C2-continuous orientation trajectory planning for robot based on spline quaternion curve

2018 ◽  
Vol 38 (3) ◽  
pp. 282-290 ◽  
Author(s):  
Xuejuan Niu ◽  
Tian Wang
Keyword(s):  
Spherical Surface ◽  
Industrial Applications ◽  
Practical Case ◽  
Unit Quaternion ◽  
Content Type ◽  
Mapping Algorithm ◽  
C2 Continuity ◽  
Quaternion Interpolation ◽  
Teaching Orientations ◽  
Continuous Orientation

Purpose To realize the smooth interpolation of orientation on robot end-effector, this paper aims to propose a novel algorithm based on the unit quaternion spline curve. Design/methodology/approach This algorithm combines the spherical linear quaternion interpolation and the cubic B-spline quaternion curve. With this method, a C2-continuous smooth trajectory of multiple teaching orientations is obtained. To achieve the visualization of quaternion curves on a unit sphere, a mapping algorithm between a unit quaternion and a point on the spherical surface is given based on the physical meaning of the unit quaternion. Findings Finally, the curvature analysis of a practical case shows that the orientation trajectory (OT) constructed by this algorithm satisfied the C2-continuity. Originality/value This OT satisfies the requirement of smooth interpolation among multiple orientations on robots in industrial applications.

A biomimetic 3D airflow sensor made of an array of two piezoelectric metal-core fibers

Sensor Review ◽  
2017 ◽  
Vol 37 (3) ◽  
pp. 312-321 ◽  
Author(s):  
Yixiang Bian ◽  
Can He ◽  
Kaixuan Sun ◽  
Longchao Dai ◽  
Hui Shen ◽  
...  
Keyword(s):  
Design Methodology ◽  
Spherical Surface ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Piezoceramic Cylinder ◽  
Metal Core ◽  
Content Type ◽  
3D Space ◽  
Highly Sensitive ◽  
Airflow Sensor

Purpose The purpose of this paper is to design and fabricate a three-dimensional (3D) bionic airflow sensing array made of two multi-electrode piezoelectric metal-core fibers (MPMFs), inspired by the structure of a cricket’s highly sensitive airflow receptor (consisting of two cerci). Design/methodology/approach A metal core was positioned at the center of an MPMF and surrounded by a hollow piezoceramic cylinder. Four thin metal films were spray-coated symmetrically on the surface of the fiber that could be used as two pairs of sensor electrodes. Findings In 3D space, four output signals of the two MPMFs arrays can form three “8”-shaped spheres. Similarly, the sensing signals for the same airflow are located on a spherical surface. Originality/value Two MPMF arrays are sufficient to detect the speed and direction of airflow in all three dimensions.

scholarly journals A study of ethnic perception gap on consumer boycott of Korean and Canadian University students

2016 ◽  
Vol 10 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Mie Kyung Jae ◽  
Hyang Ran Jeon
Keyword(s):  
University Students ◽  
Cross Cultural ◽  
Parent Company ◽  
Practical Case ◽  
Corporate Accountability ◽  
Cultural Backgrounds ◽  
Korean Students ◽  
Content Type ◽  
Cross Cultural Comparison ◽  
Influential Variable

Purpose In this paper, the authors aim to offer a cross-cultural comparison of the boycott intentions of university students in Canada with those of students in Korea. Design/methodology/approach The data were collected from students at Inje University and York University via self-administered questionnaire. A t-test found that Canadian students’ answers showed significantly greater scores in ethnocentrism, boycott attitudes prior to reading the target article and motivations related to self-enhancement compared to those acquired from Korean students. However, the motivation of counterarguments and the boycott intentions of Korean students’ toward Rogers, the parent company of Maclean’s magazine, showed significantly higher scores than those gained from Canadian students. Findings The boycott case used in the study is Maclean’s magazine, a Canadian news magazine, which published a controversial article called, “Too Asian? Some frosh don’t want to study at an “Asian” University”. A noticeable gap in each group of students’ boycott attitude and intentions toward Rogers, the parent company of Maclean’s magazine was found. Originality/value In the multiple regression analysis, the boycott motivation of self-enhancement was the most influential variable on boycott intentions. The boycott case examined in this paper is a practical case study of cross-national grouping as well as the perceptional difference of the locus of corporate accountability that comes from cross-cultural backgrounds.

Wearable sensors bring new benefits to continuous medical monitoring, real time physical activity assessment, baby monitoring and industrial applications

Sensor Review ◽  
2015 ◽  
Vol 35 (2) ◽  
pp. 141-145 ◽  
Author(s):  
Richard Bloss
Keyword(s):  
Real Time ◽  
Continuous Monitoring ◽  
Medical Condition ◽  
Wearable Sensors ◽  
Medical Personnel ◽  
Industrial Applications ◽  
Medical Monitoring ◽  
Content Type ◽  
Doctor's Office ◽  
Monitoring Technologies

Purpose – The purpose of this paper is to review the recent advancements in the development of wearable sensors which can continuously monitor critical medical, assess athletic activity, watch babies and serve industrial applications. Design/methodology/approach – The paper presents an in-depth review of a number of developments in wearable sensing and monitoring technologies for medical, athletic and industrial applications. Researchers and companies around the world were contacted to discuss their direction and progress in this field of medical condition and industrial monitoring, as well as discussions with medical personnel on the perceived benefits of such technology. Findings – Dramatic progress is being made in continuous monitoring of many important body functions that indicate critical medical conditions that can be life-threatening, contribute to blindness or access activity. In the industrial arena, wearable devices bring remote monitoring to a new level. Practical implications – Doctors will be able to replace one-off tests with continuous monitoring that provides a much better continuous real-time “view” into the patient’s conditions. Wearable monitors will help provide much better medical care in the future. Industrial managers and others will be able to monitor and supervise remotely. Originality/value – An expert insight into advancements in medical condition monitoring that replaces the one-time “finger prick” type testing only performed in the doctor’s office. It is also a look at how wearable monitoring is greatly improved and serving athletics, the industry and parents.

scholarly journals Value-driven engineering of E-maintenance platforms

2014 ◽  
Vol 25 (4) ◽  
pp. 568-598 ◽  
Author(s):  
Marco Macchi ◽  
Adolfo Crespo Márquez ◽  
Maria Holgado ◽  
Luca Fumagalli ◽  
Luis Barberá Martínez
Keyword(s):  
Information And Communication Technologies ◽  
Cost Benefit ◽  
Communication Technologies ◽  
Industrial Applications ◽  
Maintenance Management ◽  
Content Type ◽  
Positive Effects ◽  
A Value ◽  
New Information ◽  
Information And Communication

Purpose – The purpose of this paper is to propose a methodology for the engineering of E-maintenance platforms that is based on a value-driven approach. Design/methodology/approach – The methodology assumes that a value-driven engineering approach would help foster technological innovation for maintenance management. Indeed, value-driven engineering could be easily adopted at the business level, with subsequent positive effects on the industrial applications of new information and communication technologies solutions. Findings – The methodology combines a value-driven approach with the engineering in the maintenance scope. The methodology is tested in a manufacturing case to prove its potential to support the engineering of E-maintenance solutions. In particular, the case study concerns the investment in E-maintenance solutions developed in the framework of a Supervisory Control and Data Acquisition system originally implemented for production purposes. Originality/value – Based on literature research, the paper presents a methodology that is implemented considering three different approaches (business theories, value-driven engineering and maintenance management). The combination of these approaches is novel and overcomes the traditional view of maintenance as an issue evaluated from a cost-benefit perspective.

The role of robotics in additive manufacturing: review of the AM processes and introduction of an intelligent system

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
J. Norberto Pires ◽  
Amin S. Azar ◽  
Filipe Nogueira ◽  
Carlos Ye Zhu ◽  
Ricardo Branco ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
Computer Aided Design ◽  
Intelligent System ◽  
Material Selection ◽  
High Strength Steels ◽  
Industrial Applications ◽  
Layer By Layer ◽  
Content Type ◽  
Functional Components

Purpose Additive manufacturing (AM) is a rapidly evolving manufacturing process, which refers to a set of technologies that add materials layer-by-layer to create functional components. AM technologies have received an enormous attention from both academia and industry, and they are being successfully used in various applications, such as rapid prototyping, tooling, direct manufacturing and repair, among others. AM does not necessarily imply building parts, as it also refers to innovation in materials, system and part designs, novel combination of properties and interplay between systems and materials. The most exciting features of AM are related to the development of radically new systems and materials that can be used in advanced products with the aim of reducing costs, manufacturing difficulties, weight, waste and energy consumption. It is essential to develop an advanced production system that assists the user through the process, from the computer-aided design model to functional components. The challenges faced in the research and development and operational phase of producing those parts include requiring the capacity to simulate and observe the building process and, more importantly, being able to introduce the production changes in a real-time fashion. This paper aims to review the role of robotics in various AM technologies to underline its importance, followed by an introduction of a novel and intelligent system for directed energy deposition (DED) technology. Design/methodology/approach AM presents intrinsic advantages when compared to the conventional processes. Nevertheless, its industrial integration remains as a challenge due to equipment and process complexities. DED technologies are among the most sophisticated concepts that have the potential of transforming the current material processing practices. Findings The objective of this paper is identifying the fundamental features of an intelligent DED platform, capable of handling the science and operational aspects of the advanced AM applications. Consequently, we introduce and discuss a novel robotic AM system, designed for processing metals and alloys such as aluminium alloys, high-strength steels, stainless steels, titanium alloys, magnesium alloys, nickel-based superalloys and other metallic alloys for various applications. A few demonstrators are presented and briefly discussed, to present the usefulness of the introduced system and underlying concept. The main design objective of the presented intelligent robotic AM system is to implement a design-and-produce strategy. This means that the system should allow the user to focus on the knowledge-based tasks, e.g. the tasks of designing the part, material selection, simulating the deposition process and anticipating the metallurgical properties of the final part, as the rest would be handled automatically. Research limitations/implications This paper reviews a few AM technologies, where robotics is a central part of the process, such as vat photopolymerization, material jetting, binder jetting, material extrusion, powder bed fusion, DED and sheet lamination. This paper aims to influence the development of robot-based AM systems for industrial applications such as part production, automotive, medical, aerospace and defence sectors. Originality/value The presented intelligent system is an original development that is designed and built by the co-authors J. Norberto Pires, Amin S. Azar and Trayana Tankova.

Fast and accurate detection of surface defect based on improved YOLOv4

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jiawei Lian ◽  
Junhong He ◽  
Yun Niu ◽  
Tianze Wang
Keyword(s):  
Feature Extraction ◽  
Real Time ◽  
Surface Defect ◽  
Steel Ingot ◽  
Industrial Applications ◽  
Data Sets ◽  
Data Set ◽  
Processing Technologies ◽  
Content Type ◽  
Public Data

Purpose The current popular image processing technologies based on convolutional neural network have the characteristics of large computation, high storage cost and low accuracy for tiny defect detection, which is contrary to the high real-time and accuracy, limited computing resources and storage required by industrial applications. Therefore, an improved YOLOv4 named as YOLOv4-Defect is proposed aim to solve the above problems. Design/methodology/approach On the one hand, this study performs multi-dimensional compression processing on the feature extraction network of YOLOv4 to simplify the model and improve the feature extraction ability of the model through knowledge distillation. On the other hand, a prediction scale with more detailed receptive field is added to optimize the model structure, which can improve the detection performance for tiny defects. Findings The effectiveness of the method is verified by public data sets NEU-CLS and DAGM 2007, and the steel ingot data set collected in the actual industrial field. The experimental results demonstrated that the proposed YOLOv4-Defect method can greatly improve the recognition efficiency and accuracy and reduce the size and computation consumption of the model. Originality/value This paper proposed an improved YOLOv4 named as YOLOv4-Defect for the detection of surface defect, which is conducive to application in various industrial scenarios with limited storage and computing resources, and meets the requirements of high real-time and precision.

A study on tribological behaviour and analysis of ZnO reinforced AA6061 matrix composites fabricated by stir casting route

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sakthi Sadhasivam RM ◽  
Ramanathan K. ◽  
Bhuvaneswari B.V. ◽  
Raja R.
Keyword(s):  
Wear Rate ◽  
Sliding Wear ◽  
Stir Casting ◽  
Industrial Applications ◽  
Wear Behaviour ◽  
Matrix Composites ◽  
Tribological Behaviour ◽  
Content Type ◽  
Zno Particles ◽  
The Matrix

Purpose The most promising replacements for the industrial applications are particle reinforced metal matrix composites because of their good and combined mechanical properties. Currently, the need of matrix materials for industrial applications is widely satisfied by aluminium alloys. The purpose of this paper is to evaluate the tribological behaviour of the zinc oxide (ZnO) particles reinforced AA6061 composites prepared by stir casting route. Design/methodology/approach In this study, AA6061 aluminium alloy matrix reinforced with varying weight percentages (3%, 4.5% and 6%) of ZnO particles, including monolithic AA6061 alloy samples, is cast by the most economical fabrication method, called stir casting. The prepared sample was subjected to X-ray photoelectron spectroscopy (XPS) analysis, experimental density measurement by Archimedian principle and theoretical density by rule of mixture and hardness test to investigate mechanical property. The dry sliding wear behaviour of the composites was investigated using pin-on-disc tribometer with various applied loads of 15 and 20 N, with constant sliding velocity and distance. The wear rate, coefficient of friction (COF) and worn surfaces of the composite specimens and their effects were also investigated in this work. Findings XPS results confirm the homogeneous distribution of ZnO microparticles in the Al matrix. The Vickers hardness result reveals that higher ZnO reinforced (6%) sample have 34.4% higher values of HV than the monolithic aluminium sample. The sliding wear tests similarly show that increasing the weight percentage of ZnO particles leads to a reduced wear rate and COF of 30.01% and 26.32% lower than unreinforced alloy for 15 N and 36.35% and 25% for 20 N applied load. From the worn surface morphological studies, it was evidently noticed that ZnO particles dispersed throughout the matrix and it had strong bonding between the reinforcement and the matrix, which significantly reduced the plastic deformation of the surfaces. Originality/value The uniqueness of this work is to use the reinforcement of ZnO particles with AA6061 matrix and preparing by stir casting route and to study and analyse the physical, hardness and tribological behaviour of the composite materials.

A 12-pulse rectifier with passive harmonic reduction based on UIPT in more electric aircrafts

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rohollah Abdollahi
Keyword(s):  
Power Factor ◽  
Harmonic Distortion ◽  
Cost Savings ◽  
Cost Effective ◽  
Industrial Applications ◽  
Input Current ◽  
New Combination ◽  
Content Type ◽  
Harmonic Reduction ◽  
Simulation Results

Purpose The purpose of this paper is to provide a T autotransformer based 12-pulse rectifier with passive harmonic reduction in more electric aircraft applications. The T autotransformer uses only two main windings which result in volume, space, size, weight and cost savings. Also, the proposed unconventional inter-phase transformer (UIPT) with a lower kVA rating (about 2.6% of the load power) compared to the conventional inter-phase transformer results in a more harmonic reduction. Design/methodology/approach To increase rating and reduce the cost and complexity of a multi-pulse rectifier, it is well known that the pulse number must be increased. In some practical cases, a 12-pulse rectifier (12PR) is suggested as a good solution considering its simple structure and low weight. But the 12PR cannot technically meet the standards of harmonic distortion requirements for some industrial applications, and therefore, they must be used with output filters. In this paper, a 12PR is suggested, which consists of a T autotransformer 12PR and a passive harmonic reduction (PHR) based on the UIPT at direct current (DC) link. Findings To show the advantage of this new combination over other solutions, simulation results are used, and then, a prototype is implemented to evaluate and verify the simulation results. The simulation and experimental test results show that the input current total harmonic distortion (THD) of the suggested 12PR with a PHR based on UIPT is less than 5%, which meets the IEEE 519 requirements. Also, it is shown that in comparison with other solutions, it is cost effective, and at the same time, its power factor is near unity, and its rating is 29.92% of the load rating. Therefore, it is obvious that the proposed rectifier is a practical solution for more electric aircrafts. Originality/value The contributions of this paper are summarized as follows. The suggested design uses a retrofit T autotransformer, which meets all technical constraints, and in comparison, with other options, has less rating, weight, volume and cost. In the suggested rectifier, a PHR based on UIPT at its dc link of 12PR is used, which has good technical capabilities and lower ratings. In the PHR based on UIPT, an IPT is used, which has an additional secondary winding and four diodes. This solution leads to a reduction in input current THD and conduction losses of diodes. In full load conditions, the input line current THD and power factor are 4% and 0.99, respectively. The THD is less than 5%, which satisfies IEEE-519 and DO-160G requirements.

Experimental study of pin surface precision on lubrication behavior of pin–bush pairs in industrial roller chains

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ansheng Zhang ◽  
Mingyu Zhang ◽  
Jing Wang ◽  
Jianjun Zhang ◽  
Zhaohua Shang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Design Methodology ◽  
Industrial Applications ◽  
Experimental Basis ◽  
Reciprocating Motion ◽  
Content Type ◽  
Oil Supply ◽  
Machining Errors ◽  
Surface Precision ◽  
Straightness Error

Purpose The purpose of this paper is to study the influence of surface precision on the lubrication state of the roller chain under adequate and rare oil supply conditions, respectively. Design/methodology/approach The straightness error and roughness error of the pin generatrices were measured and the influence of surface precision on the lubrication behavior under steady state and reciprocating motion was studied through optical interference experiments. Findings The lubrication state is strongly influenced by the surface precision of the roller surface both under adequate oil supply and rare oil supply conditions. Originality/value In industrial applications, the machining errors of parts cannot be completely eliminated. Studying the influence of the surface precision on the lubrication behavior of pin–bush pairs can provide the experimental basis for the optimal design of the bush roller chains.

scholarly journals Insights into the Maturation of Pernisine, a Subtilisin-Like Protease from the Hyperthermophilic Archaeon Aeropyrum pernix

2020 ◽  
Vol 86 (17) ◽  
Author(s):  
Miha Bahun ◽  
Marko Šnajder ◽  
Dušan Turk ◽  
Nataša Poklar Ulrih
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Catalytic Domain ◽  
Industrial Applications ◽  
Binding Motif ◽  
Content Type ◽  
Hyperthermophilic Archaeon ◽  
Aeropyrum Pernix ◽  
Autocatalytic Process ◽  
Exceptional Stability

ABSTRACT Pernisine is a subtilisin-like protease that was originally identified in the hyperthermophilic archaeon Aeropyrum pernix, which lives in extreme marine environments. Pernisine shows exceptional stability and activity due to the high-temperature conditions experienced by A. pernix. Pernisine is of interest for industrial purposes, as it is one of the few proteases that has demonstrated prion-degrading activity. Like other extracellular subtilisins, pernisine is synthesized in its inactive pro-form (pro-pernisine), which needs to undergo maturation to become proteolytically active. The maturation processes of mesophilic subtilisins have been investigated in detail; however, less is known about the maturation of their thermophilic homologs, such as pernisine. Here, we show that the structure of pro-pernisine is disordered in the absence of Ca2+ ions. In contrast to the mesophilic subtilisins, pro-pernisine requires Ca2+ ions to adopt the conformation suitable for its subsequent maturation. In addition to several Ca2+-binding sites that have been conserved from the thermostable Tk-subtilisin, pernisine has an additional insertion sequence with a Ca2+-binding motif. We demonstrate the importance of this insertion for efficient folding and stabilization of pernisine during its maturation. Moreover, analysis of the pernisine propeptide explains the high-temperature requirement for pro-pernisine maturation. Of note, the propeptide inhibits the pernisine catalytic domain more potently at high temperatures. After dissociation, the propeptide is destabilized at high temperatures only, which leads to its degradation and finally to pernisine activation. Our data provide new insights into and understanding of the thermostable subtilisin autoactivation mechanism. IMPORTANCE Enzymes from thermophilic organisms are of particular importance for use in industrial applications, due to their exceptional stability and activity. Pernisine, from the hyperthermophilic archaeon Aeropyrum pernix, is a proteolytic enzyme that can degrade infective prion proteins and thus has a potential use for disinfection of prion-contaminated surfaces. Like other subtilisin-like proteases, pernisine needs to mature through an autocatalytic process to become an active protease. In the present study, we address the maturation of pernisine and show that the process is regulated specifically at high temperatures by the propeptide. Furthermore, we demonstrate the importance of a unique Ca2+-binding insertion for stabilization of mature pernisine. Our results provide a novel understanding of thermostable subtilisin autoactivation, which might advance the development of these enzymes for commercial use.

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