改进NSGA-Ⅱ算法的自动变速箱离合器接合控制

Automatic Transmission Clutch Engagement Control based on Improved NSGA-ⅡAlgorithm

为了提高车辆在起步过程中的平稳性,并延长离合器的使用寿命,首先,根据离合器的主动盘和从动盘的运动状态,建立了接合过程的动力学模型;然后,通过引入NSGA-Ⅱ算法来解决多目标优化问题,并采取了正态分布交叉和自适应变异算子对其进行改进,保持了种群的多样性,能有效防止陷入局部最优;最后,将离合器的接合时长和接合速度作为设计变量,并将冲击程度和滑动摩擦功为优化目标函数进行了仿真实验。结果表明,改进的NSGA-Ⅱ算法具有更优的Pareto前沿和更快的收敛速度,且分布更加均匀,明显优于其他两种比较算法;在相同接合时长的条件下,能够通过平稳控制离合器的接合速度获得更小的冲击程度和滑动摩擦,为设计离合器接合控制策略提供了技术支撑。

To improve the stability of the vehicle in the starting process and prolong the service life of the clutch,a dynamics model of the engagement process is established according to the motion state of the active and driven discs of the clutch.The NSGA-Ⅱalgorithm is introduced to solve the multi-objective optimization problem,and the crossover operator of normal distribution and adaptive mutation operator are adopted to improve it,which keeps the diversity of population and effectively prevents falling into local optimum.Finally,the engagement speed and time of clutch are taken as the design variable,and the impact degree and sliding friction work are taken as the optimization objective function,and the simulation experiment is carried out.The simulation results show that the improved NSGA-Ⅱalgorithm has better Pareto front and faster convergence speed,and distribution is more uniform,obviously superior to the other two comparison algorithms,and the smaller impact degree and sliding friction work can be obtained by smoothly controlling the engagement speed of clutch in the condition of the same joint time,which provides technical support for the design of clutch engagement control strategy.