scholarly journals Parameter Calibration on Replacement Manipulator for UHV Valve-Side Bushing Based on Spinor Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yanghua Zhang ◽  
Aiping Xiao ◽  
Ailing Wu ◽  
Hongqiang Yue ◽  
Xiaopeng Du
Keyword(s):  
Least Square Method ◽  
Structure Design ◽  
Error Model ◽  
Least Square ◽  
Weak Links ◽  
Robot Arm ◽  
Spinor Theory ◽  
Heavy Load ◽  
Positioning Accuracy ◽  
Replacement Device

In this paper, a structure design scheme of intelligent replacement device for the ultrahigh voltage (UHV) converter transformer valve-side bushing is put forward, and its size is determined according to the actual size of domestic converter station valve hall and UHV converter transformer valve-side bushing. Moreover, the weak links in its working state are analyzed by finite element method to ensure the safety and reliability of the structure. Based on the spinor theory, the forward kinematics and Jacobian matrix model of the manipulator are established, and the analytical solution of inverse kinematics is derived. In order to analyze the accuracy of the intelligent replacement manipulator for the UHV converter transformer valve-side bushing, considering that the end actuator of the robot arm is under heavy load, the absolute positioning accuracy and repeated positioning accuracy are analyzed. In addition, the corresponding error model is established, the least square method is proposed to identify the error model, and the influence of the error caused by the load on the repetition accuracy is analyzed. Finally, the whole process simulation in ROS provides data support for the calculation of repetitive precision and verifies the feasibility of the intelligent replacement device for the UHV converter valve-side bushing.

Error Model and Calibration Analysis of the Flexible Coordinate Measuring Machine

2011 ◽  
Vol 121-126 ◽  
pp. 3273-3277 ◽  
Author(s):  
Fang Li ◽  
Shu Gui Liu ◽  
Lei Zhao
Keyword(s):  
Mathematical Model ◽  
Coordinate Measuring Machine ◽  
Least Square Method ◽  
Coefficient Matrix ◽  
Error Model ◽  
Least Square ◽  
Parameter Calibration ◽  
Measuring Machine ◽  
Improving Accuracy ◽  
The Mathematical Model

A new 5-DOF flexible coordinate measuring machine (CMM) is introduced in this paper, which uses REVO system produced by Renishaw. According to the D-H method, the mathematical model is built, and then the error model of the flexible CMM is derived. The parameter calibration based on the nonlinear least square method is analyzed theoretically. Due to the disadvantages of Gauss-Newton method, LM method is researched, which improved the singularity of the coefficient matrix. The calibration analysis is a basis for improving accuracy of the flexible CMM.

scholarly journals Self-Calibration of an Industrial Robot Using a Novel Affordable 3D Measuring Device

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3380 ◽  
Author(s):  
Martin Gaudreault ◽  
Ahmed Joubair ◽  
Ilian Bonev
Keyword(s):  
Industrial Robot ◽  
Low Cost ◽  
Least Square Method ◽  
Calibration Method ◽  
Least Square ◽  
Geometrical Parameters ◽  
Robot Arm ◽  
Measuring Device ◽  
Self Calibration ◽  
Position Errors

This work shows the feasibility of calibrating an industrial robot arm through an automated procedure using a new, low-cost, wireless measuring device mounted on the robot’s flange. The device consists of three digital indicators that are fixed orthogonally to each other on an aluminum support. Each indicator has a measuring accuracy of 3 µm. The measuring instrument uses a kinematic coupling platform which allows for the definition of an accurate and repeatable tool center point (TCP). The idea behind the calibration method is for the robot to bring automatically this TCP to three precisely-known positions (the centers of three precision balls fixed with respect to the robot’s base) and with different orientations of the robot’s end-effector. The self-calibration method was tested on a small six-axis industrial robot, the ABB IRB 120 (Vasteras, Sweden). The robot was modeled by including all its geometrical parameters and the compliance of its joints. The parameters of the model were identified using linear regression with the least-square method. Finally, the performance of the calibration was validated with a laser tracker. This validation showed that the mean and the maximum absolute position errors were reduced from 2.628 mm and 6.282 mm to 0.208 mm and 0.482 mm, respectively.

Identification of Two Degree of Freedom Robot Arm’s Joints’ Time-Varying Stiffness

2012 ◽  
Vol 241-244 ◽  
pp. 1880-1884
Author(s):  
Rui Xu ◽  
Qiang Chen ◽  
Guo Lai Yang
Keyword(s):  
Degrees Of Freedom ◽  
Least Square Method ◽  
Identification Problem ◽  
Degree Of Freedom ◽  
Least Square ◽  
Analytical Mechanics ◽  
Time Varying ◽  
Robot Arm ◽  
Whole Process ◽  
Two Degree Of Freedom

This paper is concerned with the identification problem of two degree of freedom robot arm’s joints’ time-varying stiffness. The dynamic equation of two degrees of freedom robot arm can be obtained by using analytical mechanics method. Then by choosing limited memory least square method, time-varying stiffness can be identified. Finally, the calculative stiffness is compared to the “real” stiffness which is simulated in ADAMS. The whole process shows that the robot arm’s dynamic model and the method of identification are both effective.

Simulation Analysis and Experiment Research for a Large Span and Heavy Load Crossbeam

2011 ◽  
Vol 211-212 ◽  
pp. 1210-1215 ◽  
Author(s):  
Tie Neng Guo ◽  
Fang Jian Xi ◽  
Zhi Feng Liu ◽  
Qiang Cheng ◽  
Li Gang Cai
Keyword(s):  
Simulation Analysis ◽  
Structure Design ◽  
Numerical Control ◽  
Weak Links ◽  
Load Curve ◽  
Element Analysis ◽  
Heavy Load ◽  
Large Span ◽  
Machining Precision ◽  
Vibration Model

Aiming at solving issues of load bearing deformation compensation and sympathetic vibration, this paper takes a large span and heavy load crossbeam of a domestic heavy-type numerical control milling planer for research object, the final purpose is to improve machining precision and stability of the heavy machine tool product. The load curve considering the influence of columns deformation, natural frequency and vibration model are obtained, respectively by the dynamic and static simulation analysis of the crossbeam with the finite element analysis method. Then, the modal analysis results are verified through the model experiment. Lastly, this paper presents an approach by estimating the load curve to improve machining precision, points out the weak links, and provides guidance for crossbeam structure design, optimization and reverse manufacture.

An improved kinematic calibration method for serial manipulators based on POE formula

Robotica ◽  
2018 ◽  
Vol 36 (8) ◽  
pp. 1244-1262 ◽  
Author(s):  
Chenguang Chang ◽  
Jinguo Liu ◽  
Zhiyu Ni ◽  
Ruolong Qi
Keyword(s):  
High Precision ◽  
Least Square Method ◽  
Calibration Method ◽  
Error Model ◽  
Least Square ◽  
Identification Accuracy ◽  
Kinematic Calibration ◽  
Serial Manipulators ◽  
Serial Robots ◽  
Generic Modeling

SUMMARYExisting measurement equipments easily determine position with high precision. However, they evaluate orientation with low precision. It is necessary to minimize the effect of measurement error on identification accuracy. In this study, a method for kinematic calibration based on the product of exponentials (POE) is presented to improve the absolute positioning accuracy of a sliding manipulator. An error model with uniform and generic modeling rules is established in which the tool frame is selected as the reference frame. Furthermore, the redundant parameters of the error model are removed. Subsequently, the actual kinematic parameters are identified by using the least square method. Finally, the process of the improved method is discussed. Kinematic calibration simulations of a sliding manipulator are implemented. The results indicate that the proposed method significantly improves the precision of the sliding manipulator. The improved POE kinematic calibration method offers convenience, efficiency, and high precision. The proposed method can be applied to all types of serial robots with n-DOF

scholarly journals Research on Ground Calibration Technology for Geomagnetism Sensors

2018 ◽  
Vol 153 ◽  
pp. 07002 ◽  
Author(s):  
Zhang Hui ◽  
Li Chuanjun ◽  
Liu Yukuan
Keyword(s):  
Measurement Error ◽  
Measurement Accuracy ◽  
Least Square Method ◽  
Error Model ◽  
Least Square ◽  
Paper Analyse ◽  
Environment Factors ◽  
Sensor Error ◽  
Calibration Algorithm ◽  
Ground Calibration

The measurements of geomagnetism sensors are often affected by self-factors, install-factors and environment factors, therefore they often exist error and cause measurement accuracy reduction. Focus on these problems, this paper analyse existing ground calibration algorithms and their merits and demerits respectively. Besides, a comprehensive geomagnetism sensor error model is presented. Based on this model, a least square method based ellipsoid fitting calibration and compensation algorithm is presented. The experiment results show that this novel calibration algorithm can effectively restrain and compensate geomagnetism signal measurement error.

Forward Position Analysis and Error Modeling of the 2UPS-RPU Parallel Manipulator

2013 ◽  
Vol 397-400 ◽  
pp. 1515-1518
Author(s):  
Ya Wen Niu ◽  
Shu Hong Wen ◽  
Zhi You Feng
Keyword(s):  
Parallel Mechanism ◽  
Least Square Method ◽  
Error Model ◽  
Error Modeling ◽  
Least Square ◽  
Calculation Error ◽  
Numerical Verification ◽  
The Novel ◽  
Constrained Equations ◽  
Dimensional Equation

The forward kinematics of manipulator was studied to analyze the positive position of the novel 2UPS-RPU parallel mechanism with series connection inputs. With the restrict condition of the lengths of three actuated limbs as constraint conditions, the constrained equations were established, and the four nonlinear equations were obtained to solve forward positional problems of the mechanism. Based on the elimination method, a two-dimensional equation is obtained by eliminating the four-dimensional equation. The search method based on the least square method of the MATLAB software was utilized to analyze forward position of 2UPS-RPU parallel mechanism. The results of numerical verification showed that through this method all forward solutions can be found which are basically coincident with the inverse ones, and the little error was caused by the accumulating calculation error. An error model was established based on differential theory and kinematics equations .This model simplified the installation error as the manufacturing error. Finally the error value was obtained by MATLAB ,which proved the error model was correct.

Optimization Design and Application of Sluice Pier Sliding Formwork

2013 ◽  
Vol 671-674 ◽  
pp. 2005-2010
Author(s):  
Jun Xing ◽  
Hong Liang Cai ◽  
Jian Bing Cheng
Keyword(s):  
Optimization Design ◽  
Simulated Annealing Algorithm ◽  
High Efficiency ◽  
Low Cost ◽  
Least Square Method ◽  
Structure Design ◽  
Least Square ◽  
Advanced Technology ◽  
Design Parameters ◽  
Best Value

The sliding formwork, combining high efficiency and low cost, is a kind of advanced technology in the construction of sluice pier of hydropower projects. Number of jacks and elevating shelf spacing are two important parameters in the structure design of sliding formwork, the mathematical model of the relationship between manufacture costs and jack number, spacing between the elevating shelf was established using polynomial least square method, the best value of jack number and spacing between the elevating shelf were calculated by using the simulated annealing algorithm, thereby optimized the design parameters of sliding formwork structure, whilst expatiated the technology of installing, debugging, sliding and disassembly of sliding formwork, put forward the feasible methods for solving the problems that often appeared in the construction of sliding formwork, summed up the merits of sliding formwork, analyzed the technology and economical benefit of sliding formwork

A gantry robot system for cutting single Y-shaped welding grooves on plane workpieces

2020 ◽  
pp. 095440892096042
Author(s):  
Xiaobing Hu ◽  
Xi Deng ◽  
Qingxiang Zhao
Keyword(s):  
Least Square Method ◽  
Least Square ◽  
Robot System ◽  
Heavy Load ◽  
Velocity Planning ◽  
Full Automation ◽  
Algebra Method ◽  
Gantry Robot ◽  
Direct Vibration ◽  
Manual Assistance

To guarantee the strength and precision of the final welding assemblies, it is necessary to cut welding grooves before welding thick workpieces. General methods to cut welding grooves on plane workpieces need much manual assistance, and some even need manual operation purely. Therefore, this paper proposed a robot system for cutting Y-shaped welding grooves with full automation. Flame cutting technology has been adopted, requiring no jig to fix workpieces, which also causes no direct vibration to robot structure. Vision-based sub-system firstly captures the edges to be cut, which are composed of continuous points, and a laser range finder (LRF) starts to obtain the thickness of the edges precisely. To convert these edges into the trajectory of flamer, Least Square Method and Hermite Interpolation are respectively utilized to fit lines and curves. Robot system subsequently computes the motion-related parameters according to the position of the edges and geometric parameters of the desired welding grooves. The inverse kinematics of this robot is solved by geometry methods, which decreases computation burden and saves much time compared with traditional algebra method. Another core novelty is that a velocity planning method combining optimization algorithm has been put forward, which, we think, is not only useful in this gantry robot but also benefits other motion axes with heavy load. This further reduces vibration. Finally, the simulation and experimental results both prove the feasibility of this system. To date, no available robots or machines tool can finish this process with full automation (to the best of our knowledge).

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.

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