Adaptive real-time model on thermal error of ball screw feed drive systems of CNC machine tools

An identification technique is introduced for identifying closed loop transfer function of machine tool’s feed drive systems to be used in simulation of the tracking and contouring performance of Computer Numerical Controlled (CNC) machine tools. The identification is performed from air-cutting tests utilizing only standard G-codes containing linear motion commands. A general transfer function model is derived for representing the closed loop tracking response of the feed drive system. The model considers the drive to be controlled by commonly used controller schemes such as P-PI Cascade, PID or the Sliding Mode Controller (SMC) with feed-forward dynamic and friction compensation. The parameters of the model transfer function are fitted tominimize the discrepancy between the actual and predicted axis position on the axis. In order to guarantee the stability of the identified model transfer function, bounds on the pole locations are imposed. The resultant constrained non-linear optimization problem is solved efficiently using the Particle Swarm Optimization (PSO) method. For achieving reliable convergence of the stochastic PSO algorithm, a parameter tuning strategy is presented. Simulation and experimental studies show that the identified feed drive model captures the fundamental dynamics of the drives system accurately for simulating their closed loop response. Combined with the kinematics of the machine, contouring errors of 5-axis CNC machine tools during simultaneous multi-axis motion are predicted.

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Synthesis Modeling and Real-time Compensation of Geometric Error and Thermal Error for CNC Machine Tools

Journal of Mechanical Engineering ◽

10.3901/jme.2012.07.165 ◽

2012 ◽

Vol 48 (07) ◽

pp. 165 ◽

Cited By ~ 12

Author(s):

Wei WANG

Keyword(s):

Real Time ◽

Machine Tools ◽

Thermal Error ◽

Geometric Error ◽

Cnc Machine Tools ◽

Cnc Machine

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Adaptive on-line compensation model on positioning error of ball screw feed drive systems used in computerized numerical controlled machine tools

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/0954405417752512 ◽

2018 ◽

Vol 233 (3) ◽

pp. 914-926 ◽

Cited By ~ 6

Author(s):

Tie-jun Li ◽

Chun-yu Zhao ◽

Yi-min Zhang

Keyword(s):

Heat Transfer ◽

Machine Tools ◽

Ball Screw ◽

Positioning Error ◽

Compensation Model ◽

Feed Drive ◽

On Line ◽

Drive Systems ◽

Feed Drive System ◽

Screw Feed

The positioning error of ball screw feed systems is mainly caused by thermal elongation of the screw shaft in machine tools. In this article, an adaptive on-line compensation method of positioning error for the ball screw shaft is established. In order to explore the thermal–solid mechanism of ball screw feed drive systems, the experiments were carried out. An exponential fitting equation is presented to obtain the temperature relationship between the temperature sensitive point and its center of each heat source based on the finite element method of the feed drive system. Consequently, based on time and position exponential distribution functions, a variable separation model of heat transfer is established. Furthermore, based on the heat transfer model of multiple varying and moving heat sources, an adaptive on-line analytical compensation model of positioning error is presented. Finally, the effect of the adaptive on-line analytical compensation model of positioning error is verified through the experiments. And, this model has self-adaptive ability and robustness. Therefore, this adaptive on-line analytical compensation model based on the heat transfer theory can be applied in real-time compensation of positioning error.

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Application of Ubiquitous Sensor Network in Collection and Analysis of CNC Machine Tool Processing Status Information

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.455.621 ◽

2010 ◽

Vol 455 ◽

pp. 621-624

Author(s):

X. Li ◽

Y.Y. Yu

Keyword(s):

Machine Tool ◽

Sensor Network ◽

Machine Tools ◽

Thermal Error ◽

Development Trend ◽

Cnc Machine Tools ◽

Cnc Machine Tool ◽

Cnc Machine ◽

Status Information ◽

The Development Trend

Because of the practical requirement of real-time collection and analysis of CNC machine tool processing status information, we discuss the necessity and feasibility of applying ubiquitous sensor network(USN) in CNC machine tools by analyzing the characteristics of ubiquitous sensor network and the development trend of CNC machine tools, and application of machine tool thermal error compensation based on USN is presented.

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