基于遗传算法的卧式加工中心阶梯轨式立柱的多目标优化

Multi-objective optimization of stepped rail column in horizontal machining center based on genetic algorithm

立柱是影响机床整机刚度的薄弱环节,其性能直接影响卧式加工中心的加工精度,因此文章提出了一种卧式加工中心阶梯轨式立柱的多目标优化设计方法。首先,基于Ansys对整机进行仿真发现立柱是影响整机静动态性能最薄弱的环节,并当主轴箱处于立柱最上沿处时立柱的刚度最差;其次,选择立柱跨距、立柱高度差、丝杠面宽度、上导轨面宽度作为设计变量;再次,以立柱导轨面X向和Z向变形范围、一阶固有频率以及质量作为评价指标,利用多目标遗传算法寻求最优解,基于此通过灵敏度分析对设计变量圆整并进行仿真验证;最后,结果表明,优化后的立柱导轨面Z向最大变形减小了7.37%,Z向变形范围减小了11.57%,X向变形范围减小了2.41%,一阶固有频率提高了1.4%。

The column is a weak link that affects the overall stiffness of the machine tool,and its performance directly affects the machining accuracy of the horizontal machining center.Therefore,a multi-objective optimization design method for the stepped rail column of the horizontal machining center is proposed.Firstly,based on Ansys simulation,it was found that the column is the weakest link affecting the static and dynamic performance of the entire machine tool,and the stiffness of the column is the worst when the spindle box is at the top edge of the column.Secondly,select column span,column height difference,screw surface width,and upper guide rail surface width as design variables.Then,using the deformation range in the X and Z directions of the column guide rail surface,first-order natural frequency,and mass as evaluation indicators,a multi-objective genetic algorithm is used to seek the optimal solution.Based on this,sensitivity analysis is used to round and verify the design variables through simulation.Finally,the results showed that the maximum deformation in the Z-direction of the optimized column guide rail surface was reduced by 7.37%,the Z-direction deformation range was reduced by 11.57%,the X-direction deformation range was reduced by 2.41%,and the first-order natural frequency was increased by 1.4%.