微纳结构光学表面快速力伺服切削新方法的研究

To overcome the inherent difficulty for form accuracy improvement of the generation of micro/nanostructured optical surface in ultraprecision machining, a novel fast force servo (FFS) assisted cutting technique is proposed by controlling the main cutting force during the process. Herein, the trajectory copying mechanism in current ultraprecision machining is replaced by the motion tracking mechanism through controlling the interaction between the tool and workpiece in the FFS. The aim for tool motion in FFS lies in the tracking of the cutting force, therefore, the tool is going to follow the trajectory for the generation of the micro/nanostructures as well as to simultaneously track the accumulated motion error along the cutting chain in an adaptive way. This study will focus on the description of the coupling behavior between the trajectory and error motion along the cutting chain as well as on the description of its dependence on the cutting parameters. The determination of the accurate force trajectory and the corresponding on-line learning and updating strategy are also to be studied, and also, design and control methods for the mechatronic system of the FFS will be proposed for practical implementation of the FFS technique. In addition, experimental investigation on working performance of both the FFS mechatronic system and the practical cutting of typical micro/nanostructures will be conducted to demonstrate the effectiveness and superiority of the FFS technique. Accomplishment of this study will gain the capability for ultraprecision cutting of micro/nanostructured optical surface without sensitive dependence on the accuracy of the machine tool. It will also increase the corresponding cutting flexibility and decease the manufacturing costs, accordingly popularizing further applications of the optical surface in a wide spectrum of fields. Moreover, this study is attempting to take sufficient usage of the rich cutting information underlying the cutting force, and to conduct on-line learning and real-time feedback for performance enhancement of the cutting process. It will definitely support the construction of the future smart ultraprecision manufacturing system.

针对超精密切削微纳结构光学表面精度难以提高的固有瓶颈，以基于刀具与工件相互作用控制的运动跟随原理替代现行超精密切削轨迹复制原理，本项目提出一种基于切削力反馈的快速力伺服切削新方法。其学术思想在于：以过程切削力为刀具运动跟踪信号，促使刀具做微纳结构创成运动的同时自适应跟随切削链综合累积误差。本项目致力于：揭示切削链累积误差耦合特征及其对切削参数依赖规律，提出力轨迹生成策略及其在线学习与更新方法，提出快速力伺服机电系统设计及控制方法，最终进行机电系统性能测试及实际切削实验反馈。本研究将从原理上获得不敏感依赖于机床工作精度的超精密切削创成能力，从而提高微纳结构光学表面的制造柔性并降低制造成本，促进其在相关领域的诸多应用。同时，本项目尝试创新性利用丰富的切削力信息，对切削过程实现在线学习并反馈于切削性能提升，该研究工作的开展必将助力于未来智能超精密制造系统的构建。

微结构光学表面在光电子学、生物医学、新能源等领域发挥着越来越重要的作用，快速刀具伺服技术被认为是微结构切削创成的高效方法。为充分利用切削过程切削力所包含的丰富信息，本项目提出一种基于切削力控制的快速力伺服（FFS）切削方法。围绕FFS，本项目的主要研究进展包括：1）.给出了考虑加工面型、工件材料特征的刀具路径最优生成算法，给出了加工过程动力学误差模型，并揭示了动力学误差对加工表面的影响机理；2）分别给出了以切屑载荷为中间变量的简化切削力模型和基于滑移线理论的切削力微观力学模型，给出了模型参数辨识方法；3）设计了系列压电、电磁驱动单、多轴刀具驱动系统，并给出了系统参数优化设计方法，提出了相应的位置控制及其参数设计方法；4）提出了基于模型和硬件观测器以及基于力敏感单元的多种切削力测量方法，并给出了基于阻抗模型的力-位混合控制方法；5）加工了系列刀具驱动样机，并对系统性能进行了系统的开闭环测试实验，开展了基于纳米划痕和实际车削实验，提出了基于伺服协同的微结构功能表面切削误差在线实时补偿方法。通过本项目研究，获得了切削力传感分辨率50微牛，刀具驱动行程2微米-250微米，工作带宽500Hz-20kHz，刀具定位精度2nm；与传统微结构切削相比，在同等效率下实现了面型精度的3倍提高。在领域顶级期刊IJMTM、CIRP Annals、MSSP和IEEE Transactions系列等发表SCI论文13篇，申请国家发明专利6项。本项目的研究意义包括：研究了具有力-位移同步感知及控制的刀具纳米定位微机电系统，提高刀具伺服系统的功能集成度并丰富其系统设计与控制方法；提出了具有一般意义的微结构光学表面误差补偿与自适应切削方法，可有效提升切削表面精度与切削效率；探索了对包含诸多过程信息切削力信号的解析，助力于未来智能超精密制造系统的构建。