Kinematic modeling and verification of an articulated arm coordinate measuring machine

2016 ◽  
Author(s):  
Huaishan Zhang ◽  
Guanbin Gao ◽  
Wen Wang ◽  
Jing Na ◽  
Xing Wu
Keyword(s):  
Coordinate Measuring Machine ◽  
Kinematic Modeling ◽  
Measuring Machine

Kinematic Modeling and Error Analysis for a 3DOF Parallel-Link Coordinate Measuring Machine

2006 ◽  
Vol 532-533 ◽  
pp. 313-316 ◽  
Author(s):  
De Jun Liu ◽  
Hua Qing Liang ◽  
Hong Dong Yin ◽  
Bu Ren Qian
Keyword(s):  
Kinematic Model ◽  
Coordinate Measuring Machine ◽  
Inverse Kinematic ◽  
Differential Method ◽  
Error Model ◽  
Structural Parameter ◽  
Kinematic Modeling ◽  
Position Errors ◽  
Measuring Machine ◽  
Parallel Link

First, the forward kinematic model, the inverse kinematic model and the error model of a kind of coordinate measuring machine (CMM) using 3-DOF parallel-link mechanism are established based on the spatial mechanics theory and the total differential method, and the error model is verified by computer simulation. Then, the influence of structural parameter errors on probe position errors is systematically considered. This research provides an essential theoretical basis for increasing the measuring accuracy of the parallel-link coordinate measuring machine. It is of particular importance to develop the prototype of the new measuring equipment.

scholarly journals Modeling and Error Compensation of Robotic Articulated Arm Coordinate Measuring Machines Using BP Neural Network

Complexity ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Guanbin Gao ◽  
Hongwei Zhang ◽  
Hongjun San ◽  
Xing Wu ◽  
Wen Wang
Keyword(s):  
Neural Network ◽  
Error Compensation ◽  
Prediction Accuracy ◽  
Experimental Studies ◽  
Coordinate Measuring Machine ◽  
Joint Space ◽  
Compensation Method ◽  
Kinematic Modeling ◽  
Actual Measurement ◽  
Measuring Machine

Articulated arm coordinate measuring machine (AACMM) is a specific robotic structural instrument, which uses D-H method for the purpose of kinematic modeling and error compensation. However, it is difficult for the existing error compensation models to describe various factors, which affects the accuracy of AACMM. In this paper, a modeling and error compensation method for AACMM is proposed based on BP Neural Networks. According to the available measurements, the poses of the AACMM are used as the input, and the coordinates of the probe are used as the output of neural network. To avoid tedious training and improve the training efficiency and prediction accuracy, a data acquisition strategy is developed according to the actual measurement behavior in the joint space. A neural network model is proposed and analyzed by using the data generated via Monte-Carlo method in simulations. The structure and parameter settings of neural network are optimized to improve the prediction accuracy and training speed. Experimental studies have been conducted to verify the proposed algorithm with neural network compensation, which shows that 97% error of the AACMM can be eliminated after compensation. These experimental results have revealed the effectiveness of the proposed modeling and compensation method for AACMM.

A Kinematic Model for Parallel-Joint Coordinate Measuring Machine

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Jie Li ◽  
Lian-Dong Yu ◽  
Jing-Qi Sun ◽  
Hao-Jie Xia
Keyword(s):  
Mathematical Modeling ◽  
Data Processing ◽  
Newton Method ◽  
Measurement Accuracy ◽  
Kinematic Model ◽  
Coordinate Measuring Machine ◽  
Experimental Results ◽  
Kinematic Modeling ◽  
Kinematic Parameters ◽  
Measuring Machine

The typical nonorthogonal coordinate measuring machine is the portable coordinate measuring machine (PCMM), which is widely applied in manufacturing. In order to improve the measurement accuracy of PCMM, structural designing, data processing, mathematical modeling, and identification of parameters of PCMM, which are essential for the measurement accuracy, should be taken into account during the machine development. In this paper, a kind of PCMM used for detecting the crucial dimension of automobile chassis has been studied and calibrated. The Denavit–Hartenberg (D–H) kinematic modeling method has often been used for modeling traditional robot, but the D–H error representation is ill-conditioned when it is applied to represent parallel joints. A modified four-parameter model combined with D–H model is put forward for this PCMM. Based on the kinematic model, Gauss–Newton method is applied for calibrating the kinematic parameters. The experimental results indicate the improvement of measuring accuracy and the effectiveness of the PCMM based on the proposed method.

Kinematic Modeling and Analysis of Articulated Arm Coordinate Measuring Machines

2012 ◽  
Vol 241-244 ◽  
pp. 494-497
Author(s):  
Guan Bin Gao ◽  
Wen Wang ◽  
Hong Qiang Li ◽  
Jian Jun Zhou
Keyword(s):  
Structural Characteristics ◽  
Structural Parameters ◽  
Kinematic Model ◽  
Coordinate Measuring Machine ◽  
Measurement Range ◽  
Kinematic Modeling ◽  
Modeling And Analysis ◽  
Graphical Simulation ◽  
Measuring Machine ◽  
Numerical Computing

The articulated arm coordinate measuring machine (AACMM) is a new type coordinate measuring machine (CMM) base on the linkage structure with the characteristics of small size, light weight, large measurement range and flexible movement. The kinematic modeling methods of six degree of freedom (6-DOF) AACMMs are studied in this paper. By analyzing the structural characteristics of AACMMs the kinematic model of a 6-DOF AACMM with DH method was established. From the kinematic model the coordinate systems and structural parameters of the AACMM are obtained. Then the homogeneous transformation matrixes from the probe to the base of the AACMM are derived. Finally, methods of numerical computing and graphical simulation are used in verifying the kinematic model. The kinematic model provides a basis for measurement, calibration and error compensation of the AACMM.

scholarly journals Evaluation of dimensional accuracy of dental bridges manufactured with conventional casting technique and CAD/CAM system with Ceramill Sintron blocks using CMM

2018 ◽  
Vol 12 (4) ◽  
pp. 264-271 ◽  
Author(s):  
Alireza Izadi ◽  
Fariborz Vafaee ◽  
Arash Shishehian ◽  
Ghodratollah Roshanaei ◽  
Behzad Fathi Afkari
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Three Dimensions ◽  
Casting Technique ◽  
Dimensional Changes ◽  
Conventional Casting ◽  
Cad Cam ◽  
Milling Method ◽  
Measuring Machine

Background. Recently, non-presintered chromium-cobalt (Cr-Co) blocks with the commercial name of Ceramill Sintron were introduced to the market. However, comprehensive studies on the dimensional accuracy and fit of multi-unit frameworks made of these blocks using the coordinate measuring machine (CMM) are lacking. This study aimed to assess and compare the dimensional changes and fit of conventional casting and milled frameworks using Ceramill Sintron. Methods. A metal model was designed and scanned and 5-unit frameworks were fabricated using two techniques: (I) the conventional casting method (n=20): the wax model was designed, milled in the CAD/CAM machine, flasked and invested; (II) the milling method using Ceramill Sintron blocks (n=20): the wax patterns of group 1 were used; Ceramill Sintron blocks were milled and sintered. Measurements were made on the original reference model and the fabricated frameworks using the CMM in all the three spatial dimensions, and dimensional changes were recorded in a checklist. Data were analyzed with descriptive statistics, and the two groups were compared using one-way ANOVA and Tukey test (α=0.05). Results. The fabricated frameworks in both groups showed significant dimensional changes in all the three dimensions. Comparison of dimensional changes between the two groups revealed no significant differences (P>0.05) except for transverse changes (arch) that were significantly greater in Ceramill Sintron frameworks (P<0.05). Conclusion. The two manufacturing processes were the same regarding dimensional changes and the magnitude of marginal gaps and both processes resulted in significant dimensional changes in frameworks. Ceramill Sintron frameworks showed significantly greater transverse changes than the conventional frameworks.

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