五轴铣车机床进给系统动力学参数快变与渐变耦合的可靠性设计理论研究

The motivation of this project is to solve the problems that the reliability and machining accuracy of the five-axis milling-turning machine tool manufactured in China are 1/6 and 1/2 of the same thoses in foreign countries respectively. The relationship between the dynamical parameters and the multi-axis synchronous feed motion, the deterioration mechanism of the dynamical parameters among the lifetime and the effects of the fast-varying parameters on the deterioration process are firstly studied to formulate the fast-varying and gradually-varying coupled dynamical parameters of the feed system and to present the deterioration law of dynamical parameters under the condition of multi-axis synchronous feed motion. Then, the mathematical equation of the dynamic cutting force of the five-axis milling-turning machine tool is studied, the nonlinear dynamics equation with the fast-varying and the gradually-varying coupled dynamical parameters is derived and its stability and solution are analyzed to reveal the deterioration law of the machining accuracy and chatter and to propose the solution of improving the machining accuracy and avoiding chatter. Next, Remote quantification condition identification method of the nonlinear dynamics system is explored and the stochastic deterioration law of the fast-varying and gradually-varying coupled dynamical parameters are ascertained in the case of the small sample. Based on the above works, this project analyzes the stability reliability, machining accuracy reliability and the reliability sensitivity of the feed system with the fast-varying and gradually-varying coupled dynamical parameters including random variables and stochastic processes and studies the dynamical reliability optimization design to determine the inherent factors resulting in the low reliability of the feed system and to proposes the solution of improving the reliability of the feed system of the five-axis milling-turning machine tool manufactured in China. Finally, it is offered that the theory and method of the dynamical reliability design with the fast-varying and gradually-varying coupled dynamical parameters should be also suitable for truck crane boom, crane systems, telescoping wings, etc.

针对国产五轴铣车机床可靠性和加工精度分别约为国外产品的1/6和1/2倍问题，研究多轴联动进给诱导的动力学参数的变化行为、动力学参数全寿命周期内的退化机理、快变参数对退化过程的影响关系，建立进给系统动力学参数的快变与渐变耦合模型，揭示其在多轴联动进给条件下的演化规律；研究五轴铣车动态切削力的数学表征，构建进给系统动力学参数快变与渐变耦合的非线性动力学方程，分析方程的稳定性与瞬态响应，揭示颤振与加工精度的变化规律，提出加工精度的提升方案与防止颤振措施；探索非线性动力学部件参数退化的远程定量识别方法，探明小样本条件下动力学参数快变与渐变耦合的随机演变规律，分析动力学参数快变与渐变耦合的稳定可靠性、加工精度可靠性及敏感性，并开展动态可靠性优化设计，获得进给系统动力学特性控制的低可靠性的本质因素，提出可靠性的提升方案。最终建立普适性的动力学参数快变与渐变耦合动态可靠性设计理论与方法。

针对国产五轴铣车机床可靠性和加工精度分别约为国外产品的1/6和1/2倍问题，本项目① 构建了滚动直线导轨磨损与振动共存的动力学模型并进行了动力学分析，揭示了磨损情形下的动力学响应演变规律；② 构建了考虑滑块滑槽过渡曲线的滚动直线导轨时变刚度非线性动力学模型，获得了引起非线性现象的参数及滑块运动对非线性变化的影响规律；③ 构建了运动情形下滚动直线导轨点蚀故障时变非线性动力学模型及求解方法，得出不同的点蚀缺陷和不同的滑块长度对动态响应的影响规律；④ 提出了单向进给系统动力学模型，获得了设计和装配参数对进给系统振动幅值以及稳定性的影响规律；⑤ 推导滚珠丝杠进给系统轴向载荷与变形之间关系的解析表达式，获得了进给系统非线性动力学方程的二阶近似解析解，揭示激振力和滚珠丝杠进给系统的主要结构参数对动态响应的影响规律；⑥ 提出了多轴进给系统的多自由度振动微分方程，获得了设计和装配参数对系统动态特性以及稳定性的影响规律；⑦ 建立了柔性工件的时变动力学参数的多自由度动力学模型，分析了工件系统在半径时变下的临界转速及车削时域响应变化，获得了不同参数时变车削颤振的影响规律；⑧ 初步解决了参数具有随机性质的进给系统中滚动直线导轨的动态可靠性分析和灵敏度问题；⑨ 提出了单螺母滚珠丝杠副静刚度可靠性和可靠性灵敏度计算方法；⑩ 创建了双螺母滚珠丝杠副可靠性模型，并提出了双螺母滚珠丝杠副静刚度可靠性设计方法；⑪ 建立了三轴联动进给系统动态可靠性分析模型，采用结合主动学习函数的Kriging模型初步解决了三轴联动进给系统的动态可靠性分析和灵敏度问题。本项目的研究为五轴机床乃至其他机床的进给系统的可靠性及优化设计提供理论和方法基础。