数控机床回转工作台进给系统的分析与研究

发布时间：2019-02-12 11:17

【摘要】：数控机床回转工作台是数控机床实现圆周回转运动的关键机床部件,其性能的优良直接影响到数控机床的加工精度和稳定性。伴随着当今数控机床性能不断的提升,随之而来的是对回转工作台的传动精度、响应速度及加工稳定性的更高要求。数控机床回转工作台动态特性很大程度上取决于其进给系统的表现,数控机床回转工作台进给系统广义上是由机械传动系统和伺服驱动两大部分组成。机械进给系统一般是由齿轮副和蜗轮蜗杆副组成的多级齿轮传动系统,齿轮传动系统的振动主要是以扭转振动为主,齿轮系统的扭转振动不仅使回转工作台的加工稳定性变差,而且缩短了齿轮传动系统的疲劳寿命。回转工作台伺服系统是指以位置和速度作为控制对象的自动控制系统,而且伺服系统的性能很大程度上决定了回转工作台的响应速度和稳定性。伺服系统的控制形式通常为PID三环控制,PID控制器参数对于伺服系统的性能有着至关重要的作用。本文针对回转工作台进给系统的齿轮传动系统及伺服驱动系统主要做了以下的工作：(1)根据拉格朗日方程建立回转工作台齿轮传动系统的七自由度扭转振动动力学模型；(2)根据建立的工作台齿轮传动扭振系统,求得了其固有频率及主振型；(3)运用直接积分法newmark-β对齿轮传动系统在时变啮合刚度激励及齿轮误差激励下的动态响应分析,分析了系统的动态特性；(4)对工作台伺服系统进行了设计整定,运用单纯形法并利用三种不同的优化准则对PID控制器的参数进行了优化。通过对比知GISE优化准则优化后的参数对提高伺服系统的稳定性和响应速度更为有效。
[Abstract]:The rotary table of NC machine tool is the key part of NC machine tool to realize circumferential rotation, and its excellent performance directly affects the machining accuracy and stability of NC machine tool. With the continuous improvement of the performance of the CNC machine tools, the higher requirements for the transmission accuracy, response speed and machining stability of the rotary table are followed. The dynamic characteristics of the rotary table of NC machine tools depend on the performance of the feed system to a great extent. In a broad sense, the feed system of the rotary table of the NC machine tool is composed of two parts: mechanical drive system and servo drive system. The mechanical feed system is generally a multistage gear transmission system composed of the gear pair and the worm gear pair. The vibration of the gear transmission system is mainly torsional vibration. The torsional vibration of the gear system not only makes the machining stability of the rotary table worse, Moreover, the fatigue life of gear transmission system is shortened. The servo system of rotary table refers to the automatic control system with position and speed as the control object, and the performance of the servo system largely determines the response speed and stability of the rotary table. The control form of servo system is usually PID three-loop control. The parameters of PID controller play an important role in the performance of servo system. The main works of this paper are as follows: (1) according to Lagrange equation, the seven degree of freedom torsional vibration dynamic model of rotary table gear transmission system is established; (2) according to the torsional vibration system of the gear drive of the worktable, the natural frequency and the main vibration mode are obtained; (3) the dynamic response of gear transmission system under time-varying meshing stiffness excitation and gear error excitation is analyzed by direct integration method newmark- 尾, and the dynamic characteristics of the system are analyzed. (4) the servo system of the worktable is designed and tuned. The parameters of the PID controller are optimized by using simplex method and three different optimization criteria. It is found that the optimized parameters of GISE optimization criterion are more effective to improve the stability and response speed of servo system.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG659

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