| With the widespread using of the commercial vehicles such as tractor-trailer and semi tractor-trailer, the ensuing security problems have become more and more concerned by people. The tractor and the trailer can not coordinate well because of delaying of the braking signal in its transmission process and change of load in the tractor when the pneumatic braking system of the tractor-trailer is working. Impingement of the trailer to the towing vehicle, in the braking process,decrease the braking capacity of the tractor-trailer riding comfort, which result in accident in emergency.In this paper, based on the tractor-trailer which was designed and produced by an automobile company in Jiangsu province, the tractor-trailer braking coordination was investigated using theoretical, numerical and experimental methods. The mainly achievements are shown as follows:(1)The structure and working process of the pneumatic braking system of the tractor-trailer was introduced. The discordant operation between the trailer and the tractor in the working process of the pneumatic braking system and the impact of coordination of the tractor-trailer on the braking performance were analyzed. This paper also come up with the evaluating indicators of the coordination of the tractor-trailer.(2)A braking dynamic model of the tractor-trailer and the pneumatic braking system model were built on the Matlab/Simulink and AMESim platform. Combined the two models above, collaborative simulations of the tractor-trailer braking system were conducted. Various factors, which would affect coordination of the tractor-trailer, were analyzed.(3)In consideration of various influencing factors above, a pneumatic brake electronic control system the tractor-trailer was designed to deal with the uncoordinated problem of the tractor-trailer.Some key issues of electronic control system of the tractor-trailer were researched which include pneumatic braking control system structure design, characteristics of the high speed on-off valve,pressure changing characteristic of the braking chamber and pressure control method system of the pneumatic braking electronic control system.(4)In order to verify the performance of the pneumatic braking electronic control system designed in this paper, a controller and test system which can realize the pressure signal acquisition,brake pedal signal acquisition, high speed on-off valve control function were designed. A semi-physical simulation platform was designed and the random braking signal pressure followingexperiments was conducted with the platform to verify the validity and feasibility of the pneumatic braking electronic control system designed for the tractor-trailer.The research work of this paper has important reference value and guiding significance for the design and reformation of the enterprise in the pneumatic braking system of the tractor-trailer. |
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