Research On The Steering And Pitching Motion Performance Of The All-Terrain Articulated Tracked Vehicle

Because of its large capacity,high mobility,strong off-road capability and other advantages,the all-terrain articulated tracked vehicle is widely applied in the various engineering fields such as: military strategic materials transportation,agriculture/forestry transportation,emergency disaster relief and forest fire protection,and other engineering fields.It also has made an outstanding contribution to the national economic and security construction.At present,although the various countries in the world have developed different types of all-terrain articulated tracked vehicle,such as: Swedish“BV206”,Russian “Warrior”,China “Python”and other all-terrain articulated tracked vehicles,the theory research on the all-terrain articulated tracked vehicle is still in a serious hysteretic state,especially for the driving mechanics research work of the all-terrain articulated tracked vehicle.Therefore the driving mechanics research on the all-terrain articulated tracked vehicle has an important practical significance for the development of the all-terrain articulated tracked vehicle.The steering performance as an important evaluation indicator of the articulated tracked vehicle mobility,and it is also an important part of the driving mechanics research on the all-terrain articulated tracked vehicle.However,the existing methods mostly focused on the steering performance of the single tracked vehicle,and only a few papers study the steering performance of the all-terrain articulated tracked vehicle without considering the effect of centrifugal force,and the steering dynamic model of the tracked vehicle is established based on the coulomb friction force between the track and the soil,therefore the friction coefficient between the track and the soil needs to be determined from the pull–slip tests on the soil.In this way,it will affect the model generality.To solve these problems,this paper proposes an improved steering model of the articulated tracked vehicle to solve the abovementioned problems.This steering dynamic model of the articulated tracked vehicle is proposed based on the soil shear stress analysis.Meanwhile,this model considers the effect of the centrifugal force on the vehicle steering performance.In this way,the related parameters in this model can be easily obtained by looking for the existing references without conducting pull–slip tests on the soil.This proposed model here can improve the model generality,and make up for the existing methods deficiency,and also make the analysis results to be more close to the engineering practice.All-terrain articulated tracked vehicle often encounters the small steering radius road condition.At this time,the vehicle needs to go through this road condition by using the spin steering movement.To comprehensive evaluation the passing ability of the articulated tracked vehicle,it needs to analysis the spin steering performance of the articulated tracked vehicle.However,the most researches focused on studying the vehicle steering performance,and less paid attention to the vehicle spin steering performance.To this issue,it adopts the mathematical modeling method to set up the kinematic and mechanical model of the all terrain articulated tracked vehicle in the spin steering process.Then the established model is applied to analysis the spin steering performance of a specific articulated tracked vehicle.This proposed model here can make up for the existing methods deficiency for studying the spin steering performance of the articulated tracked vehicle.The pitching motion as the all-terrain articulated tracked vehicle unique movement form,it can help the all-terrain articulated tracked vehicle get through some extremely complex road conditions,such as: trenches,vertical obstacle,and other complex road conditions.However the existing methods mostly focused on the vehicle steering performance,and less paid attention to the pitching motion performance of the articulated tracked vehicle.In this paper,on the basis of deeply studying the pitching movement mechanism of the all-terrain articulated tracked vehicle,it sets up the kinematic and mechanical model of the all terrain articulated tracked vehicle in the pitching movement process.Theoretically it deduced the maximum pitching angles of the front and rear vehicles,the maximum pitching heights of the front and rear vehicles,the motion trail radii of the centers of gravity of the front and rear vehicles,and the minimum pulling/thrusting force of the articulated units etc formula.This proposed method here can make up for the shortage of the existing research methods on studying the pitching motion performance of articulated tracked vehicle.Nowadays,the virtual prototype simulation technology is the commonly used method to study the dynamic characteristic of the crawler walking system.All-terrain articulated tracked vehicle is a complicated system,and it involves the traditional mechanical system,hydraulic control system,electrical system and other systems.So it is difficult to adopt the single simulation software for accurately modeling and simulation.This paper adopts the multi-body dynamics simulation software(Recurdyn)and AMESim software to establish mechanical-control united simulation model of all-terrain articulated tracked vehicle,the multi-body dynamics simulation software(Recurdyn)is mainly used to build the mechanical movement system of the all-terrain articulated tracked vehicle,and the AMESim software is mainly used to build the hydraulic control system of the all-terrain articulated tracked vehicle.This paper mainly simulated analysis the driving steering motion,the spin steering motion and the pitching motion.Finally the simulation results are compared with the theoretical calculation results.The comparison results show that: the simulation results are consistent with the theoretical calculation results,and the relative errors between the simulation results and the theoretical calculation results do not exceed 14.7%.It illustrates that the simulated results are consistent with the theoretical calculation results.Finally,a real vehicle test is made for studying the driving steering motion,the spin steering motion and the pitching motion performance of an all-terrain articulated tracked vehicle.The actual experimental results of the articulated tracked vehicle are compared with the theoretical calculation results of the articulated tracked vehicle.The contrast analysis results show that: the theoretical calculation results are consistent with the experimental results.It can verify the correctness of the theoretical model proposed in this paper.The proposed method here also has an important practical significance for designing and optimization the structure of the articulated tracked vehicle,vehicle driving performance evaluation and the development of the all-terrain articulated tracked vehicle.