非平稳随机循环工况离合器接合优化及跟踪控制

为更好地解决系统参数摄动和外负荷扰动等不确定性因素下离合器接合轨迹可变性及其跟踪偏差带来的接合过程问题,提出了离合器接合轨迹的优化及跟踪控制方法. 以装载机V型工况重载后退换挡中离合器接合过程为研究对象,建立冲击度和滑磨功相结合的二次型性能指标泛函,在干扰矩阵有参数化表达的非平稳随机项下,通过构造Hamiltonian函数并依据Pontryagin极大值原理和解析Riccati微分方程,得到时变最优控制律和权重系数调整下的可变扭矩最优轨迹；为提高非线性特性执行机构参数摄动下最优轨迹的跟踪精度,将接合过程品质优化问题转化为轨迹跟踪的单一目标问题,采用指数趋近律滑模控制方法设计的控制器实现了跟踪误差在0.3%以内的精准跟踪,用Lyapunov理论对其进行了稳定性分析. 数值仿真结果表明,该控制方法降低了离合器接合冲击度及滑磨功,有助于提高离合器接合过程品质,对解决同类问题具有理论性工程参考价值.

Optimization and tracking control of the clutch engagement process under non-stationary random cyclic conditions

To better solve the problem of clutch engagement process caused by variability of the clutch engagement trajectory and the tracking deviation under uncertain factors such as system parameter perturbation and external load disturbance, the optimization and tracking control method of the clutch engagement trajectory are proposed. Taking the clutch engagement process in the heavy-duty reverse shifting of the loader V-type working condition as the research object, a quadratic performance index function combining the jerk and friction work is established. Under the non-stationary random term with parameterized expression in the disturbance matrix, the variable torque optimal trajectory under the time-varying optimal control law and weight coefficient adjustment is obtained by constructing the Hamiltonian function and solving the Riccati differential equation based on Pontryagin maximum principle. To improve the tracking accuracy of the optimal trajectory under perturbation of nonlinear characteristic actuator, the quality optimization problem of the engagement process is transformed into a single target problem of trajectory tracking. The controller designed by sliding mode control method with exponential approach law achieves accurate tracking with tracking error within 0.3%, and its stability analysis is carried out by Lyapunov theory. The numerical simulation results show that the control method achieves the minimization of the friction work under the condition that the clutch engagement impact is lower than the national standard. The control method proposed in the paper will be beneficial to improve the quality of the clutch engagement process and have theoretical engineering reference value for solving similar problems.