bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of the Robust Stability Limit for Multi-Cutter Turning Processes
Authors: Reith Marta J. , Bachrathy Daniel , Stepan Gabor
Published: January 2016

Multi-cutter turning systems bear huge potential in increasing cutting performance. In this study we show that the stable parameter region can be extended by the optimal tuning of system parameters. The optimal parameter regions can be identified by means of stability charts. Since the stability boundaries are highly sensitive to the dynamical parameters of the machine tool, the reliable exploitation of the so-called stability pockets is limited. Still, the lower envelope of the stability lobes is an appropriate upper boundary function for optimization purposes with an objective function taken for maximal material removal rates. This lower envelope is computed by the Robust Stability Computation method presented in the paper. It is shown in this study, that according to theoretical results obtained for optimally tuned cutters, the safe stable machining parameter region can significantly be extended, which has also been validated by machining tests.
A Mathematical Model for Pressure Compensating Emitters
Authors: Taylor Katherine A. , Shamshery Pulkit , Wang Ruo-Qian , Winter Amos G.
Published: January 2016

This paper presents a mathematical model investigating the physics behind pressure-compensating (PC) drip irrigation emitters. A network of PC emitters, commonly known as drip irrigation, is an efficient way to deliver water to crops while increasing yield. Irrigation can provide a means for farmer to grow more sensitive, and profitable crops and help billions of small-holder farmers lift themselves out of poverty. Making drip irrigation accessible and economically viable is important for developing farmers as most face the challenges of water scarcity, declining water tables and lack of access to an electrical grid. One of the main reasons for the low adoption rate of drip irrigation in the developing world is the relatively high cost of the pumping power. It is possible to reduce this cost by reducing the required activation pressure of the emitters, while maintaining the PC behavior. The work presented here provides a guide of how design changes in the emitter could allow for a reduction in the activation pressure from 1 bar to approximately 0.1 bar. This decrease in the activation pressure of each emitter in turn decreases the system driving pressure. This reduction of driving pressure will decrease the energy need of pumping, making a solar-powered system affordable for small-acreage farmers.

This paper develops a mathematical model to describe the PC behavior in a commercially available emitter. It is a 2D model that explains the relationship between the pressure, structural deformation and fluid flow within a PC emitter. A parametric study has been performed to understand the effects of geometric and material parameters with regards to the activation pressure and PC behavior. This knowledge will help guide the designs and prototypes of optimized emitters with a lower activation pressure, while also providing the PC behavior.
Environmental Impact Assessment During Product Development: A Functional Analysis Based Approach to Life Cycle Assessments
Authors: Santucci Alissa , Esterman Marcos
Published: January 2016

As global environmental concerns increase, industries continue to respond prominently to meeting sustainable practice standards through technological innovations and new business models. By implementing sustainable practices companies can create a competitive advantage and ultimately drive profitability in addition to mitigating environmental impacts. However, this potential is limited because current comprehensive environmental metrics, including Life Cycle Assessment (LCA), cannot be completed until after the product bill of materials is developed and the manufacturing process has been defined. In addition, the current LCA standards do not provide practitioners with a sufficiently standardized method of conducting an assessment, which makes its application to product development less reliable. This research develops a framework by which environmental impacts of a product system can be assessed and addressed during product development using a more standardized and precise LCA method. The basis of this method integrates systems engineering tools and a functional analysis based approach to LCA. Using this framework, designers can easily develop, classify, and explore different product designs based on predictive environmental impacts.
Enhancing the Design of Solar-Powered Flapping Wing Air Vehicles Using Multifunctional Structural Components
Authors: Perez-Rosado Ariel , Bruck Hugh A. , Gupta Satyandra K.
Published: January 2016

Flapping wing aerial vehicles (FWAVs) are limited to small batteries due to constraints on the available onboard payload. To increase the energy available for the vehicle, solar cells can be integrated to harvest energy during flight. This addition of available onboard energy increases the flight time of the vehicle and could eventually lead to an infinite flight as long as there is sunlight. However, integration of solar cells is expected to alter flight performance. The changes in performance must be measured and understood. Previously, solar cells have been integrated to the wings of Robo Raven III, a FWAV developed at the University of Maryland. Changes in flight performance were observed, but ultimately the vehicle was still able to maintain flight and an increase in flight time was observed. This paper extends the previous work and further integrates solar cells to the body and tail of the FWAV. Different tail designs were built and the change in performance caused by the difference in each tail was measured and compared. The new FWAV generated 1.8W more than the previous Robo Raven IIIv2 design. The best tail design has provided the longest operational flight time so far and is known as Robo Raven IIIv3. This new platform benefited from an improved tail design and carried 13g more than the original Robo Raven III tail, despite an increase in vehicle mass.
A Software for Kinetostatic Synthesis of Compliant Mechanisms
Authors: Turkkan Omer Anil , Su Hai-Jun
Published: January 2016

This paper presents a computer program for kinetostatic synthesis for design automation of compliant mechanisms. Kinetostatic synthesis is solving the geometric (e.g. link lengths) and elastic parameters (e.g. spring constants) for a prescribed set of kinematic and static force specifications. Although many kinematic synthesis algorithms and methods for compliant mechanism synthesis are available, a unified software tool that integrates algorithms and methods is yet to be developed. In our previous work, we have developed a unified framework for kinematic and static analysis of rigid body and compliant mechanisms. In this work, we extend this framework to kinetostatic synthesis of compliant mechanisms. Optimization algorithms for kinetostatic synthesis problems are presented and examples from different kinetostatic synthesis modules such as the bistable and constant force compliant mechanisms are given to demonstrate the current capability.
Algorithms for Multilayer Conformal Additive Manufacturing
Authors: Davis Joshua D. , Kutzer Michael D. , Chirikjian Gregory S.
Published: January 2016

Despite the rapid advance of additive manufacturing technologies in recent years, methods to fully encase objects with multilayer, thick features are still undeveloped. This issue can be overcome by printing layers conformally about an object’s natural geometry, as opposed to current methods that utilize planar layering. With this mindset, two new methods are derived to generate uniformly distributed layers between initial and desired geometries in both two and three dimensions. The first method is based on variable offset curves and can only be applied to convex or star-convex geometries. The second method is based on manipulated solutions to Laplace’s equation and is applicable to all geometries. Using each method, we present examples of layer generation for several geometries of varying convexities. Results are compared, and the respective advantages and limitations of each method are discussed.
Study of Current Trade-In Programs Available for Used Consumer Electronics: Investigation of Cellphones Design Features
Authors: Jayaram Sunayana , Goyal Harshit , Behdad Sara
Published: January 2016

This paper carries out an analysis of various trade-in programs available for cellphones in the United States. Product trade-in is one of the methods to recover End-of-Life (EoL) products from consumers. Currently, there is a lack of knowledge amongst consumers about such programs. The study aims to determine the factors which influence the product trade-in price. Cell phone trade-in programs of the following types of companies are studied: Phone network operator, online retailer and recycler, and educational institution. Apple’s iPhone was selected to carry out a case study to analyze various features of the trade-in programs. Age of the cell phone model, memory size of the phone, cellphone condition and phone carrier were found to be the most significant factors of a cell phone trade-in program. Newer phone models and higher memory size capacity phones were found to be offered higher price to the consumer. Cellphones of one particular phone carrier and unlocked cell phones were found to obtain the highest price quote. An attempt is made to evaluate and discuss the prospect of trade-in programs as an effective end of life recovery method. Product recovery by trade-in programs and conventional methods is compared based on factors drawn from consumer behavior studies. Improvements in trade-in programs are suggested, followed by a discussion on ways in which data from trade-in programs can benefit product designers.
Feasibility Study of an Electrodialysis System for In-Home Water Desalination and Purification in Urban India
Authors: Nayar Kishor G. , Sundararaman Prithiviraj , Schacherl Jeffrey D. , O’Connor Catherine L. , Heath Michael L. , Orozco Gabriel Mario , Wright Natasha C. , Winter Amos G.
Published: January 2016

Desalination of high salinity water is an effective way of improving the aesthetic quality of drinking water and has been demonstrated to be a characteristic valued by consumers. Across India, 60% of the groundwater, the primary water source for millions, is brackish or contains a high salt content with total dissolved solids (TDS) ranging from 500 parts per million (ppm) to 3,000ppm. The government does not provide sufficient desalination treatment before the water reaches the tap of a consumer. Therefore consumers have turned to in-home desalination. However, current products are either expensive or have low recovery, product water output per untreated feed water, (∼30%) wasting water resources. Electrodialysis (ED) is a promising technology that desalinates water while maintaining higher recovery (up to 95%) compared to existing consumer reverse osmosis (RO) products. This paper first explores the in-home desalination market to determine critical design requirements for an in-home ED system. A model was then used to evaluate and optimize the performance of an ED stack at this scale and designated salinity range. Additionally, testing was conducted in order to validate the model and demonstrate feasibility. Finally, cost estimates of the proposed in-home ED system and product design concept are presented. The results of this work identified a system design that provides consumers with up to 80% recovery of feed water with cost and size competitive to currently available in-home RO products.
Principles of Transference in Theoretical Kinematics
Authors: Kim Jin Seob , Chirikjian Gregory S.
Published: January 2016

The concept of symmetrical parameterizations of rigid-body motions was introduced in a paper in the Yang Symposium in 2014 in the context of biomolecular docking applications. These parameters are symmetrical in the sense that they “look the same” in a motion and in its inverse. Here we examine properties of special symmetrical parameterizations of rotations and full rigid-body motions in the plane and three-dimensional space. In particular, it is shown how special kinds of motions can “pass through”, or transfer, from left to right. And conjugations of rotation or homogeneous transforms can transfer to the symmetrical parameters.
Modeling Noncompensatory Choices With a Compensatory Model for a Product Design Search
Authors: Shin Jaekwan , Ferguson Scott
Published: January 2016

Market-based product design has typically used compensatory models that assume a simple additive part-worth rule. However, marketing literature has demonstrated that consumers use various heuristics called noncompensatory choices to simplify their choice decisions. This study aims to explore the suitability of compensatory modeling of these noncompensatory choices for the product design search. This is motivated by the limitations of the existing Bayesian-based noncompensatory mode, such as the screening rule assumptions, probabilistic representation of noncompensatory choices, and discontinuous choice probability functions in the Bayesian-based noncompensatory model. Results from using compensatory models show that noncompensatory choices can lead to distinct segments with extreme part-worths. In addition, the product design search problem suggests that the compensatory model would be preferred due to small design errors and inexpensive computational burden.
Wind Farm Layout Optimization in Complex Terrains Using Computational Fluid Dynamics
Authors: Kuo Jim Y. J. , Wong I. Amy , Romero David A. , Beck J. Christopher , Amon Cristina H.
Published: January 2016

The aim of wind farm design is to maximize energy production and minimize cost. In particular, optimizing the placement of turbines in a wind farm is crucial to minimize the wake effects that impact energy production. Most work on wind farm layout optimization has focused on flat terrains and spatially uniform wind regimes. In complex terrains, however, the lack of accurate analytical wake models makes it difficult to evaluate the performance of layouts quickly and accurately as needed for optimization purposes. This paper proposes an algorithm that couples computational fluid dynamics (CFD) with mixed-integer programming (MIP) to optimize layouts in complex terrains. High-fidelity CFD simulations of wake propagation are utilized in the proposed algorithm to constantly improve the accuracy of the predicted wake effects from upstream turbines in complex terrains. By exploiting the deterministic nature of MIP layout solutions, the number of expensive CFD simulations can be reduced significantly. The proposed algorithm is demonstrated on the layout design of a wind farm domain in Carleton-sur-Mer, Quebec, Canada. Results show that the algorithm is capable of producing good wind farm layouts in complex terrains while minimizing the number of computationally expensive wake simulations.
A Multi-Objective Simulated Annealing Approach Towards 3D Packing Problems With Strong Constraints: CMOSA
Authors: Cao Pei , Fan Zhaoyan , Gao Robert , Tang Jiong
Published: January 2016

This research concerns the packing problem frequently encountered in engineering design, where the volume and weight of a number of structural components such as valves and plumbing lines need to be minimized. Since in real applications the constraints are usually complex, the formulation of computationally tractable optimization becomes challenging. In this research, we propose a novel multiobjective simulated annealing (MOSA) approach towards the design optimization, i.e., optimizing the placement of valves under prescribed constraints to minimize the volume occupied, and the estimated plumbing line length. The objectives and constraints are described by analytical expressions. Our case study indicates that the new MOSA algorithm has relatively better performance towards 3D packing with strong constraints and the design can indeed be automated. The outcome of this research may benefit both existing manufacturing practice and future additive manufacturing.
Investigation of Separation Force for Bottom-Up Stereolithography Process From Mechanics Perspective
Authors: Ye Hang , Das Sonjoy , Zhou Chi
Published: January 2016

Relative to the free surface stereolithography (SLA) process, the bottom-up process has several advantages that include better vertical resolution, higher material filling rate, less production time, and less waste of photopolymer materials. However, one of the major concerns of the bottom-up SLA process is that the built-up part may break due to the resultant force generated during the pulling up process. This resultant force may become significant if the adhesive mechanism between the two contact surfaces (i.e., newly cured layer and the bottom of the resin vat) produces a strong bonding characteristic. In this work, the traction force is monitored using FlexiForce® force sensors. The experimental data are analyzed in order to obtain the initial guess for the fracture properties of the separation process. Then the separation process has been modelled based on the concept of Cohesive Zone Model (CZM) in order to study crack propagation behavior in the field of fracture mechanics. The classic bi-linear traction-separation law is adopted in the present work as the nominal constitutive law that relates the resultant traction stress and the separation distance between the two contact surfaces. The results from simulation are compared with experimental data, a good agreement for maximum traction force is found, and the discrepancy is discussed.
Quantification of Model-Form Uncertainty in Drift-Diffusion Simulation Using Fractional Derivatives
Authors: Wang Yan
Published: January 2016

In modeling and simulation, model-form uncertainty arises from the lack of knowledge and simplification during modeling process and numerical treatment for ease of computation. Traditional uncertainty quantification approaches are based on assumptions of stochasticity in real, reciprocal, or functional spaces to make them computationally tractable. This makes the prediction of important quantities of interest such as rare events difficult. In this paper, a new approach to capture model-form uncertainty is proposed. It is based on fractional calculus, and its flexibility allows us to model a family of non-Gaussian processes, which provides a more generic description of the physical world. A generalized fractional Fokker-Planck equation (fFPE) is proposed to describe the drift-diffusion processes under long-range correlations and memory effects. A new model calibration approach based on the maximum accumulative mutual information is also proposed to reduce model-form uncertainty, where an optimization procedure is taken.
Mode Shapes in Compliant Mechanisms, and a Procedure to Identify Appropriate Pseudo-Rigid-Body Model Type
Authors: Midha Ashok , Bagivalu Prasanna Pratheek
Published: January 2016

The mobility characteristics of compliant mechanisms are a function of the structural arrangement of the comprising segments and links, their types, as well as the load and/or displacement boundary conditions. It is hypothesized that an earlier defined concept of compliance number and stored strain energy in a compliant mechanism are strongly correlated. It therefore becomes necessary to define and better understand the characteristics of deformation mode shapes of compliant mechanisms. A compliant mechanism may exhibit a variety of mode shapes. In keeping with the classical mechanics notions, this paper systematically develops the mode shapes in compliant mechanisms, utilizing two distinct categories: i) segmental (elemental) mode shapes, and ii) mechanism (system) mode shapes. The possible mode shapes of the basic segment types are identified. Based on the energy storage capability of the segment types, segmental mode shapes are further classified into higher and lower order mode shapes. Similar identification is extended to compliant mechanisms as well, and the possible mechanism mode shapes are illustrated with the help of a few examples. Finally, the utility of this methodology in identifying an appropriate pseudo-rigid-body model (PRBM) corresponding to a given compliant mechanism is demonstrated. An experimental procedure aids in this process.
Considering Mechanical Advantage in the Design and Actuation of an Origami-Based Mechanism
Authors: Wilcox Eric W. , Shrager Adam , Bowen Landen , Frecker Mary , Von Lockette Paris , Simpson Timothy , Magleby Spencer , Lang Robert J. , Howell Larry L.
Published: January 2016

Increased interest in origami-based mechanisms has resulted in designers looking to them for solutions to engineering problems. Of particular interest is the ability to develop self-folding mechanisms that perform a pre-determined function in the presence of an applied field, requiring models that predict the mechanism’s force-deflection behavior and actuation input needs. In order to assist in the design of such mechanisms, this paper presents a model of the mechanical advantage for origami-based forceps (Oriceps) and explores how modifying the parameters of the model affects their behavior. The model is used to predict the force output of Oriceps actuated in an applied magnetic field. The predictions of the model are validated through experimental data.
Degree-of-Freedom-Based Instantaneous Energetic Cost of Robotic Biped Gait With Benchmarking Implications
Authors: Roberts Dustyn , Quacinella Joseph , Kim Joo H.
Published: January 2016

Instantaneous robotic gait energetics is evaluated at each joint actuator, and is characterized relative to those of humans. A degree-of-freedom (DOF)-based instrumentation system is designed for instantaneous evaluation of electrical energy expenditure (EE) rates at each DC servomotor, and implemented into a DARwIn-OP biped robot. The robot’s EE rates for the entire lower body are in agreement with its periodic gait cycle, and their trends between gait phases are similar to those of humans. The robot’s cost of transport (COT) as a function of normalized speed is also in agreement with the human COT with respect to its convexity. The contrasting distributions of EE throughout the robot and human DOFs and the robotic COT curve’s considerably large magnitudes and small speed ranges illustrate the energetic consequences of stable but inefficient static walking in the robot versus the more efficient dynamic walking of humans. These characteristics enable the identification of the DOFs and gait phases associated with the inefficiency in the robotic gait, and reflect the differences in the system parameters and gait strategies in terms of the efficiency and stability. The proposed instrumentation system provides a quantitative benchmarking approach.
Computational Metabolic Energy Expenditure Model With Novel Heat Dissipation Formulation
Authors: Peng William , Kim Joo H.
Published: January 2016

The limitations of empirical models for human metabolic energy expenditure (MEE) have motivated the search for general-purpose models based on investigations of heat dissipation. As opposed to the muscle-space approach to MEE modeling, the study outlined here adopts a joint-space MEE model developed from thermodynamics and multibody system dynamics principles. The MEE is formulated as a function of joint-space kinematic and kinetic variables and commonly measured system kinetic and kinematic parameters. This study builds on previous work by introducing an updated heat dissipation formulation that contains additional kinetic variables and accounts for the different energetic costs of negative and positive work. A multiple regression analysis is used to develop a 12 parameter MEE model with experimental MEE data obtained from human steady-state walking experiments. The resulting model was able to reliably predict the MEE of different subjects walking over a large range of speeds.
An Efficient Design Optimization Method for Functional Gradient Material Objects Based on Finite Element Analysis
Authors: Zhang Feng , Zhou Chi , Das Sonjoy
Published: January 2016

Functional Gradient Material (FGM) is one of the most promising heterogeneous materials for its spatial continuity of material properties and functional flexibility. FGM is a well-studied research topic. In this paper, we utilize Finite Element Analysis (FEA) method to model objects with spatially varying material property. A two-stage optimization framework including Monte Carlo based global optimizer and gradient descent based local optimizer is proposed to achieve the optimal material composition in response to different user defined objectives. An error diffusion based halftoning technique is utilized to convert the continuous material distribution into discrete material distribution for viable manufacturing. The transition of the material properties are governed by predefined equations and only a few coefficients instead of large number of elements are to be optimized, therefore this optimization process is more computationally efficient than traditional techniques. Meanwhile it can automatically guarantee the smoothness of material transition along the body. Such design and optimization method has the potential to enable interactive multiple material modeling and simulation. Several experiments are carried out to demonstrate its efficiency and effectiveness.
An Automated Approach to the Design of Small Aerial Systems Using Rapid Manufacturing
Authors: Mangum Pete , Fisher Zachary , Cooksey K. Daniel , Mavris Dimitri , Spero Eric , Gerdes John W.
Published: January 2016

Traditional engineering design processes focus on the generation of a completely defined solution for a specific set of design requirements. However, in the modern, rapidly evolving battlespace, Soldiers face the need for situationally specific aerial reconnaissance. Recent advances in automated manufacturing techniques, such as 3-D printing, have enabled the design of small unmanned aerial vehicles in which discrete components can be integrated with parametrically scaled and printed components. This approach enables mission-driven sizing, design, and synthesis of a product family using a small set of components. An integrated requirements and design process that separates the Soldier from any design engineering is presented. Mission requirements, performance models, component attributes, and manufacturing constraints are used to suggest a product architecture capable of fulfilling requirements. The process is executed to design an on-demand solution to specific aerial reconnaissance needs. Assembly takes place in a virtual environment prior to physical integration with off-the-shelf components. The resulting vehicle is then flown in a controlled environment to mimic the mission. A comparison of requirements to actual performance is presented. An assessment is made of the proposed capability and conclusions are drawn about the applicability and scalability of the approach.
Interdisciplinary Design Education Based on Collaboration Between Arts and Engineering Schools
Authors: Leem Soo Yeon , Lee Sang Won
Published: January 2016

In this paper, the new graduate course, referred to as “Creation and Innovation”, for interdisciplinary design and innovation is introduced based on the collaboration between arts and engineering. In this course, students having various backgrounds in arts and engineering schools participates and forms several interdisciplinary teams for project-based learning. The systematic methods such as Design Thinking Process and Strategic Foresight and Innovation have been combinatorially adopted for this course. Those methods are human-centered approaches, which allow deep understanding on users’ needs and wants by being empathized with users and their environments. This empathy activity can enable the students to actively consider users’ various aspects, which has been of much significance in the current interdisciplinary design education. It is also shown that the collaboration among the team members with the backgrounds of arts and engineering can be effective to generate more creative and innovative ideas by combining their holistic and analytic views.
Towards an Integrated Data Schema Design for Additive Manufacturing: Conceptual Modeling
Authors: Lu Yan , Choi Sangsu , Witherell Paul
Published: January 2016

Large amounts of data are generated, exchanged, and used during an additive manufacturing (AM) build. While the AM data from a single build is essential for establishing part traceability, when methodically collected, the full processing history of thousands of components can be mined to advance our understanding of AM processes. Hence, this full body of data must be captured, stored, and properly managed for easy query and analysis. An innovative, AM-specific data model is necessary for establishing of a comprehensive AM information management system.

This paper introduces our work towards designing a complete and integrated data model for AM processes. We begin by defining the scope and specifying the requirements of such a data schema. We investigate how information created and exchanged in the AM process chain is identified based on an AM process activity diagram. A comprehensive survey shows that existing AM standards are unable to provide both the breadth and the depth needed for an integrated AM information model. We propose a conceptual design for an additive manufacturing integrated data model, AMIDM, based on a well-defined product lifecycle management (PLM) data modeling method called PPR (product, process, and resource). The proposed AM model has a core scheme composed of product, process, and resource entities. The process entities play critical roles in transforming product input into product output using assigned resources such as equipment, material, personnel, and software tools. The proposed model has been applied to an information system design for Powder Bed Fusion based AM experimental data management. An XML (eXtensible Markup Language) schema is presented in the paper to demonstrate the effectiveness of the conceptual model.
Design of Eight-Bar Linkages With an Application to Rectilinear Motion
Authors: Sonawale Kaustubh H. , McCarthy J. Michael
Published: January 2016

This paper explores an automated methodology to design eight-bar linkages for five positions, by constraining the user defined 4R open chain and 6R closed chain using RR dyads. The application in focus is that of rectilinear motion. The paper lays down the rules for systematic selection of link pairs for the application of RR constraints, that help automate the synthesis of eight-bar linkages. The methodology performs a random search within the user specified tolerance zones around the task specifications to increase the number of candidate linkage solutions. These linkages are then subjected to forward kinematic analysis using the Dixon determinant elimination procedure to find all possible linkage configurations over the range of motion of the input link. Linkages that have all the task configurations on one branch ensure their smooth movement through them. The result is an array of defect-free eight-bars that can perform approximate rectilinear motion. This method provides increased flexibility and control over the synthesized linkage compared to other known rectilinear motion linkages, owing to the ability to specify the backbone chain. A couple of examples are presented to illustrate the results.
Application of X-Ray Micro-CT Method to Assess Damage/Flaw Presence and Progression in Tire Rubber Materials
Authors: Liu Ruofan , Sancaktar Erol
Published: January 2016

We have demonstrated that the X-ray Micro-CT (Computed Tomography – 3D) method can be used to progressively assess damage/flaw presence and progression in SBR-based (styrene butadiene rubber) tire rubber materials. Our experimental results reveal that progression of flaws due to cyclic (fatigue) loading may not occur at a fast rate until a catastrophic failure occurs in the tire material.
A Semantic Similarity Based Dispatching Rule Selection System for Job Shop Scheduling With Multiple Production Objectives
Authors: Zhang Heng , Roy Utpal
Published: January 2016

Job shop scheduling is an important activity which properly assigns production jobs to different manufacturing resources before production starts. Compared to other scheduling approaches that use optimal branch and bound algorithms, meta-heuristics, etc., the dispatching rule based approach has been widely used in the industry because it is easier to implement, and it yields reasonable solutions within a very short computation time. The dispatching rule based approach uses a selected single dispatching rule (e.g. Shortest Processing Time or Earliest Due Date) or a rule combination depending on the current production objective like maximizing productivity, minimizing makespan or meeting the due dates. However, a dispatching rule or a pre-set rule combination always pursues a single and fixed production objective. This characteristic confines the flexibility of the scheduling system in practice. In order to address this issue, this paper proposes a semantic similarity based dispatching rule selection system that can achieve the intelligent selection of dispatching rules based on the user selected one or more production objectives for job shop scheduling. The intelligent selection is addressed by measuring the semantic similarities (based on ontology) between the user selected production objectives and the characteristics of the dispatching rules. The rule combinations will then be constructed by combining individual dispatching rules with similarity value based weights. A proof-of-concept demo has also been provided as a case study in this paper.
Development of a Servohydraulic Roller Test Bench for Indoor Evaluation of the Vibrational Comfort of Bicycle Components
Authors: Petrone Nicola , Trabacchin Francesco , Panizzolo Fausto
Published: January 2016

One of the most important parameters evaluated by racing and trekking cyclists is vibrational comfort: as generally accepted, it is closely correlated to the response of bicycle components in combination with the cyclist’s characteristics.

Vibration transmissibility of wheels and saddles was recently studied during lab tests using a wooden dummy bottom resting on the saddle or in road tests on an instrumented racing bicycle at different speeds on different surfaces.

The use of shakers is also well established in the evaluation of cyclist’s posture effects on the overall bicycle behaviour. In fact, in previous works, either a servohydraulic actuator was applied to the seatpost of a bicycle frame hinged at the front wheel axle with a cycling tester, or two electrodynamic shakers were applied under the wheels of a fully equipped bicycle, with a cyclist sitting statically on the saddle. In the present study, the combination of a servohydraulic actuator and a roller type bench allowed to overcome the limitations of the former experiences. Random vibrations were input to the bicycle-cyclist complex by means of rollers supporting the rear wheel while cyclists were cycling unrestrained on the rollers. The test bench setup and tuning approach are presented for comparison with results available from previous bench and road tests.
Design Talking: How Design Practitioners Talk About Design Research Methods
Authors: Roschuni Celeste , Kramer Julia , Agogino Alice
Published: January 2016

To support the development of TheDesignExchange — a portal to a comprehensive set of design methods applicable to a range of disciplines — we hosted a series of workshops with design students, educators and practitioners. In this paper, we summarize insights gained from the three practitioner workshops associated with early stage design methods used to: Research, Analyze and Communicate. We contrast the practitioner feedback with insights from previous workshops with design students and educators. We also discuss implications for enhancing professional skills and industry practice into design education.
Design of a Soft Multi-Degree of Freedom Tool Positioner With Variable Stiffness Integrating Molded Air Muscles Actuation, Granular Jamming and Dielectric Elastomer Sensing
Authors: Bouliane-Blais Guillaume , Plante Jean-Sébastien
Published: January 2016

Soft technology is more and more present in robotics allowing safe interaction with humans, high dexterity in constrained environments, and safe manipulation of fragile or undefined objects. However, soft robotics is limited by a fundamental trade-off between available workspace and stiffness. Position feedback is also challenging as soft robots generally use deformable mechanisms instead of discrete joints. Here, the design of a soft four-degree-of-freedom tool positioner integrating a brake system and a soft sensor is proposed to address these issues. The design integrates molded air muscle actuators, granular jamming brakes, and Dielectric Elastomer Sensors (DES). The design is experimentally validated based on the requirements of a manipulator for liver cancer treatment, which is a representative application of soft robotics. The use of granular jamming mitigates the fundamental trade-off of soft robotics as it allows the manipulator to reach a large workspace (1500 cm3) while having the capacity to provide a high stiffness (up to19 times the initial stiffness). DES provides satisfactory position feedback, demonstrating a 0.69 mm accuracy that is lower than the 1 mm requirement. The proposed design using granular jamming and DES could greatly benefit human-safe and medical robotics.
Development of an Image-Based Biomechanical Model for Assessment of Hip Fracture Risk
Authors: Nasiri Sarvi Masoud , Luo Yunhua
Published: January 2016

Low-trauma hip fracture, usually caused by fall from standing height, has become a main source of morbidity and mortality for the elderly. Factors affecting hip fracture include sex, race, age, body weight, height, body mass distribution, etc., and thus, hip fracture risk in fall differs widely from subject to subject. It is therefore necessary to develop a subject-specific biomechanical model to predict hip fracture risk. The objective of this study is to develop a two-level, image-based, subject-specific biomechanical model consisting of a whole-body dynamics model and a proximal-femur finite element (FE) model for more accurately assessing the risk of hip fracture in lateral falls. Required information for constructing the model is extracted from a whole-body and a hip DXA (Dual Energy Xray Absorptiometry) image of the subject. The proposed model considers all parameters subject-specifically, which will provide a fast, accurate, and non-expensive method for predicting hip fracture risk.
Uncertainty Quantification in Time-Dependent Reliability Analysis
Authors: Hu Zhen , Mahadevan Sankaran , Du Xiaoping
Published: January 2016

One of the essential steps in time-dependent reliability analysis is the characterization of stochastic load processes and system random variables based on experimental or historical data. Limited data results in uncertainty in the modeling of random variables and stochastic loadings. The uncertainty in random variable and stochastic load models later causes uncertainty in the results of reliability analysis. An uncertainty quantification framework is developed in this paper for time-dependent reliability analysis. The effects of two kinds of uncertainty sources, namely data uncertainty and model uncertainty on the results of time-dependent reliability analysis are investigated. The Bayesian approach is employed to model the epistemic uncertainty sources in random variables and stochastic processes. A straightforward formulation of uncertainty quantification in time-dependent reliability analysis results in a double-loop implementation, which is computationally expensive. Therefore, this paper builds a surrogate model for the conditional reliability index in terms of variables with imprecise parameters. Since the conditional reliability index is independent of the epistemic uncertainty, the surrogate model is applicable for any realizations of the epistemic uncertainty. Based on the surrogate model, the uncertainty in time-dependent reliability analysis is quantified without evaluating the original limit-state function, which increases the efficiency of uncertainty quantification. The effectiveness of the proposed method is demonstrated using a mathematical example and an engineering application example.
Map-Based Navigation of an Autonomous Car Using Grid-Based Scan-to-Map Matching
Authors: Furukawa Tomonari , Takami Kuya , Tong Xianqiao , Watman Daniel , Hamed Abbi , Ranasinghe Ravindra , Dissanayake Gamini
Published: January 2016

This paper presents the map-based navigation of a car with autonomous capabilities using grid-based scan-to-map matching. The autonomous car used for demonstration is built based on Toyota Prius and can control the throttle, the brake and the steering by a computer. The proposed grid-based scan-to-map matching method represents a map with a finite number of grid cells, represents a scan and the map with scan points at each grid as normal distributions (NDs) and constructs a map by matching the scan NDs to the map NDs. The proposed method enables scan-based mapping at high speed while maintaining high accuracy. The representation of a grid cell of a map in terms of multiple NDs further enhances speed and accuracy. The accuracy analysis of the proposed method shows that a small robot with a wheel diameter of 8cm had yielded no loop closure error after the travel of 186m while the terminal position error by the GMapping was approximately 1m with the error growth of 1%. The application of the proposed method with the autonomous car has then demonstrated the ability of the proposed method for autonomous driving with varying and high speed and has also quantified the significance of speed for successful mapping in autonomous driving.
Verification of Models of Personal Perception of Faces by Closed-Eye Classifier Using Histogram Correlation
Authors: Romero J. , Diago L. , Shinoda J. , Hagiwara I.
Published: January 2016

People rapidly form impressions from facial appearance, and these impressions affect social decisions. Data-driven, computational models are the best available tools for identifying the source of such impressions. However, the computational models cannot be accepted unless they have passed the tests of validation to ascertain their credibility.

In this paper, the condition of the eyes of the person is used to validate the fuzzy rules extracted from the computational models. A simple and effective classifier is proposed to evaluate the closeness of the eyes during the evaluation of a small database of portraits. The experimental results show that closed-eyes can be detected only after the proposed shift of the normalized histogram is applied. Although it is very simple, the proposed classifier can achieve better accuracy than other state of the art classifiers. The relationship between the closeness of the eyes and the evaluation of the subjects is also analyzed.
Development of a Methodology for Pseudo-Rigid-Body Models of Compliant Beams With Inserts, and Experimental Validation
Authors: Midha Ashok , Kuber Raghvendra S. , Bapat Sushrut G.
Published: January 2016

Compliant mechanisms have shown a great deal of potential, in just a few decades of its development, in providing innovative solutions to design problems. However, their use has been limited due to challenges associated with the materials. With ever increasing focus on the applications of compliant mechanisms, it is necessary to find alternatives to the existing material usage and methods of prototyping. This paper presents a methodology for the design of compliant segments and compliant mechanisms with improved creep resistance and fatigue life properties using the current state-of-the-art materials. The methodology proposes using a stronger material at the core of a softer casing. The paper provides an equivalent pseudo-rigid-body model and a closed-form elliptic integral formulation for a fixed-free compliant segment with an insert. The equivalent pseudo-rigid-body model is verified experimentally for the prediction of beam end point displacements. The paper also presents experimental results that show improvements obtained in the creep recovery properties as expected using the proposed design philosophy.
Systematic Dimensional Calibration Process for 3D Printed Parts in Selective Laser Sintering (SLS)
Authors: Ha Sangho , Han Hweeyoung , Kwon Daeil , Kim Namhun , Kim Hyeonnam , Hwang Cheolwoong , Shin Hyunshik , Park Kyujong
Published: January 2016

The selective laser sintering (SLS) processes, known for enhancing engineering properties and durability of products, are widely used in auto part development processes. The dimensional displacements of the 3D printed parts, however, hinder utilizing the technology directly to enhance their development process. In general, the SLS process causes curved shapes (convex) due to thermal deformation (thermal expansion and thermal contraction) in the powder sintering and cooling processes, which accompanies multi-phase changes of the raw materials (polymer powders). In this research, we aim to present a systematic dimensional calibration process by investigating and analyzing the dimensional deformation patterns of 3D printed samples in SLS platform (using 3D Systems’ sPro60 SD). Firstly, the test samples with complex features are produced to check the reference dimensional deviation of the SLS process. Secondly, the deformation patterns are measured and analyzed as a form of a 2nd order polynomial regression model in the global Cartesian coordinates of the platform. Lastly, the dimensional calibration methods to minimize the process errors are presented by the pre-processing of the original CAD file (.stl) with inverse transformation of the features using the 2nd order polynomial regression model. At the end of the paper, we will propose an algorithm that predicts the deformation and calibrates point-based 3D CAD STL files of samples in order to mitigate the dimensional deformation, along with test samples for illustrative purposes.
Convergence Study of Genetic Programming Approach to Estimate Surface Integrity on Additive Manufacturing Parts
Authors: Jamiolahmadi Saeed , Barari Ahmad
Published: January 2016

Surface integrity in additive manufacturing technology is of utmost importance. In order to improve surface roughness of additive manufactured products a detailed understanding of the surface is required. One of the precise methods to model the surface integrity is Genetic Programming. However, convergence of the metaheuristic methods demands a thorough study of the approach. Throughout this paper, a new methodology is developed to improve the accuracy of the surface function extracted using Genetic Programming. The proposed approach introduces a deviation space to reduce the common deviational errors that inherently exists in acquiring the surface integrity using optical sensors. This space redefines the points in a new coordinate system which is computed using total least square method. To validate the process, actual case study on an additive manufactured part is examined for the convergence of the Genetic Programming on surface integrity.