bluuebunny/crossref_metadata_2025 huggingface dataset:
Augmented Microscopy for DNA Damage Quantification: A Machine Learning Tool for Environmental, Medical and Health Sciences
Authors: Bernardini Michele , Ferri Alessandro , Migliorelli Lucia , Moccia Sara , Romeo Luca , Silvestri Sonia , Tiano Luca , Mancini Adriano
Published: November 2019

The Comet Assay is a well-known procedure employed to investigate the DNA damage and can be applied to several research areas such as environmental, medical and health sciences. User dependency and computation time effort represent some of the major drawbacks of the Comet Assay. Starting from this motivation, we applied a Machine Learning (ML) tool for discriminating DNA damage using a standard hand-crafted feature set. The experimental results demonstrate how the ML tool is able to objectively replicate human experts scoring (accuracy detection up to 92%) by solving the related binary task (i.e., controls vs damaged comets).
Design for Additive Manufacturing Using a Master Model Approach
Authors: Wiberg Anton , Persson Johan , Ölvander Johan
Published: November 2019

The introduction of Additive Manufacturing opens up possibilities for creating lighter, better and customized products. However, to take advantage of the possibilities of Additive Manufacturing, the design engineer is challenged. In this paper, a general design process for the creation of complex products is proposed and evaluated. The proposed method aims to aid a design process in which Topology Optimization (TO) is used for concept development, and the result is then interpreted into a Master Model (MM) supporting design evaluations during detailed design. At the same time as the MM is created, information regarding manufacturing is saved in a database. This makes it possible to automatically generate and export models for manufacturing or CAE analyses. A tool that uses Knowledge-Based Engineering (KBE) to realize the presented methodology has been developed. The tool is specialized for the creation of structural components that connect to other components in an assembly. A case study, part of an aircraft door, has been used for evaluation of the tool. The study shows that the repetitive work when interpreting the topology-optimized design could be reduced. The result comes in the form of a parametric CAD model which allows fast changes and the coupled database enables the export of models for various purposes.
Checking Application Level Properties Using Assertion Synthesis
Authors: Wenzl Matthias , Roessler Peter , Puhm Andreas
Published: November 2019

This work presents a proof-of-concept of a new approach on automatic generation of digital hardware that is able to check application-level properties of an embedded system such as a faulty system behavior at runtime. The approach makes use of assertion-based verification setups that today are very common in the area of digital hardware design with, however, the sole focus on logic simulation. Thus, a PSL-to-VHDL compiler is introduced that generates VHDL (Very High Speed Integrated Circuit Description Language) code out of PSL (Property Specification Language) assertions which can be further processed by a traditional digital logic synthesis tool. That way, runtime checker units can be automatically generated with little effort because of the already existing assertion-based test benches. Furthermore, a model railway demonstrator is presented herein as an example for a safety-critical application to prove the proposed tool flow on a use case. Implementation results based on that use case are discussed. Finally, the paper concludes with a brief outlook on related future work of the authors.
Dimensional Prediction for FDM Machines Using Artificial Neural Network and Support Vector Regression
Authors: Lyu Jiaqi , Manoochehri Souran
Published: November 2019

With the development of Fused Deposition Modeling (FDM) technology, the quality of fabricated parts is getting more attention. The present study highlights the predictive model for dimensional accuracy in the FDM process. Three process parameters, namely extruder temperature, layer thickness, and infill density, are considered in the model. To achieve better prediction accuracy, three models are studied, namely multivariate linear regression, Artificial Neural Network (ANN), and Support Vector Regression (SVR). The models are used to characterize the complex relationship between the input variables and dimensions of fabricated parts. Based on the experimental data set, it is found that the ANN model performs better than the multivariate linear regression and SVR models. The ANN model is able to study more quality characteristics of fabricated parts with more process parameters of FDM.
sBF-BO-2CoGP: A Sequential Bi-Fidelity Constrained Bayesian Optimization for Design Applications
Authors: Tran Anh , Wildey Tim , McCann Scott
Published: November 2019

Bayesian optimization is an effective surrogate-based optimization method that has been widely used for simulation-based applications. However, the traditional Bayesian optimization (BO) method is only applicable to single-fidelity applications, whereas multiple levels of fidelity exist in reality. In this work, we propose a bi-fidelity known/unknown constrained Bayesian optimization method for design applications. The proposed framework, called sBF-BO-2CoGP, is built on a two-level CoKriging method to predict the objective function. An external binary classifier, which is also another CoKriging model, is used to distinguish between feasible and infeasible regions. The sBF-BO-2CoGP method is demonstrated using a numerical example and a flip-chip application for design optimization to minimize the warpage deformation under thermal loading conditions.
Wide Range Highly Sensitive Pressure Sensor Based on Heated Micromachined Arch Beam
Authors: Alcheikh Nouha , Hajjaj Amal Z. , Younis Mohammad I.
Published: November 2019

Miniaturized air-pressure sensing devices has received increasing attention during the past few decades. Pressure sensors have been explored in various potential applications, such as industrial control, healthcare, medical testing, and environmental monitoring [1–2]. Different sensing mechanisms and designs have been used for the detection of air-pressure. Of particular importance are resonant pressure sensors based on tracking the change in resonance frequency of the device with pressure. To improve the pressure sensor sensitivity, various designs have been investigated including carbon nanotubes, microcantilever, and bridge resonators. In a recent study [3], we showed a resonant pressure sensor based on an electrothermally heated clamped-clamped straight beam (cooling effect). We showed that operating the resonator near the buckling point maximizes its sensitivity [3]. In this work, we will focus on the detection of air pressure using an electrothermally heated initially curved beam exhibiting veering among its first two symmetric vibration modes, which offers more continuity in frequency variations, and hence measurements compared to buckled beams. The presented approach shows significant advantages in term of sensitivity and wide pressure range.
Multibody Dynamics vs. Fluid Dynamics: Similarities and Differences
Authors: Rakhsha Milad , Kelly Conlain , Olsen Nic , Serban Radu , Negrut Dan
Published: November 2019

In large, rigid multibody dynamics problems with friction and contact, encountered for instance in granular flows, one can witness distinctly different system-level dynamics. This contribution concentrates on the case of fluid-like behavior of large multibody dynamics systems such as granular materials, when the system experiences large strains. The results reported herein draw on computer simulation; on the one hand, we solve the Newton-Euler equations of motion, which govern the evolution of multibody dynamics system featuring frictional contact. On the other hand, we solve the Navier-Stokes equations which describe the time evolution of fluids. To demonstrate the similarities and differences between the multibody and fluid dynamics we consider three problems modeled and solved using different methods; (i) a compressibility test; (ii) the classical dam break problem, and (iii) the dam break simulation with an obstacle. These experiments provide insights into conditions under which on can expect similar characteristics from multibody and fluid dynamics systems governed by manifestly different equations of motion and solved by vastly different numerical solution methods. The models and simulation platform used are publicly available and part of an open source code called Chrono. Both the multibody and fluid dynamics simulations are carried out using GPU computing.
Data Association and Fusion Framework for Decentralized Multi-Vehicle Cooperative Perception
Authors: Yoon DoHyun Daniel , Ali G. G. Md. Nawaz , Ayalew Beshah
Published: November 2019

Vehicular communication technology (V2V, V2I, V2X, etc.) allows participating vehicles to actively exchange information about their surrounding traffic. By sharing the local field of view (FoV) perception along with their own instantaneous states, communicating vehicles can cooperatively broaden and improve their perceptions of the overall traffic which allows more effective maneuver planning and vehicle energy management. This paper outlines a framework for decentralized multi-vehicle cooperative perception where each vehicle broadcasts its perception information and also acts as an individual fusing node for the received data. The Bhattacharyya distance filter (BDF) is applied for the data association process, identifying and grouping a set of estimates potentially representing the same vehicle. The associated estimates are then passed down to a covariance intersection-based fusion scheme that yields a single fused state estimate and covariance matrix for each vehicle. A metric is adopted to assess the performance of the cooperative perception scheme. The workings of the proposed framework and its potential advantages over other solutions is illustrated via simulations of connected vehicles in highway traffic scenarios with different vehicle densities.
Investigating the Nonlinear Dynamics of Human Balance Using Topological Data Analysis
Authors: Siegrist Kyle W. , Chagdes James R. , Kramer Ryan M.
Published: November 2019

Understanding the mechanisms behind human balance has been a subject of interest as various postural instabilities have been linked to neuromuscular diseases (Parkinson’s, multiple sclerosis, and concussion). This paper presents a classification method for an individual’s postural stability and estimation of their neuromuscular feedback control parameters. The method uses a generated topological mapping between a subjects experimental data and a data set consisting of time series realizations generated using an inverted pendulum mathematical model of upright balance. The performance of the method is quantified using a time series realizations with known stability and neuromuscular control parameters. The method was found to have an overall sensitivity of 85.1% and a specificity of 91.9%. Furthermore, the method was most accurate when identifying limit cycle oscillations with a sensitivity of 91.1% and a specificity of 97.6%. Such a method has the capability of classifying an individual’s stability and revealing possible neuromuscular impairment related to balance control, ultimately providing useful information to clinicians for diagnostic and rehabilitation purposes.
Design and Testing of a Solar-Powered Bicycle in Nairobi, Kenya
Authors: Maranga Ignatius , Burleson Grace , Christen Roger , Da Silva Izael
Published: November 2019

Globally, access to reliable and clean transportation vehicles is a growing concern. Using off-the-shelf components, researchers in Kenya have developed a solar-powered bicycle called the “Solar-E-Bike.” The bike has the potential to support the demand for mobility and electric power of the growing African population. A fully solar powered vehicle/generator for commuting and light cargo transportation as a source of electricity in the home is technically feasible and would respond to real user needs, impact the lives of many of people living in off-grid communities in Africa. Incorporating renewably-powered transportation methods could be a significant contribution to avoiding CO2 emissions in the future. The prototypes for this product have proven that a solar vehicle could easily be a practical transportation device with a daily range of 50 km per day. However, a test drive across 500 km showcased valuable design changes, such as improved component selection and durable frame design, that are needed for this product to be usable on a commercialized scale. Vehicles such as the one discussed in this paper could provide additional benefits such as power generation and provide infrastructure support for health, education, water and communications.
Online Trajectory Optimization for Legged Robotics Incorporating Vision for Dynamically Efficient and Safe Footstep Locations
Authors: Hooks Joshua R. , Ahn Min Sung , Hong Dennis
Published: November 2019

This paper presents a trajectory optimization algorithm for legged robotics that uses a novel cost function incorporating point cloud data to simultaneously optimize for footstep locations and center of mass trajectories. This novel formulation transforms the inherently discrete problem of selecting footstep locations into a continuous cost. The algorithm seamlessly balances the desire to choose footstep locations that enhance the dynamic performance of the robot while still choosing locations that are viable and safe. We demonstrate the success of this algorithm by navigating the ALPHRED V2 robotic system over unknown terrain in a simulation environment.
Design and Dynamics of Hybrid Wave and Current Energy Converter
Authors: Chen Shuo , Jiang Boxi , Li Xiaofan , Xiong Qiuchi , Huang Jianuo , Zuo Lei
Published: November 2019

The ocean has been identified as one of the most promising energy sources and it can be comprehended as the “unlimited” energy source as well. Therefore, a reasonable exploitation and development on ocean energy recovery are applicable in this energy shortage era. This paper investigates the design and dynamic analysis of the Hybrid Wave and Current Energy Converter (HWCEC), which uses current and wave to recover energy from the ocean. In general, the HWCEC system contains the oscillating buoy and rotating turbine, while the ocean wave and current pass through the system. The energy harvested from the ocean flows through the Mechanical Motion Rectifier (MMR) gearbox [1], and the oscillating motion is converted to a unidirectional rotational motion, which will drive the generator and produce electricity. The dynamic of the HWCEC is developed by combing the dynamics of a heaving buoy, a horizontal axis hydro-turbine and the working status of an MMR-based Power Take-off system (PTO). A 1:10 scaled down prototype has been manufactured and assembled. Further tests will be conducted in the cooperating facilities. Simulation is conducted based on hydrodynamic coefficients obtained from WAMIT and the blade element momentum theory for the scaled-down prototype. Considering a regular wave with 0.08 meters of wave height with 1 second of wave period together with 0.3m/s constant current velocity, Results show that the HWCEC has an improvement in the energy extraction ratio compared to a traditional Wave Energy Converter (WEC) by 53%. The simulation indicates the fact that harvesting energy from both wave and current is simply more efficient than the traditional types of ocean energy harvester, which consists of only harvesting energy from a single source.
A Customer-to-Manufacturer Design Model for Custom Compression Casts
Authors: Zhang Yunbo , Kwok Tsz-Ho
Published: November 2019

This paper presents a computational framework for designing and optimizing custom compression casts/braces. Different from the conventional cast/brace design, our framework generates custom casts/braces with fitness, lightweight, and good ventilation. The computational pipeline is an end-to-end solution, directly from customer to the manufacturer, which starts from a 3D scanned human model represented by mesh and ends with the 3D printed cast/brace. Our interactive tools allows users to define and edit the 3D curves on the mesh surface, and trim the mesh surface to form the cast/brace shape using the curves. These tools are efficient and simple to use, and also they enable designing the custom casts/braces fitting to the given human body. In order to reduce the weight and improve the ventilation, we adopt the topology optimization (TO) method to optimize the cast/brace design. We extend the existing three-dimensional (3D) TO method to the mesh surface by simplifying the optimization problem to a 2D problem. Therefore, the efficiency of the TO computation is improved significantly. After the optimized cast/brace design is obtained on the mesh surface, a solid model is generated by our design interface and then sent to a 3D printer for fabrication. Simulation results show that our method can better re-disturb the stresses compared with the conventional 3D TO.
Component-Based Modeling and Sensitivity Analysis of Composite Beam Cross-Sections
Authors: Scapolan Matteo , Sonneville Valentin , Callejo Alfonso , Bauchau Olivier A.
Published: November 2019

Flexible multibody systems often include slender bodies that can be modeled as beams. In contrast with their three-dimensional counterparts, beam formulations are much more efficient and produce models that are more intuitive from engineering and design standpoints. This paper presents a modular approach for the analysis and design of complex beam cross-sections made of heterogeneous and isotropic materials. This approach builds on previous research by the authors, namely research that dealt with cross-sectional analysis and adjoint sensitivity analysis. In addition to the theoretical and software developments, a number of practical examples are shown and verified. The results show that this parametric approach facilitates the definition, analysis and design of complex beam cross-sections, all of which are necessary components in real-life design and manufacturing.
Methodology for the Estimation of the Aerodynamic Drag Parameters of Cyclists
Authors: Polanco Alejandra , Fuentes Juan , Porras Sebastián , Castiblanco Daniel , Uribe Julián , Suárez Daniel , Muñoz Luis
Published: November 2019

The aerodynamic drag force has a relevant effect on cycling performance since it is one of the major resistive forces acting on the bicycle. For this reason, this paper presents the development of an experimental methodology to estimate the aerodynamic parameters of a bicycle-cyclist set. The methodology combines outdoor measurements to estimate the drag area with indoor measurements to measure the projected frontal area.

The methodology was implemented to quantify the effect of posture in the aerodynamic parameters of a group of cyclists. The tests were performed to characterize the drag parameters associated with three postures defined by the position of the grip on the handlebar: tops, hoods, and drops.

Significant differences in the aerodynamic parameters were found for the postures studied through the proposed methodology. The posture variation led to reductions of up to 11.8% in the drag area of the cyclists when passing from tops to drops posture. The results obtained are in agreement with the literature indicating that the implementation of the methodology is feasible for the estimation of the aerodynamic parameters in cycling.
Electromagnetic and Mechanical Analysis of an Origami Helical Antenna Encapsulated by Fabric
Authors: Zekios Constantinos L. , Liu Xueli , Moshtaghzadeh Mojtaba , Izadpanahi Ehsan , Radnezhad Hamid Reza , Mardanpour Pezhman , Georgakopoulos Stavros V.
Published: November 2019

In this work an origami based helical antenna is electromagnetically and mechanically analyzed and tested. The Kresling pattern is used to accommodate the helical nature of the antenna design. First, a mechanical analysis is performed showing that by increasing the number of the sides, the structure becomes more stable and it is easier to fold. An 8-sided design is chosen based on our results. The electromagnetic analysis of the antenna shows that it achieves a realized gain of 8.1 dB and that is circularly polarized. The antenna is fabricated and tested. Our results exhibit very good agreement between simulations and measurements.
Job Shop Scheduling Optimization Using Genetic Algorithm With Global Criterion Technique
Authors: Xu Ke , Manoochehri Souran
Published: November 2019

The Job Shop Scheduling Problem (JSSP) is a method which assigns multiple jobs to various machines. The large dimension of JSSP and the dynamic manufacturing environment have always been a difficult problem to optimize due to its size and complexity. In this study, three objective functions are selected namely, minimizing makespan, minimizing total cost and maximizing machine utilization. Genetic Algorithm (GA) is used to solve this scheduling problem. Lot size optimization technique is investigated for the potential of optimizing the makespan, total cost, and machine utilization objectives. Global Criterion (GC) Technique is implemented which can optimize multiple objectives all at once and obtain the best schedule. Finally, a case study is presented.
Successes and Challenges in Implementing Lean Product Development
Authors: Godbole Hrushikesh , Esterman Marcos , Palekar Shridhar , Arciniegas Alvaro Rojas
Published: November 2019

Lean thinking is a successful management philosophy that originated in the production dominated mid-20th century. More recently, these principles have been contextualized in a product development setting. However, few companies have successfully adopted lean product development. The gap between the existing knowledge within the academic community and the current practices within the industry motivated an industry-academia research roundtable to identify the successes and challenges in implementing lean product development. This paper shares the successful practices, and the implementation challenges that industry faces in the context of lean product development, which include nomenclature, visual management and metrics, knowledge repository and lean education & training. The paper concludes with a roadmap of research required to enable the adoption of lean product development in the industry.
Modeling and Analysis of Subsystem Interactions in Robotic Assembly
Authors: Shriyam Shaurya , Gupta Satyandra K.
Published: November 2019

We present a modeling framework for a production line consisting of multiple robotic assembly cells by integrating probabilistic modeling and temporal logic verification techniques. A production line is a complex system comprising of multiple assembly cells which in turn comprises of multiple assembly stations. We evaluate the performance of the proposed operations plan by decomposing the whole system into smaller subsystems which are analyzed separately. This allows us to design optimized systems. We first model an assembly cell in a probabilistic model checking tool. Contingencies may arise in each cell during the production operations and are resolved by humans or the assembly robots themselves. We simulate multiple cells operating cooperatively to finish production of parts. We perform formal analysis for each cell, which is a sub-system of the production line and then study the aggregate behavior of the resulting production line. Based on our analysis of individual cell behavior, we can determine how to change cell settings to achieve the best production performance.
Voxel-Based CAD Framework for Planning Functionally Graded and Multi-Step Rapid Fabrication Processes
Authors: Brauer Cole , Aukes Daniel M.
Published: November 2019

In this paper we describe a new framework for planning functionally graded and multi-step fabrication processes for use in rapid prototyping applications. This framework is contributing to software tools that will simplify planning multi-material manufacturing processes and thereby make this type of manufacturing more accessible. We introduce the material description itself, low-level operations which can be used to combine one or more geometries together, and algorithms which assist the designer in computing manufacturing-compatible sequences. We then apply these tools to several example scenarios. First, we demonstrate the use of a Gaussian blur to add graded material transitions to a model which can then be produced using a multimaterial 3D printing process. Our second example highlights our solution to the problem of inserting a discrete, off-the-shelf part into a 3D printed model during the printing sequence. Finally, we implement this second example and manufacture two example components. The results show that the framework can be used to effectively generate the files needed to produce specific classes of parts.
Characteristics of Self-Deployment in Origami-Based Systems
Authors: Wilson Mary E. , Magleby Spencer P. , Howell Larry L. , Bowden Anton E.
Published: November 2019

The potential of compliant mechanisms and related origami-based mechanical systems to store strain energy make them ideal candidates for applications requiring an actuation or deployment process, such as space system arrays, minimally invasive surgical devices and deployable barriers. Many origami structures can be thought of as a compliant mechanism because, like compliant mechanisms, its function is performed through the elastic deformation of its members. This stored strain energy could prove useful. There are opportunities using strain energy to develop approaches to deploy particular mechanical systems. In order to better understand the principles of self-actuation and promote the designs of such systems, a taxonomy of deployable origami mechanisms is presented. This taxonomy demonstrates that there are several different types of deployable origami mechanisms and provides an organizational method to better understand the design space. Characteristics of self deployment in concentrated, deployable origami strain energy mechanisms with internal actuation are identified and examples of strain energy based deployment are provided.
Effects of Cut Boundary Location on Finite Element Submodels With Contacts
Authors: Elke William J. , Sracic Michael W.
Published: November 2019

Submodeling is a method used in Finite Element Modeling in order to evaluate features of interest, such as fillets or contact interfaces at a reduced cost. Submodeling can be done by creating a full-structure, coarse-mesh, “global” model and solving it. Once the solutions for this model are solved, a model just of the feature of interest, or “submodel”, can be solved using boundary conditions estimated based on global model results. The location of the submodel boundary has large effects on the accuracy of the solution and has been examined by the authors previously, but not for models with contact interfaces. This work uses the submodeling procedure on a model with two cantilever beams sandwiched together with a bolt close to the free end (dubbed “sandwich beam”). Numerous models are produced with different submodel boundary locations in order to better understand how those locations affect the solutions of a model with contact interfaces. The maximum contact pressure was the main metric used to examine the effects and the feature of interest was the bolt.

In previous works, it was determined that the global model mesh size and submodel boundary locations are the main sources of error in submodeling [15]. From this work, it was concluded that the inaccuracies of the global model mesh size are magnified when the submodel mesh is too close to the feature of interest. Furthermore, contact pressure tends to be overestimated as the submodel is refined, but it tends to converge as the global model is converged. This work also demonstrated that errors in global model solution (due to meshing) are mitigated when the entire feature of interest is included in the submodel and the submodel boundary locations are far enough away from that feature.
Energy Optimal Control of Dielectric Elastomer Actuators via Adaptive Dynamic Programming
Authors: Massenio Paolo Roberto , Naso David , Rizzello Gianluca
Published: November 2019

This paper presents an optimal motion control scheme for a mechatronic actuator based on a dielectric elastomer membrane transducer. The optimal control problem is formulated such that a desired position set-point is reached with minimum amount of driving energy, characterized via an accurate physical model of the device. Since the considered actuator is strongly nonlinear, an approximated approach is required to practically address the design of the control system. In this work, an Adaptive Dynamic Programming based algorithm is proposed, capable of minimizing a cost function related to the energy consumption of the considered system. Simulation results are presented in order to assess the effectiveness of the proposed method, for different set-point regulation scenarios.
Conceptualizing Stable States in Origami-Based Devices Using an Energy Visualization Approach
Authors: Avila Alex , Greenwood Jacob , Magleby Spencer P. , Howell Larry L.
Published: November 2019

In many origami-based applications a device needs to be maintained in one or more fold states. The origami stability integration method (OSIM) presented in this paper provides an approach for graphically combining various techniques to achieve stability. Techniques are divided into four groups based on whether they are intrinsic or extrinsic to the origami pattern and whether they exhibit differentiable or non-differentiable energy storage behaviors. These categorizations can help designers select appropriate techniques for their application. The paper also contains design considerations and resources for several intrinsic techniques. Finally, two case studies are presented which use the OSIM and the technique guidelines to conceptualize stability in origami-based devices.
Phase Transformation Advancements of the Enriched Analytic Solution Method for Additive Manufacturing Applications
Authors: Steuben John C. , Birnbaum Andrew J. , Iliopoulos Athanasios P. , Michopoulos John G.
Published: November 2019

Renewed interest in additive manufacturing (AM) and rapid prototyping technologies has driven great demand for corresponding modeling and simulation tools. While most such models are defined via the finite-element discretization of the relevant multi-physics, the authors have recently developed a method based on the enrichment of classical analytic solutions to the heat equation. The principal advantage of this enriched analytic solution methodology (EASM) is its high computational efficiency that can enable in-the-loop process control in a manner that removes assumptions made for classic analytical solutions and accounts for additional physics. These features enable the efficient and accurate exploration of the high-dimensional AM process parameter space. This work presents a further enrichment of the underlying analytic solutions to include the effects of phase transformation upon melting and solidification, which are shown to be significant in magnitude. It is demonstrated that the available property data for common AM materials are not adequate for accurate thermal modeling (via finite-element, EASM, or other means), and must be improved via future experimental efforts. A discussion of the accuracy and significance of the results achieved, and a summary of further work necessary to bring the EASM to maturity concludes this work.
Using a Point-Line-Plane Representation for Unified Simulation of Planar and Spherical Mechanisms
Authors: Sharma Shashank , Purwar Anurag
Published: November 2019

This paper presents a geometric constraints driven approach to unified kinematic simulation of n-bar planar and spherical linkage mechanisms consisting of both revolute and prismatic joints. Generalized constraint equations using point, line and plane coordinates have been proposed which unify simulation of planar and spherical linkages and are demonstrably scalable to spatial mechanisms. As opposed to some of the existing approaches, which seek to derive loop-closure equations for each type of mechanism separately, we have shown that the simulation can be made simpler and more efficient by using unified version of the geometric constraints on joints and links. This is facilitated using homogeneous coordinates and constraints on geometric primitives, such as point, line, and plane. Furthermore, the approach enables simpler programming, real-time computation, and ability to handle any type of planar and spherical mechanism. This work facilitates creation of practical and intuitive design tools for mechanism designers.
Students’ Decision-Making in a Product Design Process: An Observational Study
Authors: Shergadwala Murtuza N. , Panchal Jitesh H. , Ramani Karthik
Published: November 2019

The objective of this study is to investigate students’ decision-making during the information gathering activities of a design process. Existing literature in engineering education has shown that students face difficulties while gathering information in various activities of a design process such as brainstorming and CAD modeling. Decision-making is an important aspect of these activities. While gathering information, students make several decisions such as what information to acquire and how to acquire that information. There lies a research gap in understanding how students make decisions while gathering information in a product design process. To address this gap, we conduct semi-structured interviews and surveys in a product design course. We analyze the students’ decision-making activities from the lens of a sequential information acquisition and decision-making (SIADM) framework. We find that the students recognize the need to acquire information about the physics and dynamics of their design artifact during the CAD modeling activity of the product design process. However, they do not acquire such information from their CAD models primarily due to the lack of the project requirements, their ability, and the time to do so. Instead, they acquire such information from the prototyping activity as their physical prototype does not satisfy their design objectives. However, the students do not get the opportunity to iterate their prototype with the given cost and time constraints. Consequently, they rely on improvising during prototyping. Based on our observations, we discuss the need for designing course project activities such that it facilitates students’ product design decisions.
The Impact of Consumer Preference Distributions on Dynamic Electricity Pricing for Residential Demand Response
Authors: Dunbar Samuel , Ferguson Scott
Published: November 2019

Demand Response (DR) is the adjustment of consumer electricity demand through the deployment of one or more strategies, e.g. direct load control, policy implementation, dynamic pricing, or other economic incentives. Widespread implementation of DR is a promising solution for addressing energy challenges such as the integration of intermittent renewable energy resources, reducing capacity cost, and improving grid reliability. Understanding residential consumer preferences for shifting product usage and how these preferences are distributed amongst a population are key to predicting the effectiveness of different DR strategies. In addition, there is a need for a better understanding of how different DR programs, system level objectives, and preference distributions will impact different segments of consumers within a population. Specifically, the impacts on their product use behavior and electricity bill. To address this challenge, a product based approach to modeling consumer decisions about altering their electricity consumption is proposed, which links consumer value to their products, instead of directly to the amount of electricity they consume. This model is then used to demonstrate how population level preference distributions for altering product use impact system level objectives.
A Spatial Linkage Exoskeleton for a Shape-Adaptive Mobile Robot
Authors: Geyer David E. , Turner Cameron J.
Published: November 2019

With the goal of developing a spatial linkage exoskeleton for a shape-adaptive mobile robot, capable of navigating obstacle-laden environments through changes in geometry, initial research focused on the nature of axis transformations, and parameters affecting linkages, such as the Denavit-Hartenberg (DH) parameters. Building on this background, angulated linkages are developed such that a series of scissor pairs, two angulated linkages connected at their midpoints, forming a closed-loop. Using the DH parameters, the geometries are considered in the development of a planar model. A kinematic model is also developed to replicate the design in future work. A linkage was designed using SolidWorks, and then imported into MATLAB’s Simscape Multibody software where a visual, analytical model was developed. The nominal planar model acts as the basis of a spatial model. Using the spatial model, initial prototypes were built to verify the virtual model. A concept for an actuation mechanism is discussed, with a prototype built to identify any limitations. Through experimentation and analysis of the prototypes, areas for improvement in the design are identified. Future work is discussed to further mature the design and development of this solution.
Research on Minimum Pressure Angle of Bennett Linkage
Authors: Bai Lele , Hang Lubin , Huang Xiaobo , Wang Mingyuan , Liu Ziyu
Published: November 2019

Space deployable structures that are constructed by the single loop over-constrained linkages have been extensively applied in the fields of aerospace and construction. The pressure angle regarded as an important index to measure the performance of the basic units has attracted more and more attention. The kinematic model of the Bennett linkage is studied by the D-H matrix and the analytic formula of the pressure angle has been deducted through kinematic equations. The rule of the Bennett linkage has been discovered that the minimum pressure angle occurs while the input angle equals nπ + π / 2(n ∈ N). According to the linkage configuration at the input angle of π / 2, the geometric meaning is revealed that the minimum pressure angle of the linkage is the same as the twist angle of the joint axes of the output link. Finally, conclusions can also be drawn that the smaller the twist angle of the output link is, the smaller the minimum pressure angle will be. The research enriches the kinematics of Bennett linkage and provides a reference for its engineering applications.
Similarity in Engineering Design: A Knowledge-Based Approach
Authors: Chaudhari Ashish M. , Bilionis Ilias , Panchal Jitesh H.
Published: November 2019

Similarity assessment is a cognitive activity that pervades engineering design practice, research, and education. There has been a significant effort in understanding similarity in cognitive science, and some recent efforts on quantifying the similarity of design problems in the engineering design community. However, there is a lack of approaches for measuring similarity in engineering design that embody the characteristics identified in cognitive science, and accounts for the nature of design activities, particularly in the embodiment design phase where scientific knowledge plays a significant role. To address this gap, we present an approach for measuring the similarity among design problems. The approach consists of (i) modeling knowledge using probabilistic graphical models, (ii) modeling the functional mapping between design characteristics and the performance measures relevant in a particular context, and (iii) modeling the dissimilarity using KL-divergence in the performance space. We illustrate the approach using an example of a parametric shaft design for fatigue, which is typically a part of mechanical engineering design curricula, and test the validity of the approach using an experiment study involving 167 student subjects. The results indicate that the proposed approach can capture the well-documented characteristics of similarity, including directionality, context dependence, individual-specificity, and its dynamic nature. The approach is general enough that it can be extended further for assessing the similarity of design problems for analogical design, for assessing the similarity of experimental design tasks to real design settings, and for evaluating the similarity between design problems in educational settings.
Speed Based Power Control of Integrated Powertrain With Two-Speed Transmission for PEV
Authors: Lu Zhenghong , Yu Liangyao , Song Jian , Fang Shengnan , Abi Lanie
Published: November 2019

Multi-speed transmissions with 2–3 speed are considered to be an effective and compact equipment for pure electric vehicles’ (PEV) dynamic and economical improvement. However, the characteristics of fewer gears and larger speed ratio gap not only request uninterrupted shifting quality but also smooth pedalpower pattern to derive demand power of motor from drivers’ input. Due to these features of multi-speed transmissions for PEV, using one fixed pedal-power pattern in conventional ways will cause output torque shock after shifting or force drivers to passively adjust the pedal for constant acceleration. A speed-based unified pedal-power pattern (SUPP) is proposed to interpret the demand power of motor according to the vehicle speed instead of motor speed. The SUPP contains three components including a base, a feedforward and a feedback part to satisfied the different dynamic request under different gears and different speed. Furthermore, the SUPP is integrated with the innovative clutch-to-clutch shifting algorithm which achieves uninterrupted shifting on PEV, and realizes in optimal trajectory of motor operating points during and after shifting. A case study of SUPP is conducted with a two-speed transmission for PEV through both simulation and experiments. The simulation and experimental results prove that the SUPP is able to obtain uninterrupted wheel torque during and after shifting with constant drivers’ intention, and prevent drivers from unnecessary adaptation.
Reduced-Order Modeling and Experimental Studies of Two-Way Coupled Fluid-Structure Interaction in Flapping Wings
Authors: Schwab Ryan K. , Reid Heidi E. , Jankauski Mark A.
Published: November 2019

Flapping, flexible wings deform under both aerodynamic and inertial loads. However, the fluid-structure interaction (FSI) governing flapping wing dynamics is not well understood. Conventional FSI models require excessive computational resources and are not conducive to parameter studies that consider variable wing kinematics or geometry. Here, we present a simple two-way coupled FSI model for a wing subjected to single-degree-of-freedom (SDOF) rotation. The model is reduced-order and can be solved several orders of magnitude faster than direct computational methods. We construct a SDOF rotation stage and measure basal strain of a flapping wing in-air and in-vacuum to study our model experimentally. Overall, agreement between theory and experiment is excellent. In-vacuum, the wing has a large 3ω response when flapping at approximately 1/3 its natural frequency. This response is attenuated substantially when flapping in-air as a result of aerodynamic damping. These results highlight the importance of two-way coupling between the fluid and structure, since one-way coupled approaches cannot describe such phenomena. Moving forward, our model enables advanced studies of biological flight and facilitates bio-inspired design of flapping wing technologies.
A Blockchain Platform for Protecting Intellectual Property: Implications for Additive Manufacturing
Authors: Esmaeilian Behzad , Deka Angshuman , Behdad Sara
Published: November 2019

Prior studies have already predicted that enforcement of IP on the additive manufacturing industry will not be successful due to the widespread use of file-sharing technologies, similar to the entertainment and music industry. This paper discusses the capabilities of Blockchain technology for protecting IP in the design and manufacturing area. A conceptual framework for a digital platform is defined in this paper and further, a survey study of engineering design and manufacturing students has been conducted to identify the main motivation behind developing these platforms and the types of features that should be included in Blockchain-based IP platforms for asset protection, particularly for product design. In addition, respondents provided their opinions about the type of industry that might be affected more by the threat of counterfeiting products and the role of Blockchain-based IP systems on the growth and development of innovation.
The Study of Magnetorheological Elastomer Based on Natural Rubber (NR)/Thermoplastic Elastomer SEBS Hybrid Matrix: Experimental and Numerical Simulation
Authors: Song Xincheng , Wang Wenju , Yang Fufeng , Wang Guoping , Rui Xiaoting
Published: November 2019

Magnetorheological elastomers (MREs) is one kind of smart materials which is mainly made up of matrix materials and magnetic particles, their mechanical properties can be controlled under an external magnetic field. Applications of MREs are limited as a result of their poor MR effect and mechanical performance, so enhancing MR effect of MREs are critical for their application. This study aimed to fabricate MREs with high MR effect, the thermoplastic elastomer styrene-ethylene butylene-styrene triblockcopolymer (SEBS) was added into natural rubber (NR) and physical blending technology was used to fabricate hybrid matrix based MREs. The results of dynamic mechanical analysis showed that, with the addition of SEBS, zero modulus of MREs increased from 0.50 MPa to 0.64 MPa and MR effect increased from 28.00% to 43.75%. The multiphase model in ANSYS software was adopted to analysis the process of physical blending. The numerical simulation result showed that it was more easy to mix matrix evenly with the increase of volume fraction of SEBS.
Electrode-Skin Impedance Component Estimation in the Time-Domain
Authors: Fortune Benjamin C. , McKenzie Lachlan R. , Chatfield Logan T. , Pretty Christopher G.
Published: November 2019

This paper presents a method to estimate the individual component values of a bipolar electrode-skin interface, with future intent of applying compensatory electrode-skin impedance balancing prior recording bio-signals with electromyography. The electrode-skin interface was stimulated by a step input and the output behaviour was characterised using a single exponential model per electrode. The method was applied to simulated circuitry, passive component circuitry and a human subject. The accuracy of the method was determined using the known values that comprised the simulated and passive component circuitry. Nine of ten simulated data sets resulted in accurate estimations, with a maximum error of 0.763% and a mean error of 0.076% per component. The method also produced successful estimates for nine of the ten physical circuitry data sets, with a maximum error of 10.2% and a mean error of 3.49% per component. The method was unsuccessful in estimating the individual electrode-skin impedance components for the human subject: this was due to the system failing to reach steady state during the stimulation period. The authors suspect a DC offset caused by the half-cell potentials associated with the electrode-skin interface were the cause of the unexpected behaviour.