Analysis of Dynamic Characteristics of the Dual Ball Screw-Driven Linear Feed System in Z Direction

2013 ◽  
Vol 470 ◽  
pp. 593-597 ◽  
Author(s):  
Jun Huang ◽  
Zhen Hua Wang ◽  
Jun Tang Yuan

The vibration modals and harmonic responses of the dual ball screw-driven feed system in Z direction are analyzed by the software ANSYS. In this paper, the equivalence of characteristics of fixed and rolling joints is emphasized, while the influence of joint faces on the dual ball screw-driven feed system is analyzed. In addition, the FEM results of spindle and spindle box connecting the feed system are compared with the modal testing value. The results show that the relative errors between corresponding order natural frequency and the test results are within 10%, which verified the accuracy of the modeling method, and the influence of combination on the analysis of the ball screw feed system can't be ignored. Depending on the above, weaknesses of dual ball screw-driven feed structure is found out, which provides the basis for structural optimization.

2020 ◽  
Vol 150 ◽  
pp. 103890
Author(s):  
Mengtao Xu ◽  
Bing Cai ◽  
Changyou Li ◽  
Hongzhuang Zhang ◽  
Zhendong Liu ◽  
...  

2014 ◽  
Vol 543-547 ◽  
pp. 1409-1412 ◽  
Author(s):  
Chen Li ◽  
Cui Ping Liu ◽  
Zhe Wang

A model reference adaptive modeling method of ball screw feed system is proposed. Using a low-level system with excellent dynamic characteristics as the reference model and ball screw feed system as the controlled object, this paper establishes model reference adaptive system by Narendra program, achieving exact match between the adjustable system and the reference model through experiment and deriving the low-level model of the ball screw feed system. Then taking the X axis of X-Y work table as an example, a second-order model of the ball screw feed system is established by this method. When 40000 pulse signals are input into the model and the ball screw feed system in 160s respectively, the output error between the two is within ± 0.005mm, thus testifying the higher accuracy of the model obtained.


Author(s):  
Jianguo Gu ◽  
Yimin Zhang

In this study, a single-degree-of-freedom model is established to investigate the dynamic characteristics of a single-nut double-cycle ball screw feed system by considering the contact states of the nonlinear kinematic joints. Based on fully considering the parameters of the ball screw feed system, the axial deformations and forces of the key components are calculated to construct a set of piecewise-nonlinear restoring force functions of the system displacement and worktable position. The variations of the contact stiffnesses of the kinematic joints and transmission stiffness of the system with different boundary conditions are analyzed and the results indicate that they all have abrupt changes when the system displacement reaches a critical value. The changing law of the system transmission stiffness in the whole stoke is discussed. Additionally, the effects of excitation force, worktable position and system mass on the dynamic characteristics of the system and its correlative components are analyzed.


Author(s):  
Zaiwu Mei ◽  
Liping Chen ◽  
Jianwan Ding

An accurate dynamic model for the computer numerical control machine tool feed system is of great significance to improve the machining accuracy. However, the accurate dynamic model of the feed system is difficult to be established because its dynamic characteristics not only depend on the performance of subsystems, such as mechanical, electrical, and control, but also on the interaction between them. In order to solve this problem, a modular modeling method based on a non-causal connection is proposed in this article, and the multi-domain seamless integrated model for the ball screw feed system is established. First, the feed system is decomposed by modularization, and the interface models in each domain are defined. Then all the subsystems are modeled strictly, and the nonlinear characteristics of each subsystem are analyzed. Finally, the multi-domain seamless integrated model of the ball screw feed system is established by the non-causal connection of subsystem models, and the experiment is carried out to validate the system model. The experimental results show that the multi-domain seamless integrated model of the ball screw feed system established in this article can accurately reflect the dynamic characteristics of the real physical system, and has high prediction accuracy for the dynamic following error. It is of great significance to further study the multi-domain coupling characteristics and compensation control methods of the machine tool system.


2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Cunfan Zou ◽  
Huijie Zhang ◽  
Jun Zhang ◽  
Dongdong Song ◽  
Hui Liu ◽  
...  

AbstractThe distinguishing feature of a vertical ball screw feed system without counterweight is that the spindle system weight directly acts on the kinematic joints. Research into the dynamic characteristics under acceleration and deceleration is an important step in improving the structural performance of vertical milling machines. The magnitude and direction of the inertial force change significantly when the spindle system accelerates and decelerates. Therefore, the kinematic joint contact stiffness changes under the action of the inertial force and the spindle system weight. Thus, the system transmission stiffness also varies and affects the dynamics. In this study, a variable-coefficient lumped parameter dynamic model that considers the changes in the spindle system weight and the magnitude and direction of the inertial force is established for a ball screw feed system without counterweight. In addition, a calculation method for the system stiffness is provided. Experiments on a vertical ball screw feed system under acceleration and deceleration with different accelerations are also performed to verify the proposed dynamic model. Finally, the influence of the spindle system position, the rated dynamic load of the screw-nut joint, and the screw tension force on the natural frequency of the vertical ball screw feed system under acceleration and deceleration are studied. The results show that the vertical ball screw feed system has obviously different variable dynamics under acceleration and deceleration. The influence of the rated dynamic load and the spindle system position on the natural frequency under acceleration and deceleration is much greater than that of the screw tension force.


2019 ◽  
Vol 57 ◽  
pp. 30-44
Author(s):  
Wei Zhang ◽  
Xing Zhang ◽  
Jun Zhang ◽  
Wanhua Zhao

Author(s):  
Cunfan Zou ◽  
Huijie Zhang ◽  
Dun Lu ◽  
Jun Zhang ◽  
Wanhua Zhao

The study on the position-dependent dynamic characteristics of a vertical ball screw feed system without counterweight is an important step in the enhancement of the structural performance of mini-type vertical milling machines. The ball screw is generally driven by a servomotor, which converts a rotary motion into a linear motion through a screw–nut pair. To assess the position-dependent dynamic characteristics of a vertical ball screw feed system subjected to the influence of the screw–nut joint stiffness, a variable-coefficient lumped parameter model of the system is developed. This model is established taking into account the screw–nut joint stiffness under three different strategies: (1) considering the preload and the weight of the spindle system, (2) considering the elastic deformation but ignoring the effect of the weight, and (3) a perfectly rigid model. The differences between the three models in predicting the position-dependent dynamic characteristics of the system are compared, revealing that the stiffness of screw–nut joint greatly affects the vibratory behavior of the spindle system in the transmission direction. A set of conducted experimental results demonstrate that the stiffness model under the preload and the weight of the spindle system is the most accurate model for the prediction of the position-dependent natural frequency and displacement response of the system with the spindle system position. Therefore, it is more suitable for structure design, performance simulation, and evaluation of a vertical ball screw feed system without counterweight.


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