多源随机误差影响下精密机床加工精度可靠度动态优配方法研究

As an important index to measure the working performance of CNC machine tools, machining accuracy reliability refers to the possibility of fulfill the specified machining accuracy under the stated conditions for a given period of time. How to control the machining accuracy reliability in the scope of the design requirement is a scientific issue, which exists in design stage of the high precision machine tool and has to be settled urgently. Taking the geometric errors, spindle thermal errors and tool wear errors as the typical error sources which influence the machining accuracy reliability , a machining accuracy dynamic prediction model of high precision machine tool is established based on multi-body system theory; considering the stochastic characteristic of the parameters which influence the typical error sources, Copula theory is applied to develop the machining accuracy reliability and reliability sensitivity dynamic analysis models of high precision machine tools with the parameters drawn from arbitrary distributions; and then a machining accuracy reliability dynamic optimization model of high precision machine tool is constructed. In such model, the cost of high precision machine tool was the optimization objective, the dynamic machining accuracy reliability was the constraint, and the reliability sensitivity was to identify the design parameters to be optimized. Then a machining accuracy reliability dynamic optimization method of high precision machine tool on the influence of multisource stochastic errors is formed, which is to be validated by a specific product. The method can offer the theory and method support to the accuracy design of high precision machine tool, and it is of great important theoretical value and practical significance to promote the independent development ability of high precision machine tools made in China.

加工精度可靠度作为评价数控机床工作性能的依据，是在规定的时间和条件下，数控机床达到理想加工精度要求的概率。如何使加工精度可靠度控制在所追求的目标范围内，是高档数控机床研发中亟待解决的科学难题。项目拟将几何误差、主轴单元热误差和刀具磨损误差作为影响加工精度可靠度的典型误差源，基于多体系统理论，构建精密机床加工精度动态预测模型；考虑误差源影响参数具备随机性特征，基于Copula理论，建立参数服从任意分布的精密机床加工精度可靠度和可靠性敏感度动态分析模型；以精密机床制造成本为优化目标，以动态加工精度可靠度满足设计要求为约束条件，以动态可靠性敏感度辨识关键设计参数，构建精密机床加工精度可靠度动态优配模型，形成多源随机误差影响下精密机床加工精度可靠度动态优配方法，并结合具体产品进行验证。项目的研究为精密机床精度设计提供理论和方法支持，对提升我国高档数控机床的自主开发能力具有重要的理论价值和实际意义。

数控机床作为先进制造业的高端制造设备，其加工水平的不断提高能够推动国家制造业的发展和提升国际竞争力。加工精度可靠度反映出机床在规定时间和条件下，完成规定加工精度的能力，受几何误差、主轴单元热误差和刀具磨损误差三类典型误差源影响显著。项目综合考虑几何误差、主轴单元热误差和刀具磨损误差和误差参数的随机性，深入研究刀具磨损规律和主轴单元热误差产生机理，构建基于MEA- NARX网络的刀具磨损误差模型和基于免疫算法的主轴热误差模型，并基于多体系统理论，构建精密机床加工精度动态预测模型。基于Latin超立方抽样蒙特卡洛方法，构建参数服从任意分布的精密机床加工精度可靠度动态分析模型；考虑测量坐标系与设计坐标系不重合，建立基于POS-SQP算法和Monte-Carlo的S件加工质量评估模型；构建参数服从任意分布的精密机床加工精度可靠性敏感度动态分析模型，辨识对精密机床加工精度可靠度贡献较大的设计参数；基于人工鱼群算法，提出精密机床几何参数优化模型，最终形成一种多源随机误差影响下精密机床加工精度可靠度动态优配方法，实现精密机床零部件几何误差的合理分配和整机精度及加工精度可靠度的全面提升。通过实验验证，说明提出方法的正确性和优越性。