bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Testing of a High-Efficiency Rapid Throughput Community-Scale Water Pasteurization System
Authors: MacCarty Nordica , Burleson Grace , Moses Nicholas , Mulky Tejas , Johnson Joshua , Andreyka Elizabeth , Ogle Damon , Colgan Fred , Creighton Adam , Carter Tom , Andreatta Dale
Published: November 2017

Procurement of clean drinking water is one of the most important challenges facing 1 in 10 people in the world today. While there are many technologies available to disinfect water, there is still great opportunity for appropriate, sustainable technologies for low-resource or emergency situations. Pasteurizing water is an effective way to eliminate life-threatening pathogens such as bacteria, viruses, and protozoa, and requires a lower temperature (71° C) compared to traditional boiling (100° C).

This research details the development and testing of a water pasteurization system that works with the 60 Liter InStove to produce upwards of 4,500 liters of safe drinking water per day at minimal cost to the users and the environment. This flow-through system uses a combination of a heating coil, thermostatic valve, fixed volume kill chamber, and heat exchanger for heat recovery immersed in a large pot of heated water. Initial performance testing revealed that the pasteurizer produced 6.7 liters of water per minute with an energy input of 9.1 grams of equivalent dry wood per liter (175 kJ/L) at steady-state operation accounting for startup time. Microbiological testing revealed that water initially inoculated with >100,000 bacteria/ml of E. coli had no colonies remaining after treatment, for a 99.999% reduction in contamination levels. Future work will include measurement and modeling of the flow and temperature profiles throughout the system to optimize its heat transfer performance and production costs, field testing, and user-centered system-level design that develops the end-to-end solution needed to acquire and deliver clean drinking water including maintenance, container disinfection, and development of business models to support local water production.
A Preliminary Experimental Study of Additive Manufacturing Energy Consumption
Authors: Dunaway Daniel , Harstvedt James Dillon , Ma Junfeng
Published: November 2017

Additive manufacturing (AM) refers to a group of manufacturing techniques that produce components by melting and bonding material powders in a layer-by-layer fashion. By virtue of its capability of producing parts with complex geometry and functionally graded materials, AM is leading the charge of the “third industrial revolution” and has attracted great attention in multiple industrial sectors, such as manufacturing, healthcare, aerospace, and others. Sustainability of AM remains an open question. AM is inherently an energy expensive process and may be energy inefficient as compared to the traditional manufacturing process. Thus, there exists an urgent need to identify the key influence factors and quantify the energy consumption during AM production. The proposed study aims to obtain a preliminary understanding of the impact of part surface geometry on AM energy consumption. The study addresses the effect of part geometry on AM energy consumption through experimental design method. Part geometry consists of two level meanings, part surface area and part surface complexity. The study utilizes a MakerGear M2 fused deposition modeling (FDM) 3D printer to complete the designed experiments. By implementing experimental design and statistical analysis technologies, the study firstly identifies the correlation between part geometry and AM energy consumption. The result shows that part surface area is positively correlated with AM energy consumption and no significant statistical evidence to support that part surface complexity is associated with AM energy consumption. Such findings are of significance to AM energy consumption in terms of both qualitative and quantitative analysis. In addition, the study has significant potentials to guide the future AM energy consumption model development and to be extended to future AM process improvement.
Design of a Bistable Origami Reverse-Fold Using Spherical Kinematics
Authors: Alfattani Rami , Lusk Craig
Published: November 2017

This paper presents a new design concept for bistability that can be implemented as a reverse-fold origami mechanism or as a spherical four-bar mechanism. The design is based on the conceptual overlap between a certain simple class of origami mechanisms (the reverse-fold) and a class of spherical change-point mechanisms. Using both a partially compliant spherical mechanism and a piece of origami made with two sheets of paper, we implement the design concept for bistable behavior. The design concept consists in adapting planar two position synthesis to spherical mechanisms and in using a formal analogy between spherical mechanisms and certain simple origami folds. The dimensional synthesis of these two mechanisms is performed using parametric CAD. The design concept was successfully prototyped both as origami and as a partially compliant spherical mechanism.
Design and Manufacturing of a Clutch and Brake System for Indoor Tire Testing
Authors: Khan Aamir K. , Sandu Corina
Published: November 2017

The primary goal of this work is to implement a clutch and brake system on the single tire Terramechanics rig of Advanced Vehicle Dynamics Laboratory (AVDL) at Virginia Tech. This test rig was designed and built to study the performance of tires in off-road conditions on surfaces such as soil, sand, and ice. Understanding the braking performance of tires is crucial, especially for terrains like ice, which has a low coefficient of friction. Also, rolling resistance is one of the important aspects affecting the tractive performance of a vehicle and its fuel consumption. Investigating these experimentally will help improve tire models performance. The current configuration of the test rig does not have braking and free rolling capabilities. This study involves modifications on the rig to enable free rolling testing when the clutch is disengaged and to allow braking when the clutch is engaged and the brake applied. The first part of this work involves the design and fabrication of a clutch system that would not require major changes in the setup of the test rig; this includes selecting the appropriate clutch that would meet the torque requirement, the size that would fit in the space available, and the capability to be remotely operated. The test rig’s carriage has to be modified in order to fit a pneumatic clutch, its adapter, a new transmission shaft, and the mounting frame for the clutch system. The components of the actuation system consisting of pneumatic lines, the pressure regulator, valves, etc., have to be installed. Easy operation of the clutch from a remote location is enabled through the installation of a solenoid valve. The second part of this work is to design, fabricate, and install a braking system. The main task is to design a customized braking system that satisfies the various physical and functions constraints of the current configuration of the Terramechanics rig. Some other tasks are: design and fabrication of a customized rotor, selection of a suitable caliper, and design and fabrication of a customized mounting bracket for the caliper. A hydraulic actuation system is selected, since it is suitable for this configuration and enables remote operation of the brake. Finally, the rig is calibrated for the new testing configurations.
MEMS Coupled Resonator for Filter Application in Air
Authors: Ilyas Saad , Jaber Nizar , Younis Mohammad I.
Published: November 2017

We present a mechanically coupled MEMS H resonator capable of performing simultaneous amplification and filter operation in air. The device comprises of two doubly clamped polyimide microbeams joined through the middle by a coupling beam of the same size. The resonator is fabricated via a multi-layer surface micromachining process. A special fabrication process and device design is employed to enable the device’s operation in air and to achieve mechanical amplification of the output response. Moreover, mixed-frequency excitation is used to demonstrate a tunable wide band filter. The device design combined with the mixed-frequency excitation is used to demonstrate simultaneous amplification and filtering in air.
Understanding the Impact of Climate Zones for Occupancy Trends in Sustainable Housing Designs
Authors: Lin Sean , Albarhami Bahaa , Mayoral Salvador , Piacenza Joseph
Published: November 2017

The purpose of the paper is to provide a model prediction to capture how energy usage in sustainable buildings on college campuses is affected by different climate zones. A case study focus is on the California State University, Fullerton (CSUF) Student Housing Phase III which received a Platinum Leadership in Energy and Environmental Design (LEED) certification for the Building Design and Construction category. In a previous CSUF study, the energy usage and cost data for the 2014–2015 academic year was compared to the predicted data from the LEED NC 2.2. The comparison revealed there was a small discrepancy, 10%, between the values for predicted electrical consumption versus actual consumption; however, a greater difference, 135%, between the gas consumption exists. Using LEED approved simulation software, the ASHRAE 90.1 and LEED California Nonresidential Title 24 (NRT 24) compliant energy simulation models is compared; the results will provide input over which variables within student dormitory life affect the energy usage of the building. Some solutions may update the LEED project certification as well as reduce student energy usage.
A Theoretical Investigation of the Effect of the Stochasticity in the Material Properties on the Chatter Detection During Turning
Authors: Sykora Henrik T. , Bachrathy Daniel , Stepan Gabor
Published: November 2017

In this work the effect of the inhomogeneous material properties are investigated in regenerative turning processes by introducing white noise in the cutting coefficient. The model is a one degree of freedom linear delayed oscillator with stochastic parameters. A full discretization method is used to calculate the time evolution of the second moment to determine the moment stability of the turning process. The resultant stability chart is compared with the deterministic turning model.
Further Remarks on the Existence of Periodic Solutions of Linear Time Varying Periodic Fractional Order Systems
Authors: Zhang XueFeng , Chen YangQuan
Published: November 2017

Existence of periodic solutions of fractional order dynamic systems is an important and difficult issue in fractional order systems field. In this paper, the non existence of completely periodic solutions and existence of partly periodic solutions of fractional order linear time varying periodic systems and fractional order nonlinear time varying periodic systems are discussed. A new property of Laplace transform of periodic function is derived. The non existences of completely periodic solutions of fractional order linear time varying periodic systems and fractional order nonlinear time varying periodic fractional order systems are presented by Laplace transform method and contradiction approach. The existence of partly periodic solutions of fractional order dynamic systems are proved by constructing numerical examples and considering Laplace transform property approaches. The examples and state figures are given to illustrate the effectiveness of conclusion presented.
Experimental Power Model Identification of a Flapping Wing Air Vehicle With Flight Test Data
Authors: Gerdes John , Bruck Hugh A. , Gupta Satyandra K.
Published: November 2017

Current mission planning typically involves feed-forward strategies that do not adapt flight conditions and mission properties according to live vehicle power state updates. This results in autonomous flights that adhere to rigid rules for flight time, potentially missing opportunities to enhance mission range or improve recovery likelihood. To address these shortfalls, aircraft states and flight dynamics under varying conditions are experimentally characterized using a customized on-board data collection suite consisting of sensors and microprocessors. Post-processing is used to improve the quality of the data extracted from the sensors. A custom filtering window design provides timescale separation and filtering and cycle-synchronized averaging reduces noise in the data set. A linear vehicle power model is derived from the test data that describes operation in the neighborhood of stable cruising flight conditions. The vehicle power model is extended with models of the drive motors and battery to provide a framework for making mission-level predictions about the power requirements. The framework described is suitable for usage in adapting autonomous flight behaviors and mission planning to changing power availability.
Iterative Most Probable Point Search Method for Problems With Mixture of Random and Interval Variables
Authors: Cho Hyunkyoo , Choi K. K.
Published: November 2017

To represent input variability accurately, input distribution model for random variables should be constructed using many observations or data. However, for certain input variables, engineers may have only their bounds which represent input uncertainty. In practical engineering applications, both random and interval variables could exist at the same time. For the applications, to consider both input variability and uncertainty, inverse reliability analysis should be carried out considering the mixed variables and their mathematical correlation in performance measure. In this paper, an iterative most probable point (MPP) search method has been developed for the mixed variable problem. The random and interval variables update procedures are developed considering the features of mixed variable in the inverse reliability analysis. Both variable update methods proceed one iteration simultaneously to consider the mathematical correlation. An interpolation method is introduced to find better candidate MPP without additional function evaluations. Mixed variable design optimization (MVDO) has been formulated to obtain cost effective and reliable design in the presence of the mixed variables. In addition, the design sensitivity of probabilistic constraint has been developed for effective and efficient MVDO procedure. Using numerical examples, it is found that the developed MPP search method finds accurate MPP more efficiently than generic optimization method. In addition, it is verified that the developed method enables MVDO process with small number of function evaluations.
Exploration of Entrepreneurial Student Teams Performance and Student Team Members’ Personality via the Big Five Test
Authors: Lugo José E. , Zapata-Ramos Mari Luz , Puig Carla P.
Published: November 2017

Entrepreneurial teams are generally interdisciplinary in nature; they tend to combine business, design, and engineering disciplines/expertise. The effectiveness of interdisciplinary design teams has become more important for both start-ups and companies that want to innovate; however, it is often troublesome to determine the group composition that delivers a good product/business idea. The purpose of this study is to investigate the traits in personalities that are needed in a successful entrepreneurial student design team. A study was conducted in which 40 students were divided into seven groups to deliver a technology-based product using design thinking techniques, and consumer behavior theories and research. The personality for each team member was evaluated utilizing the Big Five Test and analyzed jointly as a team, denoted as Team’s Overall Personality (TOP); and by the variability of their personalities in the group, referred as Team Personality Distribution (TPD). The teams’ performances were accounted, ranking them in Best of Best (BOB) and Worst of Worst (WOW) by taking into consideration their performance in: interview collection, idea generation, prototyping, and final presentation. The results demonstrated that the teams with best performance had high variability in Neuroticism and Extraversion when analyzed by TPD and average personality traits in Extraversion and Agreeableness when analyzed with TOP. Therefore, analysis supported that each member’s personality affects his or her team’s performance. It is recommended that the relationship is further investigated for a better representation of efficient group compositions. Recommendations on how to compose entrepreneurial design teams are provided.
Semiconductor to Metal Transition Study of Oxidized Vanadium Thin Film
Authors: Yu Shifeng , Wang Shuyu , Lu Ming , Zuo Lei
Published: November 2017

Since vanadium atom has a half-filled d-shell, there exist a set of valence states to form a number of oxide phases. In this paper, the deposited vanadium thin film is oxidized under different conditions. The electrical characterization shows some oxides of vanadium undergo a transition from semiconductor state to a metal phase at a critical temperature. Such vanadium oxides have potential use, particularly in thin film form, for a wide variety of applications involving thermally activated electronic switching devices. The surface morphology is studied under SEM. The temperature coefficient of resistivity of other vanadium oxide states is studied as well.
Maximizing Battery Life and Usable Capacity With Battery Management System in Electric Vehicles
Authors: Szeli Zoltán , Szakállas Gábor , Szauter Ferenc
Published: November 2017

In terms of the electric vehicles is an important issue of sizing a battery pack. The designer must take account of parameters such as cost, weight and durability. We can optimize these parameters with the help of a battery management system with integrated active cell balancing function. The article describes the development of a battery management system that developed by the Research Centre of Vehicle Industry at Széchenyi István University, Győr, Hungary.
Development of a Passive and Slope Adaptable Prosthetic Foot
Authors: Amiot David E. , Schmidt Rachel M. , Law Angwei , Meinig Erich P. , Yu Lynn , Olesnavage Kathryn M. , Prost Victor , Winter Amos G.
Published: November 2017

Historically, users of prosthetic ankles have relied on actively operated systems to provide effective slope adaptability. However, there are many drawbacks to these systems. This research builds upon work previously completed by Hansen et al. as it develops a passive, hydraulically operated prosthetic ankle with the capability of adapting to varying terrain in every step. Using gait cycle data and an analysis of ground reaction forces, the team determined that weight activation was the most effective way to activate the hydraulic circuit. Evaluations of the system pressure and energy showed that although the spring damper system results in a loss of 9J of energy to the user, the footplate stores 34J more than a standard prosthesis. Therefore, the hydraulic prosthetic provides a 54% increase in stored energy when compared to a standard prosthesis. The hydraulic circuit manifold prototype was manufactured and tested. Through proof of concept testing, the prototype proved to be slope adaptable by successfully achieving a plantarflexion angle of 16 degrees greater than a standard prosthetic foot currently available on the market.
Reduced-Order Modelling of Multibody Contact Problems: A Novel Semi-Analytic Method
Authors: Cappellini Niccolò , Blockmans Bart , Fiszer Jakob , Tamarozzi Tommaso , Cosco Francesco , Desmet Wim
Published: November 2017

In this paper we present a novel method to efficiently solve gear contact simulations in a flexible multi-body environment. Semi-analytical contact approaches have been recently used in Finite Element (FE) simulations for describing the displacement field in the contact zone and eliminating the need for highly refined FE meshes. In the proposed method, we integrate a semi-analytic strategy with a Model Order Reduction (MOR) scheme, which allows us to decrease further the reduced order model complexity as well as the computational burden. We validate the method against state-of-the-art MOR techniques, for both static and dynamic gear contact problems. Finally the results show how the presented method is able to more efficiently capture quantitatively the transmission error in case of spur geared transmission for different torque levels.
Pseudo-Rigid-Body Models for Dynamics of Compliant Robotic Links
Authors: She Yu , Meng Deshan , Su Hai-Jun
Published: November 2017

In this paper, we present new Pseudo-Rigid-Body (PRB) models for clamped-free cantilever beams and pinned-free compliant links for predicting natural frequency in dynamics analysis. In recent decades, PRB models have been extensively studied for predicting statics and kinematics of 2D or 3D beams subject to large deformation under tip loads. However, few studies focus on their accuracy for predicting dynamic analysis. Not like in statics and kinematics, the mass distribution of PRB model plays an important factor in dynamics of compliant beams. In this paper, we introduce mass property parameters to the PRB models. By comparing with the continuous model, we search for the optimal set of mass property parameters for minimizing the error of natural frequency. To demonstrate the procedure, we study two cases: clamped-free cantilever beams and pinned-free compliant links both have an end mass. The results show that the natural frequency of the optimized PRB model well agrees with that from the continuous beam model. The modified PRB model will significantly simplify the dynamics modeling in compliant mechanisms.
Resilient System Design Using Cost-Risk Analysis With Functional Models
Authors: Keshavarzi Elham , McIntire Matthew , Goebel Kai , Tumer Irem Y. , Hoyle Christopher
Published: November 2017

This paper presents a framework to compare the resiliency of different designs during the conceptual design, when information about implementation details is unavailable. We apply the Inherent Behavioral Functional Model (IBFM) tool to develop an initial functional model for a system and simulate the failure behavior. The simulated failure scenarios provide us the information on the unique failure propagation paths and the end state/final behavior of the system assigned to each failure. Each failure path is caused by injecting one or multiple simultaneous faults into the functional model. Within this framework, we generate a population of functional models from a baseline seed model, and evaluate its potential failure scenarios. We also develop a cost-risk model to compare resiliency of different designs, and produce a preference ranking. select the most resilient one, based upon the cost-risk objective. The risk is calculated based on the probability of having an undesired end state for each design, and a consequential cost is assigned to each failure to quantify the cost-risk for a given design. In this paper, we implement and demonstrate the proposed method on the design of a resilient mono-propellant system.
Development of a Keyword Search Algorithm for Bioinspired Design of Foldable Engineering Applications
Authors: Morris Elissa , McAdams Daniel A.
Published: November 2017

The abstraction of biological folding mechanisms can lead to the development of novel foldable solutions for engineering problems. Examples of biological structures that are analogous to foldable engineering solutions are discussed and serve as inspiration for this research effort. Numerous folding mechanisms exist in nature and have not been considered for engineering solutions simply because they are not well-known or studied by designers. These folding mechanisms may provide useful design inspiration for novel engineering applications. To retrieve meaningful biological design analogies, information retrieval techniques are employed and a text-based search algorithm is developed to return useful passages where folding mechanisms in nature are observed. The search algorithm integrates tailored keywords and filtering methods to retrieve passages from an extensive biological corpus. Keywords are established using literature review and WordNet. The search algorithm is validated using an inter-rater reliability analysis and statistical methods for information retrieval. Passages describing biological systems are evaluated and potential engineering applications are discussed to demonstrate the functionality of the search algorithm. Methods for improvement and areas for future work are discussed.
Non-Reciprocity in Structures With Nonlinear Internal Hierarchy and Asymmetry
Authors: Fronk Matthew D. , Tawfick Sameh , Daraio Chiara , Vakakis Alexander F. , Leamy Michael J.
Published: November 2017

Acoustic reciprocity is a property of linear, time invariant systems in which the locations of the source of a forcing and the received signal can be interchanged with no change in the measured response. This work investigates the breaking of acoustic reciprocity using a hierarchical structure consisting of internally-scaled masses coupled with cubically nonlinear springs. Using both direct results and variable transformations of numerical simulations, energy transmission is shown to occur in the direction of decreasing scale but not vice versa, constituting the breaking of acoustic reciprocity locally. When a linear spring connects the smallest scale of such a structure to the largest scale of another identical structure, an asymmetrical lattice is formed. Because of the scale mixing and transient resonance capture that occurs within each unit cell, it is demonstrated through further numerical experiments that energy transmission occurs primarily in the direction associated with the nonlinear coupling from the large to the small scale, thus signifying the breaking of reciprocity globally. This nonlinear hierarchical structure exhibits strong amplitude-dependency in which reciprocity-breaking is associated with specific ranges of excitation amplitudes for both impulse and harmonic forcing.
On-Line Task Decomposition for Collaborative Surveillance of Marine Environment by a Team of Unmanned Surface Vehicles
Authors: Shriyam Shaurya , Shah Brual C. , Gupta Satyandra K.
Published: November 2017

In this paper, we introduce an approach for decomposing exploration tasks among multiple Unmanned Surface Vehicles (USVs) in port regions. In order to ensure effective distribution of the workload, the algorithm has to consider the effects of the environment on the physical constraints of the USVs. The performance of the USV is influenced by the surface currents, risk of collision with the civilian traffic, and varying depths as a result of tides, and weather. In our approach, we want the team of USVs to explore certain region of the harbor. The algorithm has to decompose the region of interest into multiple sub-regions by considering the maximum operating velocity of each USV in the given environmental conditions. The algorithm overlays a 2D grid upon a given map to convert it to an occupancy grid, and then proceeds to partition the region of interest among the multiple USVs assigned to explore the region. During partitioning, each USV covers the maximum area that is possible by operating at maximum velocity at each time-step. The objective is to minimize the time taken for the last USV to finish claiming its area exploration. We use the particle swarm optimization (PSO) method to compute the optimal region partitions. The method is verified by running simulations in different test environments. We also analyze the performance of the developed method in environments with unknown velocity profiles.
Usage of Product Lifecycle Data to Detect Hard Disk Drives Failure Factors
Authors: Kumare Gopalakrishnan Praveen , Behdad Sara
Published: November 2017

Data collected during product lifecycle phases ranging from the beginning of Life (BOL), to the middle of life (MOL) and the end of Life (EOL) assist designers to make informed decisions in various operational and strategic levels. The specific focus of this paper is to show that the data collected during the usage phase of Hard Disk Drives (HDDs) can be used to identify the failure rates of HDDs. Two sources of data were applied: quantitative data extracted from Self-Monitoring Analysis and Reporting Technology (SMART) software, and qualitative data collected from consumer reviews. The data were analyzed to predict the most reliable HDDS available in the market. Some of the important factors to be considered during manufacturing of an HDD are suggested based on the results obtained.
Two Operating States-Based Low Energy Consumption Vehicle Control
Authors: Kőrös Péter , Horváth Ernő , Lakatos István , Szauter Ferenc
Published: November 2017

The current paper presents a realization of a complex vehicle control task. The goal was to consume the lowest possible energy in a less than 100 kg, wheel hub motor-driven vehicle. The realization is based on two distinguishable operating states which states characterizes well the driving cycle of the vehicle. The main contribution of the proposed method is that it reliably estimates the external loads which interacts the vehicle, the controller can adapt to this changes thus it can guarantee the minimal energy consumption. The vehicle described in the paper is a participant at the Shell Eco-marathon Europe competition in Urban Concept - Battery Electric category.
Electrical Impedance Matching of PZT NanoGenerators
Authors: Galos Richard , Shi Yong , Ren Zhongjing , Sun Hao
Published: November 2017

PZT nanofibers are piezoelectric and can produce a relatively high electrical output under strain that is useful for self-powered nanogenerators. To obtain maximum power output from these devices, their internal impedance needs to be matched with their applicable load impedance. Electrical impedance measurements of PZT nanofibers were performed using a variety of methods over a frequency spectrum ranging from DC to 3.0 GHz. These methods include Conductive AFM and Scanning Microwave Impedance Microscopy. Nanofibers formed by electro-spinning with diameters ranging from 3 to 150 nm were collected and measured. The nanofiber impedance was extremely high at low frequency, decreased considerably at higher frequency and varied with nanofiber diameter as well. The results are applicable for the analysis of many types of nanogenerators and nanosensors including those produced at Stevens.
An Integrated Framework for Predicting Consumer Choice Through Modeling of Preference and Product Use Data
Authors: Ghosh Dipanjan D. , Olewnik Andrew , Lewis Kemper E.
Published: November 2017

A critical task in product design is mapping information from consumer space to design space. Currently, this process is largely dependent on the designer to identify and map how psychological and consumer level factors relate to engineered product attributes. In this way, current methodologies lack provision to test a designer’s cognitive reasoning, which could introduce bias while mapping from consumer to design space. Cyber-Empathic Design is a novel framework where user-product interaction data is acquired using embedded sensors. To understand consumer perceptions about a particular product, a network of latent psychological constructs is used to form a causal model allowing designers to better understand user preferences. In this work, we extend this framework by integrating choice-based preference modeling to develop a Discrete Choice Analysis integrated Cyber-Empathic design framework (DCA-CED). We model user preferences and ultimately consumer choice by considering perceptions estimated by psychological latent variables and user-product interaction data. To demonstrate the effectiveness of the framework, a case study using a sensor integrated shoe design is presented where data to represent user demographics, sensor readings, and product choice is simulated. Using the DCA-CED method, the model parameters are recovered and compared with the original parameter values in the simulator. In addition, the ability of the framework to predict choice based on user product-interaction data is tested. The results show that the analytical method effectively captures the underlying data generation process thereby validating the proposed framework and the analytical method.
Dynamic Modeling and Optimal Design of a 2R Compliant Mechanism
Authors: Ma Wenshuo , Xie Yan , Yu Jingjun , Pei Xu
Published: November 2017

Dynamic performance is of great importance to compliant mechanisms which are employed in dynamic applications, especially if the dynamic problems in DOC (degree of constraint) directions are to be met. An investigation on the dynamic characteristics of a 2R compliant mechanism is presented. Based on the substructure techniques, the in-plane dynamic model of the preceding compliant mechanisms is developed. The natural frequencies and sensitivities are then analyzed. The numerical result verifies the validity of the proposed method. Finally, optimal design of compliant mechanism is investigated.
On Improvement of Operation Bandwidth of Duffing-Like Vibration-Based Harvesters Using a Mechanical Motion Rectifier
Authors: Tai Wei-Che , Liu Mingyi , Yuan Yue , Zuo Lei
Published: November 2017

A novel vibration-based energy harvester which consists of a monostable Duffing oscillator connected to an electromagnetic generator with a mechanical motion rectifier (MMR-Duffing) is studied. The mechanical motion rectifier converts the bi-directional vibratory motion from ambient environments into uni-directional rotation to the generator and causes the harvester to periodically switch between a larger- and small-inertia system, resulting in nonlinearity in inertia. By means of the method of averaging, it is analytically shown that the proposed Duffing-MMR harvester outperforms traditional monostable Duffing oscillator energy harvesters in twofold. First of all, it increases the bandwidth of energy harvesting, given identical nonlinear stiffness. Second of all, it mitigates the jump phenomenon due to nonlinear stiffness and thus exploits more potential bandwidth of energy harvesting without inducing any jump phenomenon. Finally, the analytical analyses are verified via numerical simulations of a prototype of the proposed Duffing-MMR harvester.
An Approximate Analysis of Quasi-Periodic Systems via Floquét Theory
Authors: Sharma Ashu , Sinha Subhash C.
Published: November 2017

Parametrically excited systems are generally represented by a set of linear/nonlinear ordinary differential equations with time varying coefficients. In most cases, the linear systems have been modeled by Mathieu or Hill equations (periodic coefficients) because their stability and response can be determined by Floquét theory. However, in many cases the parametric excitation is not periodic but consists of frequencies that are incommensurate, making them quasi-periodic. Unfortunately, there is no complete theory for linear dynamic systems with quasi-periodic coefficients. Motivated by this fact, in this work, an approximate approach has been proposed to determine the stability and response of quasi-periodic systems. Although Floquét theory is applicable only to periodic systems, it is suggested here that a quasi-periodic system may be replaced by a periodic system with an appropriate large principal period and thus making it suitable for an application of the Floquét theory. Based on this premise, a systematic approach has been developed and applied to two typical quasi-periodic systems. The approximate boundaries in stability charts obtained from the proposed method are extremely close to the exact boundaries of the original quasi-periodic equations. The exact boundaries are detected by computing the maximal Lyapunov exponents. Further, the frequency spectra of solutions generated near approximate and exact boundaries are found to be almost identical ensuring a high degree of accuracy. The coefficients of the parametric excitation terms are not necessarily small in all cases. ‘Instability loops’ or ‘Instability pockets’ that appear in the stability diagram of Meissner’s equation are also observed in one case presented here. The proposed approximate approach would allow one to construct Lyapunov-Perron (L-P) transformation matrices that reduce quasi-periodic systems to systems whose linear parts are time-invariant. The L-P transformation would pave the way for controller design and bifurcation analysis of quasi-periodic systems.
Correct-by-Construction Approach for Self-Evolvable Robots
Authors: Chen Gang , Kong Zhaodan
Published: November 2017

The paper presents a new formal way of modeling and designing reconfigurable robots, in which case the robots are allowed to reconfigure not only structurally but also functionally. We call such kind of robots “self-evolvable”, which have the potential to be more flexible to be used in a wider range of tasks, in a wider range of environments, and with a wider range of users. To accommodate such a concept, i.e., allowing a self-evovable robot to be configured and reconfigured, we present a series of formal constructs, e.g., structural reconfigurable grammar and functional reconfigurable grammar. Furthermore, we present a correct-by-construction strategy, which, given the description of a workspace, the formula specifying a task, and a set of available modules, is capable of constructing during the design phase a robot that is guaranteed to perform the task satisfactorily. We use a planar multi-link manipulator as an example throughout the paper to demonstrate the proposed modeling and designing procedures.
Design and Development of 5-Axis Cranial Implant Laser Cutting System
Authors: Liu Joshua , Fang Jerry , Murphy Ryan J. , Gordon Chad , Armand Mehran
Published: November 2017

Cranioplasty is a procedure for skull reconstruction after removal of bone defects such as tumors. Recent approaches for cranioplasty involve the use of customized cranial implants (CCIs). A challenge in performing the cranioplasty with CCI is that the actual size/shape is unknown until the tumor is removed. Often the procedure is performed in two stages. After removing the cranial defect, the surgeon works with an implant manufacturer to develop a CCI using computer-aided design and manufacturing (CAD/CAM) techniques. The CCI attachment to the skull will then require a second surgery. We recently proposed a robot-assisted single-stage cranioplasty. For conventional, single-stage CCI, the CCIs are usually made in oversized profiles and require manual intraoperative modification by the surgeon. The challenge, however, is that for complex cases the surgeon may spend a long time reshaping the CCI. This paper presents the development of a 5-axis laser cutting machine that has the capability of automatically shaping CCI profiles during single-stage cranioplasty. Preliminary results indicate a superior fit with only mm size gaps between the implant and the remaining skull.
Vibration Amplitude and Fastener Torque Dependence of Damping in a Jointed Structure
Authors: Jerome Trevor W. , Hambric Stephen A. , Shepherd Micah R.
Published: November 2017

The resonance frequency, stiffness, and damping of a structure with screws, bolts, or rivets is strongly influenced by the nonlinear interaction of connected faying surfaces. During the design phase of built-up systems, those system properties and their uncertainty must be understood to meet vibroacoustic design criteria. However, the frictional interaction of fastened joints is poorly understood, and hypotheses are still being made in an attempt to explain the causes of damping in fastened joints. Friction models that do exist either require onerous methods or are overly simplistic. To provide measured data to support future model development, this research uses experimental modal analysis and a time-domain approach to track damping via the ringdown of a pair of plates with a fastened joint with varying applied torques. Amplitude-dependent plots of the loss factor for several modes are provided, which represent the system better than their single-value counterparts. Frequency decrements due to increased fastener torque were less than one-half of a percent in the presented modes. Counterintuitively, increasing fastener torque in the experiment increased the loss factor and slightly reduced the resonance frequencies of the presented modes. Loss factors vary by 67–96%; in the case of the second mode, loss factor depends heavily on vibration amplitude.
Experimental Validation of Unlumped Model and its Design Implications for Rotary Series Elastic Actuators
Authors: Yoon Jeong H. , Sun Daniel , Sanandan Vidur , Hong Dennis
Published: November 2017

Series Elastic Actuators (SEA) have been in development for multiple decades. In spite of this, few design guidelines exist and stiffness selection for the compliant element still remains a trial-and-error process. In this paper, we experimentally validated the unlumped model first proposed by Orekhov for Rotary SEA (RSEA) and outlined a design methodology for selecting the spring stiffness based on the open loop force control bandwidth of unlumped model for series elastic actuators. We modified the unlumped model to apply to Rotary SEAs. Through experimental system identification, we demonstrated that our new unlumped model for RSEA is a valid model of actuator dynamics. Additionally, we recommended design guidelines for RSEA to achieve desired force control bandwidth based on the pure torque source assumption. An example of the design process was given and actuator performance was verified through dynamic simulations in ADAMS.
Measuring Information Content of Freehand Sketches Using a Cognitive Chunk Visualization Protocol
Authors: Sen Chiradeep , Parrish Quintcey , Galil Omar
Published: November 2017

This paper first presents a protocol study and its software realization for visualizing cognitive chunks as they form in real time during freehand sketching of design concepts, and then illustrates a method and metrics for measuring the information content of freehand sketches based on those chunks. A manual protocol for detecting cognitive chunks during sketching was reported earlier. In this research, the said protocol was automated into a software program and validated in a new protocol study, using new participants. The chunks detected by the program, by definitions in cognitive science literature, serve as entities or units of information conceived at once by the designer. The relations between these entities, esp. spatial relations, are then computed using a new method, which represents the sketch as an entity-relation (ER) model. An established protocol for measuring information of ER models is then applied to compute the information content of the sketches.
The Dimension Match and Parameters Setting of the Hydraulic Motor for the Hydraulic-Electromagnetic Energy-Regenerative Shock Absorber
Authors: Mi Jia , Xu Lin , Guo Sijing , Abdelkareem Mohamed A. A. , Meng Lingshuai , Zuo Lei
Published: November 2017

Hydraulic-electromagnetic Energy-regenerative Shock Absorber (HESA) has been proposed recently, with the purpose of mitigating vibration in vehicle suspensions and recovering vibration energy traditionally dissipated by oil dampers simultaneously. The HESA is composed of hydraulic cylinder, check valves, accumulators, hydraulic motor, generator, pipelines and so on. The energy conversion from hydraulic energy to mechanical energy mainly depends on the hydraulic motor between two accumulators. Hence, the dimension match and parameter settings of hydraulic motor for the HESA are extremely important for efficiency of the whole system. This paper studies the methods and steps for dimension matching and parameter settings of the hydraulic motor in a case of a typical commercial vehicle. To evaluate suspension’s vibration characteristics, experiments on the target tour bus have been done. Simulations are conducted to investigate the effects of the hydraulic motor in different working conditions. The simulation results verify that the methods and steps adopted are accurate over a wide range of operating conditions and also show that appropriate matching and parameter settings of the hydraulic motor attached in the HESA can work with high efficiency and then effectively improving energy conversion efficiency for the whole system. Therefore, the theory of the matching progress can guide the future design of an HESA.
Kinetostatics Modeling and Decoupling Analysis of a Crosshair Flexures-Based Nanopositioner
Authors: Liu Pengbo , Lu Songsong , Yan Peng , Zhang Zhen
Published: November 2017

In the present paper, we take the input and output decoupling into account and propose a 2-DOF parallel nanopositioner, which is composed of lever amplification mechanisms, compound parallelogram mechanisms and novel crosshair flexures. In order to demonstrate the decoupling performance improvement of the crosshair flexures, the stiffness model of the crosshair flexures and the kinetostatics model of the nanopositioner are established based on Castigliano’s theorem and the compliance matrix method. Accordingly, the input and output decoupling compliance matrix models are derived to demonstrate the excellent decoupling property of the crosshair flexures based nanopositioner, which is further verified by finite-element analysis and experimental results. The open-loop experiments on the prototype stage demonstrate the maximum stroke of the nanopositioner is up to 65μm and the cross axis coupling errors are less than 1.6%.
Uncovering Hidden Costs in R&D Outsourcing: A Case Study
Authors: Gruszewski Richard , Smith Bruce H. , Thresh Donald E. , Van Bortel James , Esterman Marcos
Published: November 2017

Global corporations are facing competitive pressures and as result are outsourcing products or services to improve profitability, reduce delivery schedules, increase product features, and increase value to their shareholders. However hidden or unexpected costs can come with these benefits that erode the expected profits and outweigh the cost savings. This includes unintended consequences that arise from employee lay-offs and knowledge loss. This can result in negative perceptions on the value of outsourcing within the firm. This paper will report on a study of an outsourced development project at a Fortune 500 company that examined the drivers that impede accurate cost estimates used to assess the viability of outsourcing R&D activities. A result of the case study was that while there was hidden costs uncovered, significant misperceptions within the firm initially eroded the value of the outsourced activities.
Proof-of-Concept Design of Electronic Wedge Brake With Multi-Rollers
Authors: Yu Liangyao , Chang Jinghu , Zheng Sheng
Published: November 2017

In this paper, a new braking system EWB (Electronic Wedge Brake) with multi-rollers is presented. EWB is a BBW (Brake by Wire) braking system, using self-reinforcement effect of the wedge mechanism. This effect makes EWB reduce consumption of electricity. Compared with traditional EMB (Electronic Mechanical Brake), EWB can work at lower power supply, such as 12V, which makes EWB has great advantage over those EMB braking systems with higher power supply, e.g.42V.

The proposed design can realize normal braking function, and also can realize parking braking. In this paper, the configuration of EWB with multi-rollers is presented, and the modelling of main parts of the EWB system is given using the software Matlab/Simulink. Meanwhile, the EWB experimental bench is built, and preliminary experiments are carried out. The results of experiment show the practicability of the proposed design.
Decoupling Stiffness From Position in Joint Mechanisms: Applied to Powered Ankle Prosthesis
Authors: Holgate Robert , Sugar Thomas
Published: November 2017

A method for decoupling joint stiffness and joint position for simple mechanisms was developed. This method was then demonstrated on a powered ankle prosthesis. Linear and circular mechanisms were fit to the resulting data to simplify the required actuator output. The resulting performance of desired ankle moment with corresponding ankle angle was shown to be highly correlated with able bodied walking data.