Dynamic Coordination And Traction Control Of Hybrid Military Off-road Vehicle

As an important equipment in the army,the military off-road vehicle bears the important task of transporting troops and materials and plays an indispensable role in the war.Applying hybrid technology to military off-road vehicles not only reduces energy consumption,expands its operational radius,but also increases its power and safety.Therefore,hybridization is an important development direction for military off-road vehicles.Considering the advantages and disadvantages of various configuration schemes,this paper chooses the planetary hybrid four-wheel drive hybrid system which can decouple the engine’s speed and torque as the research object.In order to make the hybrid military off-road vehicle play a better role and enhance its driving dynamics,safety reliability and environmental adaptability,this paper deals with the problem of torque coordination during mode shifting and driving on bad road surface.The driving problem was studied and the corresponding control strategy was formulated.The main research contents include:Firstly,based on the idea of optimal engine operating curve control,a steady-state energy management strategy is established.Engine model,motor model,battery model,planetary gear mechanism model and vehicle seven-degree-of-freedom model are established under AMESim platform and MATLAB/Simulink platform respectively.And the simulation of the steady state energy management strategy is carried out.The results show that military off-road vehicles with planetary hybrid four-wheel drive systems have good dynamic and economical levels;Secondly,since the hybrid military off-road vehicle has multiple working modes,and the power sources’ driving condition are different under different working modes,the changes of several power sources’ driving condition during the mode shifting process are likely to bring shock to the hybrid military off-road vehicle,which greatly reduce the riding comfort.Aiming at this problem,this paper deduces the dynamic relationship under the front-wheel drive condition and the four-wheel drive condition,and analyzes the cause of the shock during the mode shifting according to the dynamic relationship.According to the cause of the shock,the torque change rate of each power source during the mode shifting is limited,so that the torque changes of the respective power sources are coordinated and suppressed,and the whole driving torque of the vehicle is smoothly changed,thereby the jerk of the mode shifting process can b e reduced.Then,aiming at the problem of excessive sliding of driving wheels caused by vehicle driving under poor road conditions,this paper designs a traction control strategy based on PID control and "feedforward + feedback" control based on optimal slip efficiency.The torque transmitted to the driving wheels is reduced when the drive wheels are excessively slipped,and the traction performance of the vehicle is improved.Finally,the joint simulation verification of dynamic coordination control strate gy and traction control strategy is carried out by AMESim software and Simulink software.The results show that the shock of the vehicle during mode shifting is greatly improved by dynamic coordinated control,and the traction performance of the vehicle is effectively improved by traction control.In summary,the dynamic coordinated control and traction control in this paper laid a certain foundation for the development of hy brid military offroad vehicles.