bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards a Cyber-Physical Gaming System for Training in the Construction and Engineering Industry
Authors: Sivanathan Aparajithan , Abdel-Wahab Mohamed , Bosche Frederic , Lim Theodore
Published: January 2015

Introducing serious gaming systems (SGS) has the potential to enhance trainee experience and performance across the construction industry and its supply chain, such as mechanical engineering services. SGS as an ‘enabler’ in architectural engineering has received limited research in its role to assess and enhance the performance of its workforce. In a personnel high-risk environment, improving training standards to eliminate or reduce health and safety risks, in addition to providing an understanding of workers’ ergonomics, ensures sustainability of both the project and its workforce.

This paper presents an activity tracking and feedback system that captures the physical activity of a construction worker climbing a ladder. Climbing is captured with a 3D motion capture system and processed in real-time to identify potential areas of underperformance. A simple and representative scoring method was established as a reporting method (game statistics) for giving feedback about the correctness of the activity. It can nonetheless be tuned to characterise and adjust to various complexity levels in-line with the required training standards. Furthermore, the motion data and feedback information are fed into a virtual gaming environment enabling the real-time visualisation of the trainee’s motion and experiential learning of the performance through visual and audio feedback. The gaming concepts are employed here with multiple purposes, particularly for accelerating and facilitating the learning process of the trainee. In addition to the 3D motion capturing system, this paper outlines and tests a proposed serious cyber-physical gaming system that incorporates wearable technologies that has the potential to support both construction training and practice.
A Hierarchical Material Flow Based Automated Functional Decomposition for Conceptual Design of Working Machines
Authors: Yuan Lin , Liu Yusheng
Published: January 2015

The purpose of conceptual design is to build the function structure and find the principle solution for fulfilling it. A formal functional representation is needed for decomposing the overall function to sub-functions with the computer-aid reasoning process. However, the existing functional representations lack of supporting the description of attributes and internal structures of input/output material flows. Material flow may be much more complicated than the other two kinds of flows (signal flow and energy flow) since its geometry and topology may be very complex, and which hinders the automated functional decomposition. In this paper, we propose a hierarchical material representation for the working machines which use material as the primary input/output flows. We combine input/output transformation model with “verb+noun” pairs, using the standard vocabulary of functional basis, to model function formally and objectively. Therefore, the functional effects can be inferred from the information contained in flows. Moreover, we propose the concept of action as an operation process that bridge what and how of one function to guide the further decomposition. Finally, a prototype tool is developed as a MagicDraw’s plug-in to implement the decomposition process.
A Novel Synthesis Method of Polygon-Scaling Mechanisms
Authors: Bai Guochao , Wei Shimin , Li Duanling , Liao Qizheng , Kong Xianwen
Published: January 2015

A polygon-scaling mechanism is a single DOF (degree-of-freedom) mechanism for scaling a polygon. This paper presents a tetragon-elements based synthesis method of polygon-scaling mechanisms. According to movable conditions of radial scaling elements, four basic tetragon elements (rhombus element, parallelogram element, kite element and general tetragon element) are proposed. For a given polygon, these four types of elements can be selected based on the characteristics of target polygons to construct polygon-scaling mechanisms in a straightforward manner. Using this synthesis method, some planar 1-DOF scaling mechanisms are obtained with the characteristics of retracting and deploying. Their 3D models are also presented to proof the validity of the proposed method. Finally, a table of tetragon elements with the characteristics of their associated polygon-scaling mechanisms is summarized using which polygon-scaling mechanisms can be easily constructed.
Simulation of the Cryogenic Machining for Improved Energy Efficiency and Surface Integrity
Authors: Qian Jingxing , Tao Jing , Yu Suiran
Published: January 2015

Idea of global sustainable development dictates greener machining processes. Cryogenic machining technologies enable cleaner, more energy efficient and less health hazardous process with possible lower production costs and higher productivity. In this paper, a 2D orthogonal cryogenic cutting process simulation model to predict the thermo-mechanical fields and the residual stress distribution remains in the machined surface of AZ31B magnesium alloy has been developed using ABAQUS FEM software. The proposed model can be applied to analyze influence of cutting condition parameters on the cutting forces and on the residual stress distribution in the machined surface and subsurface, which is a critical issue concerning energy efficiency and surface integrity of a cutting process.
Control Concepts for a Vibration Absorber With an Adaptive Joint Connection
Authors: Reuss Pascal , Gaul Lothar
Published: January 2015

The use of absorbers to reduce vibrations of machines is common in industry and can be found in various applications. In most cases passive absorbers are used to cancel one particular eigenfrequency. The disadvantage of this solution is that due to the introduction of an additional degree-of-freedom two resonance peaks occur next to the absorbed eigenfrequency. Given the case that the machine operates in a wider frequency band these two eigenfrequencies could be excited and feature similarly high amplitudes. To address this concern, in the present case an adaptive absorber is used, which is able to adjust its eigenfrequency to the actually excited frequency. Therefore, the anti-resonance can be shifted such that a full cancellation of the resonance is possible. The absorber consists of a mass and two springs. One spring is fixed to the mass permanently and the second can be coupled to the system by an adaptive joint connection. The normal force in the frictional contact serves as control variable to achieve adaptivity of the dynamic eigenfrequency of the absorber. Two control concepts are presented. Both concepts include isolated curves characterizing the nonlinear relation between the dynamic stiffness and the related normal force based on simulations using the Harmonic Balance Method. Due to the isolation of the nonlinearity, linear control concepts like LQR can be applied, which is done in the present case. Furthermore, a direct control of the eigenfrequency is done. The adaptive absorber is applied to a simplified machine tool carriage.
A Plate Element With Second-Order Absolute Nodal Coordinate Slopes: Numerical Computation of Shape Functions
Authors: Olshevskiy Alexander , Dmitrochenko Oleg , Kim Chang-Wan
Published: January 2015

In this paper, the procedure of construction of geometrical and structural matrices of plate finite elements employing absolute nodal coordinate formulation (ANCF) is studied. The kinematic and topological properties of an arbitrary plate finite element are described using universal digital code dncm that provides systematic enumeration of finite elements. This code is formed using the element’s dimension d, the number of nodes it possesses n, the number of scalar coordinates per node c, and a multiplier describing the process of transforming a conventional finite element to an ANCF element m. The detailed generation of a new type of triangular plate finite element 2343 using numerical computation of shape functions is discussed in the paper. The new triangular element employs position vectors and slope vectors up to second order mixed-derivative slope vector. A detailed derivation of the equations of motion of the element is provided; the examples of numerical simulation and validation are presented. The features of creating the models and numerical methods as well as results obtained by applying both approaches are discussed in the paper.
A Parameterization Approach for Compliance Analysis and Synthesis of Flexure Mechanisms
Authors: Jia M. , Jia R. P. , Yu J. J.
Published: January 2015

This paper presents an approach based on parameterized compliance for type synthesis of flexure mechanisms with serial, parallel, or hybrid topologies. The parameterized compliance matrixes have been derived for commonly used flexure elements which are significantly influenced by flexure parameters including material and geometric properties. Different parameters of flexure elements generate different degree of freedom (DOF) characteristic of types. Enlightened by the compliance analysis of flexure elements, a parameterization approach with detailed processes and steps is introduced in this paper to help analyze and synthesize flexure mechanisms in the case study as serial chains, parallel chains, and combination hybrid chains. For a hybrid flexure, finite element modeling simulations results are compared to analytical compliance elements characters. Within linear deformations, the maximum compliance errors of analytical models are less than 6% compared with FE models. The final goal of this work is to provide a parameterized approach for type synthesis of flexure mechanisms that can be used to configure and change the parameters of flexure mechanisms to achieve desired DOF requirements of types initially.
Kinetostatic Performance Analysis of a Redundantly Driven Parallel Kinematic Manipulator
Authors: Lorenz Michael , Corves Burkhard , Riedel Martin
Published: January 2015

In general the mechanical handling of objects in space is performed by manipulators, whose number of actuators is consistent with the number of required degrees of freedom. In addition, manipulators can be equipped with redundant drives, providing the manipulator with more actuators than the mobility actually requires. Thus, an active distribution of drive torques is enabled.

Accordingly, this research intends to analyze the effects of torque distribution in over-actuated manipulators relating to load-optimized and energy-efficient handling. By developing torque distribution strategies the maximum torque levels can be reduced and the required drive power thus be decreased. This results in an increased drive utilization, which improves the energy-efficiency of the handling system. On this basis, an innovative handling concept is analyzed, which represents an over-determined system given the number of actuators. Hence, it is shown that the drive utilization of manipulators can be significantly improved by means of actuation redundancy. For this purpose different mathematical optimization approaches are analyzed, which solve the over-actuated system with defined optimization targets. Here, the optimal torque distribution is found using an algorithm, which minimizes the maximum torque for each object position. The results demonstrate the efficiency of active torque distribution in terms of over-actuated manipulators. For a further approach it is planned to develop control methods including optimized torque distribution strategies in order to improve the performance and the energy efficiency of the entire manipulator.
Tracking Project Health Using Completeness and Specificity of Requirements: A Case Study
Authors: Joshi Shraddha , Summers Joshua D.
Published: January 2015

Requirements play a critical role in the design process. Much of the project time is spent eliciting the requirements. However, it is observed that students primarily only consider requirements while evaluating the concepts. This paper presents a case study conducted with senior mechanical engineering design students in a capstone course to begin to understand requirement evolution throughout a project. Data in the form of weekly requirements was collected from four teams working in parallel on the same industry sponsored project. The paper introduces the concepts of completeness and specificity that could allow the use of requirements as a tool for measuring project health. The findings from the case study reveal that the completeness and specificity of requirements increase from initial week to final week.
Requirements Evolution: Relating Functional and Non-Functional Requirement Change on Student Project Success
Authors: Summers Joshua D. , Joshi Shraddha , Morkos Beshoy
Published: January 2015

This paper presents findings from a study of the evolution of requirements in eight parallel student semester long design projects. Weekly requirements documents were collected and analyzed for the number of functional and non-functional requirements defined by each team. Trends were compared with end of project performance success. The findings provide suggestive, not definitive, evidence that (a) a higher number of defined requirements predicted higher project success, (b) early functional requirement definition relates to project success, and (c) it is important to continually evolve the requirements throughout the project. A set of guidelines and recommendations are developed.
A Framework for Problem Standardization and Algorithm Comparison in Multibody System
Authors: Lu Ying , Williams Jedediyah , Trinkle Jeff , Lacoursière Claude
Published: January 2015

The underlying dynamic model of multibody systems takes the form of a differential Complementarity Problem (dCP), which is nonsmooth and thus challenging to integrate. The dCP is typically solved by discretizing it in time, thus converting the simulation problem into the problem of solving a sequence of complementarity problems (CPs). Because the CPs are difficult to solve, many modelling options that affect the dCPs and CPs have been tested, and some reformulation and relaxation options affecting the properties of the CPs and solvers have been studied in the hopes to find the “best” simulation method. One challenge within the existing literature is that there is no standard set of benchmark simulations.

In this paper, we propose a framework of Benchmark Problems for Multibody Dynamics (BPMD) to support the fair testing of various simulation algorithms. We designed and constructed a BPMD database and collected an initial set of solution algorithms for testing. The data stored for each simulation problem is sufficient to construct the CPs corresponding to several different simulation design decisions. Once the CPs are constructed from the data, there are several solver options including the PATH solver, nonsmooth Newton methods, fixed-point iteration methods for nonlinear problems, and Lemke’s algorithm for linear problems. Additionally, a user-friendly interface is provided to add customized models and solvers.

As an example benchmark comparison, we use data from physical planar grasping experiments. Using the input from a physical experiment to drive the simulation, uncertain model parameters such as friction coefficients are determined. This is repeated for different simulation methods and the parameter estimation error serves as a measure of the suitability of each method to predict the observed physical behavior.
On-Line Tracking and Monitoring of Rolling Element Bearing Faults
Authors: Chatterton S. , Borghesani P. , Pennacchi P. , Vania A.
Published: January 2015

Diagnostics of rolling element bearings is usually performed by the analysis of vibration signal using suitable signal analysis tools, such as the most used and simplest method, Envelope Analysis. This method is based on the identification of bearing damage frequency components in the so-called Square Envelope Spectrum. If the assessment of the bearing health is quite a simple task, the on-line monitoring and the real-time evaluation of the trend of a suitable damage index is a complex task to be performed in an automatic way. The damage index must be robust against variations of system operating conditions and external vibration sources to avoid misleading results. The damage index should be also simple to be evaluated in the case of real-time applications. In the paper, the case of a rolling element bearing in which the defect develops until a permanent failure is described as well as the algorithm implemented for alarm signaling.
Design of a Compact, Lightweight, Electromechanical Linear Series Elastic Actuator
Authors: Knabe Coleman , Lee Bryce , Orekhov Viktor , Hong Dennis
Published: January 2015

Series Elastic Actuators (SEAs) have several benefits for force controlled robotic applications. Typical SEAs place an elastic element between the motor and the load, increasing shock tolerance, allowing for more accurate and stable force control, and creating the potential for energy storage. This paper presents the design of a compact, lightweight, low-friction, electromechanical linear SEA used in the lower body of the Tactical Hazardous Operations Robot (THOR). The THOR SEA is an evolutionary improvement upon the SAFFiR SEA [1]. Design changes focused on reducing the size and fixed length of the actuator while increasing its load capacity. This SEA pairs a ball screw-driven linear actuator with a configurable elastic member. The elastic element is a titanium leaf spring with a removable pivot, setting the compliance to either 650 or 372 [kN/m]. The compliant beam is positioned parallel to the actuator, reducing overall packaging size by relocating the space required for spring deflection. Unlike typical SEAs which measure force through spring deflection, the force applied to the titanium beam is measured through a tension/compression load cell located in line with each actuator, resulting in a measurable load range of +/−2225 [N] at a tolerance of +/−1 [N]. A pair of universal joints connects the actuator to the compliant beam and to the robot frame. As the size of each universal joint is greatly dependent upon its required range of motion, each joint design is tailored to fit a particular angle range to further reduce packaging size. Potential research topics involving the actuator are proposed for future work.
Robust Design of High-Performance Transparent Solar Cell Structure Considering Natural Sunlight Illumination
Authors: Yu Shuangcheng , Wang Chen , Sun Cheng , Chen Wei
Published: January 2015

Transparent organic solar cells have recently attracted extensive interest considering their potential application for the power-generating window. By allowing the transmission of visible light while converting ultraviolet and near infrared light in the solar spectrum into electricity, transparent solar cells integrated into building facade provide a smart solution to the energy dilemma in urban area. However, current works mainly optimize the performance of solar cells for very limited incident condition, such as only considering normal incidence, which results in impractical designs for real applications. In this paper, we propose a robust design approach to achieve high-performance transparent solar cell based on a non-periodic photonic structure considering a broad range of incident conditions representing natural sunlight illumination. Statistical performances are used in the robust design formulation and efficient sampling techniques are further employed to improve the computational efficiency. The Pareto-optimal solutions are obtained according to the multicriteria preference with respect to maximizing the expected cell transparency and the expected energy conversion efficiency, and minimizing the performance variance due to the incidence variation. As one example of the optimized design, the absorbing efficiency of the solar cell could be up to 85% that of its opaque counterpart with 32% visible light transmission and 0.13% variation coefficient of transparency under the actual solar illumination and incident angles from 9am to 3pm. By using this design methodology, practically efficient cell structure is achieved based on the location and installation orientation of the solar window.
Proof-of-Concept Evaluation of a Low-Cost and Low-Weight Tractor for Small-Scale Farms
Authors: Arelekatti V. N. Murthy , Björkdal Douglas H. , Graves Carmen W. , Wong Anthony , Mkrtchyan Armen , Winter Amos G.
Published: January 2015

About 80% of farms in India are less than five acres in size and are cultivated by farmers who use bullocks for farming operations. Even the smallest tractors available in the Indian market are too expensive and large, and not designed to meet the unique requirements of these farmers. To address these needs, we have developed a proof-of-concept lightweight (350 kg) tractor in collaboration with Mahindra and Mahindra Limited, an Indian tractor manufacturer. Given the challenges of accurately predicting traction in Indian soils by applying existing terramechanics models, an alternative design approach based on Mohr-Coulomb soil-failure criterion is presented. Analysis of weight, power and drawbar of existing tractors on the market, a single wheel traction test, and a drawbar test of a proof-of-concept small tractor prototype suggest that ∼200kg is the maximum drawbar force that could be achieved by a 350kg tractor of conventional design. In order to attain higher drawbar performance of 70% of the tractor weight needed for specific agricultural operations, additional design changes are required. An approach for increasing traction by adding tires is investigated and discussed. Additional research on weight distribution, dynamic drawbar testing and tread design is suggested as future work.
A Conceptual Design and Modeling Approach for Determining the Revised Energy Generation Potential due to Site Obstructions for Micro-Scale Wind Turbines
Authors: Hurdelbrink Keith , Siddique Zahed
Published: January 2015

Wind energy is one of the fastest growing sectors of renewable energy technologies. Micro-scale wind turbines are becoming increasingly more popular as individuals seek more innovative and efficient ways of reducing their energy demand. However, even with more efficient wind energy harvesting devices, it is not uncommon for the anticipated energy harvesting potential for a wind turbine to be vastly different from the actual energy generation capability for a site. This paper will introduce the problems associated with accurately predicting the energy generation potential of wind energy harvesting systems considering several power loss factors. The focus of this paper is on the use of commonly available engineering tools and simulations to evaluate obstructions on the implementation site and energy harvesting technologies in order to maximize the energy generation potential.

The issues of energy generation prediction accuracy will be addressed by incorporating high-resolution weather data and computer simulations into a predictive model. Additionally, several correction factors and design guidelines for the successful implementation of micro-scale wind turbines will be introduced and discussed. A multi-step approach is introduced to collect weather data, generate revised energy generation potential models for various land regions, account for common site obstructions through the use of correction factors, and formulate a final set of recommendations for the wind turbine implementation site. A set of design guidelines are also developed to assist in turbine placement for specific site locations. The guidelines are based on the revised energy generation prediction model, wind speed correction factors for common site obstructions, orientation and placement of the wind turbine, and other factors. Verification of the guidelines has been performed through Computational Fluid Dynamics simulation. The design approach and guidelines are examined and results presented for one case study.
On the Development of a Novel Class of “Mechanical Stepper Motors”
Authors: Rastegar Jahangir , Feng Dake
Published: January 2015

The development of a novel class of actuation devices, referred to as “mechanical stepper motors”, which can be constructed to provide high-force linear or high-torque rotary motion is presented. The operation of this novel class of mechanical stepper motor type actuators is based on the principles of operation of a simple Vernier. The actuators may be constructed to provide multiple step sizes. The motion generation mechanism of the stepper motors may be designed to lock the actuator at each motion step, thereby providing the actuator with a built-in precision in-position braking mechanism. The actuators may be powered pneumatically, hydraulically, electrically or via gas-generating charges. The actuators operating pneumatically or hydraulically may be constructed with non-metallic materials and be fully submersible, making them particularly suitable for use in medical, food, beverage and chemical industries and where electricity poses fire or explosion hazard. In this paper, the basic design and operation of this novel class of mechanical stepper motors are described. As examples of such mechanical stepper motors, the details of the design and construction of a linear and a rotary mechanical stepper motor and their characteristic are provided.
Frameworks for Organizing Design Performance Metrics
Authors: Lucero Briana , Ngo Peter , Linsey Julie , Turner Cameron J.
Published: January 2015

Computational tools for aiding design-by-analogy have so far focused on function- and keyword-based retrieval of analogues. Given the critical role of performance and benchmarking in design, there is a need for performance metrics-driven analogy retrieval that is currently unmet. Towards meeting this need, a study has been done to investigate and propose frameworks for organizing the myriad technical performance metrics in engineering design, such as measures of efficiency. Such organizational frameworks are needed for the implementation of a computational tool which can retrieve relevant analogies using performance metrics. The study, which takes a deductive approach, defines a hierarchical taxonomy of performance metrics akin to the functional basis vocabulary of function and flow terms. Its derivation follows from bond graphs, control theory, and Design for X guidelines.
Assessment of Crack Initiation in Tire Synthetic Rubber by Residual Strength Method
Authors: Sancaktar Erol , Chang I-Ta , Liu Ruofan , Bower Andrew
Published: January 2015

Classically, fatigue analysis such as Miner’s Rule is a representation of the “Residual Strength” method; however it is typically applied to relatively brittle materials using the methods of elasticity. We propose a fatigue-based “Residual Strength” method for synthetic rubber materials used in tire production. We model progressive but very slow cumulative damage by using constant strain rate behavior of the neat material, and material subjected to fatigue loading and by assessing the differences in failure stress and strain values as well as resilience and toughness values. Results are planned to be reflected to S-N curves. Our method will serve as an accurate predictive durability tool for tires build using different materials, fillers, reinforcements and different manufacturing methods.
Validity and Predictive Ability of Wilde’s Cognitive Teamology Model to Design Team Outcomes
Authors: Freiheit Theodor
Published: January 2015

An extensive analysis of the validity of Wilde’s Teamology cognitive diversity model was undertaken with 120 teams composed of over 661 participants. Myers-Briggs Type Indicator (MBTI) data was collected using a qualified test over five years from students enrolled in a fourth year capstone design course. Cognitive factor scores using Wilde’s Teamology model were calculated from the MBTI data for eight factors associated with Wilde’s Information Collection and Decision Making dimensions. Wilde’s team formation model was found to nominally contribute 10.2% to the overall prediction of the variance observed in design team outcomes using a linear regression model with a threshold that the cognitive scores must exceed. Wilde’s Teamology factors of Imagination (“prophetic, guided by inner fantasies and visions”), Community (“expressive, tactful builder of group moral”), and Evaluation (“uses personal values to distinguish good/bad”) were found to be statistically associated to design team outcomes.
Closed-Form Elliptic Integral Solution of Initially-Straight and Initially-Curved Small-Length Flexural Pivots
Authors: Midha Ashok , Kuber Raghvendra
Published: January 2015

Compliant mechanisms gain some or all of their mobility from the deflection of their flexible members. The pseudo-rigid-body model (PRBM) concept allows compliant mechanisms to be modeled using existing knowledge of rigid-body mechanisms, thereby, simplifying the design process. A pseudo-rigid-body model represents a compliant segment with two or more rigid-body segments, connected by pin joints or characteristic pivots. A compliant segment that is small in length, compared to the relatively rigid segments between which it is affixed, is termed a small-length flexural pivot (SLFP). This paper presents closed-form deflection solutions using the elliptic integral method for initially-straight and initially-curved SLFPs. The assumptions made in modeling the small-length flexural pivots in a PRBM are validated by means of the elliptic integral solutions.
Inverse Determination of Moving Heat Flux Distributions Using Reduced Order Models
Authors: Dennis Brian H. , Akbariyeh Ashkan , Michopoulos John , Komninelli Foteini , Iliopoulos Athanasios
Published: January 2015

Optimization-based solutions to inverse problems involve the coupling of an analysis model, such as a finite element model, with a numerical optimization method. The goal is to determine a set of parameters that minimize an objective function that is determined by solving the analysis model. In this paper, we present an approach that dramatically reduces the computational cost for solving this inverse problems in this way by replacing the original full order finite element model (FOM) with a reduced order model (ROM) that is both accurate and quick to compute. The reduced order model is constructed with basis functions generated using proper orthogonal decomposition of set of solutions from the FOM. A discrete Galerkin method is used to project the differential equation on the basis functions. This approach allows us to transform the linear full order finite element model into an equivalent discrete ROM with far fewer unknowns. The method is applied to a parameter estimation problem in heat transfer. Specifically, we determine the parameters governing the magnitude and distribution of an unknown surface heat flux moving at a constant velocity across the surface of a solid bar of material. A finite element model was implemented in the commercial package COMSOL and a corresponding ROM was constructed. The ROM was coupled with an optimization algorithm to determine the parameter values that minimized the distance between the computed surface temperatures and the target surface temperature. The target surface temperature was generated using simulated measurements produced from the full order finite element model. Several optimization methods were used. The results show the approach can recover the parameters with high accuracy with twenty seven FOM runs.
The Affordance of Absence
Authors: Srivastava Jayesh , Shu L. H.
Published: January 2015

We originally studied affordances to design products that encourage resource-efficient behavior in users. This paper was motivated by the observation that a lack of resources affected the ability of impoverished slum residents to perceive affordances. Data gathered from a trip to Bangladesh support recent postulations that affordance perception depends on user intention and socio-cultural norms, which are also influenced by fixation and training. We thus became interested in how absence, whether of material, components, or entire products, affected the utility of objects. We describe three dimensions of absence, one major and two minor. The major dimension is used to express the range of physical absence, i.e., of material in a part, of a part in a product, and of the entire product. Minor dimensions include the extent of user control and the permanence of absence, each of which can be used to increase utility in objects. We provide existing examples along these dimensions and describe concepts along the major, physical dimension of absence. We propose that the affordance of absence can be used as an approach to identify novel affordances, and conclude by placing it in the context of existing affordance-based design methods.
Design of Nonlinear Energy Harvester With Snap-Through Buckling Mechanism
Authors: Seong Sumin , Lee Soobum
Published: January 2015

Vibration energy harvesting (EH) has been initiated from linear vibration principle, which utilizes a single frequency to obtain power. Unfortunately, linear energy harvesters do not yield appreciable power because of random nature of vibration in the real world. In order to overcome the weakness of linear harvesters and account for the arbitrary nature of vibration, multiple nonlinear vibration energy harvesters have been developed and studied. This paper presents parametric study on the design of nonlinear vibration EH device that utilizes snap-through mechanism to obtain high power from broadband excitation frequency. The device is comprised of a cantilever beam with curved shell implemented in the middle of the beam. When vibrating, the curved shell causes snap-through buckling and the nature of vibration becomes nonlinear. For practical purposes, a broadband frequency vibration input is used to optimize the energy harvester design. Design variables are assigned and optimized in order to create optimal design of the energy harvester, which maximizes power output. The presented design will have positive effect by providing means to practically capturing wasted vibration energy in consideration of its broadband frequency utilization.
Investigating Divergent Thinking in Creativity Exercises Through Alternative Uses Tests
Authors: Nix Anthony , Arlitt Ryan , Immel Sebastian , Lemke Mark , Stone Rob
Published: January 2015

Creativity is a valuable skill for today’s workplace and one that universities should be emphasizing in the classroom. Teaching creativity usually involves the completion of “creative exercises” that help an individual understand how to think outside the box. Often individuals that are considered creative “practice” creativity on a daily basis, either through their own will or through their occupation, which increases their creative potential. Creativity is shown to be divided into multiple aspects, one of which is divergent thinking. This study examines participants’ divergent thinking skills over nine weeks as they perform a simple design task each week. The participants are split into two groups as they perform an alternative uses test on a weekly basis. Each week a new item is presented and the results are collected and entered in a database. The number of entries per card is analyzed to determine if the participants have increased their divergent thinking ability throughout the nine weeks.
A Systematic Method for Model Parameter Identification of Nonlinear Dynamics Systems Using Trajectory Pattern Method
Authors: Rastegar Jahangir , Feng Dake
Published: January 2015

In this paper, a new method is presented for model parameter identification of a large class of fully controlled nonlinear dynamics systems such as robot manipulators. The method uses trajectory patterns with feed-forward controls to identify model parameters of the system. The developed method ensures full system stability, does not require close initial estimated values for the parameters to be identified, and provides a systematic method of emphasizing on the estimation of the parameters associated with lower order terms of the system dynamics model and gradually upgrading the accuracy with which the model parameters, particularly those associated with the higher order terms of the system dynamics, are estimated. The developed method is based on Trajectory Pattern Method (TPM). In this method, for a pattern of motion the inverse dynamics model of the system is derived in algebraic form in terms of the trajectory pattern parameters. The structure of the feedback error with feedforward signal calculated with the estimated model parameters will then be fixed, and its measurement can be used to systematically upgrade the model parameter estimation. The mathematical proof of convergence of the developed method and results of its implementation on a robot manipulator with highly non-linear dynamics are provided.
Concurrent Surrogate Model Selection (COSMOS) Based on Predictive Estimation of Model Fidelity
Authors: Chowdhury Souma , Mehmani Ali , Messac Achille
Published: January 2015

One of the primary drawbacks plaguing wider acceptance of surrogate models is their low fidelity in general. This issue can be in a large part attributed to the lack of automated model selection techniques, particularly ones that do not make limiting assumptions regarding the choice of model types and kernel types. A novel model selection technique was recently developed to perform optimal model search concurrently at three levels: (i) optimal model type (e.g., RBF), (ii) optimal kernel type (e.g., multiquadric), and (iii) optimal values of hyper-parameters (e.g., shape parameter) that are conventionally kept constant. The error measures to be minimized in this optimal model selection process are determined by the Predictive Estimation of Model Fidelity (PEMF) method, which has been shown to be significantly more accurate than typical cross-validation-based error metrics. In this paper, we make the following important advancements to the PEMF-based model selection framework, now called the Concurrent Surrogate Model Selection or COSMOS framework: (i) The optimization formulation is modified through binary coding to allow surrogates with differing numbers of candidate kernels and kernels with differing numbers of hyper-parameters (which was previously not allowed). (ii) A robustness criterion, based on the variance of errors, is added to the existing criteria for model selection. (iii) A larger candidate pool of 16 surrogate-kernel combinations is considered for selection — possibly making COSMOS one of the most comprehensive surrogate model selection framework (in theory and implementation) currently available. The effectiveness of the COSMOS framework is demonstrated by successfully applying it to four benchmark problems (with 2–30 variables) and an airfoil design problem. The optimal model selection results illustrate how diverse models provide important tradeoffs for different problems.
Using a Feasibility Study of Human Computation for Failure Scenario Identification
Authors: Arlitt Ryan , Papakonstantinou Nikolaos , O’Halloran Bryan , Hoyle Chris , Stone Robert
Published: January 2015

Expert opinion is a common resource for identifying potential failure scenarios, but experts can miss novel failure combinations that have no historical precedent. A variety of computational techniques offer their own strengths for failure scenario identification, but can be limited by historical data availability or prescribed models. This paper examines the question of whether a distributed group of non-expert humans can outperform a brute force algorithm in a failure scenario prediction task. This approach uses human intuition to guide solution space exploration, and provides feedback through a system simulation. The results of the paper show that human non-experts outperformed a Monte Carlo simulation, but converge to relatively few critical failure scenarios. These results indicate that while non-expert reasoning may not be directly applicable to effective exploration of many possible failure modes, human computation has the potential to augment or compete with stochastic algorithms in a complex systems failure analysis context.
A Novel Low-Cost Stereolithography Process Based on Vector Scanning and Mask Projection for High-Accuracy, High-Speed, High-Throughput and Large-Area Fabrication
Authors: Zhou Chi , Ye Hang , Zhang Feng
Published: January 2015

Photopolymerization based process is one of the most popular additive manufacturing processes. Two primary configurations for this process are laser based vector by vector scanning (0D) and projection based layer by layer exposing (2D). With the highly focused fine laser, the scanning based process can accomplish very high surface finishing and precision, however, due to the serial nature of scanning, this process suffers from the problem of slow speed. In contrast with laser scanning, projection based process can form the whole layer in one exposure, which leads to higher fabrication efficiency. However, due to the limited resolution of projection device and various optical defects, the surface quality will be significantly deteriorated for large area fabrication. To solve this problem, a novel hybrid process by integrating vector scanning and mask projection has been presented. In this process, laser is focused into a fine spot and used to scan the boundary of the layer, whereas the projector is focused onto a large platform surface and used to form the interior area of the layer. An efficient slicing method is proposed for extracting the contour for laser scanning. A slice to image conversion algorithm is also developed to convert the offset contour to grayscale image for mask projection. Experimental results have verified that the proposed hybrid process can significantly improve the fabrication speed without losing the surface quality.
Spectral and Modal Behaviour of 3D Euler-Bernoulli Gyroelastic Beams
Authors: Hassanpour Soroosh , Heppler G. R.
Published: January 2015

A material with a continuous distribution of embedded angular momentum, called gyricity, was first proposed with a view to modelling structures that have numerous discrete gyroscopic elements. Gyroelastic beams, a special case of general gyroelastic systems, are analyzed in this paper where the governing equations for a slender gyrobeam are formulated first and then these equations are used to study the spectral and modal behaviour of gyroelastic beams.
Improving Preference Prediction Accuracy With Feature Learning
Authors: Burnap Alex , Ren Yi , Lee Honglak , Gonzalez Richard , Papalambros Panos Y.
Published: January 2015

Motivated by continued interest within the design community to model design preferences, this paper investigates the question of predicting preferences with particular application to consumer purchase behavior: How can we obtain high prediction accuracy in a consumer preference model using market purchase data? To this end, we employ sparse coding and sparse restricted Boltzmann machines, recent methods from machine learning, to transform the original market data into a sparse and high-dimensional representation. We show that these ‘feature learning’ techniques, which are independent from the preference model itself (e.g., logit model), can complement existing efforts towards high-accuracy preference prediction. Using actual passenger car market data, we achieve significant improvement in prediction accuracy on a binary preference task by properly transforming the original consumer variables and passenger car variables to a sparse and high-dimensional representation.
Proto-TAI: Quick Design Prototyping Using Tangible Assisted Interfaces
Authors: Piya Cecil , Ramani Karthik
Published: January 2015

In the real world, we use our innate manual dexterity to create and manipulate 3D objects. Conventional virtual design tools largely neglect this skill by imposing non-intuitive 2D control mechanisms for interacting with 3D design models. Their usage is thus cumbersome, time consuming and requires training. We propose a novel design paradigm that combines users’ manual dexterity with the physical affordances of non-instrumented and ordinary objects to support virtual 3D design constructions. We demonstrate this paradigm through Proto-TAI, a quick prototyping application where 2D shapes are assembled into 3D representations of ideated design concepts. Here, users can create 2D shapes in a pen-based sketch medium and use expressive handheld movements of a planar proxy to configure the shapes in 3D space. The proxy provides a metaphorical means for possessing and controlling the shapes. Here, a depth sensor and computer vision algorithms track the proxy’s spatial movement. The 3D design prototype constructed in our system can be fabricated using a laser cutter and physically assembled on-the-fly. Our system has vast implications in many design and assembly contexts, and we demonstrate its usability and efficacy through user studies and evaluations.
Out-of-Plane Nonlinear Dynamic Analysis of Wind Turbine Blades
Authors: Ramakrishnan Venkatanarayanan , Feeny Brian F.
Published: January 2015

In this work, the out-of-plane equation of motion of a wind turbine blade modeled as a beam is developed using the Lagrange formulation. The modeling of aerodynamic loads is done with the blade element momentum theory. The equation of motion has combined effects of parametric and direct excitations and is reduced to a single mode. Perturbation analysis based on previous work shows how various terms affect the steady-state responses near resonance. Numerical simulations using parameters from a real turbine, reveal that these resonance become critical as the blades increase in size. The out-of-plane vibration model shows resonances that would not be expected by blade designers without analysis and modeling techniques presented in this work. The influence of these superharmonic blade vibration responses on the increased loads on the gearbox components would provide insight into premature failure of wind turbine blades and gearboxes.
Algorithm for the Actuation Mode Selection of the Parallel Manipulator NAVARO
Authors: Caro Stéphane , Chablat Damien , Hu Yue
Published: January 2015

Kinematic and dynamic performances of parallel manipulators are usually not homogeneous throughout their operational workspace. This problem is usually solved by introducing actuation redundancy, which involves force control algorithms. Another approach is the selection of the best actuation modes along a trajectory to be followed with regard to the kinetostatic, elastostatic and dynamic performances of the parallel manipulator. Accordingly, this paper introduces a three degree-of-freedom planar parallel manipulator with variable actuation modes, named NAVARO. NAVARO stands for NAntes Variable Actuation RObot and has eight actuation modes. First, the prototype of the manipulator is presented. Then, its transmission systems are presented. The kinematic and dynamic models of the NAVARO are developed. Finally, an algorithm for multiobjective actuation mode selection based on graph theory is detailed.
Real-Time Indoor Mobile Robot Localization Based on the Recognition of Omni-Directional Artificial Landmarks
Authors: Zhong Xu , Zhou Yu , Liu Hanyu
Published: January 2015

This paper proposes a real-time robust localization scheme for mobile robots in indoor environments, based on the recognition of omnidirectional artificial landmarks captured by a single onboard camera. Considering the need of omnidirectional recognition and the disturbance of lighting condition, we encode the landmark identity with nested circles in black and white. The recognition algorithm consists of a global and a local recognition layers. The global recognition is a fast overall recognition process, including light detection, image clustering, region of interest (ROI) extraction, and ROI identification. If the number of identified ROIs does not meet the requirement of the localization algorithm, the local recognition will process those unidentified ROIs through adaptive ROI expansion and template cutting. Based on the landmark recognition, the absolute position and orientation of the camera in the environment are estimated using the geometric mapping between the image and global frames. The proposed approach is tested via experiments in a real indoor environment, and the result reveals high localization robustness and consistency to the lighting condition.