Research On Ramp Start Control Of Medium/heavy Trucks Based On EPB

Hill-start depends on the driver's skill to coordinate with the clutch,throttle,and brake to achieve a smooth start,the failure of performing such actions will result in engine stalling,even cause the vehicle to rollback,and may bring stress and panic to the driver.The hill start assist(HSA)system provides the driver with the possibility of starting with safety and comfort by controlling the brake release process.For medium and heavy duty vehicles,the vehicle mass changes frequently and hugely,which contributes very largely to the control effect of HSA,and may cause the failure of HSA.Taking a medium duty vehicle as the research object,the primary objective of this study is to develop a vehicle mass adaptive HSA control framework to improve the hill start quality of the medium and heavy duty vehicles equipped with electronic parking brake(EPB)in hill start scenarios.First,the change of forces on vehicle in ideal hill start situation is analyzed,the control target of HSA is proposed;then the control effect is researched to construct the mass estimation method during hill start process.Combined with the working principle of the EPB,the acquisition method of vehicle parameters are studied.According to the characteristics of EPB pneumatic pressure system,the logical threshold control method of HSA is designed,and the control flow of HSA is presented.Then a co-simulation environment involving Matlab/Simulink,Trucksim and AMESim is established to determine the acceleration threshold,and the control effect of the proposed HSA method is verified in several typical conditions.Finally,the hardware-in-the-loop test and the vehicle experiment is implemented,the experiment results validate the effective implementation of the proposed HSA method.