Error Compensation of Complex Three-Dimensional Surfaces Machined on Computer-Numeric-Control Grinding Machine Tools

2009 ◽  
Vol 9 (7) ◽  
pp. 1356-1361 ◽  
Author(s):  
M. Raoufinia ◽  
Y.V. Petrakov ◽  
A. Ataei ◽  
R. Parand ◽  
K. Abou-El-Ho
Keyword(s):  
Error Compensation ◽  
Machine Tools ◽  
Three Dimensional ◽  
Computer Numeric Control ◽  
Grinding Machine

Accuracy Enhancement of CNC Multi-Axis Machine Tools through an On-Line Error Identification and Compensation Strategy

2013 ◽  
Vol 718-720 ◽  
pp. 1388-1393
Author(s):  
Abderrazak El Ouafi ◽  
Noureddine Barka
Keyword(s):  
Error Compensation ◽  
Machine Tools ◽  
Three Dimensional ◽  
Error Identification ◽  
Error Components ◽  
Three Dimensional Measurement ◽  
On Line ◽  
Bridge Type ◽  
Compensation Approach ◽  
Reliable Methods

In order to improve multi-axis machine accuracy, error compensation techniques have been widely applied. However, the lack of reliable methods for direct, global and comprehensive estimation implies that all compensation techniques are based on off-line sequential error components measurement. These measurements provide static results, and cannot reflect the actual machine conditions. Thus, these results are not representative of the real working conditions because of disturbances from thermal distortions and dynamic perturbations. This paper presents an on-line error identification and compensation approach for CNC multi-axis machine tools. Based on the simultaneous measurement of error components, the proposed identification scheme is built to ensure volumetric error prediction for an adaptive error compensation system. Implemented on a moving bridge type CMM, the approach led to a significant improvement of the three-dimensional measurement accuracy.Compared to the conventional off-line error compensation techniques, the proposed identification and compensation approach can further improve the compensation adaptability and efficiency.

scholarly journals Rapid Measurement and Identification Method for the Geometric Errors of CNC Machine Tools

2019 ◽  
Vol 9 (13) ◽  
pp. 2701 ◽  
Author(s):  
Li ◽  
Yang ◽  
Gao ◽  
Su ◽  
Wei ◽  
...  
Keyword(s):  
Error Compensation ◽  
Machine Tools ◽  
Degrees Of Freedom ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Two Dimensional ◽  
Cnc Machine ◽  
Angle Sensor ◽  
Identification Method ◽  
Measuring Machine

Error compensation technology offers a significant means for improving the geometric accuracy of CNC machine tools (MTs) as well as extending their service life. Measurement and identification are important prerequisites for error compensation. In this study, a measurement system, mainly composed of a self-developed micro-angle sensor and an L-shape standard piece, is proposed. Meanwhile, a stepwise identification method, based on an integrated error model, is established. In one measurement, four degrees-of-freedom errors, including two-dimensional displacement and two-dimensional angle of a linear guideway, can be obtained. Furthermore, in accordance with the stepwise identification method, the L-shape standard piece is placed in three different planes, so that the measurement and identification of all 21 geometric errors can be implemented. An experiment is carried out on a coordinate measuring machine (CMM) to verify the system. The residual error of the angle error, translation error and squareness error are 1.5″, 2 μm and 3.37″, respectively, and these are compared to the values detected by a Renishaw laser interferometer.

Improving Contour Accuracy of Machine Tools Using an Integral-Gain Scheduler

2005 ◽  
Vol 219 (7) ◽  
pp. 511-518 ◽  
Author(s):  
R C Ko ◽  
M C Good
Keyword(s):  
Machine Tools ◽  
High Performance ◽  
Pulse Width Modulation ◽  
Tracking Error ◽  
Contour Error ◽  
Current Loop ◽  
Pwm Inverter ◽  
Current Controller ◽  
Reversal Error ◽  
Grinding Machine

In high-precision machine tools, contour error at axis reversal can significantly reduce the quality of products. Resulting from non-linear friction behaviour, the reversal error is traditionally handled by the velocity controller, which highly relies on a high-performance current servo. However, the widely employed pulse width modulation (PWM) inverter in the power stage of the current servo operates with a severe non-linearity known as deadband. The deadband effect degrades the current-loop tracking performance and consequently hinders the velocity controller in responding to friction disturbances. The result is a significant and oscillatory tracking error, or contour error in a multiaxis system. Unlike other approaches where the deadband is compensated via measurement or estimation, a control system approach is proposed in this paper where the deadband is treated as a voltage perturbation in the current loop. The proposed scheme incorporates a feedforward signal from the current command and schedules the integral action in the current controller accordingly. The proposed scheme was implemented in digital servo drives of a commercial grinding machine. Experiments show that the proposed scheme is an effective and practical solution for this type of problem.

Volumetric error modeling and compensation considering thermal effect on five-axis machine tools

2012 ◽  
Vol 227 (5) ◽  
pp. 1102-1115 ◽  
Author(s):  
Yi Zhang ◽  
Jianguo Yang ◽  
Sitong Xiang ◽  
Huixiao Xiao
Keyword(s):  
Error Compensation ◽  
Machine Tools ◽  
Data Communication ◽  
Zero Point ◽  
Compensation System ◽  
Error Modeling ◽  
Volumetric Error ◽  
Position Errors ◽  
Homogeneous Transformation Matrix ◽  
Five Axis

This article intends to provide an error compensation system for five-axis machine tools. A volumetric error model is established with homogeneous transformation matrix method, from which compensation values of both orientation and position errors can be obtained. Thirty-seven errors on a five-axis machine tool are classified into three categories – functional, random, and negligible errors, among which the effect of the first one on volumetric accuracy is considered as great enough to be included in this model. Some typical modeling methods are discussed on positioning and straightness errors, considering both geometric and thermal effects. Then, we propose a compensation implementation technique based on the function of external machine zero point shift and Ethernet data communication protocol for machine tools. Finally, laser diagonal measurements have been conducted to validate the effectiveness of the proposed volumetric error compensation system.

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