The Mathematical Model of Welding Process Comparative Study of Identification Method

2012 ◽  
Vol 472-475 ◽  
pp. 2241-2244 ◽  
Author(s):  
Jun Feng Wu ◽  
Jing Huang
Keyword(s):  
Weld Pool ◽  
Academic Research ◽  
Welding Process ◽  
Least Square Method ◽  
Mathematic Model ◽  
Least Square ◽  
Complex Object ◽  
Strong Nonlinearity ◽  
Area Method ◽  
Pulsed Gtaw

The dynamic process of the weld pool is a high complex object with strong nonlinearity, mult-variable coupling and a mount of stochastic and uncertain factors. It is very difficult to obtain an analysis mathematic model of weld pool dynamics. Pulsed Gas Tungsten Arc Welding (GTAW) is an important metal’s welding technology, which has been widely applied in the aerospace and manufacturing areas. Therefore, the dynamic characteristic of the welding process has always been hot and difficult in the field of academic research and engineering applications. In order to solve the difficulties of modeling and controlling of nonlinear system, this paper investigates the dynamic characters of the pulsed GTAW from the classic control systems. It obtains the SISO transfer function model by the area method and least square method. The results of simulation experiment show that the area method is better between the two methods.

Minimum Zone Evaluation of Symmetry Error for Flatness to Flatness Based on the New Generation GPS

2013 ◽  
Vol 662 ◽  
pp. 887-891
Author(s):  
Qian Qian ◽  
Mei Fa Huang ◽  
Huan Yu Li
Keyword(s):  
Least Square Method ◽  
Mathematic Model ◽  
Least Square ◽  
Adaptive Genetic Algorithm ◽  
Machining Error ◽  
Minimum Zone ◽  
New Generation ◽  
Tolerance Method ◽  
The Mathematical Model ◽  
Better Than

Least square method (LSM) is the most popular method used to evaluate machining error nowadays. However, LSM is likely to overestimate the error value, therefore its solution is only approximate and rather than minimum. In order to obtain the minimum, we study the principle of the minimum zone tolerance method (MZT), analyze the characteristics of the new generation GPS, and give the minimum zone mathematic model of the symmetry error for flatness to flatness. For the purpose of optimizing the mathematical model, this paper describes the application of adaptive genetic algorithm to achieve the best estimation. Simultaneously, the process of optimization is realized by MALTAB. Finally, the experiment shows that the evaluation results of MZT is better than evaluation results of LSM.

Intelligent Control of Arc Welding Dynamics during Robotic Welding Process

2010 ◽  
Vol 638-642 ◽  
pp. 3751-3756 ◽  
Author(s):  
San Ben Chen ◽  
W.Y. Wang ◽  
H.B. Ma
Keyword(s):  
Weld Pool ◽  
Intelligent Control ◽  
Arc Welding ◽  
Visual Information ◽  
Control Strategies ◽  
Welding Process ◽  
Control Methods ◽  
Welding Robot ◽  
Robotic Welding ◽  
Pulsed Gtaw

This paper presents a sequential research works on visual information acquirement and intelligent control of arc weld pool dynamics and seam formation during pulsed GTAW (Gas Tungsten Arc Welding) in robotic welding process. The visual information acquirement methods are focused in computer vision sensing, image processing and characteristic extraction of the weld pool surface from the single-item pool images by particular algorithms for robotic welding process. Based on acquired visual characteristics of weld pool and established neural network and knowledge models for predicting dynamical characteristics of weld pool during robotic welding, corresponding control methods, such adaptive control, self-learning and other composite intelligent control strategies are developed to control welding pool dynamics during pulsed GTAW by welding robot. Some experiments and applications of intelligent control methods in welding robot systems are shown in the paper.

A welding seam identification method based on cross-modal perception

2019 ◽  
Vol 46 (3) ◽  
pp. 453-459
Author(s):  
Xinde Li ◽  
Pei Li ◽  
Mohammad Omar Khyam ◽  
Xiangheng He ◽  
Shuzhi Sam Ge
Keyword(s):  
Real Time ◽  
Great Influence ◽  
Welding Process ◽  
Least Square Method ◽  
Least Square ◽  
Welding Fumes ◽  
Automatic Welding ◽  
Robust Method ◽  
Welding Seam ◽  
Content Type

Purpose As an automatic welding process may experience some disturbances caused by, for example, splashes and/or welding fumes, misalignments/poor positioning, thermally induced deformations, strong arc lights and diversified welding joints/grooves, precisely identifying the welding seam has a great influence on the welding quality. This paper aims to propose a robust method for identifying this seam based on cross-modal perception. Design/methodology/approach First, after a welding image obtained from a structured-light vision sensor (here laser and vision are integrated into a cross-modal perception sensor) is filtered, in a sufficiently small area, the extended Kalman filter is used to prevent possible disturbances to search for its laser stripe. Second, to realize the extraction of the profile of welding seam, the least square method is used to fit a sequence of centroids determined by the scanning result of columns displayed on the tracking window. Third, this profile is then qualitatively described and matched using a proposed character string method. Findings It is demonstrated that it maintains real time and is clearly superior in terms of accuracy and robustness, though its real-time performance is not the best. Originality/value This paper proposes a robust method for automatically identifying and tracking a welding seam.

Numerical Correction High Temperature of Near-Infrared Colorimetry

2011 ◽  
Vol 301-303 ◽  
pp. 1378-1383
Author(s):  
Li Hua Yuan ◽  
Guan Hua Wu ◽  
Ming Li
Keyword(s):  
High Temperature ◽  
Surface Temperature ◽  
Near Infrared ◽  
Least Square Method ◽  
Mathematic Model ◽  
Least Square ◽  
Radiation Pyrometer ◽  
Surface Emissivity ◽  
Relationship Of ◽  
The Relationship

Colorimetry is commonly used to measure the surface temperature as true one when the surface emissivity is constant. That is, the target is regarded as greybody. But in fact, most materials are not greybody. Spectrum emissivity has to do with wavelength and temperature. And in the most case, it is difficult to assure the exact values of the emissivity .This makes the relative error of the temperature big. Therefore, it is necessary to modify the emissivity response of radiation pyrometer. The factor influencing the spectrum was researched through the application of least square method to create the relationship of spectrum emissivity with wavelength and temperature, at last mathematic model was established which provided numerical correction of infrared two-color thermometry.

The Research on Milling Temperature and Heat Deformation of Tool in Virtual Numerical Control Simulation

2010 ◽  
Vol 97-101 ◽  
pp. 2865-2870 ◽  
Author(s):  
Xiu Lin Sui ◽  
Li Juan Jin ◽  
Jiang Hua Ge ◽  
Jia Tai Zhang ◽  
Zheng Wei Kong
Keyword(s):  
Correlation Coefficients ◽  
Least Square Method ◽  
Mathematic Model ◽  
Joint Modeling ◽  
Least Square ◽  
Numerical Control ◽  
Technical Problems ◽  
Nc Simulation ◽  
Milling Temperature ◽  
Heat Deformation

Joint modeling of exponentially fitting and least square method was proposed for key technical problems on milling temperature and heat deformation of tool in virtual numerical control (NC) simulation. Mathematic model of surface temperature and its influencing factors based on ball-end mill was established. Correlation coefficients of model are over 0.8, and the errors comparing with the experimental ones are within 10%, which shows that the model meets precision requirement, and fitting effect is good. By this model a mathematical model of the ball-milling cutter’s thermal deformation was established, and the relative error is small by comparing with test values, which proves that this model has high calculation precision and practical meaning. A simulation prediction system of milling temperature and ball-end mill’s heat deformation in virtual NC was developed based on above mentioned models, which can provide theoretical basis for machining error prediction, optimizing milling parameters and improving machining quality.

Direct Assessment of Effective Renal Plasma Flow from Renoscintigraphy with a Gamma Camera and an On-Line Computer

1981 ◽  
Vol 20 (06) ◽  
pp. 274-278
Author(s):  
J. Liniecki ◽  
J. Bialobrzeski ◽  
Ewa Mlodkowska ◽  
M. J. Surma
Keyword(s):  
Count Rate ◽  
Renal Plasma Flow ◽  
Early Period ◽  
Least Square Method ◽  
Least Square ◽  
Uptake Coefficient ◽  
Positive Linear Correlation ◽  
On Line ◽  
Best Fit ◽  
Plasma Activity

A concept of a kidney uptake coefficient (UC) of 131I-o-hippurate was developed by analogy from the corresponding kidney clearance of blood plasma in the early period after injection of the hippurate. The UC for each kidney was defined as the count-rate over its ROI at a time shorter than the peak in the renoscintigraphic curve divided by the integral of the count-rate curve over the "blood"-ROI. A procedure for normalization of both curves against each other was also developed. The total kidney clearance of the hippurate was determined from the function of plasma activity concentration vs. time after a single injection; the determinations were made at 5, 10, 15, 20, 30, 45, 60, 75 and 90 min after intravenous administration of 131I-o-hippurate and the best-fit curve was obtained by means of the least-square method. When the UC was related to the absolute value of the clearance a positive linear correlation was found (r = 0.922, ρ > 0.99). Using this regression equation the clearance could be estimated in reverse from the uptake coefficient calculated solely on the basis of the renoscintigraphic curves without blood sampling. The errors of the estimate are compatible with the requirement of a fast appraisal of renal function for purposes of clinical diagknosis.

PENGARUH KNOWLEDGE MANAGEMENT, KOMPETENSI, MOTIVASI TERHADAP KINERJA KARYAWAN

2015 ◽  
Vol 5 (2) ◽  
pp. 1
Author(s):  
Miftahol Arifin
Keyword(s):  
Knowledge Management ◽  
Linear Regression ◽  
Significant Influence ◽  
Employee Performance ◽  
Least Square Method ◽  
Least Square ◽  
Analysis Tool ◽  
Ordinary Least Square ◽  
Competence Motivation ◽  
Performance Analyze

The purpose of this research is to analyze the influence of knowledge management on employee performance, analyze the effect of competence on employee performance, analyze the influence of motivation on employee performance). In this study, samples taken are structural employees PT.centris Kingdom Taxi Yogyakarta. The analysis tool in this study using multiple linear regression with Ordinary Least Square method (OLS). The conclusion of this study showed that the variables of knowledge management has a significant influence on employee performance, competence variables have an influence on employee performance, motivation variables have an influence on employee performance, The analysis showed that the variables of knowledge management, competence, motivation on employee performance.Keywords: knowledge management, competence, motivation, employee performance.

Peristaltic Carreau-Yasuda nanofluid flow and mixed heat transfer analysis in an asymmetric vertical and tapered wavy wall channel

2020 ◽  
Vol 1 (1) ◽  
pp. 128-140 ◽  
Author(s):  
Mohammad Hatami ◽  
◽  
D Jing ◽  
Keyword(s):  
Heat Transfer ◽  
Least Square Method ◽  
Weissenberg Number ◽  
Least Square ◽  
Heat Transfer Analysis ◽  
Phase Method ◽  
Nanofluid Flow ◽  
Two Phase ◽  
Nanoparticles Concentration ◽  
The Right

In this study, two-phase asymmetric peristaltic Carreau-Yasuda nanofluid flow in a vertical and tapered wavy channel is demonstrated and the mixed heat transfer analysis is considered for it. For the modeling, two-phase method is considered to be able to study the nanoparticles concentration as a separate phase. Also it is assumed that peristaltic waves travel along X-axis at a constant speed, c. Furthermore, constant temperatures and constant nanoparticle concentrations are considered for both, left and right walls. This study aims at an analytical solution of the problem by means of least square method (LSM) using the Maple 15.0 mathematical software. Numerical outcomes will be compared. Finally, the effects of most important parameters (Weissenberg number, Prandtl number, Brownian motion parameter, thermophoresis parameter, local temperature and nanoparticle Grashof numbers) on the velocities, temperature and nanoparticles concentration functions are presented. As an important outcome, on the left side of the channel, increasing the Grashof numbers leads to a reduction in velocity profiles, while on the right side, it is the other way around.

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