基于模糊PID的CVT夹紧力控制

Clamping force control of CVT based on fuzzy-PID

针对金属带式无级变速器(CVT)夹紧力不合理造成传动效率低的问题,提出基于模糊PID的CVT夹紧力控制方法.为保证主、从动带轮夹紧力满足转矩传递要求同时实现夹紧力控制、速比控制解耦,研究了夹紧力的唯一控制原理.提出目标夹紧力的模糊计算方法,使目标夹紧力控制在最佳范围内.设计模糊PID控制方法,首先应用模糊控制使夹紧力快速稳定在目标夹紧力小范围内,然后通过PID寻优达到目标夹紧力.试验结果表明通过对目标夹紧力的模糊计算可以在保证不打滑的情况下,有效降低目标夹紧力;通过从动轮夹紧力的模糊PID控制方法,可以使从动轮夹紧力快速、准确达到目标夹紧力,并消除比例溢流阀饱和特性对控制性能的影响.

Concerning the problem of transmission inefficiency due to improper clamping force, a unique control theory of clamping force was presented. A fuzzy calculating method of controlling the object clamping force was proposed in order to meet the torque transmissions by controlling the secondary pulley clamping force. A fuzzy-PID control method was designed. Firstly, the fuzzy control method stabilizes the object clamping force quickly around the required, and then the required pressure by PID optimizing controller is given. The results show that the fuzzy calculating method can reduce the object clamping force and guarantee no sliding. Fuzzy-PID control method causes secondary pulley clamping force to reach the object clamping force quickly and accurately, and eliminates the effect of saturation characteristic in a proportional relief valve.