Shape Optimization of 2D Compliant Links for Design of Inherently Safe Robots

2015 ◽  
Author(s):  
Yu She ◽  
Hai-Jun Su ◽  
Carter J. Hurd
Keyword(s):  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Mechanical Design ◽  
Longitudinal Direction ◽  
Head Injury Criterion ◽  
Impact Simulation ◽  
Novel Method ◽  
Safety Constraint ◽  
The Cost ◽  
Traditional Approaches

In this paper, we represent a preliminary work towards the design of compliant mechanisms for human safe co-robots. We developed a shape optimization framework for design of planar compliant links for inherently safe robotic manipulators. It is well known intentionally introducing compliance to mechanical design can increase safety of robots. However traditional approaches such as elastic joints or uniform compliant links, were either at the cost of significantly reduced performance or with increased extra complexity and cost. Here, we propose a novel method to design compliant robotic links with a safety constraint which is quantified by Head Injury Criterion (HIC). The robotic links are modeled as a 2D beam with a variable width. Given a safety threshold i.e. HIC constraint, the width of the beam is optimized to give a uniform distribution of HIC along the longitudinal direction of the link. Links with a uniform HIC distribution have a better control performance. Finally, this solution is validated by an huamn-robot impact simulation program built in Matlab.

scholarly journals Design and Modeling of a Compliant Link for Inherently Safe Corobots

2017 ◽  
Vol 10 (1) ◽  
Author(s):  
Yu She ◽  
Hai-Jun Su ◽  
Deshan Meng ◽  
Siyang Song ◽  
Junmin Wang
Keyword(s):  
Mechanical Design ◽  
Dynamic Performance ◽  
Inherent Safety ◽  
Promising Alternative ◽  
Head Injury Criterion ◽  
Width Distribution ◽  
Human Operators ◽  
Safety Constraint ◽  
Traditional Approaches ◽  
And Control

In this paper, we propose a variable width compliant link that is designed for optimal trade-off of safety and control performance for inherently safe corobots. Intentionally introducing compliance to mechanical design increases safety of corobots. Traditional approaches mostly focus on the joint compliance, while few of them study the link compliance. Here, we propose a novel method to design compliant robotic links with a safety constraint which is quantified by head injury criterion (HIC). The robotic links are modeled as two-dimensional beams with a variable width. Given a safety threshold, i.e., HIC constraint, the width distribution along the link is optimized to give a uniform distribution of HIC, which guarantees inherent safety for human operators. This solution is validated by a human–robot impact simulation program built in matlab. A static model of the variable width link is derived and verified by finite element simulations. Not only stress in the link is reduced, this new design has a better control and dynamic performance quantified by a larger natural frequency and a larger bandwidth compared with designs made of uniform beams and compliant joints (CJs). The proposed variable width link takes full advantage of the link rigidity while keeps inherent safety during a human–robot impact. This paper demonstrates that the compliant link solution could be a promising alternative approach for addressing safety concerns of human–robot interactions.

scholarly journals A novel p-harmonic descent approach applied to fluid dynamic shape optimization

2021 ◽  
Author(s):  
Peter Marvin Müller ◽  
Niklas Kühl ◽  
Martin Siebenborn ◽  
Klaus Deckelnick ◽  
Michael Hinze ◽  
...  
Keyword(s):  
Shape Optimization ◽  
Large Deformations ◽  
Fluid Dynamic ◽  
Shape Optimisation ◽  
Shape Features ◽  
Floating Bodies ◽  
Novel Method ◽  
Sharp Corners ◽  
Dynamic Shape

AbstractWe introduce a novel method for the implementation of shape optimization for non-parameterized shapes in fluid dynamics applications, where we propose to use the shape derivative to determine deformation fields with the help of the $$p-$$ p - Laplacian for $$p > 2$$ p > 2 . This approach is closely related to the computation of steepest descent directions of the shape functional in the $$W^{1,\infty }-$$ W 1 , ∞ - topology and refers to the recent publication Deckelnick et al. (A novel $$W^{1,\infty}$$ W 1 , ∞ approach to shape optimisation with Lipschitz domains, 2021), where this idea is proposed. Our approach is demonstrated for shape optimization related to drag-minimal free floating bodies. The method is validated against existing approaches with respect to convergence of the optimization algorithm, the obtained shape, and regarding the quality of the computational grid after large deformations. Our numerical results strongly indicate that shape optimization related to the $$W^{1,\infty }$$ W 1 , ∞ -topology—though numerically more demanding—seems to be superior over the classical approaches invoking Hilbert space methods, concerning the convergence, the obtained shapes and the mesh quality after large deformations, in particular when the optimal shape features sharp corners.

scholarly journals Cost Analysis of a Novel Method for Ecological Compensation—A Study of the Translocation of Dead Wood

2021 ◽  
Vol 13 (11) ◽  
pp. 6075
Author(s):  
Ola Lindroos ◽  
Malin Söderlind ◽  
Joel Jensen ◽  
Joakim Hjältén
Keyword(s):  
Cost Efficiency ◽  
Dead Wood ◽  
Road Transportation ◽  
Ecological Value ◽  
Ecological Compensation ◽  
Work Time ◽  
Delivery Times ◽  
Novel Method ◽  
Cost Efficient ◽  
The Cost

Translocation of dead wood is a novel method for ecological compensation and restoration that could, potentially, provide a new important tool for biodiversity conservation. With this method, substrates that normally have long delivery times are instantly created in a compensation area, and ideally many of the associated dead wood dwelling organisms are translocated together with the substrates. However, to a large extent, there is a lack of knowledge about the cost efficiency of different methods of ecological compensation. Therefore, the costs for different parts of a translocation process and its dependency on some influencing factors were studied. The observed cost was 465 SEK per translocated log for the actual compensation measure, with an additional 349 SEK/log for work to enable evaluation of the translocation’s ecological results. Based on time studies, models were developed to predict required work time and costs for different transportation distances and load sizes. Those models indicated that short extraction and insertion distances for logs should be prioritized over road transportation distances to minimize costs. They also highlighted a trade-off between costs and time until a given ecological value is reached in the compensation area. The methodology used can contribute to more cost-efficient operations and, by doing so, increase the use of ecological compensation and the benefits from a given input.

Finding the optimum layout for cable-stayed bridge in conceptual design

2021 ◽  
Author(s):  
Sami Soppela ◽  
Esko Järvenpää
Keyword(s):  
Longitudinal Direction ◽  
Simple Calculation ◽  
Integral Calculus ◽  
Bearing Material ◽  
Load Bearing ◽  
Permanent Load ◽  
Early Design Stages ◽  
Cable Forces ◽  
The Cost ◽  
Cable Stayed Bridges

<p>In the cable-stayed bridges the primary cost components of the load-bearing material, in the longitudinal direction of the bridge, are the cables. The longer the bridge, the higher the share of the costs of the load-bearing material. The quantity of the cables and the cost optimized cable and tower topology can be reliably solved, already in very early design stages, using a simple calculation method proposed in this article. The cables are considered as a curtain structure and the cable forces are calculated for the permanent load balance. The solutions are performed mathematically by using integral calculus based on a force length method and a unit bridge concept. The results provide a good idea of the optimum pylon height for both one-pylon and two-pylon bridges. The optimum pylon height depends on the span ratio and the chosen cable system.</p>

A Study of Life Cycle Costing in the Perspectives of Research and Commercial Applications in the 21st Century

2007 ◽  
Author(s):  
Wai M. Cheung ◽  
Linda B. Newnes ◽  
Antony R. Mileham ◽  
Robert Marsh ◽  
John D. Lanham
Keyword(s):  
Life Cycle ◽  
Cost Estimation ◽  
Life Cycle Cost ◽  
Academic Research ◽  
Life Cycle Costing ◽  
Electronic Products ◽  
Commercial Applications ◽  
The Uk ◽  
The Cost ◽  
Traditional Approaches

This paper presents a review of research in the area of life cycle costing and offers a critique of current commercial cost estimation systems. The focus of the review is on relevant academic research on life cycle cost from 2000 onwards. In addition to this a comparison of the current cost estimation systems is presented. Using the review findings and industrial investigations as a base, a set of mathematical representations for design and manufacturing costs and the introduction of the critical factors is proposed. These are considered in terms of the operational, maintenance and disposal costs to create a method for ascertaining the life cycle cost estimate for complex products. This is presented using as an exemplar, research currently being undertaken in the area of low volume and long life electronic products in the UK defence sector. The benefit of the method proposed is that it aims to avoid the inflexibility of traditional approaches which usually require historical and legacy data to support the cost estimation processes.

scholarly journals Embedding Undersampling Rotation Forest for Imbalanced Problem

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Huaping Guo ◽  
Xiaoyu Diao ◽  
Hongbing Liu
Keyword(s):  
Imbalanced Data ◽  
Feature Space ◽  
Original Data ◽  
Training Set ◽  
Data Set ◽  
Minority Class ◽  
Rotation Forest ◽  
Novel Method ◽  
Individual Classifier ◽  
The Cost

Rotation Forest is an ensemble learning approach achieving better performance comparing to Bagging and Boosting through building accurate and diverse classifiers using rotated feature space. However, like other conventional classifiers, Rotation Forest does not work well on the imbalanced data which are characterized as having much less examples of one class (minority class) than the other (majority class), and the cost of misclassifying minority class examples is often much more expensive than the contrary cases. This paper proposes a novel method called Embedding Undersampling Rotation Forest (EURF) to handle this problem (1) sampling subsets from the majority class and learning a projection matrix from each subset and (2) obtaining training sets by projecting re-undersampling subsets of the original data set to new spaces defined by the matrices and constructing an individual classifier from each training set. For the first method, undersampling is to force the rotation matrix to better capture the features of the minority class without harming the diversity between individual classifiers. With respect to the second method, the undersampling technique aims to improve the performance of individual classifiers on the minority class. The experimental results show that EURF achieves significantly better performance comparing to other state-of-the-art methods.

scholarly journals Green Synthesis of Clean Edge Graphene Nanosheets Using Natural Precursor

2021 ◽  
Vol 58 (3) ◽  
pp. 210-216
Author(s):  
Balakrishnan Somasekaran ◽  
Alwarsamy Thirunarayanaswamy ◽  
Ilamathi Palanivel
Keyword(s):  
Environmental Concern ◽  
Graphene Nanosheets ◽  
Agricultural Waste ◽  
Chemical Activation ◽  
Advantages And Disadvantages ◽  
Layer Graphene ◽  
Smooth Edge ◽  
Novel Method ◽  
Traditional Approaches ◽  
Few Layer Graphene

Graphene, a two-dimensional crystalline allotrope of carbon, has received greater attention from numerous researchers due to its excellent properties. Graphene could be produced by various techniques, each method has its advantages and disadvantages. In this research article, a novel method using agricultural waste rice husk as a precursor and chemical activation to produce few-layer graphene nanosheets was developed. Traditional approaches significant shortcomings and the environmental concern of agricultural waste have been eliminated. The synthesized material was characterized using FESEM, Raman Spectroscopy, X-Ray diffractometer, UV-Vis absorbance and FTIR analysis. FESEM analysis of the surface morphology revealed smooth edge few-layer graphene. The formation of sp2 hybridized atoms can be seen in XRD spectra at 26.3 degrees. The C=C stretching bonds detected at 1612 cm-1 wavelength are responsible for the graphitic structure.

Effect of Matching Buckling Loads on Post-Buckling Behavior in Compliant Mechanisms

2021 ◽  
Author(s):  
A. Numić ◽  
T. W. A. Blad ◽  
F. van Keulen
Keyword(s):  
Compliant Mechanisms ◽  
Relative Length ◽  
Optimal Designs ◽  
Element Analysis ◽  
Buckling Loads ◽  
Actuation Force ◽  
Stepped Beam ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Novel Method

Abstract In this paper, a novel method for stiffness compensation in compliant mechanisms is investigated. This method involves tuning the ratio between the first two critical buckling loads. To this end, the relative length and width of flexures in two architectures, a stepped beam and parallel guidance, are adjusted. Using finite element analysis, it is shown that by maximizing this ratio, the actuation force for transversal deflection in post-buckling is reduced. These results were validated experimentally by identifying the optimal designs in a given space and capturing the force-deflection characteristics of these mechanisms.

Systematic Process Selection in Mechanical Design

1996 ◽  
Author(s):  
Amal M. K. Esawi ◽  
Michael F. Ashby
Keyword(s):  
Manufacturing Process ◽  
Mechanical Design ◽  
Selection Procedure ◽  
Manufacturing Processes ◽  
Process Selection ◽  
Systematic Selection ◽  
Cost Penalty ◽  
The Right ◽  
The Cost ◽  
Manufacturing Process Selection

Abstract There has been a recent awareness of the importance of making the right manufacturing decisions early in the design process before the cost penalty of making changes becomes too high. The selection of the most appropriate manufacturing process — of which there are a very large number — is one such decision. It is commonly based on human-resident experience or on established local practice. As such, some potentially-usable processes may be overlooked. This paper explores ways in which process selection might be made more systematic. It presents a procedure for manufacturing process selection which considers all manufacturing processes and eliminates the ones which cannot satisfy the design requirements. This is achieved using Process Selection Charts in which process capabilities are displayed graphically. A procedure for the ranking of the successful processes based on cost is under development. The systematic selection procedure lends itself well to computer implementation. A database of manufacturing processes and an advanced user interface thus provide ideal support for designers. Cambridge Materials Selector (CMS) software is currently being applied to manufacturing process selection.

Sign in / Sign up

Export Citation Format

Share Document