变刚度—约束阻尼减振镗杆设计及特性研究

发布时间：2018-05-04 23:20

本文选题：减振镗杆 + 变刚度　；参考：《哈尔滨理工大学》2016年博士论文

【摘要】：在切削加工过程中由于系统刚性问题容易产生振动,造成系统不稳定,加工质量降低。深孔镗削加工时镗杆的长悬伸导致动刚度、静刚度降低,尤其是镗杆的长径比较大的情况下,镗杆的刚度就会更小,加工过程中势必带来不期望存在的剧烈振动,降低加工质量,降低生产效率,如何在深孔加工过程中调节动刚度进而抑制振动己成为一个新的关注点。本文分析了国内外关于被动控制类型减振镗杆、主动控制减振镗杆等方面的研究现状,提出了变刚度-约束阻尼型减振镗杆设计,建立了变刚度-约束阻尼减振镗杆动力学模型,并根据模型进行了结构设计、仿真及刚度调节控制,主要研究内容如下:根据变刚度-约束阻尼型减振镗杆结构特点和减振特性,建立了约束阻尼-动力减振镗杆系统简化的数学模型。分析了最佳频率比、最佳阻尼比和最佳刚度比,并分析了约束阻尼层损耗因子与系统的最优匹配区域,为下一步的镗杆设计及性能仿真提供基础。根据变刚度-约束阻尼型减振镗杆数学模型,设计了具有刚度可调系统的约束阻尼减振镗杆。分析了普通镗杆、动力减振镗杆、变刚度-约束减振镗杆的幅频特性和减振块、橡胶圈、阻尼油、外壁厚度4个主要因素对镗杆减振性能的影响,在此基础上设计、制造了变刚度-约束阻尼减振镗杆,基于有限元理论仿真分析得出了最佳加工参数。根据变刚度-约束阻尼型减振镗杆刚度调节的需要,采用最小二乘法进行了实时在线辨识,采用模糊PID控制器实现了电机高精度的伺服控制,通过ASMEsim平台验证了控制方案的可行性,仿真结果表明:支撑刚度的变化可以改变刀尖振动趋于稳定的时间,提高系统响应速度。为了验证变刚度-约束阻尼型减振镗杆的有效性,分析了变刚度-约束阻尼减振镗杆的实验模态,进行了三种镗杆镗削对比实验,研究了切削参数(切削速度、进给量、背吃刀量等)对减振性能的影响规律,分析变刚度-约束阻尼减振镗杆刚度变化对镗杆减振性能的影响规律,通过实验验证了第二章所建立模型的准确性及通过调节吸振器刚度k2实现减振镗杆振动特性的调节,最终实现对减振镗杆减小振动降低振幅的目的。通过变刚度-约束阻尼减振镗杆设计及镗杆动态特性分析,提出变刚度约束阻尼减振方法,研究了变刚度控制理论,为深孔加工专用减振镗杆的研制奠定了基础,为动力吸振技术的研究提供了新的分析方法。
[Abstract]:In the cutting process, the system is unstable and the machining quality is reduced because of the system rigidity problem. The long suspension of boring bar in deep hole boring process leads to dynamic stiffness and static stiffness decrease, especially if the boring bar has a large length and diameter, the stiffness of boring bar will be smaller, and the process of machining will inevitably bring unexpected violent vibration. How to adjust dynamic stiffness and suppress vibration in deep hole machining has become a new concern. This paper analyzes the research status of passive control type vibration absorption boring bar and active control vibration absorption boring bar at home and abroad, and puts forward the design of variable stiffness and constrained damping type vibration absorption boring bar. The dynamic model of variable stiffness and constrained damping vibration absorption boring bar is established, and the structural design, simulation and stiffness regulation control are carried out according to the model. The main research contents are as follows: according to the structural characteristics and vibration absorption characteristics of variable stiffness and constrained damping type damping boring bar, a simplified mathematical model of constrained damp-dynamic damping boring bar system is established. The optimal frequency ratio, optimal damping ratio and optimal stiffness ratio are analyzed. The optimal matching region between the constrained damping layer loss factor and the system is analyzed, which provides the basis for the design and performance simulation of the boring bar in the next step. Based on the mathematical model of variable stiffness and constrained damping type vibration absorption boring bar, a constrained damping damping boring bar with adjustable stiffness is designed. This paper analyzes the amplitude and frequency characteristics of ordinary boring bar, dynamic vibration absorption boring bar and variable stiffness constraint vibration absorption boring bar, and the effects of four main factors, such as damping block, rubber ring, damping oil and outer wall thickness, on the vibration absorption performance of boring bar. The variable stiffness and constrained damping vibration absorption boring bar is manufactured, and the optimum machining parameters are obtained based on the finite element theory simulation analysis. According to the need of adjusting the stiffness of variable stiffness and constrained damping damping boring bar, the method of least square is used to identify the stiffness of boring bar in real time, and the fuzzy PID controller is used to realize the servo control of motor with high precision. The feasibility of the control scheme is verified by ASMEsim platform. The simulation results show that the change of support stiffness can change the time when the vibration of the blade tip tends to be stable and improve the response speed of the system. In order to verify the effectiveness of the variable stiffness and constrained damping type vibration absorption boring bar, the experimental modes of the variable stiffness and constrained damping boring bar are analyzed, three kinds of boring experiments are carried out, and the cutting parameters (cutting speed, feed rate) are studied. The influence law on vibration absorption performance of boring rod with variable stiffness and constraint damping is analyzed, and the influence law on vibration absorption performance of boring bar with variable stiffness and constraint damping is analyzed. The veracity of the model established in the second chapter is verified by experiments, and the vibration characteristics of the damping boring bar can be adjusted by adjusting the vibration absorber stiffness k2. Finally, the purpose of reducing the vibration and reducing the amplitude of the vibration of the damping boring bar is achieved. Based on the design of variable stiffness constrained damping damping boring bar and the analysis of dynamic characteristics of boring bar, the method of variable stiffness constrained damping damping damping is put forward, and the theory of variable stiffness control is studied, which lays a foundation for the development of special vibration absorption boring bar for deep hole machining. It provides a new analytical method for the study of dynamic vibration absorption technology.
【学位授予单位】：哈尔滨理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG53

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