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.

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.

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.

Study on Fault Diagnosis and Repair Strategy of CNC Machine Tool

2013 ◽  
Vol 791-793 ◽  
pp. 967-970
Author(s):  
Guo Min Lin ◽  
Miao Shang ◽  
Wen Guang Zhang
Keyword(s):  
Fault Diagnosis ◽  
Machine Tool ◽  
Numerical Control ◽  
Ball Screw ◽  
Cnc Machine Tools ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Repair Strategy ◽  
Hardware Faults ◽  
Main Spindle

CNC machine tool fault types, repair characteristics, the principle to be followed are described. The mechanical systems, Numerical control system, servo system fault diagnosis and repair for CNC machine tools are analyzed in detail. The strategy of the hardware faults such as main spindle part, the ball screw-nut pairs, cutter and tool change device, the strategy of the software repair are proposed.

ANALYSIS AND COMPENSATION OF STIFFNESS IN CNC MACHINE TOOL FEED SYSTEM

2011 ◽  
Vol 10 (01) ◽  
pp. 77-84 ◽  
Author(s):  
BAOSHENG WANG ◽  
JIANMIN ZUO ◽  
MULAN WANG
Keyword(s):  
Steady State ◽  
Machine Tool ◽  
Numerical Control ◽  
Axial Stiffness ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Feed System ◽  
Dead Band ◽  
Torsion Stiffness ◽  
State Error

Based on the elastic mechanics theory, the mathematical models of axial stiffness and torsion stiffness are constructed in accordance with single end thrust and two ends thrust. The effects of stiffness on dead band error are analyzed. With the analysis of displacement deviation induced by axial stiffness and angular displacement deflection caused by torsion stiffness, a formula to calculate the dead band error is presented. A model for Computer Numerical Control (CNC) machine tool feed system with stiffness is established. By applying computer simulation, dynamic performances, static performances and steady-state error of the system are analyzed. To reduce the effect of stiffness on the system, the feedforward control method is used to compensate stiffness. The simulation analysis shows the result that dynamic and static performances are improved, as well as steady-state error of the system is reduced by more than 58% with this approach.

Simulation of Fuzzy Auto-Tuning PID Control Based on MATLAB

2011 ◽  
Vol 308-310 ◽  
pp. 579-583
Author(s):  
Jian Wen Chen ◽  
Lei Li ◽  
Jin Chun Song ◽  
Zhan Jun He
Keyword(s):  
Pid Control ◽  
Pid Controller ◽  
Dynamic Performance ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Feed System ◽  
Fuzzy Pid Controller ◽  
Auto Tuning ◽  
Controlled Object

In CNC machine tools servo feed system, there are many uncertain parameters, it is difficult to establish accurate mathematical model of the Servo feed system. The parameters of conventional PID controller can’t adjust immediately to the controlled object. Fuzzy PID controller [1], which has the advantages of conventional PID control and fuzzy control, can solve these problems. We apply it in numerical control machine servo feed system. The simulation in MATLAB shows that the fuzzy auto-tuning PID controller improve the dynamic performance of the servo feed system and has better robustness.

scholarly journals Hybrid Multi-Domain Analytical and Data-Driven Modeling for Feed Systems in Machine Tools

Symmetry ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1156 ◽  
Author(s):  
Zaiwu Mei ◽  
Jianwan Ding ◽  
Liping Chen ◽  
Ting Pi ◽  
Zaidao Mei
Keyword(s):  
Analytical Model ◽  
Machine Tools ◽  
Data Driven ◽  
Ball Screw ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Feed System ◽  
Tracking Errors ◽  
Dynamic Tracking ◽  
Data Driven Modeling

Position error-compensation control in the servo system of computerized numerical control (CNC) machine tools relies on accurate prediction of dynamic tracking errors of the machine tool feed system. In this paper, in order to accurately predict dynamic tracking errors, a hybrid modeling method is proposed and a dynamic model of the ball screw feed system is developed. Firstly, according to the law of conservation of energy, a complete multi-domain system analytical model of a ball screw feed system was established based on energy flow. In order to overcome the uncertainties of the analytical model, then the data-driven model based on the back propagation (BP) neural network was established and trained using experimental data. Finally, the data-driven model was coupled with the multi-domain analytical model and the hybrid model was developed. The model was verified by experiment at different velocities and the results show that the prediction accuracy of the hybrid model reaches high levels. The hybrid modeling method combines the advantages of analytical modeling and data-driven modeling methods, and can significantly improve the feed system’s modeling accuracy. The research results of this paper are of great significance to improve the compensation control accuracy of CNC machine tools.

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.

Research on Non-Linear Parameters Identification for Servo System of CNC Machine Tools

2012 ◽  
Vol 220-223 ◽  
pp. 344-347
Author(s):  
Guang Sheng Chen ◽  
Hao Lin Li
Keyword(s):  
Machine Tools ◽  
Position Control ◽  
Taylor Series Expansion ◽  
Friction Model ◽  
Least Square ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Machine ◽  
Precise Position ◽  
Non Linear

As phenomena of friction in computer numerical control(CNC) machine tools is inevitable, accurately modeling of friction is need for precise position control and performance evaluation of CNC machine tools. This paper proposed an identification method that non-linear friction model described as Stribeck are linearized by using high order Taylor series expansion and parameters of the model are obtained by least square method (LSM). Signals of servo motor current and rotating rate which are offered in many modern CNC machine tools are needed for the identification and experiments results show that parameters of Stribeck model can be obtained accurately by identification. The method is suited for industrial condition and has its practicality.

Study on Dynamic Characteristics of Feed Systems with Single and Double Ball Screws

2013 ◽  
Vol 433-435 ◽  
pp. 3-7 ◽  
Author(s):  
Xi He Ding ◽  
Jian Yong Zheng ◽  
Jun Tang Yuan ◽  
Zhen Hua Wang
Keyword(s):  
Dynamic Characteristics ◽  
Natural Frequencies ◽  
Calculated Data ◽  
Cnc Machine Tools ◽  
Joint Surface ◽  
Vibration Modes ◽  
Cnc Machine ◽  
Feed System ◽  
Element Analysis ◽  
Screw Drive

As the executive component of CNC machine tools feed movement and auxiliary motion, feed system plays an important part in ensuring the positioning accuracy, sensitivity and stability. By taking single-screw-drive feed system and double-screw-drive feed system of CNC as the object of study, two-degree-of-freedom vibration models of them are established to analyze the dynamic characteristics, and further calculate modal vibration modes and natural frequencies. The finite element analysis models of the two systems are also established, concerning the influence of joint surface, vibration modes and natural frequencies are obtained by means of modal analysis. By comparing the simulation results and the calculated data, the feed systems vibration modes and natural frequencies can be accurately calculated by the proposed vibration models, and the relative errors of corresponding vibration frequencies are controlled within 15%.

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