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.

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.

Axial stiffness identification of a ball screw feed system using generalized frequency response functions

2020 ◽  
pp. 095440622098050
Author(s):  
Hua Zhou ◽  
Xinhua Long ◽  
Guang Meng ◽  
Xingjian Dong
Keyword(s):  
Frequency Response ◽  
Response Spectrum ◽  
Ball Screw ◽  
Axial Stiffness ◽  
Response Functions ◽  
Feed System ◽  
Restoring Force ◽  
Frequency Response Functions ◽  
Single Tone ◽  
Screw Feed

Contact of balls in screw nuts and bearings causes the nonlinearity of a ball screw feed system. The identification of nonlinear stiffness helps to understand and control the feed system. The axial vibration of the ball screw feed system can be descripted by a single-degree-of-freedom (SDOF) system with polynomial nonlinear terms. Since generalized frequency response functions (GFRFs) can be expressed in terms of linear and nonlinear system parameters, one can estimate these parameters based on the measured GFRFs. In this effort, both single-tone and multitone harmonic inputs are employed to measure GFRFs, and a simple search algorithm is proposed to find the suitable frequency set of the multitone input. Parameter identification based on these two methods has been compared by numerical simulation and experiment. Since the response spectrum measured from vibration experiment of a ball screw system has even and odd harmonics, it is suitable to simplify the restoring force with square and cubic nonlinearity form. Static experiment is also conducted to verify the identified parameters, and the results show that the method based on single-tone inputs performs effectively in identifying axial stiffness of a ball screw feed system, but the method based on multitone inputs gets the incorrect results in practical application

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.

Modeling and Load Capacity Analysis of Reciprocating Hybrid Linear Guideway With Annular Groove and Sloped Recesses

2020 ◽  
Vol 143 (6) ◽  
Author(s):  
Huanyu Du ◽  
Hongguang Li ◽  
Guang Meng
Keyword(s):  
Dynamic Characteristics ◽  
Normal Vibration ◽  
Linear Time ◽  
Load Capacity ◽  
Normal Direction ◽  
Capacity Analysis ◽  
Time Varying ◽  
Bearing Surface ◽  
Single Degree Of Freedom ◽  
Single Degree

Abstract In this work, we research a reciprocating hybrid linear guideway and study its load capacity. This hybrid guideway's bearing surface is designed with an annular groove and two sloped shallow recesses. The analysis is based on modeling by mass-conserving cavitation algorithm (p − θ cavitation algorithm), where a modified smoothing switch function is raised for better convergence. Focusing on the normal direction to reciprocation, the load-guideway system is simplified as a single-degree-of-freedom linear time-varying system and solved by Newmark-β method. Due to the hybrid guideway's time-varying dynamic characteristics, there is a normal vibration in reciprocation. By analyzing two typical load cases in detail, the results indicate that the hybrid guideway has greater load capacity than the hydrostatic guideway, and the normal vibration is small enough for most engineering situations.

Dynamics of a Simple Model for a Wind-Loaded Nonlinear Structure: Bifurcations of Codimension One and Two

1998 ◽  
Vol 65 (2) ◽  
pp. 505-512 ◽  
Author(s):  
K. Yagasaki
Keyword(s):  
Vortex Shedding ◽  
Degree Of Freedom ◽  
Force Characteristic ◽  
Restoring Force ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Nonlinear Restoring Force ◽  
Codimension One ◽  
Theoretical Predictions ◽  
The Cross

The motion induced by vortex shedding of a structure with nonlinear restoring force is investigated. In particular, a conclusion about nonexistence of bounded motions obtained for a similar problem in the previous study is improved by taking into account the nonlinear restoring force characteristic. The vortex shedding frequency is assumed to be close to the natural frequency of the cross-wind oscillation and the along-wind oscillation is not excited, so that a single-degree-of-freedom model representing the cross-wind motions is obtained. The averaging method is applied to the single-degree-of-freedom system, and the normal form and center manifold theories are used to discuss bifurcations of codimension one, saddle-node and Hopf bifurcations. Moreover, it is shown that a multiple bifurcation of codimension two, called the Bogdanov-Takens bifurcation, occurs in the averaged system. The implications of the averaging results on the dynamics of the original single-degree-of-freedom system are described. Numerical examples are also given with numerical simulation results for both the averaged and original systems to demonstrate our theoretical predictions.

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.

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.

On the Stability Properties of a Periodically Forced, Time-Varying Mass System

2009 ◽  
Author(s):  
W. T. van Horssen ◽  
O. V. Pischanskyy ◽  
J. L. A. Dubbeldam
Keyword(s):  
Periodic Solutions ◽  
Forced Vibrations ◽  
Time Varying ◽  
Mass System ◽  
Single Degree Of Freedom ◽  
Stability Properties ◽  
Single Degree ◽  
Existence Of Periodic Solutions ◽  
The Stability ◽  
Varying Mass

In this paper the forced vibrations of a linear, single degree of freedom oscillator (sdofo) with a time-varying mass will be studied. The forced vibrations are due to small masses which are periodically hitting and leaving the oscillator with different velocities. Since these small masses stay for some time on the oscillator surface the effective mass of the oscillator will periodically vary in time. Not only solutions of the oscillator equation will be constructed, but also the stability properties, and the existence of periodic solutions will be discussed.

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