大功率自动变速器换挡离合器调压控制研究

为了改善大功率自动变速器换挡过程中换挡离合器（含湿式制动器和湿式离合器）油压的调控水平，提高车辆的换挡品质，从结构上在换挡离合器中设计平衡活塞来补偿离合器旋转离心的影响，并在排油回路中增加背压阀以消除活塞腔内空气造成的不确定性。通过对换挡执行系统结构进行分析，分别针对离合器活塞、电液调压过程及离合器滑摩过程进行模型计算，在此基础上，将惯性相的充油调压控制进行拆解，即在转矩相结束时刻初始常量的基础上叠加一阶控制过程，针对换挡过程中系统存在非线性干扰和参数不确定性的特点，结合系统特性的分阶段试验标定，制定了换挡离合器调压过程的滑模控制策略，并基于MATLAB环境对控制策略的正确性和有效性进行仿真分析，最后进行实车试验验证。研究结果表明：无论是制动器充油还是旋转离合器充油，控制策略均能将惯性相持续时间、换挡冲击和滑摩功率损失等控制在合理范围；控制策略具有良好的性能，旋转离合器和制动器都能实现稳健的惯性相调压控制。

Investigation on Pressure Control of Shifting Clutch for High-power Automatic Transmission

In order to improve the control level of oil pressure which regulates the performance of shifting clutch (including wet brake and wet clutch) for high-power automatic transmission and to improve the shift quality of vehicles, the balance piston was designed to balance the centrifugal effect for the rotating clutches, and the exhaust backfill valve was also designed for the oil discharge loop to eliminate the uncertainty caused by air in the piston cavity. The low pressure can keep the shifting clutches free of air due to the exhaust backfill valve. The shift execution system of the testing automatic transmission was analyzed, and the model calculation was administered for the piston motion, the electro-hydraulic pressure regulation and the slipping process of the shifting clutch. And the pressure regulating of inertia phase during the gear shift is characterized as a one-order control based on the end of the torque phase. Combined with phased parameter calibration, the sliding mode control was presented to overcome the external disturbance and parametric uncertainties. Simulation analysis for the effectiveness of control strategy was conducted on the basis of MATLAB. The power-on 1st-2nd up-shift with B2 brake oil-charging and the power-on 3th-4th up-shift with C2 clutch oil-charging test were considered respectively. The simulation curves show that the duration time, the shift jerk and the wear power loss of the inertia phase are effectively controlled within a reasonable range. Finally, the proposed control strategy is thoroughly verified on a heavy-duty off-road vehicle equipped with a high-power automatic transmission, and the good shifting quality has been achieved in the inertia phase which is demonstrated by the experimented data.