基于传统重型车辆开发了液压辅助驱动系统，可使车辆在低附着路面上从单一的机械后轮驱动变为全轮驱动，从而提高车辆的动力性． 为提高整车牵引效率，文中设计了前馈+ 反馈控制器来调节该系统中变量泵的排量，即通过前馈环节由挡位确定泵的目标排量，再根据前后轮转速差反馈环节动态调节泵的最终排量． 基于Matlab /Simulink 和AMESim 平台的联合仿真结果表明，在典型的低附着路面条件下，使用液压辅助驱动系统后，车辆的最大爬坡度和牵引力分别提高了14． 4% 17． 2% 和13． 4% 15． 6%． 实车测试结果表明，该策略可保证液驱系统平稳工作，仿真模型具有较高的准确性．

In order to improve the power performance of heavy trucks,a new hydraulic assistance drive system ( HADS) is developed for the traditional heavy trucks,which can make the trucks on the roads of low adhesion coefficients reconfigure the traditional rear-wheel drive into the all-wheel drive.Then,a feedforward + feedback controller for a pump displacement controller in the developed system is designed to improve the transmission efficiency of the trucks.By the feedforward controller,the reference pump displacement is determined according to gears,and by the feedback controller,the final value of pump displacement is dynamically corrected according to the velocity tracking error between front wheels and rear wheels.Co-simulation results on the Matlab /Simulink and AMESim platforms show that,after employing HADS on the typical roads of low adhesion coefficients,the maximum climbing grade and traction of the trucks can be improved respectively by 14.4% 17.2% and 13.4% 15.6%.The real vehicle test results show that HADS works efficiently and smoothly,and the simulation model is accurate.