基于Fuzzy Logic与State flow的汽车换挡策略研究

针对车辆在复杂的路况下行驶时,车辆自动变速器的频繁换挡和车辆动力不足的问题,设计了一种基于升、降档模糊控制器基本模块的换挡策略.升降挡模糊控制器模块是以加速度的正负作为控制参量,加速度为正时,基于升档规律曲线的升档模糊控制器起作用;加速度为负时,基于降档规律曲线的降档模糊控制器起作用.通过State Flow的逻辑来判断哪个控制器起作用.在上述基本模块的基础上,建立了以制动力的大小,弯道大小以及坡度大小作为控制输入参数的模糊修正模块,其输出对上述基本模块的升档模糊控制器和降档模糊控制器的输出进行修正.仿真结果表明:所设计的换挡控制策略具有很好的避免频繁换挡和动力不足的问题.

Study on Shifting Strategy Based on Fuzzy Logic and State Flow

In accordance with a higher shifting rate and power shortage in an automatic transmission under the complicated road conditions,the control strategy is designed for a basic module of the shifting fuzzy controller.The module takes the acceleration of the vehicle as a control parameter.When the value of the acceleration is positive,the module is controlled by the up-shifting controller,otherwise it is controlled by the downshifting controller.By means of the State Flow,logic judgment can be made for the control strategy.On the basis of the module,a correction module is built by taking braking force,turning angle and slope as controlled inputs,and the outputs of the basic module can be modified by that of the correction module.The simulation results show that the proposed shifting control strategy is useful for solving the problem of frequent shifting and power shortage.