scholarly journals Design of Hybrid Cells to Facilitate Safe and Efficient Human–Robot Collaboration During Assembly Operations

2018 ◽  
Vol 18 (3) ◽  
Author(s):  
Krishnanand N. Kaipa ◽  
Carlos W. Morato ◽  
Satyandra K. Gupta
Keyword(s):  
Three Dimensional ◽  
System State ◽  
Hybrid Cells ◽  
Generation System ◽  
State Monitoring ◽  
Plan Generation ◽  
3D Printed ◽  
Assembly Operations ◽  
Human Robot Collaboration

This paper presents a framework to build hybrid cells that support safe and efficient human–robot collaboration during assembly operations. Our approach allows asynchronous collaborations between human and robot. The human retrieves parts from a bin and places them in the robot's workspace, while the robot picks up the placed parts and assembles them into the product. We present the design details of the overall framework comprising three modules—plan generation, system state monitoring, and contingency handling. We describe system state monitoring and present a characterization of the part tracking algorithm. We report results from human–robot collaboration experiments using a KUKA robot and a three-dimensional (3D)-printed mockup of a simplified jet-engine assembly to illustrate our approach.

A Framework for Hybrid Cells That Support Safe and Efficient Human-Robot Collaboration in Assembly Operations

2014 ◽  
Author(s):  
Carlos W. Morato ◽  
Krishnanand N. Kaipa ◽  
Jiashun Liu ◽  
Satyandra K. Gupta
Keyword(s):  
Human Model ◽  
System State ◽  
Hybrid Cells ◽  
Generation System ◽  
State Monitoring ◽  
Virtual Cell ◽  
Plan Generation ◽  
Collaboration Model ◽  
Assembly Operations ◽  
Human Robot Collaboration

In this paper, we present a framework to build hybrid cells that support safe and efficient human-robot collaboration during assembly operations. Our approach considers a representative one-robot one-human model in which a human and a robot asynchronously work toward assembling a product. Whereas the human retrieves parts from a bin and brings them into the robot workspace, the robot picks up parts from its workspace and assembles them into the product. Using this collaboration model, we explicate the design details of the overall framework comprising three modules — plan generation, system state monitoring, and contingency handling. We provide details of the virtual cell and the physical cell used to implement our framework. Finally, we report results from human-robot collaboration experiments to illustrate our approach.

System State Monitoring to Facilitate Safe and Efficient Human-Robot Collaboration in Hybrid Assembly Cells

2017 ◽  
Author(s):  
Carlos W. Morato ◽  
Krishnanand N. Kaipa ◽  
Satyandra K. Gupta
Keyword(s):  
Hybrid Cell ◽  
System State ◽  
Hybrid Assembly ◽  
State Monitoring ◽  
Matching Algorithm ◽  
Plan Generation ◽  
3D Printed ◽  
Assembly Tasks ◽  
Human Robot Collaboration

Hybrid assembly cells allow humans and robots to collaborate on assembly tasks. We consider a model of the hybrid cell in which a human and a robot asynchronously collaborate to assemble a product. The human retrieves parts from a bin and places them in the robot’s workspace, while the robot picks up the placed parts and assembles them into the product. Realizing hybrid cells requires -automated plan generation, system state monitoring, and contingency handling. In this paper we describe system state monitoring and present a characterization of the part matching algorithm. Finally, we report results from human-robot collaboration experiments using a KUKA robot and a 3D-printed mockup of a simplified jet-engine assembly to illustrate our approach.

Additive technology applied to the realization of K-band microwave terminations: reproducibility improvement

2018 ◽  
Vol 10 (1) ◽  
pp. 3-8
Author(s):  
Azar Maalouf ◽  
Ronan Gingat ◽  
Vincent Laur
Keyword(s):  
3D Printing ◽  
Frequency Band ◽  
Rectangular Waveguide ◽  
Three Dimensional ◽  
Low Density ◽  
Support Material ◽  
Additive Technology ◽  
3D Printed ◽  
K Band

This study examines K-band rectangular waveguide terminations with three-dimensional (3D)-printed loads, and proposes an Asymmetrical Tapered Wedge topology. This geometry shows a good tradeoff between microwave performance and 3D-printing issues (printing directions and support material requirements), thus improving noticeably the reproducibility of the devices. The effect of the density of the 3D-printed load on the reflection parameter of the termination was investigated. Even for a low density, reflection level remained below −27.5 dB between 18 and 26.5 GHz. Reproducibility was demonstrated by the characterization of six loads that were 3D printed under the same conditions. Measurements demonstrate that a maximum reflection parameter level of −33.5 dB can be ensured over the whole frequency band without any post-machining of the 3D-printed devices.

scholarly journals Additive Manufacturing in Customized Medical Device

2021 ◽  
Author(s):  
Ching Hang Bob Yung ◽  
Lung Fung Tse ◽  
Wing Fung Edmond Yau ◽  
Sze Yi Mak
Keyword(s):  
Mechanical Properties ◽  
Additive Manufacturing ◽  
Medical Device ◽  
Three Dimensional ◽  
Medical Industry ◽  
New Era ◽  
Medical Needs ◽  
3D Printed ◽  
Traditional Manufacturing

The long-established application of rapid prototyping in additive manufacturing (AM) has inspired a revolution in the medical industry into a new era, in which the clinical-driven development of the customized medical device is enabled. This transformation could only be sustainable if clinical concerns could be well addressed. In this work, we propose a workflow that addresses critical clinical concerns such as translation from medical needs to product innovation, anatomical conformation and execution, and validation. This method has demonstrated outstanding advantages over the traditional manufacturing approach in terms of form, function, precision, and clinical flexibility. We further propose a protocol for the validation of biocompatibility, material, and mechanical properties. Finally, we lay out a roadmap for AM-driven customized medical device innovation based on our experiences in Hong Kong, addressing problems of certification, qualification, characterization of three dimensional (3D) printed implants according to medical demands.

scholarly journals 3D-printed jars for ball-milling experiments monitoredin situby X-ray powder diffraction

2017 ◽  
Vol 50 (4) ◽  
pp. 994-999 ◽  
Author(s):  
Nikolay Tumanov ◽  
Voraksmy Ban ◽  
Agnieszka Poulain ◽  
Yaroslav Filinchuk
Keyword(s):  
Powder Diffraction ◽  
Materials Science ◽  
Three Dimensional ◽  
High Energy ◽  
X Ray ◽  
3D Printed ◽  
Background Absorption ◽  
Design And Manufacture

Mechanochemistry is flourishing in materials science, but a characterization of the related processes is difficult to achieve. Recently, the use of plastic jars in shaker mills has enabledin situX-ray powder diffraction studies at high-energy beamlines. This paper describes an easy way to design and manufacture these jars by three-dimensional (3D) printing. A modified wall thickness and the use of a thin-walled sampling groove and a two-chamber design, where the milling and diffraction take place in two communicating volumes, allow for a reduced background/absorption and higher angular resolution, with the prospect for use at lower-energy beamlines. 3D-printed polylactic acid jars show good mechanical strength and they are also more resistant to solvents than jars made of polymethyl methacrylate. The source files for printing the jars are available as supporting information.

scholarly journals Mechanical and Dimensional Investigation of Additive Manufactured Multimaterial Parts

2021 ◽  
Vol 9 ◽  
Author(s):  
Markus Königshofer ◽  
Martin Stoiber ◽  
Ewald Unger ◽  
Christian Grasl ◽  
Francesco Moscato
Keyword(s):  
Three Dimensional ◽  
Dimensional Accuracy ◽  
Tensile Tests ◽  
Biological Tissues ◽  
Test Methods ◽  
Medical Models ◽  
3D Printed ◽  
Eden Prairie ◽  
Design And Manufacture

Additive manufacturing machines, based on the multimaterial jetting technology, are widely used for three-dimensional (3D) printing of sophisticated medical models, which are aimed to be used for preoperative planning and surgical training. Gaining knowledge of process-related influences on mechanical and dimensional properties of 3D-printed parts makes up an essential basis for the design and manufacture of medical models. There are few studies on characterization of multimaterial parts, and those are limited to tests that are not based on standardized methods. Within the scope of this work, mechanical and dimensional investigations were performed on multimaterial parts that were printed using an Objet500–Connex3 3D printer (Stratasys Ltd., Minnesota, Eden Prairie, MN, USA). Among test methods listed in DIN EN ISO 17296-3, tensile tests were chosen for mechanical characterization. In the tensile tests, combinations of four different materials (Tango+, VeroClear, VeroPureWhite, MED610) were tested in three build orientations (XY, YX, ZX). To investigate the orientation-dependent printing accuracy, the tensile specimens were further checked for their dimensional accuracy. Statistically significant variations in the mechanical properties were found between different orientation levels. In general, specimens printed in XY orientation show higher tensile strength than YX- and ZX-oriented specimens. The tensile moduli determined are in the range from 0.2 to 2,500 MPa and compare well with the tensile moduli found in soft biological tissues. Dimensional deviations were found highest for the length of ZX-oriented tensile specimens. For this orientation level, it could be observed that multimaterial specimens, which contain higher percentage of the soft material Tango+, are characterized by higher shrinkage. For tensile specimens printed from the pure photopolymer Tango+, a shrinkage of 4.6% in length was determined. In summary, it was found that with multimaterial jetting technology, the increased shrinkage and lower mechanical strength in the ZX direction must be considered in the design process.

Characterization of photosystem II with the atomic-force microscope

1992 ◽  
Vol 50 (2) ◽  
pp. 1146-1147
Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon
Keyword(s):  
Photosystem Ii ◽  
Atomic Force Microscope ◽  
Three Dimensional ◽  
Biologically Active ◽  
Atomic Force ◽  
Freeze Etching ◽  
Image Averaging ◽  
Oxygen Evolving ◽  
Averaging Techniques

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.

convergent-beam diffraction from surfaces

1987 ◽  
Vol 45 ◽  
pp. 30-33
Author(s):  
J. A. Eades ◽  
A. E. Smith ◽  
D. F. Lynch
Keyword(s):  
Reciprocal Lattice ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
Three Dimensions ◽  
Plane Figure ◽  
Transmission Electron ◽  
Convergent Beam ◽  
Beam Patterns ◽  
Beam Diffraction

It is quite simple (in the transmission electron microscope) to obtain convergent-beam patterns from the surface of a bulk crystal. The beam is focussed onto the surface at near grazing incidence (figure 1) and if the surface is flat the appropriate pattern is obtained in the diffraction plane (figure 2). Such patterns are potentially valuable for the characterization of surfaces just as normal convergent-beam patterns are valuable for the characterization of crystals.There are, however, several important ways in which reflection diffraction from surfaces differs from the more familiar electron diffraction in transmission.GeometryIn reflection diffraction, because of the surface, it is not possible to describe the specimen as periodic in three dimensions, nor is it possible to associate diffraction with a conventional three-dimensional reciprocal lattice.

Construction of plastic contact deformation maps on ceramics: a case study on aluminum nitride

1996 ◽  
Vol 54 ◽  
pp. 636-637
Author(s):  
D. L. Callahan
Keyword(s):  
Plastic Deformation ◽  
Aluminum Nitride ◽  
Mechanical Response ◽  
Three Dimensional ◽  
Bright Field Image ◽  
Perfectly Plastic ◽  
Contrast Analysis ◽  
Deformation Patterns

Modern polishing, precision machining and microindentation techniques allow the processing and mechanical characterization of ceramics at nanometric scales and within entirely plastic deformation regimes. The mechanical response of most ceramics to such highly constrained contact is not predictable from macroscopic properties and the microstructural deformation patterns have proven difficult to characterize by the application of any individual technique. In this study, TEM techniques of contrast analysis and CBED are combined with stereographic analysis to construct a three-dimensional microstructure deformation map of the surface of a perfectly plastic microindentation on macroscopically brittle aluminum nitride.The bright field image in Figure 1 shows a lg Vickers microindentation contained within a single AlN grain far from any boundaries. High densities of dislocations are evident, particularly near facet edges but are not individually resolvable. The prominent bend contours also indicate the severity of plastic deformation. Figure 2 is a selected area diffraction pattern covering the entire indentation area.

Characterization of a monolayer graphitic structure

1994 ◽  
Vol 52 ◽  
pp. 760-761
Author(s):  
X. Lin ◽  
X. K. Wang ◽  
V. P. Dravid ◽  
J. B. Ketterson ◽  
R. P. H. Chang
Keyword(s):  
Three Dimensional ◽  
Single Layer ◽  
Synthesis Process ◽  
Graphitic Structure ◽  
Positive Gaussian Curvature ◽  
Graphitic Sheet ◽  
Structural And Electronic Properties ◽  
New Material ◽  
Hexagonal Network

For small curvatures of a graphitic sheet, carbon atoms can maintain their preferred sp2 bonding while allowing the sheet to have various three-dimensional geometries, which may have exotic structural and electronic properties. In addition the fivefold rings will lead to a positive Gaussian curvature in the hexagonal network, and the sevenfold rings cause a negative one. By combining these sevenfold and fivefold rings with sixfold rings, it is possible to construct complicated carbon sp2 networks. Because it is much easier to introduce pentagons and heptagons into the single-layer hexagonal network than into the multilayer network, the complicated morphologies would be more common in the single-layer graphite structures. In this contribution, we report the observation and characterization of a new material of monolayer graphitic structure by electron diffraction, HREM, EELS.The synthesis process used in this study is reported early. We utilized a composite anode of graphite and copper for arc evaporation in helium.

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