基于滑移率反馈控制无级变速器夹紧力优化策略

Optimal Strategy of Clamping Force for Continuously Variable Transmission Based on Slip Ratio Feedback Control

为了将汽车燃油消耗率降至最低,使发动机稳定在最佳转速区域,对无级变速器(continuously variable transmission,CVT)传统夹紧力控制策略进行了优化.在CVT内部现有传感器装置的基础上,根据滑移率反馈控制方法的总体结构,建立了具有非线性的滑移率动态模型方程,并在设计滑移率反馈控制器过程中,采用分级内、外双环的控制方法,解决夹紧力与速比之间的耦合问题.通过台架试验及CVT整车测试,验证了优化后的夹紧力控制策略的有效性.研究结果表明:在CVT整车百公里急加速、紧急制动以及综合工况下,滑移率反馈控制令整车动力匹配能力优于传统夹紧力控制;夹紧力在满足不发生带轮打滑及使用要求前提下,夹紧力可降低10%,燃油效率总量可提高1%.

In order to decrease vehicles＇ fuel consumption rate to the lowest and stabilize the engine running in an optimal rotary speed range, an optimization was made for the traditional clamping force control strategy of the continuously variable transmission （CVT）. According to the general structure of the slip ratio feedback control method, a slip ratio dynamic model with nonlinear equations was set up based on measurements from the existing sensor devices inside CVT. For design of the slip ratio feedback controllers, the tight coupling problem between clamping force and speed ratio are solved using a separate inner-and outer-loop control scheme. In addition, bed tests and real tests were conducted to verify the effectiveness of the optimized control strategy for clamping force. The results show that the power matching ability of the CVT vehicle equipped with slip ratio feedback control is superior to that with the traditional clamping force control in all of the 0 - 100 km/h acceleration test,emergency braking, and comprehensive conditions. Using the slip ratio feedback control, the clamping force can decrease about 10% with non-slip and other application requirements satisfied, and the total fuel efficiency of CVT vehicles can increase 1%.