A New Error Compensation Method for a Four-Axis Horizontal Machine Tool

2016 ◽  
Vol 679 ◽  
pp. 1-5 ◽  
Author(s):  
Yang Li ◽  
Ji Zhao ◽  
Shi Jun Ji ◽  
Xin Wang
Keyword(s):  
Mathematical Model ◽  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Geometric Error ◽  
Error Modeling ◽  
Compensation Method ◽  
New Method ◽  
Transformation Matrices ◽  
Error Components

A new method compensating geometric error components of a four-axis horizontal machine tool is presented in this paper. Homogeneous transformation matrices (HTMS) and error conversion are integrated in the compensation strategy. A mathematical model which contains 29 geometric error components is established based on HTMS and the errors in X, Y and Z directions are obtained through calculation. The errors in three directions are compensated by shifting the corresponding axis. But the configuration of this machine tool is X-axis, Z-axis, B-axis, C-axis without Y-axis, so the errors in X, Y and Z directions need to be converted into X, Z and C directions which is different from the traditional machine tools. The errors after conversion are used to compensation directly. This approach is significant for the error modeling and compensation which is an easy and efficient way to improve the precision of the four-axis machine tools.

Table-Based Volumetric Error Compensation of Large Five-Axis Machine Tools

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Jennifer Creamer ◽  
Patrick M. Sammons ◽  
Douglas A. Bristow ◽  
Robert G. Landers ◽  
Philip L. Freeman ◽  
...  
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Data Gathering ◽  
Measurement Data ◽  
Geometric Error ◽  
Compensation Method ◽  
Geometric Errors ◽  
Simultaneous Generation ◽  
Five Axis

This paper presents a geometric error compensation method for large five-axis machine tools. Compared to smaller machine tools, the longer axis travels and bigger structures of a large machine tool make them more susceptible to complicated, position-dependent geometric errors. The compensation method presented in this paper uses tool tip measurements recorded throughout the axis space to construct an explicit model of a machine tool's geometric errors from which a corresponding set of compensation tables are constructed. The measurements are taken using a laser tracker, permitting rapid error data gathering at most locations in the axis space. Two position-dependent geometric error models are considered in this paper. The first model utilizes a six degree-of-freedom kinematic error description at each axis. The second model is motivated by the structure of table compensation solutions and describes geometric errors as small perturbations to the axis commands. The parameters of both models are identified from the measurement data using a maximum likelihood estimator. Compensation tables are generated by projecting the error model onto the compensation space created by the compensation tables available in the machine tool controller. The first model provides a more intuitive accounting of simple geometric errors than the second; however, it also increases the complexity of projecting the errors onto compensation tables. Experimental results on a commercial five-axis machine tool are presented and analyzed. Despite significant differences in the machine tool error descriptions, both methods produce similar results, within the repeatability of the machine tool. Reasons for this result are discussed. Analysis of the models and compensation tables reveals significant complicated, and unexpected kinematic behavior in the experimental machine tool. A particular strength of the proposed methodology is the simultaneous generation of a complete set of compensation tables that accurately captures complicated kinematic errors independent of whether they arise from expected and unexpected sources.

A Review of Geometric Error Modeling and Error Detection for CNC Machine Tool

2013 ◽  
Vol 303-306 ◽  
pp. 627-631 ◽  
Author(s):  
Zhen Yu Han ◽  
Hong Yu Jin ◽  
Yu Long Liu ◽  
Hong Ya Fu
Keyword(s):  
Machine Tool ◽  
Error Detection ◽  
Error Compensation ◽  
Machine Tools ◽  
Performance Criterion ◽  
Geometric Error ◽  
Error Modeling ◽  
Cnc Machine Tool ◽  
Cnc Machine ◽  
Error Sources

Error compensation can improve the accuracy of machine tools effectively. Among the error sources affecting the accuracy of CNC machine tool, geometric error is always set as a key performance criterion. This paper summarizes several methods of geometric error modeling and reviews the characteristics of different methods. Furthermore, available methods for measuring geometric errors have been reviewed also based on the advanced instruments. This work aims at enhancing the efficiency of error detection and give a perspective for the application of error compensation in the future.

Geometric error compensation method based on Floyd algorithm and product of exponential screw theory

2016 ◽  
Vol 232 (7) ◽  
pp. 1156-1171 ◽  
Author(s):  
Qiang Cheng ◽  
Bingwei Sun ◽  
Zhifeng Liu ◽  
Qiunan Feng ◽  
Peihua Gu
Keyword(s):  
Error Compensation ◽  
Machine Tools ◽  
Screw Theory ◽  
Cost Effective ◽  
Geometric Error ◽  
Error Modeling ◽  
Compensation Method ◽  
Machining Accuracy ◽  
Distance Method ◽  
Five Axis

Error compensation technique is a recognized and cost-effective method to improve machining accuracy of machine tools. In this article, a new compensation method for geometric error is proposed based on Floyd algorithm and product of exponential screw theory. Based on topological structure and measured data, volumetric geometric error modeling is established by product of exponential screw theory. Then, the improved Floyd minimum-distance method was used to establish an error compensation model by adjusting weight unceasingly. In order to verify the effectiveness and generality of the method proposed in this article, two experiments were designed. A total of 5 five-axis machining centers of the same type with different use time were selected to carry out the simulation experiments. Results show that the Floyd method can provide higher compensation precision, that is, Floyd algorithm compensation method can keep positioning errors within the range [−8 µm, 9 µm]. In addition, roundness error, coaxial error, and surface roughness were reduced in the actual machining experiments of two machined conical tables. Therefore, it can be seen that the proposed compensation method is effective to improve machining accuracy of machine tools.

An investigation on modeling and compensation of synthetic geometric errors on large machine tools based on moving least squares method

2016 ◽  
Vol 232 (3) ◽  
pp. 412-427 ◽  
Author(s):  
Zihan Li ◽  
Wenlong Feng ◽  
Jianguo Yang ◽  
Yiqiao Huang
Keyword(s):  
Machine Tool ◽  
Least Squares ◽  
Error Compensation ◽  
Machine Tools ◽  
Geometric Error ◽  
Moving Least Squares ◽  
Geometric Errors ◽  
Position Accuracy ◽  
Type Machine ◽  
Large Machine

This article intends to provide an efficient modeling and compensation method for the synthetic geometric errors of large machine tools. Analytical and experimental examinations were carried out on a large gantry-type machine tool to study the spatial geometric error distribution within the machine workspace. The result shows that the position accuracy of the tool-tip is affected by all the translational axes synchronously, and the position error curve shape is non-linear and irregular. Moreover, the angular error combined with Abbe’s offset during the motion of a translational axis would cause Abbe’s error and generate significant influence on the spatial positioning accuracy. In order to identify the combined effect of the individual error component on the tool-tip position accuracy, a synthetic geometric error model is established for the gantry-type machine tool. Also, an automatic modeling algorithm is proposed to approximate the geometric error parameters based on moving least squares in combination with Chebyshev polynomials, and it could approximate the irregular geometric error curves with high-order continuity and consistency with a low-order basis function. Then, to implement real-time error compensation on large machine tools, an intelligent compensation system is developed based on the fast Ethernet data interaction technique and external machine origin shift, and experiment validations on the gantry-type machine tool showed that the position accuracy could be improved by 90% and the machining precision could be improved by 85% after error compensation.

The Study of Compensation Method to Numerically-Controlled Machine Tool Geometrical Error

2014 ◽  
Vol 670-671 ◽  
pp. 1403-1405
Author(s):  
Lian Bing Wang
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Geometric Error ◽  
Compensation Method ◽  
System Error ◽  
Nc Machine Tool ◽  
Geometrical Error ◽  
Compensation Methods ◽  
Nc Machine ◽  
Software Upgrade

In this paper, the cause of nc machine tool geometric error made a more detailed analysis, the system error compensation methods are summarized, and on this basis this paper expounds the applications of all kinds of error compensation method, in order to further realize the accuracy of machine tool software upgrade to lay the foundation.

Research on Volumetric Error Measurement, Modeling and Compensation for NC Machine Tools

2014 ◽  
Vol 513-517 ◽  
pp. 4202-4205
Author(s):  
Hong Xin Zhang ◽  
Qian Jian Guo
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Machine Tools ◽  
Thermal Error ◽  
Error Modeling ◽  
Cnc Machine Tools ◽  
Machining Accuracy ◽  
Volumetric Error ◽  
The Impact ◽  
Thermal Error Compensation

With the increasing requirements of the machining accuracy of CNC machine tools, the impact of thermal deformation is growing. Thermal error compensation technology can predict and compensate the thermal errors in real-time, and improve the machining accuracy of the machine tool. In this paper, the research objects of thermal error compensation is expanded to the volumetric error of the machine tool, the volumetric error modeling of a three-axis machine tool is fulfilled and a compensator is developed for the compensation experiment, which provides scientific basis for the improvement of the machining accuracy.

Error Modeling and Identification Technology for Circular Path of NC Machine Tools

2013 ◽  
Vol 278-280 ◽  
pp. 345-349
Author(s):  
Zhen Ya He ◽  
Jian Zhong Fu ◽  
Xin Hua Yao
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Measurement Method ◽  
Geometric Error ◽  
Error Modeling ◽  
Circular Path ◽  
Rate Condition ◽  
Nc Machine ◽  
High Feed ◽  
Nc Machine Tools

An error mapping modeling and identification technology for the circular path test of NC machine tools is proposed. First, geometric error modeling of the NC machine tool was established and the theory of the laser measurement method was introduced. Then through further analyzing the influence of the geometric errors to circular path deviations, the error items were identified, such as the displacement errors, backlashes and squareness errors. Finally measurement and compensation experiment of circular path was conducted. The experimental results show that the geometric error modeling is feasible, and the measurement method can be set up easily and rapidly, even can be used to measure smaller radius circular path under a high feed rate condition. After compensation, the accuracy of the circular path of the machine tool is improved by 50.88%.

Modeling and Analysis of Key Geometric Error for Gravity Deformation of Heavy-Duty CNC Machine Tool

2014 ◽  
Vol 552 ◽  
pp. 90-95
Author(s):  
Hong Ya Fu ◽  
Han Wang ◽  
Zhen Yu Han
Keyword(s):  
Machine Tool ◽  
Machine Tools ◽  
Geometric Error ◽  
Error Modeling ◽  
Influential Factor ◽  
Cnc Machine Tools ◽  
Heavy Duty ◽  
Cnc Machine ◽  
Modeling And Analysis ◽  
Huge Impact

Gravity has huge impact on the accuracy of heavy-duty machine tools. To investigate errors caused by gravity, it is essential to figure out the most influential factor. This paper presents a geometric error modeling for heavy-duty CNC machine tools. Regarding a machine tool as a rigid multi-body system (MBS), the geometric error model has been established by utilizing kinematics chain and homogeneous transfer matrix (HTM). By analyzing the Jacobi matrix, the influence of all the geometric error parameters has been calculated to find out the key geometric error that affect the accuracy most. It is revealed that gravity of beam and tool affect the accuracy of the machine tool most through the ANSYS simulation. It supports a theoretical basis for the further research on error compensation of the key component of a machine tool.

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