蜂群算法的改进及在热膨胀系数优化上的应用

Improved Bee Colony Algorithm and Its Application in Optimization of Thermal Expansion Coefficient

电主轴的热变形是机床精密加工精度的非常关键的影响因素之一,而热膨胀系数是影响电主轴热变形的关键参数。热膨胀系数受多种参数的影响,呈较强的非线性关系,且没有精确数学模型进行描述。利用人工蜂群算法不依赖精确数学模型寻优的优势,对电主轴热变形模型中的关键系数—热膨胀系数进行优化,从而提出了基于改进人工蜂群算法的电主轴热变形模型。仿真研究结果表明,改进的蜂群算法相比于标准蜂群算法优化精度提高了大约2倍,达到收敛精度的迭代次数减少10%-16%,动态寻优能力加强。以100MD60Y4型号电主轴为被控对象,对不同转速下的电主轴进行热变形研究。实验结果表明,以转速为2000rad/min为例,基于经验热膨胀系数得到的热变形量与实际测得的热变形量在X、Y、Z三个方向的误差分别为0.17μm、0.47μm、1.48μm,基于优化热膨胀系数得到的热变形量与实际测得的热变形量在X、Y、Z三个方向的误差分别为0.02μm、0.13μm、0.56μm。

The thermal deformation of electric spindle is one of the most important factors affecting the accuracy of precision machining of machine tools,while the thermal expansion coefficient is the key parameter affecting the thermal deformation of electric spindle.Influenced by many parameters,the thermal expansion coefficient has a strong nonlinear relationship and is not described by an accurate mathematical model.the thermal expansion coefficient,which is the key coefficient in the thermal deformation model of electric spindle,is optimized by using the advantage of artificial bee colony algorithm which does not depend on exact mathematical model.As such,a thermal deformation model of electric spindle based on improved artificial bee colony algorithm is proposed.The simulation results show that compared with the standard artificial bee colony algorithm,the improved algorithm promotes the optimization accuracy by about two times;what’s more,the number of iterations to achieve convergence accuracy is reduced by(10~16)%,and the dynamic optimization ability is enhanced.Applying Type-100 MD60 Y4 electric spindle as the controlled object,we study the thermal deformation of the electric spindle at different speeds.Taking 2000 rad/s as an example,the experimental results show that the errors in the three directions of X,Y and Z between thermal deformation obtained by empirical thermal expansion coefficient and the actually measured thermal deformation are 0.17μm,0.47μm and 1.48μm respectively.And the errors in the three directions of X,Y and Z between thermal deformation obtained by optimized thermal expansion coefficient and the actually measured thermal deformation are 0.02μm,0.13μm,and 0.56μm,respectively.