bluuebunny/crossref_metadata_2025 huggingface dataset:
Path Planning of a Material Handling Agent With Novel Locomotion
Authors: Sagar Keerthi , Zlatanov Dimiter , Zoppi Matteo , Nattero Cristiano , Sreekumar M.
Published: December 2016

This work proposes the application of a recently developed locomotion system to material handling for a flexible manufacturing layout. The “swing-and-dock” (SaD) model for realizing displacements has been invented for and is used by the mobile robotic fixtures developed in the SwarmItFix European project. This form of locomotion can be a valuable capability for material handling agents, enabling simultaneous handling in a non-linear fashion and increasing manufacturing flexibility. The paper focuses on the design of SaD path planning algorithms for the motion of a single agent. Several possible strategies and solutions are presented, elaborated, and tested via simulations. The results suggest that a Nearest Neighbor with a Random Insert Heuristic approach allows the generation of good solution sequences for a single agent with SaD locomotion visiting a varied size of destinations with stationary obstacles in its path.
Natural-Language-Instructed Industrial Task Execution
Authors: Liu Rui , Webb Jeremy , Zhang Xiaoli
Published: December 2016

To effectively cooperate with a human, advanced manufacturing machines are expected to execute the industrial tasks according to human natural language (NL) instructions. However, NL instructions are not explicit enough to be understood and are not complete enough to be executed, leading to incorrected executions or even execution failure. To address these problems for better execution performance, we developed a Natural-Language-Instructed Task Execution (NL-Exe) method. In NL-Exe, semantic analysis is adopted to extract task-related knowledge, based on what human NL instructions are accurately understood. In addition, logic modeling is conducted to search the missing execution-related specifications, with which incomplete human instructions are repaired. By orally instructing a humanoid robot Baxter to perform industrial tasks “drill a hole” and “clean a spot”, we proved that NL-Exe could enable an advanced manufacturing machine to accurately understand human instructions, improving machine’s performance in industrial task execution.
A Regularized Contact Model for Multibody System Simulation
Authors: Peiret Albert , Gholami Farnood , Kövecses József , Font-Llagunes Josep M.
Published: December 2016

Simulation of large-scale multibody systems with unilateral contacts requires formulations with which good computational performance can be achieved. The availability of many solver algorithms for Linear Complementarity Problems (LCP) makes the LCP-based formulations a good candidate for this. However, considering friction in contacts asks for new friction models compatible with this kind of formulations. Here, a new, regularized friction model is presented to approximate the Coulomb model, which allows to formulate the multibody system dynamics as a LCP with bounds. Moreover, a bristle approach is used to approximate the stiction force, so that it improves the numerical behaviour of the system and makes it able to handle redundancy coming from the friction interfaces. Several examples using a 3D wheel model has been carried out, and the proposed friction model shows a better approximation of the Coulomb model compared to other LCP-based formulations.
Force Balance of a Spatial Metamorphic 6R Closed-Chain Linkage With Specific Kinematic Conditions
Authors: van der Wijk Volkert , Zhang Ketao , Dai Jian S.
Published: December 2016

For deployable, reconfigurable, and metamorphic linkages force balance is an important property to bear the static and dynamic forces caused by the mass of each element, either due to gravity or due to inertia when moving. Force balance refers to ‘shaking force balance’ meaning that for all motion of the linkage, no dynamic reaction forces are exerted to its base and to the surroundings preventing base vibrations. This typically is an important feature in high-speed and high-precision robotic manipulation tasks. Force balance also refers to ‘static balancing with solely mass’. Since the center of mass of a force balanced linkage is stationary for all motion, a force balanced linkage is also statically balanced which means that the linkage is not affected by gravity and remains stationary in any pose without the need of actuators or brakes. This property is important for the design of, among others, large moving structures such as mobile platforms and deployable structures used in architecture.

In this paper the force balance of a spatial metamorphic plano-spherical 6R closed linkage with plane symmetry is investigated. It is shown that because of its specific kinematic conditions — being pantograph relations in the projected plane — advantageous balance solutions can be found for each of the four reconfiguration modes. For specific geometric conditions on the link design also solutions are found where the links balance one another without the need of any countermass. It is also shown how an advantageous compromise force balance solution for multiple modes is found. For this purpose an approximate force balance solution was investigated. The results are compared with the general force balance solutions of a general spatial 6R closed linkage, which are also shown and explained. All balance solutions are illustrated to have realistic interpretations.
Active Kinematics Suspension Integrating Milliken Moment Method in the Control Logic
Authors: Ramirez Ruiz Isabel , Sabbioni Edoardo , Cheli Federico
Published: December 2016

The idea behind the active kinematics suspension is to enhance its performance of vehicle dynamics. This includes improve steady and dynamic limit stability and faster transient reaction through optimized lateral and longitudinal dynamics. The driver’s benefits are: improved safety and higher driving pleasure.

To achieve more control over the position of the rear wheels and thus the tire contact patch on the ground, the active suspension introduces one independent linear actuator at each rear wheel that controls the wheels’ camber freely.

This paper will present the vehicle dynamics control logic methodology of a rear active vehicle suspension implementing the Milliken Moment Method (MMM) diagram to improve the vehicle stability and controllability, achieving gradually the front and rear axle limits.

A Multibody vehicle model has been used to achieve a high fidelity simulation to generate the Milliken Moment Diagram (MMD) also known as the CN-AY diagram, where the vehicle’s yaw moment coefficient (CN) about the CG versus its lateral acceleration (AY) is mapped for different vehicle sideslip angle and steering wheel angles. With the Moment Method computer program it is possible to create the limit of the diagram over the full range of steering wheel angle and side slip angle for numerous changes in vehicle configuration of rear camber wheels and operating conditions. The vehicle dynamics control logic uses the maps like a vehicle maneuvering area under different vehicle active configurations where vehicle’s control is most fundamentally expressed as a yawing moment to quantify the directional stability.
Design Optimization and Analysis of a Prescribed Vibration System
Authors: Malinga Bongani , Ferguson Scott M. , Buckner Gregory D.
Published: December 2016

Advances in technology that come with increased system complexity have accentuated the intricacy of decision making in engineering design. This has stimulated a great deal of research in ways to incorporate decision analysis and multi-attribute decision-making theory in engineering problems. In this research, Conjoint Value Analysis is incorporated into a scheme that optimizes the design of a multi-attribute Prescribed Vibration System. The influence of designer preferences is investigated by comparing design alternatives that result from different preference rankings. Monte Carlo-based uncertainty and sensitivity studies are performed to support the design process by providing additional information on the candidate designs. By understanding how small changes in the values of optimized parameters influence the system attributes, sensitivity analysis and uncertainty analyses can be used as a design robustness measure. The overall choice of the design is therefore based not only on the performance objectives but also on the resulting system robustness, which is very valuable considering manufacturing variations and tolerance stacks.
Analogy Seeded Mind-Maps: A Comparison of Verbal and Pictorial Representation of Analogies in the Concept Generation Process
Authors: Marshall K. Scott , Crawford Richard , Jensen Daniel
Published: December 2016

Recent research has investigated methods based on design-by-analogy meant to enhance concept generation. While these analogies can be developed in different ways and can come from many different areas, one of the most common methods is to use key customer needs or key functions as the starting point. One approach uses these key terms to seed a search for grammatically similar words. While these methods are promising, they can be cumbersome and difficult to apply in engineering classrooms or industrial product development settings.

This paper presents further evaluation of the Analogy Seeded Mind-Maps method, a new method to prompt generation of analogous solution principles drawn from multiple analogical domains. We randomly select a set of 10–15 words from a graph of grammatically analogical synonyms of a functional design requirement “seed” and populate the first-level nodes of a mind-map with the selected textual analogies. This mind-map then serves as a visual tool that is utilized during the concept generation process. The effectiveness of the tool in generating concepts has been evaluated in previous studies.

In the current study, we evaluate the effect of substituting pictures for the verbal analogies in the Analogy Seeded Mind-Maps method. The study involved student volunteers who were recruited from a senior-level design methodology course. The students were asked to complete a simple concept generation task (in teams) using either a purely verbal version of the Analogy Seeded Mind-Maps method or the alternative version that relied on pictorial analogies. The results were evaluated for quantity, quality and novelty of the concepts generated using the two methods. Analysis of the results shows that there is a statistically significant difference in the novelty of ideas generated by the two methods, with the pictorial version producing a larger number of novel ideas than the purely verbal version. While the differences in quantity and quality are not statistically significant at the P-Value < 0.05 level, there are differences that approach this level of statistical significance. Further studies are needed to determine if there is any benefit to a method that combines both verbal and pictorial analogies.
System-Level Design Tools Utilizing OPM and Modelica
Authors: Sutherland Joshua , Oizumi Kazuya , Aoyama Kazuhiro , Eguchi Takao , Takahashi Naoki
Published: December 2016

This paper presents a methodology and tools to synthesize and assess different System-Level Designs. It utilizes the descriptive modeling language Object Process Methodology (OPM) to hierarchically describe the functionality of the System of Interest which is mapped by way of various intermediary models to an architecture in the Modelica numerical modeling language. The resulting Modelica architecture model is subsequently used as a framework for the rapid creation of alternative System of Interest designs by the variation of components.

To enable consistent assessment of the alternatives, Assessment Scenarios are created based on the functionality identified by OPM decomposition. By defining a hierarchy of Modelica models with the Assessment Scenarios at the top, all the System of Interest alternative models can be composed into the Assessment Scenarios and the resulting models simulated. With a combined score for each alternative across all the Assessment Scenarios being computed by way of Multi Objective Decision Analysis (MODA).

This paper demonstrates the approach with an actual student solar powered autonomous boat development project.
Characterization and Design of Functional Quasi-Random Nanostructured Materials Using Spectral Density Function
Authors: Yu Shuangcheng , Zhang Yichi , Wang Chen , Lee Won-kyu , Dong Biqin , Odom Teri W. , Sun Cheng , Chen Wei
Published: December 2016

Quasi-random nanostructured material systems (NMSs) are emerging engineered material systems via cost-effective, scalable bottom-up processes, such as the phase separation of polymer mixtures or the mechanical self-assembly based on thin-film wrinkling. Current development of functional quasi-random NMSs mainly follows a sequential strategy without considering the fabrication conditions in nanostructure optimization, which limits the feasibility of the optimized design for large-scale, parallel nanomanufacturing using bottom-up processes. We propose a novel design methodology for designing quasi-random NMSs that employs spectral density function (SDF) to concurrently optimize the nanostructure and design the corresponding nanomanufacturing conditions of a bottom-up process. Alternative to the well-known correlation functions for characterizing the structural correlation of NMSs, the SDF provides a convenient and informative design representation to bridge the gap between processing-structure and structure-performance relationships, to enable fast explorations of optimal fabricable nanostructures, and to exploit the stochastic nature of manufacturing processes. In this paper, we first introduce the SDF as a non-deterministic design representation for quasi-random NMSs, compared with the two-point correlation function. Efficient reconstruction methods for quasi-random NMSs are developed for handling different morphologies, such as the channel-type and particle-type, in simulation-based design. The SDF based computational design methodology is illustrated by the optimization of quasi-random light-trapping nanostructures in thin-film solar cells for both channel-type and particle-type NMSs. Finally, the concurrent design strategy is employed to optimize the quasi-random light-trapping structure manufactured via scalable wrinkle nanolithography process.
ADAPt Design: A Methodology for Enabling Modular Design for Mission Specific SUAS
Authors: Fisher Zachary C. , Locascio David , Cooksey K. Daniel , Mavris Dimitri N. , Spero Eric
Published: December 2016

Recent advances in small unmanned aircraft systems (SUAS) have greatly broadened the scope of their potential applications. However, traditional design processes applied to SUAS produce a single design for a single set of requirements. Off-design mission performance is often greatly degraded due to the vehicle’s small scale. This paper considers a different approach to SUAS design aimed at addressing this issue. In this approach, a hybrid modular and scalable product family is coupled with linked engineering analyses in order to automatically formulate a design given a set of mission requirements. This allows multiple SUAS designs to be rapidly synthesized from multiple sets of design requirements using a common set of components. Designs are then rapidly generated and manufactured “on-demand” using automated manufacturing techniques in order to address unforeseen mission needs.

The design approach, named “Aggregate Derivative Approach to Product Design” (ADAPt Design), consists of four actions: (1) requirements analysis, (2) architecture selection, (3) interface design, and (4) concept refinement and design. The outcomes of the method are a family of designs which are highly compatible with design automation, and a toolset that automatically translates changes in requirements to changes in detailed 3-D models. Results of the application of this approach are presented via the design of several SUAS. The capability of the design paradigm is assessed through a comparison of design requirements to the measured performance of the designed vehicle, and conclusions are drawn about the approach’s applicability and scalability.
Coupling of Geometric and Material Stiffening Mechanisms in Origami Design
Authors: Kuhn Michael , Fuchi Kazuko , Bazzan Giorgio , Durstock Michael J. , Joo James J. , Reich Gregory W. , Vaia Richard A. , Buskohl Philip R.
Published: December 2016

Origami, the ancient art of paper folding, has recently garnered attention from the scientific community for its capacity for unique 2D – 3D shape change and programmable mechanical properties. Application areas of such properties include packaging, self-assembly, shock absorption and deployable structures. Recent studies have highlighted the role of the folded geometry to regulate the mechanical response of the origami structures, such as the increased compression stiffness of origami tubes or the tunable in-plane stiffness through select inversion of bi-stable fold vertices. In addition to geometric re-enforcement, the mechanical response of an origami structure can also be programmed through spatial patterning of the individual fold line stiffnesses. However, the coupling between the geometric and material stiffening design spaces for origami structures is poorly understood and design rules are needed to guide the use of material stiffening to enhance or mitigate a geometric stiffening effect. In this computational study, a modal analysis of a corrugated fold with varying degrees of pre-fold and different sets of fold stiffness distributions is evaluated to highlight the interaction between geometric and material stiffness mechanisms.
Semantic Interoperability of GD&T Data Through ISO 10303 Step AP242
Authors: Venkiteswaran Adarsh , Hejazi Sayed Mohammad , Biswas Deepanjan , Shah Jami J. , Davidson Joseph K.
Published: December 2016

Industries are continuously trying to improve the time to market through automation and optimization of existing product development processes. Large companies vow to save significant time and resources through seamless communication of data between design, manufacturing, supply chain and quality assurance teams. In this context, Model Based Definition/Engineering (MBD) / (MBE) has gained popularity, particularly in its effort to replace traditional engineering drawings and documentations with a unified digital product model in a multi-disciplinary environment. Widely used 3D data exchange models (STEP AP 203, 214) contains mere shape information, which does not provide much value for reuse in downstream manufacturing applications. However, the latest STEP AP 242 (ISO 10303-242) “Managed model based 3D engineering” aims to support smart manufacturing by capturing semantic Product Manufacturing Information (PMI) within the 3D model and also helping with long-term archival. As a primary, for interoperability of Geometric Dimensions & Tolerances (GD&T) through AP 242, CAx Implementor Forum has published a set of recommended practices for the implementation of a translator. In line with these recommendations, this paper discusses the implementation of an AP 203 to AP 242 translator by attaching semantic GD&T available in an in-house Constraint Tolerance Graph (CTF) file. Further, semantic GD&T data can be automatically consumed by downstream applications such as Computer Aided Process Planning (CAPP), Computer Aided Inspection (CAI), Computer Aided Tolerance Systems (CATS) and Coordinate Measuring Machines (CMM). Also, this paper will briefly touch base on the important elements that will constitute a comprehensive product data model for model-based interoperability.
Village Drill: A Case Study in Engineering for Global Development, With Five Years of Data Post Market-Introduction
Authors: Mattson Christopher A. , Wood Amy E. , Renouard John
Published: December 2016

This paper presents a case study in engineering for global development. It introduces the Village Drill, which is an engineered product that has now — five years after its introduction to the market — enabled hundreds of thousands of people across 15 countries and three continents to have access to clean water. The Village Drill creates a 15 cm (6 inch) borehole as deep as 76 m (250 feet) to reach groundwater suitable for drinking. It was designed and developed by the authors together with a team of talented individuals from various disciplines. The case study presents facts and figures for the actual development and sustaining scenario and are unaltered for the purpose of publication. This approach provides the reader with a realistic view of the development time, testing conditions, fundraising, and the work needed to sustain the drill through five years of sales and distribution. The purpose of the case study is to provide sufficient and frank data about a real project so as to promote discussion, critique, and other evaluations that will lead to new developments that inspire and inform successful engineering for global development. As part of the case, the paper describes six fundamental items related to the endeavor; the product, the customer, the impact, the manufacturing, the delivery, and the revenue model of the drill.
Approximation of the Frequency-Energy Dependence in the Nonlinear Dynamical Systems
Authors: Al-Shudeifat Mohammad A.
Published: December 2016

In this work, a method is introduced for extracting the approximate backbone branches of the frequency-energy plot from the numerical simulation response of the nonlinear dynamical system. The duffing oscillator is firstly considered to describe the method and later a linear oscillator (LO) coupled with a nonlinear energy sink (NES) is also considered for further demonstration. The systems of concern are numerically simulated at an arbitrary high level of initial input energy. Accordingly, the obtained responses of these systems are employed via the proposed method to extract an approximation for the fundamental backbone branches of the frequency-energy plot. The obtained backbones have been found in excellent agreement with the exact backbones of the considered systems. Even though these approximate backbones have been obtained for only one high energy level, they are still valid for any other initial energy below that level. In addition, they are not affected by the damping variations in the considered systems. Unlike other existing methods, the proposed approach is applicable to well-approximate the backbone branches of the large-scale nonlinear dynamical systems.
Shape Parameterization Comparison for Full-Film Lubrication Texture Design
Authors: Lee Yong Hoon , Schuh Jonathon , Ewoldt Randy H. , Allison James T.
Published: December 2016

Minimizing energy loss and improving system load capacity and compactness are important objectives for fluid power applications. Recent studies have revealed that a micro-textured surface can reduce friction in full-film lubrication, and an asymmetric textured surface can further improve the performance by reducing friction and increasing normal force simultaneously. As an extension of these previous discoveries, we explore how enhanced texture design can maximize these objectives together. We design the surface texture using a set of distinct parameterizations, ranging from simple to complex (including very general geometries), to improve friction and normal force properties beyond what is possible for limited texture geometries. Here we use a rotational visco-rheometer configuration with a fixed bottom disc, a periodic textured surface, and a rotating top flat disc. The Reynolds equation is formulated in a cylindrical coordinate system and solved using a pseudo-spectral method to model Newtonian fluid flow within the gap between discs. Model assumptions include incompressibility, steady flow, constant viscosity, and a small gap height to texture radius ratio. Multiobjective optimization problems are solved using the epsilon-constraint method with an interior-point algorithm. The trade-off between competing objectives is quantified, revealing important insights. Arbitrary continuous texture geometries are represented using two dimensional cubic spline interpolation. Shifting to more general texture geometries resulted in significant simultaneous improvement in both performance metrics for full-film lubrication texture design. An important qualitative result is that textures resembling a helical blade tend to improve performance for rotating contacts in fluid power systems.
An Experiment in Engineering Ethnography in the Developing World
Authors: Wood Amy E. , Mattson Christopher A.
Published: December 2016

Designers have recently borrowed a tool called ethnography from social scientists to develop empathy and understanding for a user group before designing a product. This tool is particularly important for designers from the developed world working on products for customers in developing communities as differences in culture, language, and life experience make the designer’s intuition less reliable in the context of product use. This paper reports the use of engineering ethnography under a variety of conditions in the developing world. The authors worked in three different communities with varying degrees of language familiarity, cultural familiarity, and partners within the community in an effort to understand how each of those factors affects the process of conducting an ethnographic study. The results will help other engineers choose the most appropriate ethnographic activities for their particular project and situation.
A Robust Method to Improve Estimation Accuracy of Walking Gait Kinematics by Considering Geometrical Constraints on Kinect Data
Authors: Ghobadi Mostafa , Esfahani Ehsan T.
Published: December 2016

In this paper, we present a robust post processing method to improve the accuracy of kinematics information of human walking gait obtained from the Kinect sensor to be used for home-based gait analysis purposes. The accuracy of raw skeleton tracking data provided by Kinect suffers from a considerable level of uncertainty that compromises any reliable motion analysis. To address this issue, we have developed a comprehensive framework that reconstructs the joint trajectories from the Kinect’s uncertain measurements. The proposed algorithm detects valid motion periods as well as valid segments that represent starting and ending points of fully observed walking gait cycles. It then estimate the skeleton parameters based on the data within these valid periods. The variations of the estimated parameters is significantly reduced when only the data within valid periods are used. Moreover, by considering human motor control principles, the orientation of each limb is filtered through a 5th order polynomial fitting algorithm (Savitzky-Golay). This process removes sudden jumps/deviations which are inconsistent with human motor control. This fitting process along with the estimated skeleton parameters as geometrical constraints are used to reconstruct the joint trajectories. The experimental results demonstrate higher repeatability and less dispersion of the reconstructed joint trajectories compared to the raw skeleton information.
Toward Implementing Quantifiable Social Justice Metrics in the Design Process
Authors: Van Bossuyt Douglas L. , Dean Jered
Published: December 2016

The recent increased popularity in teaching social justice in an engineering context has revealed issues related to implementing social justice criteria in a design process. Recent experiences with undergraduate engineering students from a variety of disciplines at the Colorado School of Mines indicate that quantifying the six social justice criteria may aid in the understanding and acceptance of social justice in the design process. This paper presents our efforts toward quantifying the social justice criteria and implementing that quantification into the design process as a set of metrics that can be tracked and potentially used as part of a design space exploration or optimization effort. While the implications of quantifying and using social justice criteria as part of the design process may at first seem ripe for misuse or misunderstanding, we have found our students more receptive of social justice as an integral part of engineering design when presented in the proposed quantified manner. Much work remains to be done to fully integrate social justice into the design process. The initial efforts to more strongly link social justice with the design process and findings of that effort are presented in this paper and indicate that this is a promising area of further research.
Reconfigurable User Interfaces for CAD Applications
Authors: Kelley Mitchell J. , Rosen David W.
Published: December 2016

CAD systems have powerful features for creative technical design, yet these features are exposed through highly restrictive user interfaces. We argue that CAD users would be more productive and creative if they had greater control over their interface configuration. We propose and specify a feature set for a reconfigurable CAD user interface system. We review our prototype implementation of the proposed system and several use cases where a reconfigurable user interface would be beneficial. We present insights from our experience with popular CAD systems, various reconfigurable text editors, and our prototype CAD system. This work focuses on enhancing the utility of mice and keyboards but can be extended to any input device. Planned user studies are presented.
Human Performance in a Mixed Human-Robot Team: Design of a Collaborative Framework
Authors: Memar Amirhossein H. , Esfahani Ehsan T.
Published: December 2016

In a mixed human-robot team, adaptive automation methods can be used based on mental and cognitive states of human operators. Such adaptive behaviors can be designed such that lead to mitigation of human errors and consequently improvement of the task performance. However, real-time estimation of human internal states and their effects on the task performance remained a challenging issue and it has been the focus of many research in the recent years. Several studies have shown the capabilities of physiological feedbacks to assess human states in multi-tasking environments. In this paper, we present the early development of an experimental setup to investigate human physiological data during interaction with a small group of robotic agents. A simulated tele-exploration task is accomplished by participants and their brain activity and eye movements are recorded across the experiment. Statistical analysis are applied on the quantitative metrics to investigate the main effects and correlations between task performance and physiological features.
Development and Validation of a Göttingen Miniature Pig Brain Finite Element Model
Authors: Yates Keegan , Fievisohn Elizabeth , Hardy Warren , Untaroiu Costin
Published: December 2016

The Center for Disease Control and Prevention reports that there are approximately 1.4 million emergency department visits, hospitalizations, or deaths per year in the USA due to traumatic brain injuries (TBI) [1]. In order to lessen the severity or prevent TBIs, accurate dummy models, simulations, and injury risk metrics must be used. Ideally, these models and metrics would be designed with the use of human data. However, available human data is sparse, so animal study data must be applied to the human brain. Animal data must be scaled before it can be applied, and current scaling methods are very simplified. The objective of our study was to develop a finite element (FE) model of a Göttingen mini-pig to allow study of the tissue level response under impact loading. A hexahedral FE model of a miniature pig brain was created from MRI images. The cerebrum, cerebellum, corpus callosum, midbrain, brainstem, and ventricles were modeled and assigned properties as a Kelvin-Maxwell viscoelastic material. To validate the model, tests were conducted using mini-pigs in an injury device that subjected the pig brain to both linear and angular motion. These pigs are commonly used for brain testing because the brains are well developed with folds and the material properties are similar to human brain. The pigs’ brains were embedded with neutral density radio-opaque markers to track the motion of the brain relative to the skull with a biplanar X-ray system. The impact was then simulated, and the motion of nodes closest to the marker locations was recorded and used to optimize material parameters and the skull-brain interface. The injuries were defined at a tissue level with damage measures such as cumulative strain damage measure (CSDM). In future the animal FE model could be used with a human FE model to determine an accurate animal-to-human transfer function.
Combined Lumped and Continuum Parameter Design Optimization of Electro-Thermal Systems.
Authors: Lohan Danny J. , Allison James T. , Dede Ercan M. , Ishigaki Masanori
Published: December 2016

In this article we explore a coupled design strategy for the simultaneous optimization of lumped-parameter (electrical) and continuum parameter (thermal) systems. In terms of electrical circuit response, advances in the development of wide band-gap semiconductors and the high speed transient behavior of these devices leads to challenges associated with damping or over-shoot. To address such issues, traditional circuit design strategies should evolve to incorporate next generation electrical components effectively. Thus, we propose the incorporated design of circuit layout and routing in conjunction with heat spreader design as a more comprehensive means to optimize the layout of power-dense electronics. The effects of this multidisciplinary design are evaluated by analyzing the Pareto set, which was observed to shift towards the utopia point with each additional design consideration.
The Prototype for X (PFX) Framework: Assessing the Impact of PFX on Desirability, Feasibility, and Viability of End Designs
Authors: Menold Jessica , Simpson Timothy W. , Jablokow Kathryn W.
Published: December 2016

Each year, companies spend billions of dollars on product research and design. Studies indicate that anywhere from 40–50% of those resources are wasted on cancelled products or those which yield poor results. The largest sunk cost of product development occurs during the prototyping phase of the design process, yet engineering design research has largely overlooked this pivotal stage in the design process. This study is a portion of a larger project based on a new theoretical framework for prototyping called Prototype for X or PFX. PFX draws from Human-Centered Design (HCD), Design Thinking (DT), and Design for X (DFX) frameworks and methods to enhance the design process and enable designers to prototype more effectively. Among the anticipated impacts of PFX are increases in user satisfaction, technical quality, and manufacturability of end designs. The research described in this paper marks the first step in testing the impact of PFX on final design outcomes. Results from a between-subjects analysis indicate that PFX methods helped increase the desirability, feasibility, and viability of end designs. These results imply that teams introduced to PFX methods produced prototypes that outperformed designs from the control teams across user satisfaction, perceived value, and manufacturability metrics. These results improve our understanding of the prototyping process and highlight the potential impact that structured prototyping methods could have on end designs.
Sensitivity of Final Field Position to the Punt Initial Conditions in American Football
Authors: Turner James D. , Mann Brian P.
Published: December 2016

The starting field position is often a deciding factor in an American football game. In the case of a defensive stop, a kick, known as a punt, is used to give the receiving team a field position that is more advantageous to the kicking team when possession changes. The goal of the punter is to kick the ball along a desired flight path, where a delicate balance between the distance traveled before impact, hang time in the air, and the distance traveled after bouncing is favorable for the kicking team. However, the punter has only imprecise control over the initial conditions, such as the angular velocity, linear velocity, and orientation of the football. Due to the highly nonlinear behavior of the football, from aerodynamic and impact forces, even small changes in initial conditions can produce large changes in the final position of the football, but there may be regions of initial conditions with relatively consistent results. If punters could target such large contiguous regions of initial conditions with desirable football paths, they could improve their chances of successful kicks.

For nonlinear systems, basins of attraction diagrams are often used to graphically display the initial conditions that lead to different final attractors. In this case, the regions of initial conditions that lead to a desirable final field position can be grouped and shown graphically. A numerical simulation program was developed including models for aerodynamic flight and bouncing of the irregularly shaped football. The flight model used fourth order Runge-Kutta integration of the equations of motion of the football, including gravitational and aerodynamic forces and moments with empirical lift, drag, and yaw coefficients in three dimensions. The bounce model was based on an empirical two-dimensional coefficient of restitution model that was published in the literature. The behavior of a football in flight and during bouncing was simulated for a range of initial angular velocities and launch angles, and the characteristics of the flight paths were analyzed. The characteristics of some regions of initial conditions were relatively sensitive to small changes, while other regions were relatively uniform. This shows that this approach, with a quantitatively accurate bounce model, could be practically applied to develop a guide for punters to optimize their kicks. With such a guide and sufficient practice, punters could select and target the larger regions of initial conditions that produced desirable behavior, which would improve their chances of successful punts.
Design and Control of an Active Palm Roll Joint for the Human Prosthetic Hand
Authors: Newby Brad , Youngers Nicholas , Adhikari Visharath , Yihun Yimesker , Lankarani Hamid
Published: December 2016

This paper presents the design and control of a human prosthetic hand with an active palm roll joint. An active palm roll to a prosthetic hand will add a new degree-of-freedom, which can maximize the functionality and capability of performing complex tasks. The palm roll combined with the thumb allows the finger tips to touch one another and pinching to become a possible task for the user. In addition to maximizing the functionality of the hand, the inclusion of an active palm joint in the design provides a useful function for the design of prosthetics for children and the elderly who do not have enough upper arm strength to grasp objects firmly in their hand. The kinematics and workspace analyses of the pinky fingertips with the active palm joint and the thumb are also conducted in this study. With the added palm joint, the interaction of the workspace of the pinky fingertip and the thumb-tip is maximized, which allows grasping and manipulating different sizes and shapes of an object. Experiments are conducted to demonstrate the use of the active palm joint in grasping of objects.
An Integrative Framework for Design and Control Optimization of a Variable-Ratio Gearbox in a Wind Turbine With Active Blades
Authors: Lall Amrita , Khakpour Nejadkhaki Hamid , Hall John
Published: December 2016

A variable ratio gearbox (VRG) provides discrete variable rotor speed operation, and thus increases wind capture, for small fixed-speed wind turbines. It is a low-cost, reliable alternative to conventional variable speed operation, which requires special power-conditioning equipment. The authors’ previous work has demonstrated the benefit of using a VRG in a fixed-speed system with passive blades. This work characterizes the performance of the VRG when used with active blades. The main contribution of the study is an integrative design framework that maximizes power production while mitigating stress in the blade root. As part of the procedure, three gear ratios are selected for the VRG. It establishes the control rules by defining the gear ratio and pitch angle used in relation to wind speed and mechanical torque. A 300 kW wind turbine model is used for a case study that demonstrates how the framework is implemented. The model consists of aerodynamic, mechanical, and electrical submodels, which work collaboratively to convert kinetic air to electrical power. Blade element momentum theory is used in the aerodynamic model to compute the blade loads. The resulting torque is passed through a mechanical system and subsequently to the induction machine model to generate power. The BEM method also provides the thrust and bending loads that contribute to blade-root stress. The stress in the root of the blade is also computed in response to these loads, as well as those caused by gravity and centrifugal force. Two case studies are performed using wind data that was obtained from the National Renewable Energy Laboratory (NREL). Each of these represents an installation site with a unique set of wind conditions that are used to customize the wind turbine design. The framework uses dynamic programming to simulate the performance of an exhaustive set of combinations. Each combination is evaluated over each set of recorded wind data. The combinations are evaluated in terms of the total energy and stress that is produced over the simulation period. Weights are applied to a multi-objective cost function that identifies the optimal design configurations with respect to the design objectives. As a final design step, a VRG combination is selected, and a control algorithm is established for each set of wind data. During operation, the cost function can also be used to bias the system towards higher power production or lower stress. The results suggest a VRG can improve wind energy production in Region 2 by roughly 10% in both the low and high wind regions. In both cases, stress is also increased in Region 2, as the power increases. However, the stress in Region 3 may be reduced for some wind speeds through the optimal selection of gear combinations.
Modeling of 3D Printer Based on a Flexible Cartesian Mechanism
Authors: Okabe Eduardo Paiva , Masarati Pierangelo
Published: December 2016

This work presents the computational modeling of a three dimensional printer based on a flexible Cartesian mechanism using a multidisciplinary open source software. The dynamic simulation of the flexible mechanism was compared to that of a rigid one to highlight the differences between both approaches. The flexible components of the printer were modeled using beam elements. The simulation showed that the flexibility of the deposition mechanism contributes to its error positioning and vibration.
Development of an Affordable 7-DOF Robotic Arm for Education in Mechanisms and Robotics
Authors: Kavousanakis Stylianos , Jones Anthony H. , Kenway Stefan , Wei Guowu
Published: December 2016

Although there are a number of commercialized 7-DoF robotic arms that are suitable for industrial applications and project research use, the high cost of such robotic arms has impeded the hands-on sessions constructed in the undergraduate and postgraduate level courses/modules for the purpose of studying, understanding and investigating of the redundant 7-DoF robotic arm for the education in mechanisms and robotics. In order to provide an affordable solution, this paper presents the development of a low-cost module-based 7-DoF robotic arm. Structure design of the robot arm is introduced and its kinematics is formulated based on product of exponentials representation. By using 3D printing system, the proposed robotic arm is then fabricated and assembled, and integrated with servo motors and Arduino low-level control kits, a functionally feasible prototype is developed. Tests are subsequently carried out so as to check the performance of the proposed robotic arm and to identify errors and defects for improving and optimizing the design. Integrating with MATLAB Robotic Toolbox and Arduino low-cost control platform, the robotic arm presented in this paper can be used for the purpose of mechanisms and robotics education in the courses such as robotic kinematics, automation and control, and robotic programming and planning.
An Approximate Model of the Dynamics of the Bacteriophage T4 Injection Machinery
Authors: Maghsoodi Ameneh , Chatterjee Anupam , Andricioaei Ioan , Perkins Noel
Published: December 2016

Bacteriophage T4 is one of the most common and complex of the tailed viruses that infect host bacteria using an intriguing contractile tail assembly. Despite extensive progress in resolving the structure of T4, the dynamics of the injection machinery remains largely unknown. This paper contributes a first model of the injection machinery that is driven by elastic energy stored in a structure known as the sheath. The sheath is composed of helical strands of protein that suddenly collapse from an energetic, extended conformation prior to infection to a relaxed, contracted conformation during infection. We employ Kirchhoff rod theory to simulate the nonlinear dynamics of a single protein strand coupled to a model for the remainder of the virus, including the coupled translation and rotation of the head (capsid), neck and tail tube. Doing so provides an important building block towards the future goal of modeling the entire sheath structure which is composed of six interacting helical protein strands. The resulting numerical model exposes fundamental features of the injection machinery including the time scale and energetics of the infection process, the nonlinear conformational change experienced by the sheath, and the contribution of hydrodynamic drag on the head (capsid).