| The braking system plays an critical role among the many subsystems that ensure the safety of the vehicle.It is an indispensable way to realize the various deceleration intentions of the vehicle,as well as ensuring the safety of the driver.Traditional brake systems usually adopt air brake,air-top fluid brakes and full hydraulic brake.Among them,full hydraulic brake is widely used thanks to its high specific power density,compact layout,high reliability and many other advantages.As the braking system is given more tasks,the new braking system is required to provide more freedom of manipulation,obtain more accurate braking force,perceive more external information,and provide a standard interface for working with other systems.The traditional braking system can no longer fully meet newly needs.Therefore,this study benefited from the Equipment Pre-research Project produced by Jilin University and Inner Mongolia First Machinery Group Co.,Ltd.Research Institute,which taking a certain model of 8×8 all-electric off-road vehicle as the research object,based on the existing full-hydraulic braking system for tracked vehicles,where an electro-hydraulic combined braking system has been developed and designed in accordance with the requirements of a new generation of wheeled mobile platforms for independent electric drive.The paper introduces the working principle of the electro-hydraulic combined braking system and its components(power source,parking brake,service brake)in detail,and describes the functions and principles of key hydraulic components such as dual-circuit foot brake valve and relay valve;the theoretical model of the dual-circuit foot brake valve,relay valve and the AMESim simulation model of the electro-hydraulic combined braking system have been established,and the accuracy of the simulation model of the electro-hydraulic combined braking system has been verified through bench experiments.The simulation model of the electro-hydraulic combined brake system is used to analyze the single-loop and dual-loop characteristics and synchronization of the dual-circuit foot brake valve,as well as the proportional characteristics of the relay valve;by changing the initial pressure,volume of the accumulator,the spring stiffness of the circuit foot brake valve,the spool covering amount,the relay valve return spring stiffness and many other parameters in the simulation model one by one,the degree of influence on the output and response characteristics of the electro-hydraulic combined brake has been analyzed.The research results show that this set of electro-hydraulic combined braking system meets the braking requirements,and provides a reference for the vehicle loading experiment and the development of electro-hydraulic combined braking system. |
