基于Kriging模型的动力总成悬置系统多目标优化

Multi-Objective Optimization of Powertrain Mounting System Based on Kriging Model

针对轮式装载机在怠速NVH性能差的问题,提出了一种基于Kriging模型的动力总成悬置系统的优化设计方法.建立了包含动力总成系统的整车虚拟样机模型.结合最优拉丁超立方试验设计、Kriging近似模型以及NSGA-II多目标优化方法,选取悬置的刚度作为设计变量,以动力总成系统解耦度、驾驶室地板垂向加速度以及底盘动能作为目标函数进行优化,得到Pareto前端.通过权重系数法求得最优解,并通过整车模型进行验证.结果表明,该方法能够快速有效地对悬置系统进行优化,优化后的悬置系统解耦率得到提升,同时,优化后的整车模型在模拟的5个稳态工况下,驾驶室的振动及底盘动能均有所降低,驾驶室振动最大降幅为23.6%,(怠速),底盘动能最大降幅为22.0%(2,000,r/min),整车平顺性得到提升.

Aiming at the problem of poor performance of noise,vibration and harshness(NVH) at idle speed of wheel loader,an optimal design method of powertrain mounting system(PMS) based on Kriging model was proposed.A virtual model of the loader was established including the powertrain mounting system.Taking mounts 'stiffness as design variables,optimal Latin hypercube design,Kriging approximation models and NSGA-II multiobjective optimization were applied to optimize the objectives,including the energy decoupling of the powertrain and the root mean square(RMS)values of floor's vertical and kinetic energy of chassis.The weight coefficient method was used to get one optimal solution from the Pareto optimal set obtained previously.Furthermore,a virtual model test was conducted by using the optimal solution as verification.The result indicates that the method of Kriging approximation model can optimize PMS quickly and effectively.The energy distribution of optimized PMS is improved.Meanwhile,the vibration of cab and the kinetic energy of chassis both decrease under five simulation conditions,the biggest decline in vibration of cab and kinetic energy of chassis being 23.6%,(idling)and 22.0% (2,000,r/min)respectively.The ride comfort of wheel loader model with optimized PMS is greatly improved.