不确定因素影响下的机床支承件多目标稳健性设计

Machine tool support multi-objective robustness design under uncertainties

针对机床支承件制造及工作过程中的不确定因素对其性能的影响问题,提出了以支承件静态刚度和重量为目标的稳健性优化设计方法。采用区间不确定性和稳健性设计方法构建了不确定性因素影响下的稳健性多目标优化问题的目标函数。以某立式铣削加工中心支承件立柱为例,选择机床切削点载荷作用下的位移和立柱重量为优化目标;通过分析立柱特征尺寸对目标函数的灵敏度确定优化变量;选取立柱密度、弹性模量及切削载荷为不确定变量;利用支持向量机方法构建了目标函数对优化变量和不确定变量的响应模型。利用隔代遗传算法和非支配排序遗传算法求解立柱多目标优化问题。对比分析了立柱不确定性优化和确定性优化设计结果,表明其在重量降低的前提下,刚度得到明显提升,且稳健性提高40%。

To solve the performance reduction problem caused by uncertain factors existed in the process of support manufacturing and working,a robustness optimization method on machine tool support was proposed with the support static stiffness and weight as objectives.The objective function of robustness multi-objective optimization problem under the influence of uncertain factors was built based on the idea of interval method and robustness analysis,and a case study on a particular type of machine tool column was carried out with this method.The machine cutting point displacement under the loads action and the column weight were selected as the optimization objectives.The optimization variables were selected based on the sensitivity analysis of column feature sizes relative to the optimization objectives.With the column material density,material elasticity modulus and cutting loads as uncertain variables,the response models of optimization objectives related to optimization variables and uncertain variables were established.By adapting to IP-GA and NSGA-II algorithms,the column multi-objective optimization problem was solved.By comparing with the result of certainty optimization,the result obtained from the proposed method proved validity on support weight reduction and stiffness enhancement,especially on the stiffness robustness improvement（40%improvement compared with original column）.