bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Performance With Control of a 2DOF Parallel Robot
Authors: Coppola Gianmarc , Zhang Dan , Liu Kefu , Gao Zhen
Published: September 2013

In this work the dynamic performance and control of a 2DOF parallel robot is conducted. The study is partly motivated by large variations in dynamic performance and control within the reachable workspace of many parallel manipulators. The forward dynamic model of the robot is derived in detail. The connection method is directly utilized for this derivation. Subsequently, a dynamic performance study is undertaken. This reveals important information whilst using a forward dynamic model. A performance index is proposed to determine the variability of performance of the parallel manipulator. Then a trajectory-tracking scenario is undertaken using a linear controller. By means of control, the simulations illustrate the validity of the proposed index for parallel manipulators.
Acquirement and Interpretation of Spatially Distributed Impulsive Acceleration Signals in a Flexible Shaft-Propeller System
Authors: Georgiou Ioannis T.
Published: September 2013

This work reports on the spatio-temporal characterization of collocated ensembles of experimental time series of the impulsive dynamics in a complex flexible structural-machinery system composed of a shaft supporting at its free end a three-bladed boat propeller. A few state-of-the-art piezoelectric accelerometers sample simultaneously the impulsive response of the system as a function of the location of a modal hammer force applied sequentially over a global interrogation curve. The typical ensemble of collocated signals is subject to a systematic coherence analysis by advanced tools based on the theory of Proper Orthogonal Decomposition (POD) transforms. It turns out that three different collocated ensembles of acceleration signals, collected at the blades at symmetric locations, are very coherent and robust as distributed information over the space-time domain. The characteristics of coherence of the collocated databases are studied in depth by presenting a detailed POD analysis at the system and subsystems levels. The main result is the fact that the POD modes of collocated acceleration databases that exploit structural symmetries seem to provide reliable means to detect sharply differences-due to damage and perhaps design fault-in the subsystem impulsive response.
Fatigue Analysis of Adhesively Bonded Single Lap Joints Under Vibration Loads
Authors: Li Weidong , Wu Kunyue , Du Yu , Pang Jian , Hu Ping
Published: September 2013

Many structural applications of adhesive joints experience vibration loads. The dynamic loads due to vibration motions are therefore one of the primary causes for structural damage, especially when the outside cyclic stir vibration frequency is adjacent to the natural frequencies of the adhesive joint frame. This is so called the vibration fatigue. In this paper, the fatigue behavior of adhesively bonded single lap joint (SLP) subject mainly to normal stresses induced by vibration excitations is investigated. Combining with static tests, the NI PXI-1045 vibration measurement and analysis system are used to analyze the effect of vibration loading on the fundamental modal frequency with long-term fatigue cycle. Furthermore, a virtual fatigue analysis approach for the fatigue damage prediction of adhesive joints subject to vibration loads is performed in this study. It is found that the joint stiffness decreases with the cyclic durations under which the vibration loads are applied. As a result, a stable decrease of the fundamental resonance frequency of the joint structure is observed during the tests. The experimental data demonstrate a significant correlation between the shear strength of adhesive joints and the vibration cycling time. A gradual decrease in the shear strength with increasing load cycles is seen in vibration fatigue, the maximum shear strength of adhesively bonded joints drops about 12% after 1.35e8 cycles. Based on the test data, a new approach called virtual fatigue analysis modeling (VFAM) is proposed for the fatigue damage of the adhesive joints under vibration loads. The VFAM shows that the fatigue damage occurs first at the end of the overlap area of the adhesive layer.
A Frame-Independent Vector Expression of the Singularity Locus of the Gough-Stewart Platform
Authors: Doyon Karine , Gosselin Clément , Cardou Philippe
Published: September 2013

This paper presents a vector expression of the singularity locus of the Gough-Stewart platform. In order to obtain this expression, several algebraic operations are performed on the manipulator’s Jacobian matrix such as relocating the origin of the reference frame and linearly combining columns. The third-degree vector expression thus obtained does not contain a constant term, which allows the factorization of an instance of the position vector. An alternative notation that reduces the number of times that the position vector appears in the expression is then presented. It is also demonstrated that a simplified architecture such as that of the MSSM can significantly reduce the length of the expression.

Finally, some numerical examples of singularity loci are presented, which were estimated by combining the proposed formulation with interval analysis in the cases of a generic Gough-Stewart platform and of an MSSM. The results obtained illustrate how the precision of interval analyses are influenced by the form of the symbolic expression of the singularity locus.
Improving Failure Mode and Effects Analysis as a Cognitive Simulation
Authors: Foster Chad R.
Published: September 2013

In this paper the failure mode and effects analysis (FMEA) process is studied as a human simulation. The cognitive challenges of availability bias, probability inconsistency, and experience weighting are reviewed against a large number of actual FMEAs. The challenges are outlined and improvements to the process presented including pooled scoring and the use of the criticality index.
Toward an Interactive Visualization Environment for Architecting Microgrids in Ultra Low Energy Communities
Authors: Stump Gary , Simpson Timothy W. , Oggianu Stella , Khire Ritesh
Published: September 2013

In this paper we describe the development of an interactive visualization tool to support the design and evaluation of microgrid architectures in ultra low energy communities. The work is motivated by recent Department of Defense regulations to reduce energy costs at and increase energy conservation at military installations. Using two sets of energy analysis models derived from existing energy modeling software packages, we illustrate how such a design environment can be used to (1) run a fast, low fidelity model to support an initial trade space exploration, (2) understand key trends and relationships, (3) filter microgrid architectures based on desired constraints, (4) identify architectures of interest, (5) run high fidelity analyses for architectures of interest, and (6) select an architecture and use a map view to change device type locations. The process is demonstrated through a web-based design environment that we prototyped and applied to two design examples. In both cases, promising microgrid architectures are identified from an initial set of 500 randomly generated designs. Manual adjustments of the position and location of the device types were used to further improve system performance. The end result in each case was a microgrid architecture that offered low fixed and operating costs based on the assumed electrical and thermal loads. The prototype effectively illustrates how Visual Analysis might be performed during Steps 4 & 5 of the Army’s Real Property Master Planning Process. Future enhancements to support the design decision-making process are also discussed.
A Model-Based Failure Identification and Propagation Framework for Conceptual Design of Complex Systems
Authors: Mehrpouyan Hoda , Jensen David C. , Hoyle Christopher , Tumer Irem Y. , Kurtoglu Tolga
Published: September 2013

In this paper, a model-based failure identification and propagation (MFIP) framework is introduced for early identification of potential safety issues caused by environmental disturbances and subsystem failures within a complex avionic system. The MFIP framework maps hazards and vulnerability modes to specific components in the system and analyzes failure propagation paths. Block definition diagrams (BDD) are used to represent system functional requirements in the form of demonstrating the relationships between various requirements, their associations, generalizations, as well as dependencies. These concept models help to identify hazardous factors and the relationships through which their detrimental effects are transferred through-out the proposed system architecture. As such, the approach provides the opportunity to reduce costs associated with redesign and provide important information on design viability. Using this technique, designers can examine the impacts of environmental and subsystem risks on the overall system during the early stages of design and develop hazard mitigation strategies.
A Family of Overconstrained 6R Linkages With the Rotational Symmetry of Order 2
Authors: Zhang Ketao , Dai Jian S.
Published: September 2013

This paper presents a family of overconstrained 6R linkages with the rotational symmetry of order 2 which refers to rotation by an angle of 360°/n (n = 2) with respect to a particular axis leaves the linkage unchanged. The overconstrained 6R linkages are evolved from a reconfigurable 8R linkage which is extracted from deployable origami-fold. The structure evolution of the 8R linkage takes the concept of metamorphosis in the sense of structural evolution. This leads to a generic way for investigating new mechanisms inspired from origami fold. The geometry and two-fold rotational symmetry reveal that the overconstrained 6R linkages are special line-symmetric Bricard 6R loops and the parametric constraints of the 6R linkages are identified. The kinematics of the overconstrained 6R linkage is analyzed and motion parameters of the joint space are derived. The unique mobility of the overconstrained 6R linkages is further verified in terms of screw theory.
Probabilistic Approach for Digital Human Kinematic and Dynamic Reliabilities
Authors: Gragg Jared , Yang Jingzhou (James) , Yang Guolai
Published: September 2013

Traditionally, deterministic methods have been applied in digital human modeling (DHM). Transforming the deterministic approach of digital human modeling into a probabilistic approach is natural since there is inherent uncertainty and variability associated with DHM problems. Typically, deterministic studies in this field ignore this uncertainty or try to limit the uncertainty by employing optimization procedures. Due to the variability in the inputs, a deterministic study may not be enough to account for the uncertainty in the system. Probabilistic design techniques allow the designer to predict the likelihood of an outcome while also accounting for uncertainty, in contrast to deterministic studies. The purpose of this study is to incorporate probabilistic approaches to a deterministic DHM problem that has already been studied, analyzing human kinematics and dynamics. The problem is transformed into a probabilistic approach where the human kinematic and dynamic reliabilities are determined. The kinematic reliability refers to the probability that the human end-effector position (and/or orientation) falls within a specified distance from the desired position (and/or orientation) in an inverse kinematic problem. The dynamic reliability refers to the probability that the human end-effector position (and/or velocity) falls within a specified distance from the desired position (and/or velocity) along a specified trajectory in the workspace. The dynamic equations of motion for DHM are derived by the Lagrangian backward recursive dynamics formulation.
A New Discrete Event System Model for Supervising and Controlling Robotic Arm Path Tacking Tasks Based on Adaptive Masking
Authors: Arastehfar Soheil , Liu Ying , Lu Wen Feng
Published: September 2013

This paper introduces a new discrete event system (DES) model for supervising and controlling trajectory planning tasks and robot motion using automata. This model is proposed based on a new approach, namely mask description. Masks are constructed adaptively and are modified based on the error between the original path and the planned path. The model acts in two phases, mask construction phase (MCP) and end-effecter positioning phase (E2P2). In MCP, it tries to plan a path, and in E2P2 it tries to place the end-effecter along the sequence of points on the path. The model describes a path in the Cartesian space and moves the end-effecter in the joint variable space, and therefore, MCP plans the path as accurate as Cartesian space description, and E2P2 position the robot as fast as joint space description. Results show that the proposed adaptive masking is remarkably efficient in computing.
A Numerically Efficient Frequency Domain Method for Analysis of Non-Linear Multi Degree of Freedom Systems
Authors: Özer Mehmet Bülent
Published: September 2013

Linear structural models contain mass, stiffness and damping matrices as well as a forcing vector. Once these matrices and the forcing vector are known, the response can be calculated through the methods of linear algebra. The system matrices of the linear model do not contain any terms that depend on the system response vector, therefore the calculation of the system response do not require an iterative procedure. On the other hand, frequency domain analysis of non-linear structural models generally contain terms that are non-linear functions of the system response vector. Therefore these terms make the system matrices become dependent on the non-linear system response vector itself. This forces one to employ an iterative solution. The disadvantage of the iterative solution is more pronounced when large degree of freedom systems are analyzed. For each frequency value, the iterative procedure requires solution of large system of equations to be evaluated several times until the iterative procedure converges to a value. Therefore the numerical cost significantly increases as the model size gets larger. This study introduces a method which requires one-time calculation of response of the linear part of the system. After finding the response of the linear part, no further matrix inversions are needed to iteratively find the non-linear system response. In the case studies it will be shown that the proposed method has significant computation time advantages to conventional time domain and frequency domain methods for solution of large non-linear structural models. In order to employ this numerically efficient method, describing function theory is used to obtain a non-linearity matrix which contains the non-linear terms. Also, a computationally efficient recursive method is used to evaluate the inverse of the sum of the linear system impedance and the non-linearity matrix. In order to employ this recursive method the non-linearity matrix is decomposed into summation of rank-one matrices.
Optimum Design of Columns Under Elastic Buckling
Authors: Abd El Gawad Moataz A. M. , Hegazi Hesham A. , Metwalli Sayed M.
Published: September 2013

In this paper, a generalized approach is developed to optimize column configuration subjected to buckling load. The configuration utilizes B-spline contour to provide more freedom to model the column shape. Previous columns in literature use tapered or parabolic tapered for configuration. This work considers hinged-hinged columns of circular solid cross-sectional area. Two sample applications are optimized using Genetic Algorithm with the finite difference method to satisfy the buckling constraints. The length and load are fixed. The objective is to minimize the volume considering the cross-sectional diameters as the design variables. B-Spline quadratic with three and five control points and cubic with five control points are applied. The proposed configuration is compared with tapered and parabolic tapered columns. Results show that continuity provides a better optimum against column buckling than other tapered columns. Even though volume is more than some configurations by about 1.67%, but those configurations would not satisfy buckling constraints over the entire length of the column.
Experimental Bifurcation Analysis by Control-Based Continuation: Determining Stability
Authors: Bureau Emil , Santos Ilmar Ferreira , Thomsen Jon Juel , Schilder Frank , Starke Jens
Published: September 2013

The newly developed control-based continuation technique has made it possible to perform experimental bifurcation analysis, e.g. to track stable as well as unstable branches of frequency responses directly in experiments. The method bypasses mathematical models, and systematically explores how vibration characteristics of dynamical systems change under variation of parameters. The method employs a control scheme to modify the response stability. While this facilitates exploration of the unstable branches of a bifurcation diagram, it unfortunately makes it impossible to distinguish previously stable and unstable equilibrium states. We present the ongoing work of developing and applying the control-based continuation method to an experimental mechanical test-rig, consisting of a harmonically forced nonlinear impact oscillator controlled by electromagnetic actuators. Furthermore we propose and test ideas on how to determine the stability of equilibria states during continuation.
Bifurcation Analysis of a Two-DoF System Subject to Digital Position Control
Authors: Habib Giuseppe , Rega Giuseppe , Stépán Gabor
Published: September 2013

This paper analyzes the stability of a two-DoF system, subject to PD digital position control. In the model the control force is considered piecewise constant. Introducing the nonlinearity related to the saturation of the control force, the bifurcations occurring in the system are analyzed. The system is generally loosing stability through Neimark-Sacker bifurcations, with a relatively simple dynamics. However, the interaction of two different Neimark-Sacker bifurcations steers the system to much more complicated behaviors. About this kind of bifurcation, namely double Neimark-Sacker bifurcation, there are very few studies in the literature. Our analysis is carried out using the method proposed by Kuznetsov. The performed investigation shows the appearance of quasiperiodic motions and the existence of regions with coexisting periodic stable attractors, in the space of the control gains. Numerical simulations validate the results obtained analytically.
Classification of Screw Systems Composed of Three Planar Pencils of Lines
Authors: Kong Xianwen , Johnson Andrew
Published: September 2013

Screw systems composed of three planar pencils of lines are closely related to the singularity analysis of a number of 3-legged parallel manipulators in which the passive joints in each leg are a spherical joint and a single-DOF (degree-of-freedom) kinematic joint or generalized kinematic joint. This paper systematically classifies the screw systems composed of three planar pencils of lines. The classification is based on the intersection of two planar pencils of lines, the classification of screw systems of order 2, and the reciprocal screw system of the three planar pencils of lines. The classification in this paper is more comprehensive than those in the literature. The above results are illustrated using CAD figures. This work may help readers better understand the geometric characteristics of the singular configuration of a number of 3-legged parallel manipulators.
Indicator of Feasibility for Layout Problems
Authors: Bénabès Julien , Guédas Benoît , Poirson Emilie , Bennis Fouad
Published: September 2013

Layout optimization problems deal with the search for an optimal spatial arrangement of components inside a container. Global performances of many engineering products and systems sharply depend on layout design. Because of the great complexity of most real-world layout applications, recent studies focus on the development of efficient optimization algorithms used to solve layout problems. These algorithms, which have to take into consideration multi-constraint and multi-objective optimization problems, aim to be generic to adapt to lots of layout problems. However, the solving of these layout problems is time consuming and designers know if an optimal solution is available for their problem at the end of the optimization process. Designer cannot know a priori if the layout problem can be solved. Then, this paper proposes a new indicator to assess the feasibility of layout problems. This indicator is based on the layout description of the problem and the formulation of designer’s requirements. In particular, it takes into account the non-overlap constraints between layout components. It allows the designer to know if the layout problem can be solved before running the optimization algorithm. After defining the new indicator of feasibility, this paper tests it on a simple layout application.
Product Architectures Generation Under Uncertainty: Comparison Between Two Methods
Authors: Moullec Marie-Lise , Jankovic Marija , Bouissou Marc , Bocquet Jean-Claude
Published: September 2013

Complex product architecture definition involves technological and architectural choices in order to reach defined system performances. These choices form a wide combinatorial design space whose complete exploration requires a computational method. The latter is made difficult because of the lack and the fuzziness of data and knowledge in preliminary design. To introduce this type of uncertainty, we have proposed an approach based on Bayesian nets: a Bayesian net architecture generation and clustering method is proposed. However, in recent research, lots of conceptual design problems were addressed with Constraint Satisfaction Problem (CSP). The purpose of this paper is to compare these two methods and advantages and challenges in view to design situations under uncertainty. The comparison consists in modeling a sample problem with both methods. The modeling process of each method is described, providing preliminary highlights on advantages and disadvantages of both methods. Then, the methods are evaluated in terms of modeling capabilities and easiness. The number of generated architectures and the execution time of each simulation are also analyzed with regard to the influence of uncertainty introduction in the models. The final objective is to determine which method seems to be the more appropriate to help designers in finding new innovative designs.
Towards a Comprehensive Test of Qualitative Reasoning Skill in Design
Authors: Khorshidi Maryam , Woodward Jay , Shah Jami J.
Published: September 2013

A battery of tests for assessing the cognitive skills needed for the conceptual design is being developed. Divergent thinking and visual thinking tests were fully developed and validated previously. This paper focuses on the development of a test on qualitative reasoning skill.

Indicators of qualitative reasoning are identified and categorized as: deductive reasoning, inductive reasoning, analogical reasoning, abductive reasoning, and intuitive physics; the derivation of each is based on both cognitive science and empirical studies of design. The paper also considers the metrics for measuring skill levels in different individuals and candidate test items and grading rubric for each skill.
Seven Cognitive Concepts for Successful Sustainable Design
Authors: MacDonald Erin , She Jinjuan
Published: September 2013

For the past forty years, social science researchers have studied how to encourage pro-environmental behaviors such as the adoption of recycling programs, water conservation strategies, and purchase of sustainable products. This article presents a synthesis of these research findings as they relate to the design of sustainable products and technologies. Research from environmental psychology, consumer studies, economics, decision sciences, public policy, and behavioral psychology are organized into cognitive concepts that are crucial to the successful purchase and use of sustainable products. The cognitive concepts reviewed are: responsibility, complex decision-making skills, decision heuristics, the altruism-sacrifice link, trust, cognitive dissonance/guilt, and motivation. Product examples are provided to highlight the role of these cognitive concepts in sustainable design. Design recommendations and relevant design methods are discussed. The recommendations require dynamic and on-going coordination between designers, manufacturers, marketers, and government policy-makers to achieve positive changes in individuals’ behaviors. The success of sustainable products depends on the success of this coordination.
Camera Calibration Method for Accurate Full-Field Strain Measurement by Dot Centroid Method
Authors: Toyoshi Takuya , Wada Yoshitaka , Furukawa Tomonari
Published: September 2013

This paper presents a new method for the correction of the lens distortion for full-field measurement using dot centroid method. Displacement and strain can be obtained from full-field digital images, which include centroids represented by many dots on the specimen. The captured images are distorted by an optical system. Several ideas to remove such a distortion are developed, however the image is corrected by an interpolation for brightness intensity level. In short it is hard to achieve high accuracy for strain measurement by the interpolation, because high accuracy needs sub-pixel effect for computing a centroid.

In this paper, the dot centroid method is employed and the centroids are directly corrected by the proposed method, which directly compute the only positions of centroids. Due to the correction, 0.1% strain accuracy is accomplished and total computation time is reduced. Effectiveness of the idea is shown through numerical examples and the result of strain field measurement is presented and discussed.
Simulating Drift-Diffusion Processes With Generalized Interval Probability
Authors: Wang Yan
Published: September 2013

The Fokker-Planck equation is widely used to describe the time evolution of stochastic systems in drift-diffusion processes. Yet, it does not differentiate two types of uncertainties: aleatory uncertainty that is inherent randomness and epistemic uncertainty due to lack of perfect knowledge. In this paper, a generalized Fokker-Planck equation based on a new generalized interval probability theory is proposed to describe drift-diffusion processes under both uncertainties, where epistemic uncertainty is modeled by the generalized interval while the aleatory one is by the probability measure. A path integral approach is developed to numerically solve the generalized Fokker-Planck equation. The resulted interval-valued probability density functions rigorously bound the real-valued ones computed from the classical path integral method. The new approach is demonstrated by numerical examples.
Noise Reduction Technique for Digital Image Based Full Field Strain Measurement
Authors: Wada Yoshitaka , Furukawa Tomonari
Published: September 2013

In recent years several techniques of full-field measurement have been studied by digital image correlation method, moiré interference method and holographic interferometry method and so on. Image based method can be easily applied to large deformation problem and moving specimen at slow speed. Because digital camera capabilities, which are high resolution, low noise and faster data transfer speed, have been improved, very small strain measurement can be achieved by those improvements. The improvement will widen those applications, for example, moving object at high speed and less 0.1% strain measurement which is almost the same accuracy with a precise strain gauge. In order to apply the advanced application, noise reduction for a digital image and lens distortion correction for an optical system should be developed. In this paper we propose noise reduction technique using statistical camera model to be applied to any kinds of digital cameras.
Towards the Understanding of Hip Torque and Leg Damping Effects on Model Stability
Authors: Shen Zhuohua , Seipel Justin
Published: September 2013

A new class of actuated Spring-Loaded Inverted Pendulum (SLIP) models with hip actuation and leg damping has been developed, and is found to be more stable than the canonical version. However, it is not known how the addition of hip torque and leg damping change locomotion stability. In this paper, we study the effects of leg damping and hip torque on locomotion stability of actuated-SLIP models. All other modeling assumptions of SLIP are conserved. And hip torque is turned off during the flight phase. We show that for a given set of nondimensional SLIP parameters the hip torque and leg damping required for a periodic solution are not independent. Further, we show that adding hip torque and damping changes the dynamics of actuated-SLIP solutions in a non-intuitive way. When a very small amount of torque and damping are added the affect is initially to destabilize SLIP solutions. As torque and damping are added further, it eventually improves the stability properties of solutions.
Dimensional Synthesis of Planar Six-Bar Linkages by Mechanically Constrain a PRR Serial Chain
Authors: Soh Gim Song , Ying Fangtian , McCarthy J. Michael
Published: September 2013

In this paper, we consider the problem of designing planar six-bar linkages which can be driven by prismatic joints at its base. We explore various ways on how two RR chains can be used to constraint a PRR planar serial chain such that the system yields one-degree of freedom yet passes through a set of five specified task positions. We formulate and solve the design equations as well as analyze the resulting planar six-bar linkage. We demonstrate the synthesis process with the design of the seat of a wheelchair such that it is able to transform itself to be used as a rehabilitation guide during rehabilitation.
Application of the Generational Variety Index: A Retrospective Study of iPhone Evolution
Authors: Nadadur Gopal , Parkinson Matthew B. , Simpson Timothy W.
Published: September 2013

The generational variety index (GVI) helps identify the components of product variants that are most likely to require redesign in the future. These components can then be embedded with the flexibility required for them to be easily modifiable; the remaining components can be designed into a platform. This paper describes the application of the GVI technique in studying the evolution of the Apple iPhone, which was first released in 2007 and has since undergone multiple redesigns. The analysis includes the five generations of the iPhone (original, 3G, 3GS, 4, and 4S) and focuses primarily on mechanical sub-systems. The results of the analysis and subsequent design recommendations are compared with the actual design evolution of the iPhone product line. For certain subsystems, this comparison reveals a divergence in Apple’s design decision-making from the evolution recommended by the GVI technique. Limitations include its retrospective nature and the use of only publicly available data.
Impact of Product Design Representation on Customer Judgment With Associated Eye Gaze Patterns
Authors: Reid Tahira N. , MacDonald Erin F. , Du Ping
Published: September 2013

Researchers often use simplified product form representations, such as silhouettes, sketches, and other two-dimensional representations of products, to examine customer preferences. While these simplified representations make the analysis procedure tractable, for example linking certain design manipulations to certain preferences, the reality is that people evaluate more sophisticated product representations during purchase decisions. This paper presents the results of a study where two groups of people were shown either computer sketches and front/side view (FSV) silhouettes or simplified renderings and realistic renderings of cars and coffee carafes. Human judgments measured included opinions, objective evaluations, and inferences. Results show a variety of phenomena including preference inconsistences and ordering effects. Data collected from an eye-tracker help to elucidate these findings.
Technology Evolution Modeling and Decision Making Under Uncertainty
Authors: Arendt Jonathan L. , McAdams Daniel A. , Malak Richard J.
Published: September 2013

Design is an uncertain human activity involving decisions with uncertain outcomes. Sources of uncertainty in product design include uncertainty in modeling methods, market preferences, and performance levels of subsystem technologies, among many others. The performance of a technology evolves over time, typically exhibiting improving performance. As the performance of a technology in the future is uncertain, quantifying the evolution of these technologies poses a challenge in making long-term design decisions. Here, we focus on how to make decisions using formal models of technology evolution. The scenario of a wind turbine energy company deciding which technology to invest in demonstrates a new technology evolution modeling technique and decision making method. The design of wind turbine arrays is a complex problem involving decisions such as location and turbine model selection. Wind turbines, like many other technologies, are currently evolving as the research and development efforts push the performance limits. In this research, the development of technology performance is modeled as an S-curve; slowly at first, quickly during heavy research and development effort, and slowly again as the performance approaches its limits. The S-curve model typically represents the evolution of just one performance attribute, but designers generally deal with problems involving multiple important attributes. Pareto frontiers representing the set of optimal solutions that the decision maker can select from at any point in time allow for modeling the evolution of technologies with multiple attributes. As the performance of a technology develops, the Pareto frontier shifts to a new location. The assumed S-curve form of technology development allows the designer to apply the uncertainty of technology development directly to the S-curve evolution model rather than applying the uncertainty to the future performance, giving a more focused application of uncertainty in the problem. The multi-attribute technology evolution modeling technique applied in decision-making gives designers greater insight when making long-term decisions involving technologies that evolve.
Integrated Optimization of a Solar-Powered Humidification-Dehumidification Desalination System for Small Communities
Authors: El-Morsi Mohamed , Hamza Karim , Nassef Ashraf O. , Metwalli Sayed , Saitou Kazuhiro
Published: September 2013

Fresh water availability is essential for the economic growth and development, especially in small and semi-isolated communities. In some of these communities fresh water may be scarce, yet brackish water from wells or seawater is often abundantly available. This motivates a need for cost-effective desalination at small scale capacity driven by renewable energy sources. This paper presents an integrated optimization model of a solar powered humidification-dehumidification (HDH) desalination system. The system under investigation is a water-heated system. The design variables include the sizing of solar collectors, storage tank, humidifier and dehumidifier, as well as air circulation flow rate and operating temperature. The objective of the optimization is to minimize the unit cost of the produced fresh water. Thermodynamic performance prediction is done by solving energy and mass balance equations for each of the system components, with consideration to hourly-varying solar irradiance that corresponds to a typical one year cycle. System cost is predicted via first-order estimators. A genetic algorithm is used to obtain the designs optimized for local climate and market. A case study discusses a desalination plant on the Red Sea near the city of Hurgada.
The GF Sets: A New Kind of Performance Criterion of Mechanisms
Authors: Meng Xiangdun , Gao Feng , Yang Jialun
Published: September 2013

The fundamental work of type synthesis of robot mechanisms is to research and develop the performance criterion for evaluating the characteristics of robot end-effectors and consequently come up with the classification of mechanisms. The motion characteristics of end-effectors contain translation and rotation. Traditionally, mechanisms are classified only according to the existence and quantity of these two kinds of motion characteristics without considering the succession of motion, which has remarkable influence on the topological performance property of end-effectors. In this paper, we propose the conception of rotational completeness, which describes the rotational ability of end-effectors, based on the axis movement theorem. The GF Sets are classified into three categories according to the rotational completeness of end-effectors. We enumerated all three classes of GF sets and illustrated the effectiveness of GF sets in evaluating the characteristics of robot end-effectors.
The Transition to Alternative Powertrains: Concept for the Life-Cycle-Oriented Symbiosis of Technology, Product and Product Portfolio Planning
Authors: Herrmann Christoph , Spengler Thomas Stefan , Mennenga Mark , Wachter Katharina , Kieckhäfer Karsten
Published: September 2013

In this paper the decision situation of an automobile manufacturer (OEM), which alternative powertrains to promote, is presented by discussing the three planning levels technology, product and product portfolio planning, the interdependencies between the levels as well as the necessity to integrate a life-cycle perspective. Based on this, a concept for the life-cycle-oriented symbiosis of technology, product and product portfolio planning is developed. The concept consists of three planning modules each incorporating a life-cycle perspective: technology planning, product planning and product portfolio planning. Within each module, technologies, products and the resulting portfolio are analyzed, evaluated and selected according to the company objective(s). Referring to the developed concept, existing approaches to support the implementation and open challenges are discussed.
A New Multi-Level Attributed Graph Based Shape Matching Approach to Complex Template Design Feature Recognition
Authors: Sun Yuhang , Huang Yunbao , Chen Liping , Wang Qifu , Wan Sha
Published: September 2013

Some 3D complex shapes such as stair and compound-hole in engineering design always contains various geometric face types, adjacent geometric constraints and typical design semantics. These 3D shapes can be defined as template design features because they are frequently reused for synchronous shape modeling to greatly accelerate design and analysis process. To recognize the complex template design features, we present a new multi-level attributed graph based shape matching approach. The core idea is the Multi-level Attributed Graph (MLAG), which describes not only the geometry face types such as plane and the geometry relationships between two adjacent faces such as tangency that are usually used for 3D shape retrieval and manufacturing feature recognition, but also the design semantic features among multiple adjacent faces even non-adjacent faces such as boss. Such design semantic feature will greatly benefit MLAG matching process, so that a complex template design feature can be efficiently recognized for design modification. Finally, two experiments with some kinds of template feature recognition are also shown to demonstrate the effectiveness of the proposed method.
Structural Optimization and LCA for a Computer-Aided Sustainable Design
Authors: Russo Davide , Matina Dario
Published: September 2013

The present work sets the basis for the development of a systematic eco-sustainable computer aided design procedure. During years modules for the specific design of all phases of a product life-cycle have been developed: manufacturing, assembly, reliability, maintainability, resilience, disassembly, end-of-use, etc.

This work instead places itself in a broader context of “Design for ecology”. It means to overcome the limits of a classic design process such as “Design for X”, through an approach that makes the designer aware of the consequences that each design modification (to the geometry, the material or the manufacturing process) determines on the environmental impact of the product entire life-cycle.

This work proposes a method of integrated management of (1)virtual prototyping software (such as structural optimization, FEM and CAD), (2) function modelling methodology and (3) LCA tools. It is mainly based on the configuration of structural optimization strategies especially conceived to obtain lighter and more compact products, therefore, more eco-sustainable. The method, due to the nature of the instruments it employs, can be applied only to products that can be modelled in a CAD environment. The article, in particular, shows how to articulate the workflow between virtual prototyping and LCA tools.

A case study regarding a moped rim is used to explain the procedure while software implementation is still underway.
Towards Improved User-Product Testing With Cognitively Enhanced Scenarios
Authors: van der Vegte Wilhelm Frederik , Moes Niels C. C. M.
Published: September 2013

With the increasing information-intensiveness of products, users are challenged with expanding options and possible ways to interact. Rapidly escalating numbers of possible user-operation sequences hinder designers in anticipating all possible (unacceptable) outcomes. Interactively simulating product models with human subjects to explore all options is not practicable. Virtual simulation with computer models of users can open the way towards faster-than-real-time performance and investigation of massive numbers of interaction sequences. This paper reports on opportunities to improve realism of virtual-use simulations by incorporating knowledge about the workings of the human brain We elaborate how, in particular, cognitive-architecture simulations developed by cognitive scientists and error phenotypes identified in human reliability analysis (HRA) can extend a virtual-use simulation approach that we have proposed in foregoing work, by offering the prospective of generating interaction sequences with erroneous user actions unforeseen by the designer. We outline how such an integrated system can be implemented and also discuss validation issues.
Evaluation of Whole-Body Navigation and Selection Techniques in Immersive 3D Environments
Authors: Klompmaker Florian , Dridger Alexander , Nebe Karsten
Published: September 2013

Since 2010 when the Microsoft Kinect with its integrated depth-sensing camera appeared on the market, completely new kinds of interaction techniques have been integrated into console games. They don’t require any instrumentalization and no complicated calibration or time-consuming setup anymore. But even having these benefits, some drawbacks exist. Most games only enable the user to fulfill very simple gestures like waving, jumping or stooping, which is not the natural behavior of a user. In addition the depth-sensing technology lacks of haptic feedback. Of course we cannot solve the lack of haptic feedback, but we want to improve the whole-body interaction. Our goal is to develop 3D interaction techniques that give a maximum of freedom to the user and enable her to perform precise and immersive interactions.

This work focuses on whole-body interaction in immersive virtual environments. We present 3D interaction techniques that provide the user with a maximum of freedom and enables her to operate precisely and immersive in virtual environments. Furthermore we present a user study, in which we analyzed how Navigation and Manipulation techniques can be performed by users’ body-interaction using a depth-sensing camera and a huge projection screen. Therefore three alternative approaches have been developed and tested: classical gamepad interaction, an indirect pointer-based interaction and a more direct whole-body interaction technique. We compared their effectiveness and preciseness. It turned out that users act faster, while using the gamepad, but generate significantly more errors at the same time. Using depth-sensing based whole-body interaction techniques it became apparent, that the interaction is much more immersive, natural and intuitive, even if slower. We will show the advantages of our approach and how it can be used in various domains, more effectively and efficiently for their users.
An Experimental Approach to Assess the Disparities in the Usage Trends of Domestic Electric Lighting
Authors: Zaraket Toufic , Yannou Bernard , Leroy Yann , Minel Stephanie , Chapotot Emilie
Published: September 2013

In a country like France, electricity consumption devoted to domestic lighting represents nearly a fifth of the total energy consumption of a building. The use of electric lighting is influenced by several factors such as the building’s structural characteristics, the activities of its occupants, the lighting equipments, and the level of natural light. Designers do take into account, in their energy models, the influence of occupants on the building’s overall energy consumption. However, these models still have some drawbacks regarding the comprehension of real “occupants’ energy behaviors” which play an important role in the discrepancies between predicted and real energy consumptions. The behavioral factors behind occupants’ usage trends of energy are still not thoroughly explored. Therefore, it is assumed that a better comprehension of these behaviors and consumption mechanisms could lead to the identification of technical solutions and energy saving potentials, thus resulting in a more robust building design.

The present paper aims to provide an insight into domestic lighting usages. The main objective is to explore the key factors (socio-demographic, economic, technical and behavioral) responsible for the disparities in lighting consumption between one household and another. For this purpose, an experiment is performed concurrently to the proposal of a lighting usage model. A micro level investigation protocol is elaborated and used to conduct in-depth studies on the usage patterns of electric lighting. The survey is conducted on a sample of 8 French households. The methodology for constructing the experimental protocol, its deployment, as well as the results obtained and their analysis are presented in this paper. The need for further qualitative and quantitative studies to better understand the usage trends of electric lighting is discussed.
Global Product Family Design: Multi-Objective Optimization and Design Concept Exploration
Authors: Fujita Kikuo , Nasu Ken , Ito Yuma , Nomaguchi Yutaka
Published: September 2013

Global product family design is the problem in which product variants and supply chain configuration are simultaneously designed. It has become a significant concern of manufacturing industries under globalization. Its context is not only complicated under various factors and their interactions but also vague under strategic decision making. In this paper, first, a multi-objective mixed-integer formulation of simultaneous design of module commonalization and supply chain configuration is developed under the criteria on quality, cost and delivery, and an optimization algorithm for obtaining Pareto optimal solutions is configured by using a neighborhood cultivation genetic algorithm and simplex method. Then, this paper investigates into design concept exploration on the optimality and compromise in global product family design with data-mining techniques, a principal component analysis technique and a self-organizing map technique. This paper demonstrates some numerical case studies for ascertaining the validity and promise of the proposed mathematical model and computational techniques for supporting the designer’s decision making toward the excellence in global product family design.