scholarly journals The Influence of Environmental Conditions on Automated Fabric Handling

1998 ◽  
Vol 10 (3) ◽  
pp. 258-263 ◽  
Author(s):  
Paul M. Taylor ◽  
◽  
Didier M. Pollet ◽  
Paul J. W. Abbott ◽  
Keyword(s):  
Environmental Conditions ◽  
Material Properties ◽  
Intelligent Systems ◽  
Bending Stiffness ◽  
Experimental Results ◽  
Friction Coefficients ◽  
Pick And Place ◽  
Place Task ◽  
The Cost ◽  
Fabric Handling

The automation of garment assembly has proved to be very difficult to achieve with the cost, flexibility and reliability required by the manufacturers. The importance of two fabric properties, friction and bending stiffness, is emphasised, with a focus on a pick and place task. It is also shown that changes in humidity can cause significant changes in the unloaded friction coefficients and the bending stiffnesses of fabrics and thus affect the task operation. Both theoretical and experimental results are given. This leads to three possible approaches: close regulation of the materials and processes, handling processes tolerant to changes in the material properties, and thirdly, intelligent systems which can learn from and adapt to each situation.

scholarly journals Mechanical Properties of Glued-Laminated Timber with Different Assembly Patterns

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Shan Gao ◽  
Man Xu ◽  
Nan Guo ◽  
Ying Zhang
Keyword(s):  
Mechanical Properties ◽  
Bending Stiffness ◽  
Experimental Results ◽  
Bending Test ◽  
Material Strength ◽  
Lower Grade ◽  
Stiffness Reduction ◽  
Glued Laminated Timber ◽  
Bending Behavior ◽  
The Cost

A glued-laminated timber section with mixed-grade laminae could make an efficient use of material strength and reduce the cost. A 4-point bending test was conducted on a total of 18 specimens to investigate the mechanical properties of glued-laminated timber. Uniform-grade, asymmetrical mixed-grade, and symmetrical mixed-grade patterns were used to assemble the beam sections. The bending stiffness and reliability of the beams were assessed according to the experimental results. The influence of the assembly pattern on the bending behavior of glued-laminated timber was investigated by finite element models. The results show that the assembly pattern of the section has little influence on the failure mode of glued-laminated timber. Relative lower strength in compressive area of the section is beneficial for delaying the occurrence of the first crack on the glued-laminated timber beam. An equation for apparent bending stiffness of glued-laminated timber was proposed, whose results match well with the experimental results. The beam section assembled by the asymmetrical mixed-grade pattern retains the higher level of safety compared to those assembled by uniform-grade and symmetrical mixed-grade patterns. The grade of the second bottom lamina in tensile has little influence on the performance of glued-laminated timber, while lower grade laminae in compressive area of the section would cause a bending stiffness reduction at smaller deflection.

Determination of Charge Coefficient of Piezoelectric Films Using a Combined Finite Element Model and Dynamic Loading Technique

2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Material Properties ◽  
Accurate Determination ◽  
Substrate Material ◽  
Experimental Results ◽  
Piezoelectric Composite ◽  
Piezoelectric Film ◽  
Piezoelectric Charge

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.

Analysis of Overweight Truck Permit Policy in New Jersey

2021 ◽  
pp. 036119812110266
Author(s):  
Sami Demiroluk ◽  
Hani Nassif ◽  
Kaan Ozbay ◽  
Chaekuk Na
Keyword(s):  
New Jersey ◽  
Environmental Conditions ◽  
Decision Makers ◽  
Actual Cost ◽  
Department Of Transportation ◽  
Heavy Weight ◽  
Vehicle Route ◽  
Heavy Trucks ◽  
Maintenance And Rehabilitation ◽  
The Cost

The roadway infrastructure constantly deteriorates because of environmental conditions, but other factors such as exposure to heavy trucks exacerbates the rate of deterioration. Therefore, decision-makers are constantly searching for ways to optimize allocation of the limited funds for repair, maintenance, and rehabilitation of New Jersey’s infrastructure. New Jersey legislation requires operators of overweight (OW) trucks to obtain a permit to use the infrastructure. The New Jersey Department of Transportation (NJDOT) issues a variety of permits based on the types of goods carried. These permits allow OW trucks to use the infrastructure either for a single trip or for multiple trips. Therefore, one major concern is whether the permit revenue of the agency can recoup the actual cost of damage to the infrastructure caused by these OW trucks. This study investigates whether NJDOT’s current permit fee program can collect enough revenue to meet the actual cost of damage to the infrastructure caused by these heavy-weight permit trucks. The infrastructure damage is estimated by using pavement and bridge deterioration models and New Jersey permit data from 2013 to 2018 containing vehicle configuration and vehicle route. The analysis indicates that although the cost of infrastructure damage can be recovered for certain permit types, there is room for improvement in the permit program. Moreover, based on permit rules in other states, the overall rank of the New Jersey permit program is evaluated and possible revisions are recommended for future permit policies.

scholarly journals Multimodal Mixed Reality Impact on a Hand Guiding Task with a Holographic Cobot

2020 ◽  
Vol 4 (4) ◽  
pp. 78
Author(s):  
Andoni Rivera Pinto ◽  
Johan Kildal ◽  
Elena Lazkano
Keyword(s):  
Augmented Reality ◽  
Industrial Production ◽  
User Study ◽  
Haptic Feedback ◽  
Mixed Reality ◽  
Robot Arm ◽  
Pick And Place ◽  
Place Task ◽  
Guidance Technique ◽  
The Impact

In the context of industrial production, a worker that wants to program a robot using the hand-guidance technique needs that the robot is available to be programmed and not in operation. This means that production with that robot is stopped during that time. A way around this constraint is to perform the same manual guidance steps on a holographic representation of the digital twin of the robot, using augmented reality technologies. However, this presents the limitation of a lack of tangibility of the visual holograms that the user tries to grab. We present an interface in which some of the tangibility is provided through ultrasound-based mid-air haptics actuation. We report a user study that evaluates the impact that the presence of such haptic feedback may have on a pick-and-place task of the wrist of a holographic robot arm which we found to be beneficial.

Effect of Ramp Angle on the Anti-Loosening Ability of Wedge Self-Locking Nuts Under Vibration

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Jianhua Liu ◽  
Hao Gong ◽  
Xiaoyu Ding
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Production Technology ◽  
Material Properties ◽  
Threshold Value ◽  
Commercial Production ◽  
Experimental Results ◽  
Fe Method ◽  
Transversal Vibration

Recently, the wedge self-locking nut, a special anti-loosening product, is receiving more attention because of its excellent reliability in preventing loosening failure under vibration conditions. The key characteristic of a wedge self-locking nut is the special wedge ramp at the root of the thread. In this work, the effect of ramp angle on the anti-loosening ability of wedge self-locking nuts was studied systematically based on numerical simulations and experiments. Wedge self-locking nuts with nine ramp angles (10 deg, 15 deg, 20 deg, 25 deg, 30 deg, 35 deg, 40 deg, 45 deg, and 50 deg) were modeled using a finite element (FE) method, and manufactured using commercial production technology. Their anti-loosening abilities under transversal vibration conditions were analyzed based on numerical and experimental results. It was found that there is a threshold value of the initial preload below which the wedge self-locking nuts would lose their anti-loosening ability. This threshold value of initial preload was then proposed for use as a criterion to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively and to determine the optimal ramp angle. Based on this criterion, it was demonstrated, numerically and experimentally, that a 30 deg wedge ramp resulted in the best anti-loosening ability among nine ramp angles studied. The significance of this study is that it provides an effective method to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively, and determined the optimal ramp angle in terms of anti-loosening ability. The proposed method can also be used to optimize other parameters, such as the material properties and other dimensions, to guarantee the best anti-loosening ability of wedge self-locking nuts.

Dynamic Analysis of a Floating Offshore Wind Turbine Under Extreme Environmental Conditions

2012 ◽  
Author(s):  
Tomoaki Utsunomiya ◽  
Shigeo Yoshida ◽  
Hiroshi Ookubo ◽  
Iku Sato ◽  
Shigesuke Ishida
Keyword(s):  
Dynamic Analysis ◽  
Wind Turbine ◽  
Environmental Conditions ◽  
Aerodynamic Force ◽  
Experimental Results ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Analysis Tool ◽  
Simulation Code ◽  
Floating Offshore Wind Turbine

This paper is concerned with the development of a Floating Offshore Wind Turbine (FOWT) utilizing spar-type floating foundation. In order to design such a structure, it is essential to evaluate the dynamic response under extreme environmental conditions. In this study, therefore, a dynamic analysis tool has been developed. The dynamic analysis tool consists of a multi-body dynamics solver (MSC.Adams), aerodynamic force evaluation library (NREL/AeroDyn), hydrodynamic force evaluation library (In-house program named SparDyn), and mooring force evaluation library (In-house program named Moorsys). In this paper, some details of the developed dynamic analysis tool are given. In order to validate the program, comparison with the experimental results, where the wind, current and wave are applied simultaneously, has been made. The comparison shows that satisfactory agreements between the simulation and the experimental results are obtained. However, when VIM (Vortex Induced Motion) occurs, the current loads and cross flow responses (sway and roll) are underestimated by the simulation since the simulation code does not account for the effect of VIM.

scholarly journals Queuing theory based part-flow estimation in a pick-and-place task with a multi-robot system

2018 ◽  
Vol 12 (2) ◽  
pp. JAMDSM0061-JAMDSM0061
Author(s):  
Yanjiang HUANG ◽  
Ryosuke CHIBA ◽  
Tamio ARAI ◽  
Tsuyoshi UEYAMA ◽  
Xianmin ZHANG ◽  
...  
Keyword(s):  
Queuing Theory ◽  
Robot System ◽  
Flow Estimation ◽  
Pick And Place ◽  
Place Task ◽  
Multi Robot

Analytical and Experimental Predictor-Based Time Delay Control of Baxter Robot

2018 ◽  
Author(s):  
Mostafa Bagheri ◽  
Miroslav Krstić ◽  
Peiman Naseradinmousavi
Keyword(s):  
Time Delay ◽  
Time Delays ◽  
Input Delay ◽  
Delay Systems ◽  
Engineering Systems ◽  
Common Control ◽  
Pick And Place ◽  
Place Task ◽  
Input Delays ◽  
Time Invariant

In this paper, a predictor-based controller for a 7-DOF Baxter manipulator is formulated to compensate a time-invariant input delay during a pick-and-place task. Robot manipulators are extensively employed because of their reliable, fast, and precise motions although they are subject to large time delays like many engineering systems. The time delay may lead to the lack of high precision required and even catastrophic instability. Using common control approaches on such delay systems can cause poor control performance, and uncompensated input delays can produce hazards when used in engineering applications. Therefore, destabilizing time delays need to be regarded in designing control law. First, delay-free dynamic equations are derived using the Lagrangian method. Then, we formulate a predictor-based controller for a 7-DOF Baxter manipulator, in the presence of input delay, in order to track desirable trajectories. Finally, the results are experimentally evaluated.

scholarly journals The sources of sex differences in aging in annual fishes

2020 ◽  
Author(s):  
Martin Reichard ◽  
Radim Blažek ◽  
Jakub Žák ◽  
Petr Kačer ◽  
Oldřich Tomášek ◽  
...  
Keyword(s):  
Sex Differences ◽  
Social Environment ◽  
Social Factors ◽  
Environmental Conditions ◽  
Natural Populations ◽  
Experimental Results ◽  
Survival Difference ◽  
Captive Populations ◽  
Baseline Mortality ◽  
In The Wild

AbstractSex differences in lifespan and aging are widespread among animals, with males usually the shorter-lived sex. Despite extensive research interest, it is unclear how lifespan differences between the sexes are modulated by genetic, environmental and social factors. We combined comparative data from natural populations of annual killifishes with experimental results on replicated captive populations, showing that females consistently outlived males in the wild. This sex-specific survival difference persisted in social environment only in two most aggressive species, and ceased completely when social and physical contacts were prevented. Demographically, neither an earlier start nor faster rate of aging accounted for shorter male lifespans, but increased baseline mortality and the lack of mortality deceleration in the oldest age shortened male lifespan. The sexes did not differ in any measure of functional aging we recorded. Overall, we demonstrate that sex differences in lifespan and aging may be ameliorated by modulating social and environmental conditions.

Sign in / Sign up

Export Citation Format

Share Document