Research on Geometric Error Compensating Technique of CNC P3G Grinding Machine

2012 ◽  
Vol 462 ◽  
pp. 287-294 ◽  
Author(s):  
Yi Jian ◽  
Qian Qian Li ◽  
Hong Cheng ◽  
Bin Wu Lai ◽  
Jian Fei Zhang
Keyword(s):  
Machine Tools ◽  
Geometric Error ◽  
Error Model ◽  
Error Modeling ◽  
Numerical Control ◽  
Geometric Errors ◽  
Real Time Control ◽  
Time Control ◽  
Applied Software ◽  
Grinding Machine

Kinematic accuracy is a key reason which influence workpiece's geometric error precision on traditional working process of precisely CNC（Computerized Numerical Control）P3G（polygon profile with 3 lobes） grinding machine. A systematic geometric error model has been presented for CNC P3G grinding machine， proposed multi-body system theory integrate with the structure of CNC P3G grinding machine tools, researched on the machine's space geometric errors. By means of separate geometric errors from the machine tools, build geometric mathematical error model. Then, identify 21 error parameters through method of 9 lines, analysis and calculate the total space geometric errors of the workpiece and wheel. Finally, formed a parameter-list and applied software error compensational technique ， achieved real-time control to the motions of workpiece and wheel. Experimental results shown that the geometrical error modeling technique is accurate and efficient, and the precision of CNC P3G grinding machine is highly raised 70%.

scholarly journals New identification method for computer numerical control geometric errors

2021 ◽  
pp. 002029402110108
Author(s):  
Hongtao Yang ◽  
Mei Shen ◽  
Li Li ◽  
Yu Zhang ◽  
Qun Ma ◽  
...  
Keyword(s):  
Machine Tools ◽  
Geometric Error ◽  
Numerical Control ◽  
Identification Accuracy ◽  
Cnc Machine Tools ◽  
Geometric Errors ◽  
Cnc Machine ◽  
Identification Method ◽  
Double Ball Bar ◽  
Ball Bar

To address the problems of the low accuracy of geometric error identification and incomplete identification results of the linear axis detection of computer numerical control (CNC) machine tools, a new 21-item geometric error identification method based on double ball-bar measurement was proposed. The model between the double ball-bar reading and the geometric error term in each plane was obtained according to the three-plane arc trajectory measurement. The mathematical model of geometric error components of CNC machine tools is established, and the error fitting coefficients are solved through the beetle antennae search particle swarm optimization (BAS–PSO) algorithm, in which 21 geometric errors, including roll angle errors, were identified. Experiments were performed to compare the optimization effect of the BAS–PSO and PSO and BAS and genetic particle swarm optimization (GA–PSO) algorithms. Experimental results show that the PSO algorithm is trapped in the local optimum, and the BAS–PSO is superior to the other three algorithms in terms of convergence speed and stability, has higher identification accuracy, has better optimization performance, and is suitable for identifying the geometric error coefficient of CNC machine tools. The accuracy and validity of the identification results are verified by the comparison with the results of the individual geometric errors detected through laser interferometer experiments. The identification accuracy of the double ball-bar is below 2.7 µm. The proposed identification method is inexpensive, has a short processing time, is easy to operate, and possesses a reference value for the identification and compensation of the linear axes of machine tools.

Precise geometric error model based on z-axis motion platform of micro v-groove machine tools

2017 ◽  
Vol 92 (9-12) ◽  
pp. 3219-3224 ◽  
Author(s):  
Huabing Zou ◽  
Yuejiao Ding ◽  
Jing Zhang ◽  
Anhui Cai ◽  
Xiaohong Zhang ◽  
...  
Keyword(s):  
Machine Tools ◽  
Geometric Error ◽  
Error Model ◽  
Motion Platform ◽  
Model Based

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.

scholarly journals Geometric Error Modeling of Machine Tools Based on Screw Theory

2011 ◽  
Vol 24 ◽  
pp. 845-849 ◽  
Author(s):  
Zhao Yu ◽  
Li Tiemin ◽  
Tang Xiaoqiang
Keyword(s):  
Machine Tools ◽  
Screw Theory ◽  
Geometric Error ◽  
Error Modeling

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.

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