无级变速器速比控制仿真研究

Simulation Research of CVT Ratio Control

无级变速传动装置(CVT)的速比连续变化特性可以使发动机转速工作在理想状态下,一直以来都是无级变速系统的核心控制问题。通过对发动机试验数据的整理,获得发动机最佳经济性(动力性)目标转速图。分析无级传动系统的工作原理,建立其动力学微分方程,并基于Matlab/S imu link工具箱搭建仿真模型和设计速比控制算法,并仿真计算汽车在给定加油门起步、减油门行驶和高速制动三种典型行驶工况下的动态响应,最后由试验验证模型的正确性。结果表明设计的无级变速控制策略和模糊PID控制方法可以实现速比的合理变化,为进一步开发无级变速器的控制策略提供必要的前期准备。

The ratio - varying characteristic is the key to CVT （ Continuously Variable Transmission） system, for it makes the engine run at ideal speed. Through the treatment of the engine test data, the economy（power） engine target speed map is obtained. Then a real - time CVT model including ratio control algorithm, powertrain and vehicle dynamics is established by the Matlab/Simulink tool box. Based on the model, the dynamic responses which are validated through the on - board test are simulated under the given conditions： start with throttle increase, running with throttle decrease and sudden braking. And the corresponding results indicate that the designed control strategy and the PID control method are able to realize the ratio change reasonably and smoothly.