bluuebunny/crossref_metadata_2025 huggingface dataset:
Facilitating Design-by-Analogy: Development of a Complete Functional Vocabulary and Functional Vector Approach to Analogical Search
Authors: Murphy Jeremy , Fu Katherine , Otto Kevin , Yang Maria , Jensen Dan , Wood Kristin
Published: January 2015

Design-by-analogy is an effective approach to innovative concept generation, but can be elusive at times due to the fact that few methods and tools exist to assist designers in systematically seeking and identifying analogies from general data sources, databases, or repositories, such as patent databases. A new method for extracting analogies from data sources has been developed to provide this capability. Building on past research, we utilize a functional vector space model to quantify analogous similarity between a design problem and the data source of potential analogies. We quantitatively evaluate the functional similarity between represented design problems and, in this case, patent descriptions of products. We develop a complete functional vocabulary to map the patent database to applicable functionally critical terms, using document parsing algorithms to reduce text descriptions of the data sources down to the key functions, and applying Zipf’s law on word count order reduction to reduce the words within the documents. The reduction of a document (in this case a patent) into functional analogous words enables the matching to novel ideas that are functionally similar, which can be customized in various ways. This approach thereby provides relevant sources of design-by-analogy inspiration. Although our implementation of the technique focuses on functional descriptions of patents and the mapping of these functions to those of the design problem, resulting in a set of analogies, we believe that this technique is applicable to other analogy data sources as well. As a verification of the approach, an original design problem for an automated window washer illustrates the distance range of analogical solutions that can be extracted, extending from very near-field, literal solutions to far-field cross-domain analogies. Finally, a comparison with a current patent search tool is performed to draw a contrast to the status quo and evaluate the effectiveness of this work.
Analysis of a High Stiffness Warehousing Cable-Based Robot
Authors: Torres-Mendez Sergio , Khajepour Amir
Published: January 2015

This paper presents and analyzes a novel architecture for a fully constrained cable-based robot that is used in warehousing tasks. A mobile platform is connected to a static box by a set of twelve cables; the cables arrangement allows the mobile platform to achieve stiff positions with constant orientation along with large planar motions. The mechanical analysis of the robot includes inverse and forward kinematics, as well as static analysis and stiffness models. In addition, a workspace analysis describes the feasible boundaries for the suspended and fully constrained cases. Then, the stiffness attributes for both cases are analyzed and discussed. Simulation results show that the proposed robot meets the warehousing requirements of large workspace, high stiffness, and low force input.
Trapezoidal Fuzzy Numbers for Eco-Design Assessments in Conceptual Design
Authors: Alemam Abdulbaset , Li Simon
Published: January 2015

The research context is about eco-design improvement that focuses on modifying an existing product for reducing its environmental impacts. In this context, engineers may propose various design concepts that can potentially make the product more environmentally friendly. At this point, the research problem is how to assess environmental impacts of each concept given the uncertainty of design information at the conceptual design stage. To address this research problem, the trapezoidal fuzzy numbers are first applied to capture imprecise design information. Then, the centroid concept is applied to model different views of imprecision (i.e., pessimistic, balanced and optimistic) associated in fuzzy impact assessment. Accordingly, a decision scheme is developed for assessing different design concepts and suggesting the potential areas of a design concept to reduce environmental impacts. In an application, a coffee maker has been decomposed and analyzed to propose three possible concepts for eco-design improvements. These three concepts are then assessed by the proposed method of this paper to demonstrate the methodical workflow and utility that assists engineers to make eco-design decisions at the early design stage.
Studies on the Kinematics of Thin Shell Elements Based on the Absolute Nodal Coordinate Formulation
Authors: Hyldahl Per , Mikkola Aki M. , Balling Ole
Published: January 2015

The absolute nodal coordinate formulation (ANCF) is a finite element procedure that has been developed specifically for the dynamic analysis of large deformation problems. This study concerns compatibility problems in thin rectangular ANCF shell elements, which have been reported in a recent study revealing that these elements lead to a loss of inter-element connectivity when used to discretize non-rectangular structures. This study presents an easily implementable extension to the already used formulae that reduces the inter-element connectivity problems significantly. The new approach is based on using a set of element specific parameters that corresponds to the initial shape of the element. The ability of both the standard and the proposed methods to express curved structures are compared as well as their respective numerical performance.
Computing Carbon Dioxide and Humidity in Filtering Facepiece Respirator Cavity During Breathing Cycles
Authors: Lei Zhipeng , Yang James
Published: January 2015

Carbon dioxide (CO2) and humidity are two factors that affect respirator comfort. Whenever one uses a respirator, CO2 is reinhaled from the previous exhalation and the humidity inside the respirator cavity increases. The CO2 reinhalation causes respirator discomfort with symptoms like headache, dizziness, and etc. The increased humidity causes respirator thermal discomfort. Experimental researches focused on measuring the CO2 and humidity values in the respirator cavity during a long period of time (over 1 hour). However, these experiments ignored CO2 and humidity value variation during a breathing cycle within the respirator cavity. The objective of this study was to use computational fluid dynamics (CFD) method to calculate the CO2 and humidity values inside the respirator cavity during four breathing cycles (19.2s). In our previous work the contact between a headform and a filtering facepiece respirator (FFR) was simulated by the using finite element modeling. In this work a meshed domain was generated including the FFR cavity, the FFR and the region outside of the FFR. A breathing cycle, having both exhalation and inhalation, was then defined as a time-dependent flow rate through a breathing opening (nasal breathing, mouth breathing, and nasal-mouth breathing). Using CFD method, the breathing air flow and the species transport of CO2 and water vapor (H2O) in the domain were simulated for 4 breathing cycles. Totally 5 tests with different breathing openings and different breathing flow rates were conducted: nasal breathing with base, 2 and 3 times flow rate, mouth breathing with base flow rate, and nasal-mouth breathing with base flow rate. The simulation results showed that there were large CO2 and H2O value variations (CO2 mass fraction from 0 to 0.074 and H2O mass fraction 0.0077 and 0.0151) in the FFR cavity during a breathing cycle. The inhaled CO2 mole fraction decreased with increasing breathing flow rate. With the base flow rate, during inhalation the middle point between the nostrils and mouth had higher relative humidity than other probing positions did.
Load Calculation on Wind Turbines: Validation of Flex5, Alaska/Wind, MSC.Adams and SIMPACK by Means of Field Tests
Authors: Zierath János , Rachholz Roman , Woernle Christoph , Müller Andreas
Published: January 2015

Load calculations on wind turbines are an essential part of its development. In the preliminary design phase simplified multibody models are used for the estimation of the interface loads. The interface loads are used within an iterative development loop to design the components of the wind turbine such as gearbox, blades, tower and so on. Due to the early application of load calculations within the development process, the quality of the simulation results has a great influence on the wind turbine design.

In this contribution the simulation results of the multibody codes alaska/Wind, MSC.Adams and SIMPACK are compared with measurements obtained from a prototype of a 2.05 MW wind turbine developed by W2e Wind to Energy. Furthermore, simulation results of the special wind turbine design code Flex5, developed at the Technical University of Denmark Copenhagen, are taken into account. A statistical and dynamical evaluation of the simulation and measurement results has been done. Due to the use of the same controller procedures as used on the physical wind turbine, the wind turbine models show almost the same behaviour (electrical power, pitch angle, rotor speed) as the wind turbine in the field. Differences occur during the evaluation of the interface loads due to the different kinds of wind turbine modelling.
Modeling Human Hand and Sensing Hand Motions With the Five-Fingered Haptic Glove Mechanism
Authors: Ma Zhou , Ben-Tzvi Pinhas , Danoff Jerome
Published: January 2015

This paper presents the design and application of a newly developed five-fingered haptic glove mechanism. This haptic device is a lightweight and portable actuator system that fits on a hand. The new five-fingered glove is adaptable to a wide variety of finger sizes, without constraining the range of motion which makes it possible to accurately and comfortably track the complex motion of the finger joints and add a sense of touch to each finger of the user. Based on this glove, a novel method was developed to build an accurate human hand model which includes finger length and joints location. The parameters of the hand are determined by a circle fitting procedure from a collection of points. The method of least squares fitting of circles is used to analyze the kinematic model. The center and the radius of the fitting circle are the joint location and the finger length respectively. The experimental results demonstrate that the newly developed five-fingered glove is capable of reliably modeling hand kinematics and measuring fingers’ motion. These capabilities are often needed for monitoring and assisting rehabilitation activities of the hand as well as applications involving virtual reality and teleoperation.
Predictive, Data-Driven Product Family Design
Authors: Ma Jungmok , Kim Harrison M.
Published: January 2015

Predictive design analytics is a new paradigm to enable design engineers to extract knowledge from large-scale, multi-dimensional, unstructured, volatile data, and transform the knowledge and its trend into design decision making. Predictive, data-driven family design (PDFD) is proposed as one of the predictive design analytics methods to tackle some issues in family design. First, a number and specifications of product architectures are determined by data (not by pre-defined market segments) in order to maximize expected profit. A trade-off between price and cost in terms of the quantity and specifications of architectures helps to set the target in the enterprise level. k-means clustering is used to find architectures that minimize within architecture sum of squared errors. Second, a price prediction method as a function of product performance and deviations between performance and customer requirements is suggested with exponential smoothing based on innovations state space models. Regression coefficients are treated as customer preferences over product performance, and analyzed as a time series. Prediction intervals are proposed to show market uncertainties. Third, multiple values for common parameters in family design can be identified using the expectation maximization clustering so that multiple-platform design can be explored. Last, large-scale data can be handled by the PDFD algorithm. A data set which contains a total of 14 million instances is used in the case study. The design of a family of universal electronic motors demonstrates the proposed approach and highlights its benefits and limitations.
Coordinated Visual and Kinematic Servoing for Positioning Manipulating UAV End-Effectors
Authors: Danko Todd W. , Oh Paul Y.
Published: January 2015

Manipulating objects using arms mounted to unmanned aerial vehicles (UAVs) is attractive because UAVs may access many locations that are otherwise inaccessible to traditional mobile manipulation platforms such as ground vehicles.

However, the constantly moving UAV platform and compliance of manipulator arms make it difficult to position the UAV and end-effector relative to an object of interest precisely enough for reliable manipulation. Solving this challenge will bring UAVs one step closer to being able to perform meaningful tasks such as infrastructure repair, disaster response, law enforcement, and personal assistance.

Toward a solution to this challenge, this paper describes an approach to coordinate the redundant degrees of freedom of a six degree of freedom gantry with those of a six degree of freedom manipulator arm. The manipulator’s degrees of freedom are visually servoed to a specified pose relative to a target while treating motions of the host platform as perturbations. Simultaneously, the host platform’s degrees of freedom are servoed using kinematic information from the manipulator. This drives the base of the manipulator to a position that allows it to assume a joint-space configuration that maximizes reachability while minimizing static torque transmitted from the arm to the host.
A 5-DOF Hybrid Parallel Robotic Manipulator: Design, Analysis, Performance Modeling and Multi-Objective Optimization
Authors: Gao Zhen , Zhang Dan
Published: January 2015

The progress of the 21st century advanced and integrated manufacturing technology highly relies on the development of higher performance robotic system for rapidly adapting to the dramatic change of manufacturing environment and performance-critical applications. Based on this scenario, this research is focused on system configuration, performance analysis and multi-objective optimization of a new hybrid parallel robotic manipulator with two rotations and three translations. The structure design and the kinematic analysis are conducted. The key performance indices including local/global stiffness, local/global dexterity and workspace are modeled, visualized and optimized. The proposed method provides a unique viewpoint for the design optimization of multi-axis machine center based on system hybridization.
Open Source 3D Scanning and Printing for Design Capture and Realization
Authors: Tucker Conrad S. , Saint John David B. , Behoora Ishan , Marcireau Alexandre
Published: January 2015

Traditionally, the complexities and costs associated with design conceptualization (e.g., 3D scanning) and design realization (e.g., 3D printing) have limited the diversity of individuals capable of participating in the process to individuals/entities with advanced technical backgrounds or substantial financial resources. The authors of this work propose a methodology that utilizes low cost hardware and open source software to make the capture, reuse and management of design knowledge more accessible to the general public.

3D scanners are digital tools that facilitate the conversion of physical object information into the digital space through multiple image capture techniques. 3D scanners have the potential to revolutionize design conceptualization in society by enabling individuals to seamlessly transform physical representations of objects into a digital 3D rendered version. The 3D rendered version can then be manipulated using existing 3D CAD tools (e.g., SolidWorks) and subsequently printed using a 3D printer.

Design realization via 3D printers (e.g., RepRaps) is becoming an integral aspect of the engineering design process. While the conceptualization of designs (e.g. CAD models) helps designers visually experience potential candidate designs, product prototypes that can actually be touched and manipulated add an important ‘feedback’ dimension to the engineering design process. This scan-edit-print approach to design conceptualization and realization will enable designers collaborating in online environments to work towards achieving a common design by providing them with tools and techniques.

A case study is presented that demonstrates the feasibility of the scan (knowledge capture), edit (knowledge reuse) and print (knowledge management) approach to design using low cost hardware and open source software.
Dynamic Analysis of a High Load, High-Speed Actuator for Rock Deformation Experimentation
Authors: Saber O. , Chester F. M. , Alvarado J. L.
Published: January 2015

Experimental investigation of the sliding-velocity dependence of friction in rock is necessary to understand slip instability and earthquake phenomena, but a capability to conduct sliding friction experiments at high normal loads and at earthquake slip rates (1 m/s) must be developed. Velocity-dependent friction is ideally studied by imposing step-wise changes in rate of sliding. Velocity steps to earthquake slip rates must occur in a few milliseconds and requires high accelerations, so feedback control is not applicable because the rise time of actuators that can be used for our application is large relative to the rise time of the required velocity response. For this reason, we analyze the capability of a high-speed loading system with high load capacity to impose a velocity step, followed by constant rate of sliding, using only several preset passive-control variables. Assuming representative transient-friction response of rock test-samples, preset passive-control variables of the loading system may be obtained such that the deviation from the ideal velocity-step is minimized. A parametric exploration of the preset passive-control variables and test-sample behavior is used to define the machine workspace, and to optimize the key design characteristics of the loading system, such that the desired load paths for a range of expected sample behaviors may be achieved.
Modeling a Flat Learning Environment as a Social Network to Understand Effects of Peer-to-Peer Information Exchange on Learning
Authors: Siddique Zahed , Okudan Kremer Gül E. , Akasheh Firas
Published: January 2015

In this paper we present a technology assisted flat learning environment, Teaching to Learn (TeatoL), that capitalizes on the research findings on linkages between higher-order thinking and peer-learning. Within TeatoL students are introduced to a “flatter” instructional environment; all participants have dual roles as students and instructors who are embedded in a collaborative environment where all learn collectively from each other’s experiences, even the instructor. The main objective of this paper is to understand flat learning environment as a social network. The focus is on peer learning mode, where students are instructors to share their experience and then learn from fellow student instructors. In this paper, we present our initial analysis of a flat learning environment, implemented at the University of Oklahoma, as a network. The participants in the learning environment were given an open design problem related to sheet metal forming. We close the paper with observations from our initial implementations on peer-learning as a network.
Adjustable Sensitivity MEMS Magnetic Sensor
Authors: Park Sangtak , Al-Ghamdi Majed S. , Khater Mahmoud , Abdel-Rahman Eihab , Yavuz Mustafa
Published: January 2015

This paper introduces a novel MEMS magnetic field sensor based on the Lorentz force. It measures torsional vibrations excited via Lorentz force. The sensor sensitivity and dynamic range can be tuned by varying an electrostatic bias. Experimental demonstration shows that the sensor sensitivity can be changed from 0.7 (m/s)/T at 6 V DC bias to 1.4 (m/s)/T at 0 V DC bias.
Design of Constant-Velocity Transmission Devices Using Parallel Kinematics Principle
Authors: Yu Jingjun , Yu Jiazhu , Wu Kang , Kong Xianwen
Published: January 2015

This paper presents a new type of constant-velocity transmission devices based on parallel mechanisms with properties of equal-diameter spherical pure rolling. The method we used is essentially an extension of the planar ellipse gear to the spherical one. Both the fixed and moving axodes of a specified parallel mechanism are obtained, as traced by the spatial instant screw axis (ISA) with respect to the fixed and moving coordinate systems. Based on Poinsot’s theorem and achievements, a series of these parallel mechanisms which satisfy constant-velocity condition have been disclosed correspondingly. Their motion range and transmission performances are also explored by taking the 3-4R mechanism as an instance. As the main part of this paper, two important applications for this type of constant-velocity transmission devices are also explored. One is used as a gearless spherical gear, and the other is used as a constant-velocity universal joint (CVJ). Simulations were fulfilled on ADAMS to verify the transmission performance in terms of different applications.
Method for Turbocharging Single Cylinder Four Stroke Engines
Authors: Buchman Michael R. , Winter Amos G.
Published: January 2015

This paper presents a feasibility study of a method for turbocharging single cylinder, four-stroke internal combustion engines. Turbocharging is not conventionally used with single cylinder engines because of the timing mismatch between when the turbo is powered, during the exhaust stroke, and when it can deliver air to the cylinder, during the intake stroke. The proposed solution involves an air capacitor on the intake side of the engine between the turbocharger and intake valves. The capacitor acts as a buffer and would be implemented as a new style of intake manifold with a larger volume than traditional systems.

In order for the air capacitor to be practical, it needs to be sized large enough to maintain the turbocharger pressure during the intake stroke, cause minimal turbo lag, and significantly increase the density of the intake air. By creating multiple flow models of air through the turbocharged engine system, we found that the optimal size air capacitor is between four and five times the engine capacity. For a capacitor sized for a one-liter engine, the lag time was found to be approximately two seconds, which would be acceptable for slowly accelerating applications such as tractors, or steady state applications such as generators. The density increase that can be achieved in the capacitor, compared to air at standard ambient temperature and pressure, was found to vary between fifty percent for adiabatic compression and no heat transfer from the capacitor, to eighty percent for perfect heat transfer. These increases in density are proportional to, to first order, the anticipated power increases that could be realized with a turbocharger and air capacitor system applied to a single cylinder, four-stroke engine.
Redundancy-Free Integration of Rotational Quaternions in Minimal Form
Authors: Terze Zdravko , Mueller Andreas , Zlatar Dario
Published: January 2015

Redundancy-free computational procedure for solving dynamics of rigid body by using quaternions as the rotational kinematic parameters will be presented in the paper. On the contrary to the standard algorithm that is based on redundant DAE-formulation of rotational dynamics of rigid body that includes algebraic equation of quaternions’ unit-length that has to be solved during marching-in-time, the proposed method will be based on the integration of a local rotational vector in the minimal form at the Lie-algebra level of the SO(3) rotational group during every integration step. After local rotational vector for the current step is determined by using standard (possibly higher-order) integration ODE routine, the rotational integration point is projected to Sp(1) quaternion-group via pertinent exponential map. The result of the procedure is redundancy-free integration algorithm for rigid body rotational motion based on the rotational quaternions that allows for straightforward minimal-form-ODE integration of the rotational dynamics.
Multiscale Model Validation Based on Generalized Interval Bayes’ Rule and its Application in Molecular Dynamics Simulation
Authors: Tallman Aaron E. , Blumer Joel D. , Wang Yan , McDowell David L.
Published: January 2015

Reliable simulation protocols supporting integrated computational materials engineering requires uncertainty to be quantified. In general, two types of uncertainties are recognized. Aleatory uncertainty is inherent randomness, whereas epistemic uncertainty is due to lack of knowledge. Aleatory and epistemic uncertainties need to be differentiated in validating multiscale models, where measurement data for unconventionally very small or large systems are scarce, or vary greatly in forms and quality (i.e. sources of epistemic uncertainty). In this paper, a recently proposed generalized hidden Markov model is used for cross-scale and cross-domain information fusion under the two types of uncertainties. The dependency relationships among the observable and hidden state variables at multiple scales and physical domains are captured using generalized interval probability. The update of imprecise credence and model validation are based on a generalized interval Bayes’ rule. Its application in molecular dynamics simulation for irradiation of Fe is demonstrated.
Performance Evaluation Methods for Microgrippers
Authors: Ruggeri Serena , Fontana Gianmauro , Fassi Irene , Legnani Giovanni
Published: January 2015

In precise manipulation and assembly of components with sub-millimetric dimensions, the role of the gripping tools is fundamental. In the literature, many different types of the so-called microgrippers have been presented, based on different working principles, to cope with the issues related to the gripping, the handling and the release of different micro-components. Depending on the component properties, the task requirements and the system constraints, a microgripper could be more suitable than another and allow the achievement of higher performance. However, the performance assessment of the microgrippers lacks of a standardized and quantitative methodology. Many authors declare the good capabilities of their tools in a qualitative way or according to the results obtained executing specific and different tasks. For this reason, it is often difficult to compare different microgrippers and estimate the actual results that can be obtained e.g. in the gripping or the release of a component. In this context, after a preliminary survey of the adopted approaches in literature and of their meaning, this paper investigates the conception and formalization of methods and procedures to evaluate the performance of a generic microgripper and the definition of standard performance indices to support the presentation of the microgripper characteristics.
Multiphysics Challenges for Controlling Layered Manufacturing Processes Targeting Thermomechanical Performance
Authors: Michopoulos John G. , Lambrakos Samuel , Iliopoulos Athanasios
Published: January 2015

In an effort to enable on-demand process control of additive manufacturing processes for achieving component performance by design from a modeling and simulation perspective and context, we introduce a method for identifying relevant modeling and simulation challenges for the purpose of motivating research that addresses this problem. We first present the abstraction of the multiscale modeling processes connecting process control with functional performance both from the forward and inverse perspectives. We subsequently introduce a brief ontology describing the ordering of dependency and membership of all components of a model in order to isolate the potential areas where challenges can be exposed. We subsequently select some features that are usually ignored by the community during modeling. In particular, we demonstrate using a simple problem of mass and heat transfer, which is relevant to layered additive manufacturing, the implications and dangers related to ignoring process dependence on deposition path history.
Design of a Human-Like Range of Motion Hip Joint for Humanoid Robots
Authors: Lee Bryce , Knabe Coleman , Orekhov Viktor , Hong Dennis
Published: January 2015

For a humanoid robot to have the versatility of humans, it needs to have similar motion capabilities. This paper presents the design of the hip joint of the Tactical Hazardous Operations Robot (THOR), which was created to perform disaster response duties in human-structured environments. The lower body of THOR was designed to have a similar range of motion to the average human. To accommodate the large range of motion requirements of the hip, it was divided into a parallel-actuated universal joint and a linkage-driven pin joint. The yaw and roll degrees of freedom are driven cooperatively by a pair of parallel series elastic linear actuators to provide high joint torques and low leg inertia. In yaw, the left hip can produce a peak of 115.02 [Nm] of torque with a range of motion of −20° to 45°. In roll, it can produce a peak of 174.72 [Nm] of torque with a range of motion of −30° to 45°. The pitch degree of freedom uses a Hoeken’s linkage mechanism to produce 100 [Nm] of torque with a range of motion of −120° to 30°.
Dynamics and Control of the Bucket-Wheel Excavator: Part I — Dynamic Modeling of Bucket-Wheel Boom
Authors: Luu Quang Khanh , Söffker Dirk
Published: January 2015

Bucket-Wheel excavators (BWE) represent a specific type of complex machine system used in mining technology. During operation, the system is exposed to a number of external forces and disturbances like digging resistances on the Bucket-Wheel that cause transverse, longitudinal, and torsional vibrations. All vibrations will affect to normal working conditions, operational effectiveness, and may under specific conditions also effect the stability of the BWE. To increase working conditions advanced control systems can be applied controlling the dynamics, especially induced structural vibrations. In order to analyze and synthesize a controller for the above mentioned system, adequate modeling to describe the dynamical behavior of the system under real operating conditions is necessary. In a previous investigation, it was assumed that the Bucket-Wheel boom can be modeled as a flexible beam using the Euler-Bernoulli beam theory. Additionally it is assumed that the boom is attached to the excavator turning platform. The nonlinear modeling of the three-dimensional elastic boom considering the elasticity of suspending cables and also couplings resulting from geometrical nonlinear deformations is presented. Here the known modeling approach of higher order is used and extended to model the Bucket-Wheel boom of a Bucket-Wheel-Excavator including guided rotating motion in combination with digging resistance forces. The dynamic phenomena resulting from the higher-order modeling including higher-order geometrical couplings as well as the external excitations on the dynamic behavior of the Bucket-Wheel boom are analyzed in detail. Intensive simulation studies are realized demonstrating the effect of higher-order couplings as well as resulting destabilizing effects from the modeling.
Optimal Configuration of Valves and Plumbing Lines in Complex Housing
Authors: Cao Pei , Fan Zhaoyan , Gao Robert , Tang Jiong
Published: January 2015

In engineering design, the volume and weight of a number of systems consisting of valves and plumbing lines often need to be minimized. In current practice, this is facilitated under empirical experience with trial and error, which is time-consuming and may not yield the optimal result. This problem is intrinsically difficult due to the challenge in the formulation of optimization problem that has to be computationally tractable. In this research, we choose a sequential approach towards the design optimization, i.e., first optimizing the placement of valves under prescribed constraints to minimize the volume occupied, and then identifying the shortest paths of plumbing lines to connect the valves. In the first part, the constraints are described by analytical expressions, and two approaches of valve placement optimization are reported, i.e., a two-phase method and a simulated annealing-based method. In the second part, a three-dimensional routing algorithm is explored to connect the valves. Our case study indicates that the design can indeed be automated and design optimization can be achieved under reasonable computational cost. The outcome of this research can benefit both existing manufacturing practice and future additive manufacturing.
Use of the Harmonic Balance Method for Flexible Aircraft Engine Rotors With Nonlinear Squeeze Film Dampers
Authors: He Feng , Allaire Paul , Dimond Timothy
Published: January 2015

Squeeze film dampers in flexible rotors such as those in compressors, steam turbines, aircraft engines and other rotating machines are often modeled as linear devices. This linearization is valid only for a specified orbit where appropriate equivalent stiffness and damping coefficients can be found. However, squeeze film dampers are inherently nonlinear devices which complicates the analysis. This paper develops the harmonic balance method with a direct force model of the SFDs. This model is used for flexible rotors with squeeze film dampers where the rotor is treated as linear and the squeeze film damper is treated as nonlinear. The predictor-corrector method is employed to obtain the system forced response in the frequency domain after separating the nonlinear components from the linear components of the equations of motion. This approach is much more efficient than conventional full nonlinear transient analysis.

The application considered in this paper is the low pressure (LP) compressor of an aircraft engine. The LP compressor rotor has two roller bearings with squeeze film dampers and one ball bearing without a squeeze film damper. Orbits at the fan end dampers and the turbine end dampers for both the harmonic balance and nonlinear transient modeling are compared for accuracy and calculation time. The HB method is shown to be 5 to 12 times faster computationally for similar results. Fast Fourier transform results were obtained for various shaft operating speeds. Results were also obtained for the unbalance response at different locations with gravity loading. Finally, unbalance response of the rotor with varying centering spring stiffness values were obtained. The results show that the centering spring stiffness for the turbine end damper is less sensitive than the fan end damper.
Isogeometric Shape Optimization for Compliant Mechanisms With Prescribed Load Paths
Authors: Radaelli Giuseppe , Herder Just L.
Published: January 2015

This paper presents a method for the design of compliant mechanisms with large deflections and prescribed load paths. While the approach is general, this paper treats the shape optimization for two dimensional beams. Due to the geometric non-linearity of the problem the non-linear analysis is nested into the optimization procedure. This requires accurate and efficient analysis of the structural problem. The analysis of the beam is based on the Isogeometric Analysis formulation, an alternative for conventional FEA especially appreciated for its shape-accuracy and efficiency. The method is applied to the synthesis of a balancer for a pendulum, which involves a two step load case: first a prestressing phase and subsequently a motion phase under the influence of gravity. To this end, a prestressed compliant beam was optimized with respect to its initial shape and the preload conditions. The rotationless character of the degrees of freedom of the Isogeometric beam requested the formulation of specific boundary conditions in order to apply rotations on the beam. The results of the shape optimization have been validated with a prototype out of carbon fiber composite material, which has been successfully tested. The experimental results are in agreement with the simulation results, with an error of 3%.
Design Improvements and Design Methodology for the Gear Bearing Drive: A Compact, Powerful and Cost-Effective Robotic Actuator
Authors: Brassitos Elias , Kong Qingchao , Mavroidis Constantinos , Weinberg Brian
Published: January 2015

As modern robotic systems begin to permeate mass productions in consumer and healthcare products, the development of powerful cost-effective compact actuators represents a critical need to deliver commercially viable high performance robotic products. During the last years our team has developed a novel approach in actuator development which overcomes gearing packaging, efficiency and reliability problems of current actuators, paving the way for a new era of low-cost high-performance robotic products that are currently unattainable with existing commercial actuators. Our new actuator assembly, called the Gear Bearing Drive (GBD), uses three components comprising a brushless outrunner motor, two stage planetary gearbox, and novel rolling surfaces — all designed with overlapping functions and common features which interface together to drastically simplify and reduce the size and complexity of the actuator assembly. This unique approach allows embedding the motor within the planetary gearbox and further enables the actuator to operate without any traditional ball bearing, saving significant volume, cost, and manufacturing complexity. The low-cost gearbox combined with the high power output of brushless outrunner motors and typical high efficiencies of planetary gear arrangements results in compact, powerful and cost-effective robotic actuators with the potential to impact a number of industries ranging from consumer products to manufacturing and healthcare. In this paper we present the latest design improvements for the GBD so that we reduce friction and maximize efficiency. We also present a new design software for the GBD that has also been developed to reduce trial and error during the design phase and to speed up the production process.
Contactless Ultrasonic Energy Transfer: Acoustic-Piezoelectric Structure Interaction Modeling and Performance Enhancement
Authors: Shahab Shima , Erturk Alper
Published: January 2015

The harvesting of ambient vibrations for powering wireless electronic components has been heavily researched over the last decade. As long as sufficient vibrational energy is readily available in the neighborhood of small electronic devices, it is possible to achieve mechanical-to-electrical energy conversion by means of a proper transduction mechanism and thereby enable self-powered wireless electronic systems. An alternative scenario is the case in which the wireless electronic component has little or no vibrational energy available in its environment, yet wireless charging of its battery is still of great interest. Examples to this scenario range from medical implants to underwater sensor networks. The goal in such systems is to charge the electronic component by contactless transfer of energy without relying on mechanical or electrical connection to the wireless component. The commonly used transduction methods of wireless energy transfer are known to be inductive, capacitive, far-field electromagnetic, and optical coupling. Acoustic energy transfer based on the propagation of energy at ultrasonic frequencies is a recently explored alternative. As this field receives growing attention, it is required to develop fully coupled modeling framework to quantify the energy transfer characteristics with a focus on the transmitter, receiver, fluid medium, as well as geometric and material parameters. In this paper, we present multiphysics modeling of contactless ultrasonic energy transfer for wireless electronic components submerged in liquid medium. The source is a pulsating sphere and the receiver is a piezoelectric transducer operating in the 33-mode of piezoelectricity with fundamental underwater resonance frequency above the audible frequency range. The goal is to quantify the electrical power transmitted from the source to the electrical load across the electrodes of the receiver in terms of the source strength for a given distance between the transmitter and the receiver. Both analytical and finite-element models are developed for the resulting acoustic-piezoelectric structure interaction problem. Fixed-free and free-free mechanical boundary conditions are considered for the fluid loaded receiver to validate the analytical model against multiphysics finite-element simulations. For the electrical boundary conditions across the electrodes, resistive and resistive-inductive loads are considered. Specifically broadband power transfer is achieved by optimal resistive-inductive load tuning for performance enhancement. Effects of various system parameters on the electroelastic response are explored. The analytical model developed in this work can be used to predict and optimize the multiphysical system dynamics with very good accuracy and substantially improved computational efficiency as compared to finite-element modeling using commercial packages.
Dynamics of a 3D Micropolar Beam Model
Authors: Hassanpour Soroosh , Heppler G. R.
Published: January 2015

The development of a simplified micropolar beam model is presented and the governing dynamic equations for a micropolar beam deforming in 3D space, under different types of external loading and boundary conditions are derived. The dynamic equations are derived from Hamilton’s principle and the finite element method is used to provide numerical examples. The modal behavior of the developed micropolar beam model and the conditions under which the results of classical beam models will be recovered are presented.
Finite Element Analysis Within Component Design Process of Hydraulic Quadruped Robot
Authors: D’Imperio Mariapaola , Cannella Ferdinando , Semini Claudio , Caldwell D. G. , Catelani Daniele , Bernetti Roberto
Published: January 2015

The lightweight constructions and components stiffness play an important role in mechanics and in particular in high performance robots. In this paper the Virtual Prototyping Design (VPD) approach for addressing the robot design to this goal is shown. The VPD is applied to three mechanical problems of Walking Hydraulic Robots (WHRs): the first one deals with the leg joint sensitivity analysis; the second one concerns a force sensor optimization while the third one presents the torso structural verification. In all the aforementioned studies the experimental tests and the fitting analyses for model validation were carried out reaching satisfactory results.
Design of an Underactuated Robotic End-Effector With a Focus on Power Tool Manipulation
Authors: Rouleau Michael , Hong Dennis
Published: January 2015

End-effectors require careful design considerations to be able to successfully hold and use power tools while maintaining the ability to also grasp a wide range of other objects. This paper describes the design of an end effector for a humanoid robot built for disaster response scenarios. The end effector is comprised of two independently actuated fingers with two opposing stationary rigid hollow pylons built to allow the pinching of objects and to provide protection for the opposing fingers when retracted and not in use. Each finger has two degrees of freedom (DOF) and is actuated with one servo motor through the use of an underactuated four bar linkage. Using only two fingers and two actuators the end-effector has the ability to hold a power tool while also being able to simultaneously actuate the trigger of the tool independently. The combination of compliant fingers and rigid pylons along with the careful design of the palm structure creates a strong robust dexterous end-effort that is simple to control.
Identifying Opportunities for the Design of Innovative Reconfigurable Robotics
Authors: Sosa Ricardo , Wood Kristin L. , Mohan Rajesh E.
Published: January 2015

The creative design of reconfigurable robots presents challenges that can be tackled by the application of transformation principles for innovative design. This paper extends previous work in the systematic extraction of transformation principles in mechanical systems and reports new results that apply to the design of innovative reconfigurable robotics. Definitions of key terms are revised and a deductive research approach is used to expand and complement the conceptual classification of design operators (principles, facilitators and guidelines) based on semantic analysis of lexical structure, written and spoken conventions. The aim of this work is to produce a comprehensive taxonomy and semantic representation that can be used in the systematic identification of opportunities for the design of innovative solutions in reconfigurable robotics. This semantically robust, comprehensive and cross-domain conceptual taxonomy is tested in the mapping of large knowledge bases, demonstrating its potential to characterize large solution spaces and to identify new opportunities for the design of innovative solutions. Specialized assessments in the area of robotics and design show that this method successfully captures the qualitative reasoning of seasoned practitioners and has a clear potential to inform the design of innovative transformer designs.
Direct growth of HfO2 on graphene by CVD
Authors: Lukosius Mindaugas , Dabrowski Jarek , Wolff Andre , Kaiser David , Mehr Wolfgang , Lupina Grzegorz
Published: January 2015

Chemical vapor deposition (CVD) was applied to grow dielectric HfO2 layers on graphene/SiO2/Si and graphene/TiN/Si reference substrates directly, i.e., without a seed layer or any other functionalization of graphene. It was found that the presence of bilayer and (generally) multilayer graphene islands on nominally monolayer graphene strongly impacts the nucleation and the growth of HfO2. No damage inflicted by the CVD process on the graphene could be detected by Raman spectroscopy. According to x-ray diffraction, the films, grown on graphene at 400 °C and having thickness between 5 and 50 nm, were polycrystalline. Electrical measurements were performed for metal–insulator–metal (MIM) capacitors produced by evaporating Au and TiN top electrodes on the HfO2 film. Leakage currents were in the range of 10−8 A/cm2 at 1 V for 50 nm HfO2 grown on graphene, exceeding by one order of magnitude the currents measured for the reference HfO2/TiN MIM structures. The films grown on graphene have a dielectric constant of 17 with a quality factor of 50.
Sensing Amino Acids at the Lysosome
Authors: Ray L. Bryan
Published: January 2015

A possible sensor for detecting and signaling amino acid abundance is identified.