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 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.

scholarly journals Effect of Stiffness of Rolling Joints on the Dynamic Characteristic of Ball Screw Feed Systems in a Milling Machine

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Dazhong Wang ◽  
Yan Lu ◽  
Tongchao Zhang ◽  
Keyong Wang ◽  
Akira Rinoshika
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristic ◽  
Calculation Method ◽  
Ball Screw ◽  
Fe Model ◽  
Milling Machine ◽  
Cnc Milling ◽  
Feed System ◽  
Cnc Milling Machine ◽  
Screw Feed

Dynamic characteristic of ball screw feed system in a milling machine is studied numerically in this work. In order to avoid the difficulty in determining the stiffness of rolling joints theoretically, a dynamic modeling method for analyzing the feed system is discussed, and a stiffness calculation method of the rolling joints is proposed based on the Hertz contact theory. Taking a 3-axis computer numerical control (CNC) milling machine set ermined as a research object, the stiffness of its fixed joint between the column and the body together with the stiffness parameters of the rolling joints is evaluated according to the Takashi Yoshimura method. Then, a finite element (FE) model is established for the machine tool. The correctness of the FE model and the stiffness calculation method of the rolling joints are validated by theoretical and experimental modal analysis results of the machine tool’s workbench. Under the two modeling methods of joints incorporating the stiffness parameters and rigid connection, a theoretical modal analysis is conducted for the CNC milling machine. The natural frequencies and modal shapes reveal that the joints’ dynamic characteristic has an important influence on the dynamic performance of a whole machine tool, especially for the case with natural frequency and higher modes.

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

The Stiffness Analysis and Modeling Simulation of Ball Screw Feed System

2010 ◽  
Vol 97-101 ◽  
pp. 2914-2920 ◽  
Author(s):  
Qin Wu ◽  
Zhi Yuan Rui ◽  
Jian Jun Yang
Keyword(s):  
Machine Tool ◽  
Control Strategy ◽  
Feedforward Control ◽  
Dynamic Performance ◽  
Numerical Control ◽  
Ball Screw ◽  
Axial Stiffness ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Feed System

The computer numerical control (CNC) machine tool was investigated and the dynamics model for the servo feed system was established. Based on the fixing constraint of the ball screw, the mathematical models of axial stiffness and torsion stiffness are constructed. According to the effects of stiffness on the dynamic performance, the simulation model for CNC machine tool feed system with stiffness considered was set up by the dynamic simulation tool Simulink, and a curve representing the performance of the system was obtained. To reduce the effect of stiffness on the system, the feedforward control strategy is used for stiffness compensation. The simulation results show that the stability and response performances of the system are improved and the steady-state error of the system is reduced by the control strategy.

scholarly journals A Comprehensive Nonlinear Dynamic Model for Ball Screw Feed System With Rolling Joint Characteristics

2021 ◽  
Author(s):  
Mengtao Xu ◽  
Changyou Li ◽  
Hongzhuang Zhang ◽  
Zhendong Liu ◽  
Yimin Zhang
Keyword(s):  
Dynamic Model ◽  
Model Verification ◽  
Machining Process ◽  
Ball Screw ◽  
Nonlinear Phenomena ◽  
Feed System ◽  
Lumped Mass ◽  
Screw Length ◽  
Significant Difference ◽  
Screw Feed

Abstract Modern tendency of machine tools design requires more accurate model to predict the system dynamics, in order to anticipate its interaction with machining process. In this paper, a comprehensive dynamic model of ball screw feed system (BSFS) considering nonlinear kinematic joints is introduced to investigate the varying dynamic characteristics when worktable is subjected to combined load from six directions. The load-deformation relationship of each kinematic joint is dealt with a set of translational and angular spring elements. The nonlinear restoring force function of each joint involving coupling displacement is calculated. Based on the lumped mass method, the analytical 18-DOF dynamic equation is formulated by the analysis of force dependence between joints. Model verification tests are conducted. The worktable response exhibits the abundant and fascinating nonlinear phenomena arising in nonlinear joint and coupling effect. The nonlinear behavior behaves significant difference owing to the variations of excitation, platform position, screw length, preload and damping of joints. Thus, the model is promising for comprehension of machine dynamic behavior and for development of sophisticated control strategy.

scholarly journals Study of the Dynamic Characteristics of Ball Screw with a Load Disturbance

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Zhe Du ◽  
Xiao-Lan Zhang ◽  
Tao Tao
Keyword(s):  
Machine Tool ◽  
Dynamic Characteristics ◽  
Numerical Control ◽  
Hertzian Contact ◽  
Ball Screw ◽  
Machining Accuracy ◽  
Contact Deformation ◽  
Nc Machine Tool ◽  
Load Disturbance ◽  
Nc Machine

The dynamic character of ball screw is the key factor that influences the machining accuracy of numerical control (NC) machine tool. To improve the dynamic characteristics of the NC machine tool, it is necessary to study the dynamic characteristics of a ball screw. In this paper, the kinematics of a ball screw mechanism (BSM) are studied to expound the dynamic process of the drive, and the load disturbance is considered to analyze the contact deformation based on the Hertzian contact theory. The velocity relationships among the ball, screw, and nut are analyzed, and the influence of the contact deformation on the dynamic characteristics is simulated and investigated experimentally. The results show that the relationships between the contact deformation, which is affected by the material characteristics, the contact angle, and the load of nut are nonlinear. The contact deformation is a factor that cannot be ignored when considering the dynamic machining error of high-speed and high-precision machine tools.

Dynamic characteristics and research on the dual-drive feed mechanism

2021 ◽  
pp. 095440622098419
Author(s):  
Hong Lu ◽  
Qi Liu ◽  
Xinbao Zhang ◽  
Jingui Yu ◽  
Haoyu Dou ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Contact Stiffness ◽  
Dynamic Performance ◽  
Industrial Robots ◽  
Numerical Control ◽  
Ball Screw ◽  
Axial Stiffness ◽  
Parameter Method ◽  
Feed System ◽  
Moving Parts

The dual-drive feed mechanism (DDFM) based on the drive at the center of gravity (DCG) principle has been widely adopted in computer numerical control (CNC) machines and industrial robots that require high precision and high stability. The friction force affected by feed rates and moving parts positions can change the contact stiffness of kinematic joints, which can further impact on dynamic characteristics of the DDFM and cause dual axes difference. Considering the contact stiffness of kinematic joints, this paper adopts the lumped parameter method to establish the general dynamic model of the DDFM. The equivalent axial stiffness of kinematic joint and feed system transmission stiffness are all derived regarding the influence of feed rates and moving parts positions. The dynamic experiments on the DDFM with different feed rates and moving parts positions are carried out to verify the proposed model. The results suggest that in the motion stage, the DDFM’s natural frequency is greater than that in the static stage, and behaves differently in different feed rates and moving parts positions. The axial contact stiffness value of the ball-screw and nut B can reach 0 when the feed rate increases. When the moving parts are in the middle position of the crossbeam, the DDFM is the most stable and the dynamic performance is the best.

Analysis of Thermal Error Model of Ball Screw Feed System Based on Experimental Data

2021 ◽  
Author(s):  
Jiancheng Yang ◽  
Changyou Li ◽  
Mengtao Xu ◽  
Yimin Zhang
Keyword(s):  
Experimental Data ◽  
Thermal Expansion ◽  
Machine Tool ◽  
Thermal Deformation ◽  
Axial Direction ◽  
Ball Screw ◽  
Machining Parameters ◽  
Feed System ◽  
The Impact ◽  
Screw Feed

Abstract In order to investigate the effect of thermal expansion on the ball screw feed system (BSFS) of a precision machine tool, theoretical modeling of and experimental study on thermally induced error are focused in this paper. A series of thermal experiments are conducted on the machine tool to measure the temperature of the main heat source and measuring points of BSFS. To classify the main heat sources and discuss the impact on the ball screw feed system separately. By the experimental data of ball screw system, the thermal model of screw shaft in the axial direction is analyzed and verified. Based on the heat generation and transfer analysis of ball screw system, thermal expansion of screw shaft in the axial direction is modeled mathematically. In addition, by analyzing the effects of machining parameters such as rotational speed, preloads and lead, we get the parameter influence of BSFS’s temperature rising and thermal deformation. This work can help us reduce thermal deformation effectively, and improve the precision of CNC machining.

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