFD,and several overall design projects are compared.The initial design and the performance analysis of steering system are made by using the method of tracked vehicles.The factor of turning resistance is obtained for the skid steering wheeled vehicles.These results lay the foundation of the further theoretical analysis.The tire mechanical characteristics are analyzed during skid steering.The simplified tire model is established based on two-dimensional load distribution.The changing law between pneumatic trail and turning radius is studied during vehicle steering.According to requirements of vehicle turning,two kinds of models with asymmetric load distribution in lateral direction are presented,and the problem of different slip angle on different part of tread imprint is solved.The lateral dynamics of skid steering vehicle is analyzed.The differential equations of 2 DOF lateral dynamics are derived,and the evaluation parameters and technical index for the handling stability of skid steering wheeled vehicle are presented.The influence of vehicle parameters(include velocity,structure and so on)on the performance of skid steering is analyzed.These results lay the foundation of the virtual prototype design platform for the skid steering multi-axle light ATV.Second,the characteristics of skid steering system are analyzed.The mechanical characteristics of bulldozing resistance and compaction resistance of tires during skid steering are obtained based on the analysis of mechanical characteristics of tire-terrain interaction by using the soil pressure model.A turning resistance factor model for the skid steering multi-axle light ATV is established.Finally,the prototype vehicle test is completed,whose results indicate that the steering performance of skid steering wheeled vehicle is better than that of tracked vehicle.The turning resistance factor model for the multi-axle light ATV has higher accuracy.The analysis result of dynamics model is basically correct.