Effect of the screw–nut joint stiffness on the position-dependent dynamics of a vertical ball screw feed system without counterweight

2017 ◽  
Vol 232 (15) ◽  
pp. 2599-2609 ◽  
Author(s):  
Cunfan Zou ◽  
Huijie Zhang ◽  
Dun Lu ◽  
Jun Zhang ◽  
Wanhua Zhao
Keyword(s):  
Dynamic Characteristics ◽  
Joint Stiffness ◽  
Structure Design ◽  
Lumped Parameter Model ◽  
Ball Screw ◽  
Feed System ◽  
Spindle System ◽  
Milling Machines ◽  
Simulation And Evaluation ◽  
Screw Feed

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.

Dynamic characteristics and reliability analysis of ball screw feed system on a lathe

2020 ◽  
Vol 150 ◽  
pp. 103890
Author(s):  
Mengtao Xu ◽  
Bing Cai ◽  
Changyou Li ◽  
Hongzhuang Zhang ◽  
Zhendong Liu ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Dynamic Characteristics ◽  
Ball Screw ◽  
Feed System ◽  
Screw Feed

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
Keyword(s):  
Structural Optimization ◽  
Natural Frequency ◽  
Dynamic Characteristics ◽  
Modeling Method ◽  
Modal Testing ◽  
Ball Screw ◽  
Test Results ◽  
Feed System ◽  
Relative Errors ◽  
Screw Feed

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.

scholarly journals An Electromechanical Co-Simulation Model Based on Lumped Parameter Model of Ball Screw Feed Drive System

2018 ◽  
Vol 237 ◽  
pp. 03007
Author(s):  
Liang Luo ◽  
Weimin Zhang ◽  
Haonan Sui ◽  
Jürgen Fleischer
Keyword(s):  
Simulation Model ◽  
High Speed ◽  
Drive System ◽  
Lumped Parameter Model ◽  
Ball Screw ◽  
Feed System ◽  
Feed Drive ◽  
Lumped Parameter ◽  
Feed Drive System ◽  
Screw Feed

The continuous search for efficiency put forward higher requests to the machine tool for high speed and high acceleration, which makes the large-size and lightweight-designed feed drive system more likely to produce vibration during high-speed and high-acceleration feed operation. Ball screw feed system is the most widely used linear drive system in the field of industrial automation. Electromechanical Co-Simulation for ball screw feed drive dynamics is an important technique for solving vibration problems occurs in the feed motion. In view of the shortcomings of the current dynamic simulation model in the study of vibration of ball screw feed drive system, taking a ball screw feed drive system test bench as an example, an electromechanical co-simulation model based on the lumped parameter model of ball screw feed drive system was built up in this paper. Firstly, based on the axial and rotation vibration integrated dynamic modeling method of ball screws, the lumped parameter model of ball screw feed system was established. Secondly, through the integration of the simulation model of semi-closed-loop cascade control system and the lumped parameter model of ball screw feed drive system, an electromechanical co-simulation model was built up. Simulation result shows that, the co-simulation model of ball screw feed drive system can predict the vibration occurs in the feed operation caused by the servo controller, ball screw feed system or the coupling between them.

Dynamic analysis of a ball screw feed system with time-varying and piecewise-nonlinear stiffness

2019 ◽  
Vol 233 (18) ◽  
pp. 6503-6518 ◽  
Author(s):  
Jianguo Gu ◽  
Yimin Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Ball Screw ◽  
Time Varying ◽  
Feed System ◽  
Restoring Force ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Nonlinear Restoring Force ◽  
Abrupt Changes ◽  
Screw Feed

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.

Multi-domain integrated modeling and verification for the ball screw feed system in machine tools

2020 ◽  
Vol 234 (14) ◽  
pp. 1707-1719 ◽  
Author(s):  
Zaiwu Mei ◽  
Liping Chen ◽  
Jianwan Ding
Keyword(s):  
Machine Tool ◽  
Dynamic Model ◽  
Dynamic Characteristics ◽  
Integrated Model ◽  
Numerical Control ◽  
Ball Screw ◽  
Causal Connection ◽  
Feed System ◽  
Following Error ◽  
Screw Feed

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.

scholarly journals Acceleration-Dependent Analysis of Vertical Ball Screw Feed System without Counterweight

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Cunfan Zou ◽  
Huijie Zhang ◽  
Jun Zhang ◽  
Dongdong Song ◽  
Hui Liu ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Natural Frequency ◽  
Dynamic Load ◽  
Inertial Force ◽  
Ball Screw ◽  
Tension Force ◽  
Feed System ◽  
Spindle System ◽  
Acceleration And Deceleration ◽  
Screw Feed

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.

scholarly journals Dynamic Modeling and Experiment Research on Twin Ball Screw Feed System Considering the Joint Stiffness

Symmetry ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 686 ◽  
Author(s):  
Meng Duan ◽  
Hong Lu ◽  
Xinbao Zhang ◽  
Yongquan Zhang ◽  
Zhangjie Li ◽  
...  
Keyword(s):  
Dynamic Modeling ◽  
Dynamic Characteristics ◽  
Friction Model ◽  
Numerical Control ◽  
Ball Screw ◽  
Cnc Machine Tools ◽  
Axial Stiffness ◽  
Cnc Machine ◽  
Feed System ◽  
Lumped Mass

It is of great significance to study the dynamic characteristics of twin ball screw (TBS) feed system to improve the precision of gantry-type dual-driven computer numerical control (CNC) machine tools. In this paper, an equivalent dynamic model of the TBS feed system is established utilizing lumped mass method considering the stiffness of joints. Equivalent axial stiffness of screw-nut joints and bearing joints are both calculated by Hertz contact theory. Furthermore, a friction model is proposed because the friction force of the screw nut affects the stiffness of the joints. Then, the friction parameters are obtained by using the nonlinear system identification method. Meanwhile, a finite element model (FEM) is developed to assess the dynamic characteristics of TBS feed system under the stiffness of joints. Finally, validation experiments are conducted, and the results show that the positions of the nut and the velocities of worktable greatly affect the dynamic characteristics of the TBS feed system. Compared with the theoretical calculation, FEM and experiments indicate that the dynamic modeling proposed in this article can reach a higher accuracy.

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