基于MATLAB的电液式CVT速比最优控制系统分析与设计

分析了对普通电液式无级变速器的速比控制系统,发现其有结构复杂和可靠性低等缺点,提出了CVT速比最优控制系统的设计方案。传统比例阀被PWM高速开关数字阀所取代,建立起PWM阀数学模型及阀控缸数学模型,使得控制系统简化;并用离散系统二次型最优控制理论优化控制参数,设计出最优控制器。运用MATLAB对CVT速比控制系统进行了起步、加速、减速典型工况的模拟试验。结果显示,电液式CVT速比最优控制系统具有较好的稳态与动态特性,确保了实际速比对目标速比的有效跟踪。

Designing of Electro Hydraulic CVT Ratio Optimal Control System Based on MATLAB

Aiming at the complicated structure and the lower reliability of the traditional electro hydraulic CVT ratio control system,a CVT ratio optimal control system is designed. The generally proportion valve is replaced with the PWM high speed on-off valve,and a mathematical model of PWM valve is built taking the magnetic characteristics of the valve into consideration. Then the CVT ratio control system is simplified to build a mathematical model of control cylinder for PWM valve. By applying optimal controls parameter of quadratic form theory of the discrete system,an optimal controller is designed. The simulation experiments for starting up and accelerating and decelerating are made under MALTAB,which results show that the steady and the dynamic characteristics of the designed CVT ratio optimal control system are good with safeguarding of the effective track of the real ratio to the object ratio.