An Overview on Accuracy and Calibration Methods for Manipulators

2014 ◽  
Vol 658 ◽  
pp. 606-611 ◽  
Author(s):  
Dan Romulus Dogaru ◽  
Ioan Doroftei
Keyword(s):  
Computer Vision ◽  
Measurement System ◽  
Good Accuracy ◽  
Feedback Mechanism ◽  
The Other ◽  
Laser Tracker ◽  
End Effector ◽  
The Real ◽  
Offline Programming ◽  
Calibration Methods

Offline programming requires a good accuracy of the manipulators. The solution to the problem is to use a feedback mechanism to minimize the error. But, the real coordinate of the robot can be achieved with a measurement system. With this system the robot is calibrated and therefore errors are minimized. In this paper, an overview on some calibration methods used to reduce positioning and orientation errors of the end-effector are discussed. A set of methods are using a laser tracker for the measurements and the other methods are based on computer vision.

Comparison of two calibration methods for a small industrial robot based on an optical CMM and a laser tracker

Robotica ◽  
2013 ◽  
Vol 32 (3) ◽  
pp. 447-466 ◽  
Author(s):  
Albert Nubiola ◽  
Mohamed Slamani ◽  
Ahmed Joubair ◽  
Ilian A. Bonev
Keyword(s):  
Industrial Robot ◽  
Laser Tracker ◽  
Calibration Model ◽  
Kinematic Calibration ◽  
Absolute Accuracy ◽  
Parameter Calibration ◽  
End Effector ◽  
Coordinate Measurement ◽  
Measurement Systems ◽  
Calibration Methods

SUMMARYThe absolute accuracy of a small industrial robot is improved using a 30-parameter calibration model. The error model takes into account a full kinematic calibration and five compliance parameters related to the stiffness in joints 2, 3, 4, 5, and 6. The linearization of the Jacobian is performed to iteratively find the modeled error parameters. Two coordinate measurement systems are used independently: a laser tracker and an optical CMM. An optimized end-effector is developed specifically for each measurement system. The robot is calibrated using fewer than 50 configurations and the calibration efficiency validated in 1000 configurations using either the laser tracker or the optical CMM. A telescopic ballbar is also used for validation. The results show that the optical CMM yields slightly better results, even when used with the simple triangular plate end-effector that was developed mainly for the laser tracker.

Accuracy calibration of a 3-CRU translational parallel robot based on the subset of error measurements

2020 ◽  
pp. 095440622096769
Author(s):  
Tie Zhang ◽  
Guangcai Ma ◽  
Yachao Cao ◽  
Yingwu He
Keyword(s):  
Linear Combination ◽  
Error Compensation ◽  
Calibration Method ◽  
Parallel Robot ◽  
Laser Tracker ◽  
End Effector ◽  
Structural Error ◽  
Robot Accuracy ◽  
Calibration Methods ◽  
Complete Set

Robot accuracy calibration is an effective method to improve its kinematic accuracy. However, most of the existing calibration methods need to measure the complete set of 6-dimensional pose errors of the end-effector, which makes the calibration process especially complicated. In this paper, an accuracy calibration method for a 3-CRU translational parallel robot is proposed based on the subset of error measurements. The process is implemented by four steps: 1) the error model is established based on matrix method. Then the structural errors to be identified are separated. 2) part of pose errors of the end-effector are measured by laser tracker and used to form the subset of error measurements. 3) the minimum structural error linear combination affecting robot accuracy is determined according to the minimum parameter error linear combination theorem. After that, the structural errors can be identified based on the subset of error measurements. 4) error compensation based on the identification results. This method can not only ensure the identifiability of the structural errors, but also can realize error identification based on the subset of error measurements, which will significantly reduce the calibration workload and improve the calibration efficiency. Experiments are carried out to prove the effectiveness of the calibration method.

3D Image Media and Computer Vision -From CV as Robot Technology to CV as Media Technology-

1997 ◽  
Vol 9 (2) ◽  
pp. 92-97 ◽  
Author(s):  
Yuichi Ohta ◽  
Keyword(s):  
Computer Vision ◽  
Real World ◽  
The Other ◽  
Sensor Technology ◽  
Human Beings ◽  
3D Image ◽  
Media Technology ◽  
The Real ◽  
Computer Vision Technology ◽  
Robot Technology

The possibility to apply the computer vision technology to the development of a new image medium is discussed. Computer vision has been studied as a sensor technology between the real world and computers. On the other hand, the computer graphics are the interface technology between the computers and human beings. The invention of ""3D photography"" based on the computer vision technology will realize a new 3D image medium which connects the real world and the human beings via computer. In such a framework, computer vision should be studied as a media technology rather than a robot technology.

Ultrasound speed compensation in an ultrasonic robot tracking system

Robotica ◽  
2000 ◽  
Vol 18 (6) ◽  
pp. 633-637 ◽  
Author(s):  
W. T. Kuang ◽  
A. S. Morris
Keyword(s):  
Tracking System ◽  
The Other ◽  
Good Precision ◽  
End Effector ◽  
The Real ◽  
Best Value ◽  
Robot Tracking ◽  
Novel Method ◽  
Ultrasound Speed ◽  
Distorted Data

This paper presents a novel method for ultrasound speed compensation in ultrasonic robot tracking. It employs optimization algorithms to estimate the best value of the ultrasound speed for every computation of the robot end-effector position. Compared with the other existing method for ultrasound speed compensation, this method has the advantage that no extra equipment is required to monitor the environment conditions (temperature etc.). The simulation, which is described at the end of this paper, shows that the real trajectory is extracted with very good precision from a set of distorted data caused by serious ultrasound speed drifting.

scholarly journals Calibration Method for IATS and Application in Multi-Target Monitoring Using Coded Targets

2017 ◽  
Vol 11 (2) ◽  
Author(s):  
Yueyin Zhou ◽  
Andreas Wagner ◽  
Thomas Wunderlich ◽  
Peter Wasmeier
Keyword(s):  
Computer Vision ◽  
Target Detection ◽  
Calibration Method ◽  
Calibration Procedure ◽  
The Other ◽  
Camera System ◽  
Automatic Target Detection ◽  
Calibration Methods ◽  
Target Monitoring ◽  
The Relationship

AbstractThe technique of Image Assisted Total Stations (IATS) has been studied for over ten years and is composed of two major parts: one is the calibration procedure which combines the relationship between the camera system and the theodolite system; the other is the automatic target detection on the image by various methods of photogrammetry or computer vision. Several calibration methods have been developed, mostly using prototypes with an add-on camera rigidly mounted on the total station. However, these prototypes are not commercially available. This paper proposes a calibration method based on Leica MS50 which has two built-in cameras each with a resolution of 2560 × 1920 

Hidden “holes” in the capital of banks and the supply of credit to the real sector of economy

2018 ◽  
pp. 49-68 ◽  
Author(s):  
M. E. Mamonov
Keyword(s):  
Credit Risk ◽  
The Other ◽  
Real Sector ◽  
Capital Management ◽  
Loan Loss ◽  
Short Term ◽  
The Real ◽  
Ex Post ◽  
The One

Our analysis documents that the existence of hidden “holes” in the capital of not yet failed banks - while creating intertemporal pressure on the actual level of capital - leads to changing of maturity of loans supplied rather than to contracting of their volume. Long-term loans decrease, whereas short-term loans rise - and, what is most remarkably, by approximately the same amounts. Standardly, the higher the maturity of loans the higher the credit risk and, thus, the more loan loss reserves (LLP) banks are forced to create, increasing the pressure on capital. Banks that already hide “holes” in the capital, but have not yet faced with license withdrawal, must possess strong incentives to shorten the maturity of supplied loans. On the one hand, it raises the turnovers of LLP and facilitates the flexibility of capital management; on the other hand, it allows increasing the speed of shifting of attracted deposits to loans to related parties in domestic or foreign jurisdictions. This enlarges the potential size of ex post revealed “hole” in the capital and, therefore, allows us to assume that not every loan might be viewed as a good for the economy: excessive short-term and insufficient long-term loans can produce the source for future losses.

Computer Vision and robotics in postal automation

1999 ◽  
Vol 18 (3-4) ◽  
pp. 265-273
Author(s):  
Giovanni B. Garibotto
Keyword(s):  
Image Processing ◽  
Computer Vision ◽  
Pattern Recognition ◽  
Material Handling ◽  
State Of The Art ◽  
Short Description ◽  
The Other ◽  
Functional Requirements ◽  
Postal Automation ◽  
And Robotics

The paper is intended to provide an overview of advanced robotic technologies within the context of Postal Automation services. The main functional requirements of the application are briefly referred, as well as the state of the art and new emerging solutions. Image Processing and Pattern Recognition have always played a fundamental role in Address Interpretation and Mail sorting and the new challenging objective is now off-line handwritten cursive recognition, in order to be able to handle all kind of addresses in a uniform way. On the other hand, advanced electromechanical and robotic solutions are extremely important to solve the problems of mail storage, transportation and distribution, as well as for material handling and logistics. Finally a short description of new services of Postal Automation is referred, by considering new emerging services of hybrid mail and paper to electronic conversion.

Computer vision measurement system for standards calibration in XY plane with sub-micrometer accuracy

2019 ◽  
Vol 105 (1-4) ◽  
pp. 1531-1537 ◽  
Author(s):  
Pedro Bastos Costa ◽  
Fabiana Rodrigues Leta ◽  
Felipe de Oliveira Baldner
Keyword(s):  
Computer Vision ◽  
Measurement System ◽  
Vision Measurement

scholarly journals Stochastic Processes with a Particular Type of Variograms

2007 ◽  
Vol 2007 ◽  
pp. 1-5 ◽  
Author(s):  
Chunsheng Ma
Keyword(s):  
Stochastic Process ◽  
Brownian Motion ◽  
Stochastic Processes ◽  
Series Expansion ◽  
Real Line ◽  
Random Fields ◽  
The Other ◽  
Simple Construction ◽  
The Real ◽  
Line Form

This paper is concerned with a class of stochastic processes or random fields with second-order increments, whose variograms have a particular form, among which stochastic processes having orthogonal increments on the real line form an important subclass. A natural issue, how big this subclass is, has not been explicitly addressed in the literature. As a solution, this paper characterizes a stochastic process having orthogonal increments on the real line in terms of its variogram or its construction. Our findings are a little bit surprising: this subclass is big in terms of the variogram, and on the other hand, it is relatively “small” according to a simple construction. In particular, every such process with Gaussian increments can be simply constructed from Brownian motion. Using the characterizations we obtain a series expansion of the stochastic process with orthogonal increments.

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