基于全生命周期速度使用率的拖拉机HMCVT参数优化

Optimization of Tractor HMCVT Parameters Based on Whole Life Speed Usage Rate

摘要:

变速器设计参数直接影响车辆的动力性和燃油经济性,由于拖拉机工况复杂且工作模式多样，因此在优化拖拉机变速器设计参数时无法直接借鉴汽车基于标准循环工况的优化方法。本文以一款自主设计的液压机械无级变速传动装置为研究对象，提出了一种基于拖拉机全生命周期速度使用率的变速器设计参数优化方法，并采用多目标遗传算法进行优化求解。以燃油消耗率和爬坡度为优化目标函数，选择对优化目标有较大影响的参数作为设计变量，并确定约束条件。采用基于Pareto最优原理的多目标遗传算法结合实验设计，基于modeFrontier建立传动装置的多目标优化模型，进行全局搜索寻优，最终得到Pareto最优解。结果表明，动力性和燃油经济性之间相互矛盾，分别求得对目标函数影响较大的设计参数。通过基于全生命周期速度使用率的优化迭代得到Pareto最优解的设计变量很好地满足了传动装置的匹配要求。

Abstract:

The design parameters of the transmission directly affect the dynamics and fuel economy of the vehicle, due to the complexity of the tractor’s working conditions and a variety of operating modes, so in the optimization of the design parameters of the tractor transmission cannot be directly borrowed from the automobile based on the optimization of the standard cycle of working conditions. An independently designed hydro-mechanical continuously variable transmission (HMCVT) was taken as the research object, and a transmission design parameter optimization method based on the whole life cycle speed usage rate of the tractor was proposed, and a multi-objective genetic algorithm (MOGA) was used for optimization and solution. Fuel consumption rate and climbing ability were used as the optimization objective functions, and parameters significantly affecting the optimization objectives were selected as design variables. Constraints were determined, and a multi-objective optimization model for the transmission device was established by using modeFrontier, combining MOGA based on Pareto optimal principles and experimental design, to perform a global search for optimization, resulting in Pareto optimal solutions. The research results obtained the optimal solutions under the constraints, reflecting the contradictory characteristics between dynamic performance and fuel economy. The design variables of the Pareto optimal solutions obtained through optimization iterations well met the matching requirements of the transmission device.