A Multi-Camera Rig with Non-Overlapping Views for Dynamic Six-Degree-of-Freedom Measurement

Large-scale measurement plays an increasingly important role in intelligent manufacturing. However, existing instruments have problems with immersive experiences. In this paper, an immersive positioning and measuring method based on augmented reality is introduced. An inside-out vision measurement approach using a multi-camera rig with non-overlapping views is presented for dynamic six-degree-of-freedom measurement. By using active LED markers, a flexible and robust solution is delivered to deal with complex manufacturing sites. The space resection adjustment principle is addressed and measurement errors are simulated. The improved Nearest Neighbor method is employed for feature correspondence. The proposed tracking method is verified by experiments and results with good performance are obtained.

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Multi-View-Based Pose Estimation and Its Applications on Intelligent Manufacturing

Sensors ◽

10.3390/s20185072 ◽

2020 ◽

Vol 20 (18) ◽

pp. 5072

Author(s):

Haiwei Yang ◽

Peilin Jiang ◽

Fei Wang

Keyword(s):

Pose Estimation ◽

Large Scale ◽

Estimation Method ◽

Intelligent Manufacturing ◽

Degree Of Freedom ◽

Guidance System ◽

Visual Guidance ◽

Practical Applications ◽

Large Size ◽

Six Degree Of Freedom

Pose estimation is a typical problem in the field of image processing, the purpose of which is to compare or fuse images acquired under different conditions. In recent years, many studies have focused on pose estimation algorithms, but so far there are still many challenges, such as efficiency, complexity and accuracy for various targets and conditions, in the field of algorithm research and practical applications. In this paper, a multi-view-based pose estimation method is proposed. This method can solve the pose estimation problem effectively for large-scale targets and achieve good performance accuracy and stability. Compared with existing methods, this method uses different views (positions and angles), each of which only observes some features of large-size parts, to estimate the six-degree-of-freedom pose of the entire large-size parts. Experimental results demonstrate that the accurate six-degree-of-freedom pose for different targets can be obtained by the proposed method which plays an important role in many actual production lines. What is more, a new visual guidance system, applied into intelligent manufacturing, is presented based on this method. The new visual guidance system has been widely used in automobile manufacturing with high accuracy and efficiency but low cost.

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Development of a Measuring System for the Measurement of Motions Errors of a Linear Stage

Manufacturing Engineering and Materials Handling Engineering ◽

10.1115/imece2004-61029 ◽

2004 ◽

Author(s):

Wen-Yuh Jywe ◽

Chien-Hung Liu ◽

Sheng-Chung Tzeng ◽

Po Chou ◽

Chu-Wei Lin

Keyword(s):

Measuring Method ◽

Degree Of Freedom ◽

Angular Error ◽

Measuring System ◽

Linear Stage ◽

Process Verification ◽

Error Components ◽

Dual Beam ◽

Six Degree Of Freedom ◽

Straightness Error

A high precision six-degree-of-freedom measuring system is developed in this paper for the motion measurement of a linear stage. It integrates a miniature dual-beam fiber coupled laser interferometer with the multiple optical paths and quadrant detectors to be capable of measuring six-degree-of-freedom motion errors. The proposed measuring method provides rapid performance, simplicity of setup, and pre-process verification of a linear positioning stage. The experimental setup and algorithm for the error verification are presented in the paper. The measuring range of the proposed measuring system is ±40μm for straightness and 40 arc sec for pitch, roll and yaw. Within the range of ±40μm and 40 arc sec, it has been found that the system’s resolution and accuracy of measuring straightness error components are about 0.04 μm and ±0.06 μm, respectively. The resolution and accuracy of measuring pitch and yaw angular error components are about 0.06 arc sec and ±0.8 arc sec, respectively. The resolution and accuracy of measuring roll angular error are about 0.05 arc sec and ±0.07 arc sec, respectively.

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Research on the Dynamic Characteristic of the Bogie in Dynamic Track Stabilizer under the Excitation of the Track Irregularities

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.178-181.1438 ◽

2012 ◽

Vol 178-181 ◽

pp. 1438-1441

Author(s):

Li Hua Wang ◽

Guang Wei Liu ◽

An Ning Huang ◽

Ya Yu Huang

Keyword(s):

Spectral Density ◽

Dynamic Characteristic ◽

Time Domain ◽

Large Scale ◽

Degree Of Freedom ◽

Speed Up ◽

Critical Components ◽

The Time Domain ◽

Six Degree Of Freedom ◽

Track Irregularities

With the large-scale speed-up of the railway, the dynamic track stabilizer will play an important role on the track overhauling and railroading of new line in our country. Bogie is one of the major critical components of the dynamic track stabilizer; its vibrating characteristic will affect the vibrating characteristic of the dynamic track stabilizer directly. The method of numerical simulate was used, based on the spectral density of the track irregularities, the time domain loads of the track irregularities were gained. Then the vibrating characteristics of the dynamic track stabilizer bogie under the excitation of the track irregularities were analyzed on the bases of the ANSYS/LS-DYNA. And the lateral, dilation, ups and downs, nod, swing and anti-rolling vibrating characteristics of the bogie on the six degree of freedom were obtained. The analysis results of this paper will provide foundation for the research on the stationarity and security of the dynamic track stabilizer.

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Integrate Point-Cloud Segmentation with 3D LiDAR Scan-Matching for Mobile Robot Localization and Mapping

Sensors ◽

10.3390/s20010237 ◽

2019 ◽

Vol 20 (1) ◽

pp. 237 ◽

Cited By ~ 7

Author(s):

Xuyou Li ◽

Shitong Du ◽

Guangchun Li ◽

Haoyu Li

Keyword(s):

Pose Estimation ◽

Point Cloud ◽

Large Scale ◽

Degree Of Freedom ◽

Mobile Systems ◽

Estimation Accuracy ◽

Scan Matching ◽

Icp Algorithm ◽

Localization And Mapping ◽

Six Degree Of Freedom

Localization and mapping are key requirements for autonomous mobile systems to perform navigation and interaction tasks. Iterative Closest Point (ICP) is widely applied for LiDAR scan-matching in the robotic community. In addition, the standard ICP algorithm only considers geometric information when iteratively searching for the nearest point. However, ICP individually cannot achieve accurate point-cloud registration performance in challenging environments such as dynamic environments and highways. Moreover, the computation of searching for the closest points is an expensive step in the ICP algorithm, which is limited to meet real-time requirements, especially when dealing with large-scale point-cloud data. In this paper, we propose a segment-based scan-matching framework for six degree-of-freedom pose estimation and mapping. The LiDAR generates a large number of ground points when scanning, but many of these points are useless and increase the burden of subsequent processing. To address this problem, we first apply an image-based ground-point extraction method to filter out noise and ground points. The point cloud after removing the ground points is then segmented into disjoint sets. After this step, a standard point-to-point ICP is applied into to calculate the six degree-of-freedom transformation between consecutive scans. Furthermore, once closed loops are detected in the environment, a 6D graph-optimization algorithm for global relaxation (6D simultaneous localization and mapping (SLAM)) is employed. Experiments based on publicly available KITTI datasets show that our method requires less runtime while at the same time achieves higher pose estimation accuracy compared with the standard ICP method and its variants.

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The system design of external cladding installation robot

International Journal of Advanced Robotic Systems ◽

10.1177/1729881420969062 ◽

2020 ◽

Vol 17 (6) ◽

pp. 172988142096906

Author(s):

Dong Yang ◽

Yongbin Li ◽

Tiejun Li ◽

Tian Zhang ◽

Ming Han ◽

...

Keyword(s):

Theoretical Basis ◽

Large Scale ◽

Degree Of Freedom ◽

Test Results ◽

Robot System ◽

Automatic Installation ◽

Advantages And Disadvantages ◽

Parallel Hybrid ◽

Six Degree Of Freedom ◽

Study Designs

In the installation process of large-scale external cladding, the labor intensity is high, and it is dangerous and hard to guarantee good construction quality. In view of these issues, this study designs a construction robot for external cladding installation, as a better solution. First, the advantages and disadvantages of the current building external cladding hanging process are discussed. The components, suitable for automatic installation, are selected to develop an automatic installation process for the building external cladding. According to the process steps and installation action flow, the installation robot is first adjusted. After the design of a step-by-step workflow of positioning and installation, a robot with a six-degree-of-freedom string-mixing mechanism is designed. Finally, a prototype of the proposed external cladding installation robot is developed, and the system is experimentally verified under simulation conditions and real operation. The test results show that the external cladding installation robot system has a strong theoretical basis. The series-parallel hybrid six-degree-of-freedom structure is reasonable, design wise. It helps to complete the automatic installation of the building external cladding and improve the automation level of large-scale plate installations.

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Design and kinematics analysis of a novel six-degree-of-freedom serial humanoid torso

International Journal of Advanced Robotic Systems ◽

10.1177/1729881417748126 ◽

2018 ◽

Vol 15 (1) ◽

pp. 172988141774812 ◽

Cited By ~ 1

Author(s):

Tao Li ◽

Peng Yao ◽

Minzhou Luo ◽

Zhiying Tan ◽

Meiling Wang ◽

...

Keyword(s):

Inverse Kinematics ◽

High Speed ◽

Degrees Of Freedom ◽

Large Scale ◽

Humanoid Robots ◽

Degree Of Freedom ◽

Chaos Optimization ◽

Workspace Analysis ◽

Forward Kinematic ◽

Six Degree Of Freedom

This article presents a bioinspired humanoid torso which is supposed to be used as the trunk for humanoid robots. It can effectively mimic motions of human torso with high degrees of freedom, and it has high stiffness and easy-to-control features. The main structure of the proposed torso is a six-degree-of-freedom serial mechanism with twist angles that are not equal to 0, π/2 or π and zero-length links. Forward kinematic and workspace analysis based on Denavit–Hartenberg and Monte Carlo methods have been formulated to analyze the feasibility of this structure. In addition, a hybrid method combing the large-scale regularity search capabilities of chaos optimization and the quasi-Newton method with relatively high-speed convergence has been proposed to analyze inverse kinematics. Simulations are carried out with the aim to validate the correctness and efficiency of this method for studying the inverse kinematics.

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