scholarly journals An improved dynamic model of preloaded ball screw drives considering torque transmission and its application to frequency analysis

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771058 ◽  
Author(s):  
Fuhua Li ◽  
Yao Jiang ◽  
Tiemin Li ◽  
Yunsong Du
Keyword(s):  
Resonant Frequency ◽  
Dynamic Model ◽  
Dynamic Models ◽  
Experimental Results ◽  
Ball Screw ◽  
Axial Stiffness ◽  
Axial Thrust ◽  
Screw Drive ◽  
Proposed Model ◽  
Ball Screw Drive

A dynamic model of the ball screw drive is proposed in this article. It is revealed that when axial thrust is transmitted between the ball screw and the nut, extra torque is generated synchronously which is not proposed in existing dynamic models. And a physical model for studying the relationship between the thrust and the torque is proposed. A lumped dynamic model is established, and a kinematic compatibility equation describing motion transmission between rotary displacement and axial displacement is established. Then a preload model of a double-nut for analyzing the force and the deformation is built. An approach to analyze the first resonant frequency of the proposed model is described. Meanwhile, a tested bench with a novel preload-adjustable double-nut and two novel loading mechanisms is constructed. The axial stiffness of the supporting bearings and the preloaded double-nut is tested based on a measurement system. Then vibration tests are carried out to measure the first resonant frequency of the ball screw drive. Finally, contrastive analysis between experimental results and simulated results of three models is conducted. The results show that the proposed model agrees much better with the experimental results than the discrete model and the hybrid model do.

Dynamic Modeling of a Ball-Screw Drive and Identification of Its Installation Parameters

2020 ◽  
Vol 143 (4) ◽  
Author(s):  
Yu-Jia Hu ◽  
Yaoyu Wang ◽  
Weidong Zhu ◽  
Haolin Li
Keyword(s):  
Dynamic Model ◽  
Natural Frequencies ◽  
Data Fitting ◽  
Ball Screw ◽  
Mode Shapes ◽  
The Finite Element Method ◽  
Screw Drive ◽  
Log Normal ◽  
Ball Screw Drive ◽  
Log Normal Distribution

Abstract Parametric expressions of equivalent stiffnesses of a ball-screw shaft are obtained by derivation of its geometric parameters, the finite element method (FEM), and data fitting based on a modified probability density function of log-normal distribution. A dynamic model of a ball-screw drive that considers effects of bearing stiffnesses, the mass of the nut, and the axial pretension is established based on equivalent stiffnesses of its shaft. With the dynamic model and modal experimental results obtained by Bayesian operational modal analysis (BOMA), installation parameters of the ball-screw drive are identified by a genetic algorithm (GA) with a new comprehensive objective function that considers natural frequencies, mode shapes, and flexibility of the ball-screw drive. The effectiveness of the methodology is experimentally validated.

Techniques developed for fault diagnosis of long-range running ball screw drive machine to evaluate lubrication condition

Measurement ◽  
2018 ◽  
Vol 126 ◽  
pp. 274-288 ◽  
Author(s):  
Chang-Fu Han ◽  
He-Qing He ◽  
Chin-Chung Wei ◽  
Jeng-Haur Horng ◽  
Yueh-Lin Chiu ◽  
...  
Keyword(s):  
Fault Diagnosis ◽  
Long Range ◽  
Ball Screw ◽  
Screw Drive ◽  
Lubrication Condition ◽  
Ball Screw Drive

scholarly journals Tracking performance of NPID controller for cutting force disturbance of ball screw drive

2017 ◽  
Vol 11 (4) ◽  
pp. 3227-3239
Author(s):  
N. A. Anang ◽  
◽  
L. Abdullah ◽  
Z. Jamaludin ◽  
T.H. Chiew ◽  
...  
Keyword(s):  
Cutting Force ◽  
Tracking Performance ◽  
Ball Screw ◽  
Screw Drive ◽  
Ball Screw Drive

Effects of Velocity on Elastic Deformation in Ball Screw Drives and its Compensation

2017 ◽  
Author(s):  
Fuhua Li ◽  
Tiemin Li ◽  
Yao Jiang ◽  
Fengchun Li
Keyword(s):  
Dynamic Model ◽  
Elastic Deformation ◽  
Control Method ◽  
Experimental Tests ◽  
High Accuracy ◽  
Compensation Method ◽  
Experimental Results ◽  
Ball Screw ◽  
Tracking Accuracy ◽  
Ball Screw Drives

Ball screw drives are widely used in machine tools to provide accurate linear motion. Elastic deformation is one of the major error sources for ball screw drives in achieving high accuracy motion, and changes greatly when velocity varies. The influence of velocity on the elastic deformation can be estimated and it can be compensated by means of dynamic modeling and servo control method. This paper presents a dynamic model considering torque transmission between the ball screw and the nut. And stiffness is identified by a method of combining theoretical calculation and experimental tests on a constructed test bench, which has two novel symmetrical loading mechanisms. In order to analyze the influence of moving velocity on the elastic deformation, simulation and experiments are conducted when two trajectories which have velocity jumps are input. And the simulated elastic deformations are compared with experimental results to evaluate the accuracy of the model. The results show that the simulated results fit the experimental results with high accuracy. The relationship between the elastic deformation of ball screw drives and the velocity is linear based on the experimental results. Then the simulation results are used to compensate the elastic deformation based on the feed-forward compensation method. The results show that the differences between the actual compensation values and actual elastic deformation are small and most of the elastic deformation of the ball screw drives can be compensated. Therefore, the proposed dynamic model and compensation method can be used to improve the tracking accuracy of ball screw drives.

Online Chatter Detection for Milling Operations Using LSTM Neural Networks Assisted by Motor Current Signals of Ball Screw Drives

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Rajiv Kumar Vashisht ◽  
Qingjin Peng
Keyword(s):  
Neural Networks ◽  
Feed Rate ◽  
Short Term Memory ◽  
Ball Screw ◽  
Chatter Detection ◽  
Cnc Machine ◽  
Screw Drive ◽  
Milling Operations ◽  
Milling Tool ◽  
Ball Screw Drive

Abstract For certain combinations of cutter spinning speeds and cutting depths in milling operations, self-excited vibrations or chatter of the milling tool are generated. The chatter deteriorates the surface finish of the workpiece and reduces the useful working life of the tool. In the past, extensive work has been reported on chatter detections based on the tool deflection and sound generated during the milling process, which is costly due to the additional sensor and circuitry required. On the other hand, the manual intervention is necessary to interpret the result. In the present research, online chatter detection based on the current signal applied to the ball screw drive (of the CNC machine) has been proposed and evaluated. There is no additional sensor required. Dynamic equations of the process are improved to simulate vibration behaviors of the milling tool during chatter conditions. The sequence of applied control signals for a particular feed rate is decided based on known physical and control parameters of the ball screw drive. The sequence of the applied control signal to the ball screw drive for a particular feed rate can be easily calculated. Hence, costly experimental data are eliminated. Long short-term memory neural networks are trained to detect the chatter based on the simulated sequence of control currents. The trained networks are then used to detect chatter, which shows 98% of accuracy in experiments.

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