3-D Sensing for Flexible Linear Object Alignment in Robot Cell Production System

2010 ◽  
Vol 22 (1) ◽  
pp. 100-111 ◽  
Author(s):  
Yukiyasu Domae ◽  
◽  
Haruhisa Okuda ◽  
Yasuo Kitaaki ◽  
Yuta Kimura ◽  
...  
Keyword(s):  
Industrial Robot ◽  
Precision Measurements ◽  
Monocular Camera ◽  
Measurement Results ◽  
Automatic Alignment ◽  
Linear Object ◽  
Epipolar Constraints ◽  
Encoding Method ◽  
Technical Features ◽  
Space Encoding

We have constructed 3-D sensing system for alignment of connector-fitted cables as flexible linear objects which used to be difficult to be automated at the production sites. In the system an industrial robot has a 3-D sensor and a monocular camera mounted at the hand. 3-D sensor, using space encoding method, allows the robot to make high-precision measurements of the order of sub-millimeters, but emphasis is placed on precision at the expense of fields of view. In addition, active sensing methods such as the space encoding method is hard to take measurements for black cables, as well as it has some difficulties with measurements of semitransparent plastic connectors depending on view-points. To cope with those problems, our system is such that the monocular camera on the robot is moved for motion stereo to take measurements on cable shapes; connector’s poses are coarsely estimated from the measurement results; and such view-points as will ensure stable measurements are computed by space encoding method to take precision measurements of connectors. Technical features of the system could be summarized as follows: 1) Determination of view-points to measure connectors, based on measurements of cable shapes, requires no more than two measurements, without repeated searches, to grab semitransparent plastic connectors. 2) Performance of stereo correspondence for plain or black cables, which tends to result in a failure with the aids of no more than irradiated slit patterns and epipolar constraints, has been improved through sequential correspondence inmotion image sequence and its stability evaluations. At the operation tests in the validation system, the robot is assigned a task to assemble the cables into industrial servo amplifiers available on the market, in which automatic alignment of 200 connector-fitted cables has successfully been accomplished in succession to confirm constant performance of the system.

Effects of Powders on the Precision of a Powder Metallurgy Helical Gear

2007 ◽  
Author(s):  
Ming-Ta Yu ◽  
Chung-Biau Tsay
Keyword(s):  
Mathematical Model ◽  
Powder Metallurgy ◽  
Helical Gear ◽  
Precision Measurements ◽  
Manufacture Process ◽  
Measurement Results ◽  
Surface Deviations ◽  
Two Parameters ◽  
The Mathematical Model ◽  
The Relationship

This study refers to the conditions of practical powder metallurgy manufacture process, and proceeds to experiments and gear precision measurements as well as investigation on the effects of two parameters, powders and pitch circle radius, on gear precision. The relationship between gear parameters and gear surface deviations was derived from the mathematical model of the involute helical gear and the analysis of gear surface deviations. In accordance with the measurement results of experiments, an ideal correction on the parameters of a forming die is obtained from the computer simulations of gear surface deviations.

A Compound Recoil-Compensated Chamber Design for Free-Fall Absolute Gravimeters

2020 ◽  
Author(s):  
Yi Wen ◽  
Kang Wu ◽  
Meiying Guo ◽  
Lijun Wang
Keyword(s):  
High Precision ◽  
Free Fall ◽  
Test Mass ◽  
Precision Measurements ◽  
Gravity Measurement ◽  
Absolute Gravity ◽  
Systematic Bias ◽  
Chamber Design ◽  
Measurement Results ◽  
Gravity Measurements

Abstract The ballistic free-fall absolute gravimeters are most commonly-used instruments for high-precision absolute gravity measurements in many fields, such as scientific research, resource survey, geophysics and so on. The instrumental recoil vibrations generated by the release of the test mass can cause troublesome systematic bias, because these vibrations are highly reproducible from drop to drop with coherent phase. A compound counterbalanced design of chamber using both belt-driven mechanism and cam-driven structure is proposed in this paper. This structure is designed to achieve excellent recoil compensation as well as long freefall length for high precision measurements. Simulation results show that the recoil vibration amplitude of the compound recoil-compensated structure during the drop is about 1/4 of that with only belt-driven counterbalanced structure. This confirms the feasibility and superiority of the new design. And it is believed that the absolute gravimeter based on this newly proposed chamber design is expected to obtain more precise gravity measurement results in the future.

Fem Analysis of Micro-Stage with Duralumin Material

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1857-1862 ◽  
Author(s):  
Lee Ku Kwac ◽  
Chang Hyun Kim ◽  
Jae Yeol Kim
Keyword(s):  
Piezoelectric Transducer ◽  
Industrial Revolution ◽  
Laser Interferometer ◽  
Fem Analysis ◽  
Precision Measurements ◽  
Nano Technology ◽  
Measurement Results ◽  
The World ◽  
Ultra Precision ◽  
Micro Technology

In after the industrial revolution in the 21st century, the world is preparing for new revolution that is society with knowledge for a basis such as IT (Information Technology), NT (Nano Technology) and BT (Bio Technology). Recently, NT is applied to various fields that are composed of science, industry, media and semiconductor-micro technology. It has need of IT that is ultra-precision positioning technology with strokes of many hundreds mm and maintenance of nm precision in fields of ultra micro processes, ultra precision measurements, photo communication parts and photo magnetic memories. For optimal design of micro-stage, we measured the displacement of piezoelectric transducer that was based on voltage value. And the micro-stage was analyzed using FEM with displacement data including voltage value of piezoelectric transducer. For verification of analysis results, the displacements were measured by using Laser interferometer. And researchers confirmed to propriety on design of micro-stage with FEM, we obtained 3.5% error rate between measurement results and analyzing results.

Simulation of Vision-Based Royal Jelly Collecting Robot

2012 ◽  
Vol 233 ◽  
pp. 247-254
Author(s):  
Zhen Wang ◽  
Xiang Ming Dun ◽  
Xiang Yong Dun
Keyword(s):  
Inverse Kinematics ◽  
Royal Jelly ◽  
Industrial Robot ◽  
Three Dimensional ◽  
New Method ◽  
Forward Kinematics ◽  
Fourier Descriptors ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Monocular Camera

A new method to collect royal jelly is proposed according to the view of industrial robot. A three-dimensional model of royal jelly collecting robot with a monocular camera is built. Detecting the particular shapes via Fourier Descriptors and finding the corresponding target points though the image shot by the camera. The vision-based process and the 3-D simulation are performed alternately to simulate picking up queen bee larvae according to robotic forward kinematics and inverse kinematics.

Geometric Model Update of Blisks and its Experimental Validation for a Wide Frequency Range

2017 ◽  
Author(s):  
Thomas Maywald ◽  
Thomas Backhaus ◽  
Sven Schrape ◽  
Arnold Kühhorn
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Blue Light ◽  
Experimental Validation ◽  
Industrial Robot ◽  
Simulation Models ◽  
Element Model ◽  
Measurement Results ◽  
Model Update ◽  
Geometric Deviations

The contribution discusses a model update procedure and its experimental validation in the context of blisk mistuning. Object of investigation is an industrial test blisk of an axial compressor which is milled from solid using a state of the art 5-axis milling machine. First, the blisk geometry is digitized by a blue light fringe projector. Digitization is largely automated using an industrial robot cell in order to guarantee high repeatability of the measurement results. Additionally, frequency mistuning patterns are identified based on vibration measurements. Here, the system excitation is realized by a modal impact hammer. The blade response is detected using a laser scanning vibrometer. Furthermore, all blades except the currently excited one are detuned with additional masses. Applying these masses allows to identify a blade dominated natural frequency for each blade and every mode of interest. Finally, these blade dominated frequencies are summarized to mode specific mistuning patterns. The key part of the contribution presents a model update approach which is focused on small geometric deviations between real engine parts and idealized simulation models. Within this update procedure the nodal coordinates of an initially tuned finite element blisk model were modified in order to match the geometry of the real part measured by blue light fringe projection. All essential pre- and post-processing steps of the mesh morphing procedure are described and illustrated. It could be proven that locally remaining geometric deviations between updated finite element model and the optical measurement results are below 5 μm. For the purpose of validation blade dominated natural frequencies of the updated finite element blisk model are calculated for each sector up to a frequency of 17 kHz. Finally, the numerically predicted mistuning patterns are compared against the experimentally identified counterparts. At this point a very good agreement between experimentally identified and numerically predicted mistuning patterns can be proven across several mode families. Even mistuning patterns of higher modes at about 17 kHz are well predicted by the geometrically mistuned finite element model. Within the last section of the paper, possible uncertainties of the presented model update procedure are analyzed. As a part of the study the digitization of the investigated blisk has been repeated for ten times. These measurement results serve as input for the model update procedure described before. In the context of this investigation ten independent geometrical mistuned simulation models are created and the corresponding mistuning patterns are calculated.

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