scholarly journals Five-axis Tri-NURBS Spline Interpolation Method Considering Nonlinear Error Compensation and Correction of CC Paths

2021 ◽  
Author(s):  
Liangji Chen ◽  
Zisen Wei ◽  
Longfei Ma
Keyword(s):  
Error Compensation ◽  
Interpolation Method ◽  
Spline Interpolation ◽  
Nonlinear Error ◽  
Center Point ◽  
Spline Curves ◽  
Tool Axis ◽  
Five Axis ◽  
Tool Axis Vector ◽  
Interpolation Parameter

Abstract In order to improve the accuracy of tool axis vector position and direction in traditional five-axis NURBS interpolation methods and the controlling accuracy of cutter contacting(CC) paths between cutter and work-piece, a five-axis Tri-NURBS spline interpolation method is presented in this article. Firstly, the spline interpolation instruction format is proposed, which includes three spline curves, such as CC point spline, tool center point spline and tool axis point spline. The next interpolation parameter is calculated based on the tool center point spline combined with the conventional parametric interpolation idea. Different from the traditional spline interpolation using the same interpolation parameter for all spline curves, the idea of equal ratio configuration of parameters is proposed in this paper to obtain the next interpolation parameter of each spline curve. The next interpolation tool center point, tool axis point and CC point on the above three spline curves can be obtained by using different interpolation parameters, so as to improve the accuracy of tool axis vector position and direction. Secondly, the producing mechanism of CC paths’ nonlinear error of the traditional spline interpolation is analyzed and the mathematical calculation model of the nonlinear error is established. And then, the nonlinear error compensation and correction method is also put forward to improve the controlling accuracy of CC paths. In this method, the next CC point on the cutter can be firstly obtained according to the next interpolation tool center point, tool axis point and CC point on the three spline curves. And then, the error compensation vector is determined with the two next CC points. To correct the nonlinear error between the next CC point on the cutter and the CC point spline curve, the cutter is translated so that the two next CC points can be coincided. In the end, the new tool center point and tool axis point after translation can be calculated to obtain the motion control coordinates of each axis of machine tool. The MATLAB software is used as simulation of the real machining data. The results show that the proposed method can effectively reduce the CC paths’ nonlinear error. It has high practical value for five-axis machining in effectively controlling the accuracy of CC paths and im-proving the machining accuracy of complex surfaces.

Nonlinear Error Compensation Based on the Optimization of Swing Cutter Trajectory for Five-Axis Machining

2021 ◽  
Author(s):  
Liangji Chen ◽  
Jinmeng Tang ◽  
Wenyi Wu ◽  
Zisen Wei
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Rotation Axis ◽  
Kinematic Model ◽  
Free Form ◽  
Nonlinear Error ◽  
Center Point ◽  
Parameterized Model ◽  
Five Axis ◽  
The Impact

Abstract In order to solve the problem of deviation between actual and theoretical machining paths due to the presence of rotation axis in five-axis machining, an interpolation algorithm based on the optimization of swing cutter trajectory and the method of corresponding nonlinear error compensation are proposed. Taking A-C dual rotary table five-axis machine tool as an example, the forward and reverse kinematic model of the machine tool is established according to the kinematic chain of the machine tool. Based on the linear interpolation of rotary axis, the generation mechanism of nonlinear error is analyzed, the modeling methods of cutter center point and cutter axis vector trajectory are proposed respectively, and the parameterized model of swing cutter trajectory is formed. The formula for the nonlinear error is obtained from the two-dimensional cutter center point trajectory. According to the established model of swing cutter trajectory, the synchronous optimization method of cutter center point trajectory and cutter axis vector trajectory is proposed, and the nonlinear error compensation mechanism is established. First, pre-interpolation is performed on the given cutter location data to obtain a model of the swing cutter trajectory for each interpolated segment. Then the magnitude of the nonlinear error is calculated based on the parameters of the actual interpolation points during formal interpolation, and the interpolation points with large errors are compensated for the nonlinear error. The simulation results show that the proposed method can effectively reduce the impact of nonlinear errors on machining, and is of high practical value for improving the accuracy of cutter position and the quality of complex free-form machining in five-axis machining.

Analysis and Compensation Strategy of Non-Linear Error in Five-Axis CNC Machining

2014 ◽  
Vol 644-650 ◽  
pp. 4967-4970 ◽  
Author(s):  
Hong Jun Liu ◽  
Ai Guo Zhang ◽  
Ji Bin Zhao ◽  
Jin Shang ◽  
Jun Liu
Keyword(s):  
Complex Surface ◽  
Cnc Machining ◽  
Machining Accuracy ◽  
Machining Error ◽  
Tool Axis ◽  
Non Linear ◽  
New Strategy ◽  
Tool Position ◽  
Five Axis ◽  
Tool Axis Vector

This paper presents a new strategy of analysis and compensation of non-linear error. Non-linear error is an important source of machining error in multi-axis numerical controlled machining and it is unavoidable. In view of tool positions optimization in five-axis CNC machining of complex surface, this paper presents a strategy for non-linear error compensation in five-axis machining: Firstly, non-linear error caused by the change of tool axis vector is analyzed and the non-linear error model is established, in order to get the maximum non-linear error of interpolation segment; Then, the tool position that meets the machining accuracy is obtained; Finally, Simulation and analysis of the model show that the proposed method is effective and greatly improves the geometric accuracy.

Tool Path Planning for Five-Axis NC Machining of Implant Shaping Mold for Cranioplasty

2011 ◽  
Vol 697-698 ◽  
pp. 292-296
Author(s):  
Liang Zhang ◽  
J. Li ◽  
B.C. Lou
Keyword(s):  
Path Planning ◽  
Tool Path ◽  
Nc Machining ◽  
Normal Curvature ◽  
Tool Path Planning ◽  
Lead Angle ◽  
Tool Axis ◽  
Nc Machine ◽  
Five Axis ◽  
Tool Axis Vector

The necessity for skull patch surface for cranioplasty was introduced and it was divided according to maximum normal curvature in the discrete points after skull patch surface dispersed. Then the tool axis vector was determined by the lead angle of the tool, corresponding to generating the tool path in each area; At last, the implant shaping mold for cranioplasty was produced by five-axis NC machine.

The Research of Nonlinearity Error Control on Five-Axis Machining Post Processor

2011 ◽  
Vol 311-313 ◽  
pp. 2353-2357 ◽  
Author(s):  
Qing Chun Tang ◽  
Jun He ◽  
Lan Lan Gao ◽  
Yu Huo Lai ◽  
Xue Ming Fang
Keyword(s):  
Machine Tool ◽  
Error Compensation ◽  
Error Control ◽  
Estimation Method ◽  
Linear Interpolation ◽  
Nonlinearity Error ◽  
Motion Error ◽  
Nonlinear Error ◽  
Tool Motion ◽  
Five Axis

Abstract：This paper analyses the causes and effective estimation method of nonlinear error; By machine tool motion solution, established a five-axis machine tool BV100 motion transformation mathematical models, combined with linear interpolation principle established the error compensation and nonlinear motion error model of the machine tool .by VB language, developed nonlinear error compensation function of special post process; and through the impeller cutting experiment validate the processor is correct and practical.

A decoupled five-axis local smoothing interpolation method to achieve continuous acceleration of tool axis

2020 ◽  
Vol 111 (1-2) ◽  
pp. 449-470
Author(s):  
Yang Jiang ◽  
Jiang Han ◽  
Lian Xia ◽  
Lei Lu ◽  
Xiaoqing Tian ◽  
...  
Keyword(s):  
Interpolation Method ◽  
Local Smoothing ◽  
Tool Axis ◽  
Five Axis

Research of the Tool Orientation Optimization with Kinematical Constraints

2013 ◽  
Vol 712-715 ◽  
pp. 2143-2148
Author(s):  
Hong Jun Liu ◽  
Jing Yu Cao ◽  
Ji Bin Zhao
Keyword(s):  
Coordinate System ◽  
Correction Method ◽  
Cnc Machining ◽  
Contact Points ◽  
Axis Of Rotation ◽  
Tool Axis ◽  
Efficient Processing ◽  
Velocity Constraints ◽  
Five Axis ◽  
Tool Axis Vector

Drastic change of the tool axis vector for five-axis CNC machining due to avoid global interference, proposed gentle forward, over-backward correction method to optimize the tool axis vector. Established a machine tool axis of rotation angular velocity constraints, and feed coordinate system, through the feed coordinate system adjust the inclination angle and swing angle of the existing tool axis vector to make the tool axis vector change between each adjacent cutter contact points satisfy the machine axis of rotation kinematics constraints and to ensure the continuity of feed rate during processing. Algorithm simulation examples show that the proposed method is reasonably practicable, make the tool axis vector changes fairing to ensure the smooth and efficient processing.

Study on Five-Axis NURBS Path Generation Method and Direct-Interpolation for CNC System

2014 ◽  
Vol 621 ◽  
pp. 162-166
Author(s):  
Hui Ying Li ◽  
Liang Ji Chen
Keyword(s):  
Interpolation Method ◽  
Spline Interpolation ◽  
Experimental Result ◽  
Path Generation ◽  
B Spline ◽  
Tool Paths ◽  
Controlling System ◽  
Five Axis ◽  
The Impact ◽  
Five Axes

In this article, a new method with Non-Uniform Rational B-Spline (NURBS) technology is presented and realized in a location and federate controlling system. In the method, the tool paths and the cutter locations (CL) were represented into NURBS curves based on the same knot vector. The above CL data was firstly calculated and then transformed to five motion commands of five axes of machine through the real-time post-procession algorithm. The acceleration/deceleration controlling method is also presented to avoid the impact of machine. The proposed 5-axis spline interpolation method is realized and the experimental result of machining shows that the method is valid.

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