变构型诱导的可重构数控机床空间精度退变机理及控制方法研究

Accuracy is an important technical indicator of the machine tool, and structural reconstruction of the reconfigurable machine tool will cause reconstruction and even degeneration of the machine tool spatial accuracy. In order to ascertain degeneration mechanism and controlling method of spatial accuracy caused by the change of machine tool configuration, this project takes reconstructed spatial accuracy as the core, and is carried out from three aspects: the reconstruction of error model, the variety of geometric error sensitivity, and the spatial accuracy allocation. Firstly, the reconstruction mechanism of geometric error model is explored by establishing a new modular geometric error model of reconfigurable CNC machine tools with fusion structure configuration information. Then, transfer process of error sensitivity is analyzed by error flow theory. Variable law of geometric error sensitivity following with structural reorganization of machine tool is revealed. Efficient identification method for determining the sensitive geometric errors is proposed. The influence mechanism of sensitive error change on spatial accuracy allocation is analyzed. A forward and reverse mapping model associated with coupling machine tool configuration and sensitive error for accuracy allocation is proposed. The actual inverse kinematics method is studied to decouple the new error model. Error compensation strategy is constructed under the variable machine tool structure. Finally, the theoretical models of accuracy allocation and error compensation for spatial accuracy degeneration are formed based on the error sensitivity. The research of this project can refine the design of machine tools and can lay a theoretical foundation for controlling and ensuring the spatial accuracy before and after machine tool reconstruction, which has important scientific significance and engineering application value.

精度是机床的重要技术指标，而可重构机床的结构重构会引起机床空间精度的重构乃至退变。为探明由于机床构型变化而导致的机床空间精度退变机理及控制方法，本项目以重构的空间精度为核心，从误差模型重构、几何误差敏感性变化以及空间精度分配三方面展开研究。通过建立融合结构配置信息的可重构数控机床模块化几何误差新模型，探索几何误差模型重构机制；应用误差流理论分析误差敏感性传递过程，揭示几何误差灵敏度随机床结构重组的变化规律，确定敏感几何误差高效辨识方法；分析敏感几何误差变化对空间精度分配的影响机理，提出机床构型与敏感误差耦合关联的正逆向映射精度分配模型；研究实际逆向运动学误差模型解耦方法，构建变构型情境下误差补偿策略。最终基于误差灵敏度形成应对可重构机床空间精度退变的精度分配及误差补偿理论模型。本项目的研究能够精化机床设计，为控制和保证机床重构前后的空间精度奠定理论基础，具有重要的科学意义和工程应用价值。

可重构机床可以高效低成本地重组以满足新的加工需求，区别于传统模块化机床和组合机床，可重构机床的结构重构给机床的空间精度控制带来难题，本项目从可重构数控机床几何误差建模计算方法、敏感几何误差与机床结构配置的映射模型、可重构数控机床空间误差分配及自适应补偿算法三方面展开研究。首先提出了机床结构自适应几何误差定义和建模计算方法，构建了可重构数控机床结构配置描述和数学模型。根据几何误差物理意义提出了运动副运动属性和结构属性相关的几何误差定义方法，建立了可重构数控机床运动部件误差矩阵模块，研究了可重构数控机床多结构配置的几何误差自动化建模方法。然后建立了基于偏微分和Morris的数控机床敏感几何误差辨识模型，探索出机床结构配置变化导致的敏感几何误差项变化，分析出敏感几何误差项与机床结构配置信息的关联特性，提出了机床运动链相关的敏感几何误差标识方法。建立了可重构五轴数控机床运动链关联的敏感几何误差映射关系式，获取了可重构三轴数控机床敏感几何误差与结构配置的映射表，揭示了可重构数控机床敏感几何误差随机床结构变化的变化规律。最后提出了可重构数控机床空间精度退变的控制策略。建立了数控机床回转工作台精度退化及寿命预测模型。构建了可重构数控机床几何误差与六维空间位姿误差的映射关系，提出了数控机床几何误差建模高效计算方法。基于此建立了可重构数控机床空间精度分配优化问题数学模型，提出了变构型情境下可重构数控机床空间精度分配智能优化求解算法。实现了可重构数控机床空间误差模型迭代逆向解耦，提出了响应结构变化的可重构数控机床误差补偿显式自动求解方法。通过数值计算、仿真切削和实验验证的方式验证了空间误差模型、敏感误差辨识新方法以及机床空间精度控制策略的正确性和有效性。项目建立了可重构数控机床敏感几何误差高效辨识及控制理论体系，对于提高可重构机床空间精度、丰富机床制造共性理论具有重要的科学意义和应用价值。