Authors

Abstract

To address the challenges of strong nonlinearity, time-varying parameters, and significant external disturbances in wet clutch pressure control during tractor powershift operation, this study proposes an adaptive pressure control method based on Full-Form Dynamic Linearization Model-Free Adaptive Control (FFDL-MFAC). Sobol global sensitivity analysis is employed to identify the key controller parameters, and an Improved Mayfly Algorithm (IMA) is introduced to achieve global optimization. The controller performance is evaluated through co-simulation and hardware-in-the-loop (HIL) testing. The co-simulation results show that, compared with conventional PID control, the FFDL-MFAC controller reduces the rise and fall times in square-wave tracking from 2.63 s and 1.27 s to 0.72 s and 0.52 s, respectively, achieving fully monotonic responses without overshoot or undershoot. In sinusoidal tracking, the maximum pressure error decreases from 0.036 MPa to 0.021 MPa, while the response delay is reduced from 0.07 s to less than 0.005 s. HIL-based clutch pressure control experiments further verify the effectiveness of the optimized controller when implemented on real hardware. Compared with the PID controller, which exhibits a 9.44% overshoot, a settling time of 3.12 s, and a steady-state fluctuation of 0.40 MPa, the FFDL-MFAC controller shows no noticeable overshoot, shortens the settling time to 1.24 s, and maintains minimal steady-state fluctuation. These results confirm the effectiveness and superiority of the proposed method for wet clutch pressure regulation and provide a solid foundation for high-performance control in tractor powershift transmissions.

Abstract in Chinese

针对拖拉机动力换挡过程中湿式离合器压力控制存在的非线性强、参数时变及受外部扰动影响显著等问题，本文提出一种基于全格式无模型自适应控制（Full-Form Dynamic Linearization Model-Free Adaptive Control, FFDL-MFAC）的离合器压力自适应控制方法。本文采用Sobol全局灵敏度分析筛选控制器关键参数，并引入改进蜉蝣算法（Improved Mayfly Algorithm, IMA）进行全局优化。通过联合仿真与硬件在环（HIL）试验对控制器性能进行验证。联合仿真结果表明，与PID控制相比，FFDL-MFAC在方波压力跟随中将上升与下降段的调节时间分别由2.63s、1.27s降至0.72s、0.52s，响应单调无超调或欠调；在正弦跟随中，最大压力误差由0.036MPa 降至0.021MPa，响应延时由0.07s降至0.005s内。HIL离合器压力控制试验进一步验证了优化控制器在真实硬件执行下的有效性。与存在9.44%超调、3.12s调节时间及0.40MPa稳态波动的PID控制相比，FFDL-MFAC无明显超调，将调节时间降低至1.24s，稳态波动极小。研究结果验证了该方法在湿式离合器压力控制中的有效性与优越性，为拖拉机动力换挡过程的高性能控制提供基础。