复杂零件联动铣削的多界面耦合动力学集成建模与精度创成机制研究

Machining accuracy of parts is closely related to the multi-axis feed motion of machine tools and cutting process. Understanding the dynamic interaction mechanism between multi-axis motion and cutting process under complex working conditions is very important to reveal the generation mechanism of machining accuracy of machine tools. In view of the current theoretical research, in which the interaction between machine tool and cutting process is not considered enough, thus it is difficult to fully reflect the essence of multi-axis machining. This proposal plans to research multi-interface coupled dynamics integrated modeling and generation mechanism of machining accuracy in multi-axis milling of machine tools. Firstly, the interface interaction behavior of load-mechanical transmission and load-servo driving under reverse action of time-varying cutting load (milling force and workpiece mass/gravity) is considered, and then the dynamic characteristics of mechanical-servo system and its variation trend will be researched. Secondly, the proposal will study the cutter-workpiece dynamic engagement process under multi-axis motion with non-ideal displacement output, and then will establish a multi-interface coupled dynamics integrated model for multi-axis machining. Lastly, based on the physic simulation of part forming process, the generation, coupling, transfer and variation mechanism of machining error sources will be clarified, and the forming mechanism of workpiece contour accuracy will also be revealed. Based on the existing hardware and software foundation, an open CNC machining experimental platform is built to complete the experimental verification for the theoretical research work. This research will provide theoretical and technical basis for the realization of high precision milling during multi-axis milling of machine tools.

零件加工精度与机床进给系统运动和切削过程密切相关，深入理解复杂工况下多轴联动与切削过程之间的动力学交互作用对揭示零件加工精度形成机制至关重要。本项目针对当前研究对机床进给运动与铣削过程交互作用考虑不足，未能完全揭示联动加工物理本质的现状，拟开展复杂零件联动铣削的多界面耦合动力学集成建模与加工精度创成机制研究。研究交变切削负载（铣削力和工件质量/重力）反向作用下载荷-机械传动系统界面作用行为和载荷-伺服驱动系统界面机电耦合行为，表征切削负载对进给系统运动特性的影响；分析多轴联动非理想位移输出下刀具-工件耦合界面动态啮合过程，建立多轴联动铣削的多界面耦合动力学集成模型；实现零件轮廓成形的数值仿真，阐明加工误差源的产生、耦合、传递及演变规律，揭示零件轮廓精度的创成机制。基于现有软硬件基础，搭建开放式数控加工实验平台，完成相关理论研究的实验验证。本研究将为实现复杂零件高精度铣削加工提供理论依据。

本项目针对当前研究对机床进给运动与铣削过程交互作用考虑不足，未能完全揭示联动加工物理本质的现状，开展复杂零件联动铣削的多界面耦合动力学集成建模与加工精度创成机制研究，取得成果如下：（1）针对数控机床典型滚珠丝杠机械传动系统，研究了复杂边界条件下载荷-机械传动系统界面作用行为，考虑铣削力、预紧力等复杂力载荷的影响，分析系统丝杠-螺母副、支撑轴承副等动结合部的力-变形协调条件，理论计算其接触刚度，实验测试阻尼特性参数，建立了滚珠丝杠进给系统8自由度集中参数动力学模型，实现了电机转子-工作台跨点动刚度的准确预测。（2）解析表征了进给系统伺服驱动环节的物理机制，构建了包含运动控制器、伺服放大器、PWM整流逆变器、三相永磁同步电机、机械传动环节的进给系统机电集成模型，揭示了进给系统机-电-磁-力间的耦合关系，全息获得了系统运行过程中的动力学、电学和磁学状态量，实现了数控指令输入和切削负载共同作用下进给系统机械执行末端（刀具/工件）的瞬态/稳态跟随能力。（3）综合切削负载作用下的多轴联动运动控制模型和联动非理想位移输出下的刀具-工件动态啮合模型，建立了数控机床多轴联动铣削过程的数控-伺服驱动-机械传动-铣削闭环全参数动力学耦合集成模型，实现对联动铣削过程中机械传动系统作用界面、伺服驱动系统机电耦合界面、联动加工刀具-工件耦合界面的综合物理表征。（4）揭示了机床本体多轴联动过程、铣削过程以及界面耦合效应作用下零件加工误差源的产生、传递、耦合与演变机制，系统性阐明了刀具偏心的成因及其对零件轮廓形貌的影响规律，提出了非对称柔性工艺系统的广义铣削动力学建模方法，成功解释了进给方向依赖的非对称铣削动力学特性，揭示了复杂曲面零件轮廓精度的创成机制，为实现复杂型面零件高精度铣削加工提供理论支撑。（5）发表第一/通讯作者SCI论文9篇（均为本项目第一标注），申请高价值发明专利6项（授权4项），注册软件版权5项；培养博士研究生4人，硕士研究生4名；参与国际会议2人次；获得2021年度陕西高等学校科学技术一等奖（排名2/7）。