Research On The Hill-start Of A Light Tracked Vehicle

Military ground unmanned vehicles are an important part of future military forces.In China,a large number of old tanks are faced with the elimination and decommissioning,but its single-flow transmission system has the advantages of high efficiency and low cost.So,it is the most valuable platform to be unmanned.This topic is based on a certain type of single-flow transmission tracked vehicle,and develops the control strategy of autonomous hill-start during unmanned driving closely around its vehicle and powertrain,majors in the following research:(1)The dynamic analysis of the transmission system is carried out,the advantages and disadvantages of the steering clutch and the main clutch are compared comprehensively when hill-starting.taking the safety starting condition of the tank as the prerequisite,the evaluation index of hill-start are given.(2)The dynamic analysis of the start process of the steering clutch is given.In the sufficient safety range,the calculation formula of the slip distance and the restrictions of the driving force on both sides are given.(3)The hydraulic servo control system was installed according to the requirements of the hill-start time.The mathematical model of the hydraulic servo control system was established,and the relationship between the steering mechanism was established.The open loop characteristics of the system has been tested in simulink.(4)The fuzzy PID closed-loop control algorithm is used to realize the precise tracking of the desired displacement value of the steering clutch.In the first stage of the hill-start,the clutch half angle is determined by the slope angle provided by the inertial navigation system,and the second stage introduces the engine speed reduction rate to control the clutch engagement speed.Finally,the unmanned self hill-start strategy is added into the vehicle control system architecture.(5)By participating in the unmanned ground system challenge and real vehicle test,verify the independent hill-start strategy while self driving.It has been good results on start time and friction work while the slip distance is almost zero.