基于分段控制的CVT湿式离合器起步控制策略

针对湿式离合器起步结合过程的几个阶段的工作特点,建立离合器起步的分段控制策略,空行程阶段以一较大占空比快速接合,克服阻力阶段选择合适的初始占空比缩短克服阻力时间,速度增长阶段根据油门开度以及开度变化率的模糊推理和利用发动机转速差进行修正得出用于实时控制的占空比变化率。根据上述控制策略,设计带修正的模糊控制器。通过对控制策略的试验,结果表明实施针对各阶段工作特点的控制策略,起步过程能够在适应驾驶员起步意图的前提下,优化起步冲击度、滑磨功性能指标,同时提高了起步的灵敏度,保证了发动机的稳定运转。

Control Strategy of CVT Clutch Starting Based on Stage Control

According to the working characteristics of different engagement stages of CVT clutch,the stage control strategy of clutch engagement was established.In the stage of the null path,clutch engagement is rapid on the biggish occupation-empty ratio.In order to reduce the period of overcoming the resistance,the appropriate initial occupation-empty ratio is selected in the stage of overcoming the resistance.In the stage of speed increasing,the change rate of occupation-empty ratio for real-time control is obtained based on the fuzzy reasoning of the accelerator pedal angle and its change rate and the correction with the engine rotational speed difference.The corrective fuzzy controller was designed accordingly.The test results show that the stage control strategy can not only adapt the driver's intention and optimize performance of starting impact and sliding friction works,but also improve starting sensitivity and stabilize engine rotational speed.