Gearshift Strategy for HMPRT Base on Dynamic Programming

doi:10.3901/JME.2019.08.106

Abstract

Abstract: The external load of engineering vehicles such as wheeled loaders changes dramatically, traditional hydraulic mechanical automatic transmission is generally used, but it faces the problems of low efficiency and high fuel consumption. Therefore, a new type of hydraulic mechanical power reflux transmission system is proposed to apply to wheeled loaders. Because loaders need to adapt to complex operation requirements by shifting, the basic shift strategies are formulated according to the speed regulation characteristics of HMPRT. Considering that loaders and other engineering vehicles often work under the known typical working conditions, in order to avoid the back-and-forth switching of the dynamic and economic modes of the basic shift strategies and reduce the driver's workload, an optimal design method of the shift strategy of HMPRT is established by using dynamic programming(DP). First, according to the traits of the working condition of the loader and the gearshift characteristic of HMPRT, the DP control parameters are determined. The fuel consumption is used as cost function, and a penalty function is added to avoid frequent gearshift phenomenon. The research results indicate that the proposed DP shift strategy has good performance:the fuel consumption is reduced by 3.5% compared with the optimal dynamic shift strategy and the shift times are reduced by 33.3% compared with the optimal economic shift strategy. Considering the typical working conditions comprehensively, the frequent shifting is avoided while the power and economy are guaranteed.

Key words: dynamic programming(DP), fuel consumption, gearshift schedule, hydraulic mechanical power reflux transmission(HMPRT), speed ratio

CLC Number:

TH132

YOU Yong, SUN Dongye, LIU Junlong, QIN Datong. Gearshift Strategy for HMPRT Base on Dynamic Programming[J]. Journal of Mechanical Engineering, 2019, 55(8): 106-117.

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