bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Stair Ascent and Descent Simulations
Authors: Xiang Yujiang , Kim Joo H. , Chung Hyun-Joon , Yang James , Kwon Hyun-Jung
Published: January 2015

Human stair ascent and descent are simulated in this work by using a skeletal digital human model with 55 degrees of freedom (DOFs). Hybrid predictive dynamics approach is used to predict the stair climbing motion with weapons and backpacks. In this process, the model predicts joints dynamics using optimization schemes and task-based physical constraints. The results indicated that the model can realistically match human motion and ground reaction forces data during stair climbing tasks. This can be used in human health domain such as leg prosthesis design.
Design of Compliant Mechanisms Using a Pseudo-Rigid-Body Model Based Topology Optimization Method
Authors: Jin Mohui , Zhang Xianmin , Zhu Benliang
Published: January 2015

This paper presents a novel method for the topological synthesis of flexure-based compliant mechanisms. Such kind of mechanisms are usually obtained by replacing the kinematic pairs of existing rigid-body mechanisms with flexure hinges, which is often regarded as the rigid-body replacement approach. This approach uses the topologies from rigid-body mechanism and pays little attention to the selection of the optimal topology among them. The proposed method tries to find out the optimal topology directly from design problem, without referencing to the existing rigid-body mechanisms. The topology of the flexure-based compliant mechanisms is represented by the pseudo-rigid-body model (PRBM). The PRBM is expressed in a ground structure using an adjacency matrix. An analysis method based on the principle of minimum potential energy is introduced to evaluate the static performance of the PRBM candidates quantitatively. Using genetic algorithm (GA), the optimal PRBM can be found out according to the objective function that is based on the analysis results. The validity of the proposed method is tested on a single-input-output compliant mechanism design problem.
Feature-Based Prognosis of Performance and Cost Implications of Cyber-Physical Systems: An Illustration of Theory and Process
Authors: Opiyo Eliab Z. , Horváth Imre
Published: January 2015

Prognosis and planning for the future life cycles is critical for both customers and developers of complex systems such as cyber-physical systems (CPSs). There are often uncertainties regarding the eventual costs and performances of CPSs. Having in advance a clear sense of the expected costs and performance is vital in the early development phases for decisions on, e.g., which functional features the CPS should have, whether to proceed with the development process, or whether to own a CPS or product. We focus specifically on prognosis of functional performance and cost implications of CPSs. The problem is that the available forecasting approaches cannot be used straightaway to tradeoff between costs and benefits, or to predict the benefits of investment in the early phases of the processes of development of CPSs. As a first step in an attempt to deal with these challenges, we have developed a feature-based reference scheme for deriving aspects and criteria for forecasting functional performance and cost implications of CPSs. We illustrate the applicability of the proposed scheme in this paper. We used this scheme as the basis for deriving the aspects and criteria for forecasting functional performance and cost implications of a cyber-physical printing utility. The scheme provided a systematic way of acquiring and formulating the aspects and criteria, and of figuring out the features that a cyber-physical printing utility should encompass. Overall, it helps to reduce the chance of overlooking the aspects and criteria.
Dynamic Model of a Weld Breaking Mechanism for Automatic Circuit Recloser Applications
Authors: Korves Brian , Voglewede Philip A.
Published: January 2015

Automatic circuit reclosers protect electrical distribution systems by breaking the circuit should the current levels exceed an acceptable range. In the process of opening and closing the circuit, welds are formed between the contacts, making it difficult to separate the contacts again. In order to ensure that the contacts can be separated in the event of a fault, a mechanism has been constructed to impart an impact load on the weld. This mechanism has been designed and used for many years with little understanding of how the mechanism components affect the performance of the mechanism. In order to gain this understanding, a dynamic model of the mechanism was created.
3D Face Recognition Under Isometric Expression Deformations
Authors: Sovizi Javad , Rai Rahul , Krovi Venkat
Published: January 2015

In this paper, 3D face recognition under isometric deformation (induced by facial expressions) is considered. The main objective is to employ the shape descriptors that are invariant to (isometric) deformations to provide an efficient face recognition algorithm. Two methods of the correspondence are utilized for automatic landmark assignment to the query face. One is based on the conventional iterative closest point (ICP) method and another is based upon the geometrical/topological features of the human face. The shape descriptor is chosen to be the well-known geodesic distance (GD) measure. The recognition task is performed on SHREC08 database for both correspondence methods and the effect of feature (GD) vector size as well as landmark positions on the recognition accuracy were argued.
Low Order Continuum-Based Liquid Sloshing Formulation for Vehicle System Dynamics
Authors: Wang Liang , Jiménez Octavio Jesús R. , Wei Cheng , Shabana Ahmed A.
Published: January 2015

The objective of this investigation is to develop a low order continuum-based liquid sloshing model that can be successfully integrated with multibody system (MBS) algorithms. The liquid sloshing model proposed in this investigation allows for capturing the effect of the distributed inertia and viscosity of the fluid. The fluid viscous forces are defined using the Navier-Stokes equations. In order to demonstrate the use of the approach presented in this study, the assumption of an incompressible Newtonian fluid is considered with a total Lagrangian approach. Fluid properties such as the incompressibility condition are formulated using a penalty method. The low order model that captures the effect of the distributed fluid inertia on the vehicle dynamics is developed in this investigation using the floating frame reference (FFR) formulation. The use of this approach allows for developing an inertia-variant fluid model that accounts for the dynamic coupling between different modes of the fluid displacements. The matrix of position vector gradients and its derivative are formulated using the FFR kinematic description. The position and velocity gradient tensors are used to define the Navier-Stokes stress forces. The proposed liquid sloshing model is integrated with a MBS railroad vehicle model in which the rail/wheel interaction is formulated using a three-dimensional elastic contact formulation that allows for the wheel/rail separation. Several simulation scenarios are used to examine the effect of the distributed liquid inertia on the motion of the railroad vehicle. The results, obtained using the sloshing model, are compared with the results obtained using a rigid body vehicle model. The comparative numerical study presented in this investigation shows that the effect of the sloshing tends to increase the possibility of wheel/rail separation as the forward velocity increases, thereby increasing the possibility of derailments at these relatively high speeds.
Bifurcation Analysis of Piezoelectric Bi-Stable Plates
Authors: Chen Lihua , Yepeng Ma , Zhang Wei
Published: January 2015

The complex nonlinear dynamic behaviors of the composite bi-stable plates with piezoelectric patch are analyzed. Based on the Vo n Karman hypothesis and Hamilton’s principle, the nonlinear dynamic model is derived. Temperature and piezoelectric effect are also considered in the model. Numerical simulations are performed to study the nonlinear vibration response of the composite bi-stable plate using the Runge-Kutta method. The analysis of the phase portrait, waveforms and bifurcation diagrams of numerical simulations shows that the period, multi-period and chaotic responses can be observed with the variation of the excitation in frequency and amplitude.
An Integrated Performance Measure Approach for System Reliability Assessment
Authors: Wang Zequn , Wang Pingfeng
Published: January 2015

This paper presents an integrated performance measure approach (iPMA) for system reliability assessment considering multiple dependent failure modes. An integrated performance function is developed to envelope all component level failure events, thereby enables system reliability approximation by considering only one integrated system limit state. The developed integrated performance function possesses two critical properties. First, it represents exact joint failure surface defined by multiple component failure events, thus no error will be induced due to the integrated limit state function in system reliability computation. Second, smoothness of the integrated performance on system failure surface can be guaranteed, therefore advanced response surface techniques can be conveniently employed for response approximation. With the developed integrated performance function, the maximum confidence enhancement based sequential sampling method is adopted as an efficient component reliability analysis tool for system reliability approximation. To furthermore improve the computational efficiency, a new constraint filtering technique is developed to adaptively identify active limit states during the iterative sampling process without inducing any extra computational cost. One case study is used to demonstrate the effectiveness of system reliability assessment using the developed iPMA methodology.
Evolving Design Model Synchronization for System Health Management Using Laplace Approximation
Authors: Wang Pingfeng , Adewunmi Adebayo O. , Wang Zequn
Published: January 2015

Lifecycle health management plays an increasingly important role in realizing resilience of aging complex engineered systems since it detects, diagnoses, and predicts system-wide effects of adverse events, therefore enables a proactive approach to deal with system failures. To address an increasing demand to develop high-reliability low-cost systems, this paper presents a new platform for operational stage system health management, referred to as Evolving Design Model Synchronization (EDMS), which enables health management of aging engineered systems by efficiently synchronizing system design models with degrading health conditions of actual physical system in operation. A Laplace approximation approach is employed for the design model updating, which can incorporate heterogeneous operating stage information from multiple sources to update the system design model based on the information theory, thereby increases the updating accuracy compared with traditionally used Bayesian updating methodology. The design models synchronized over time using sensory data acquired from the system in operation can thus reflect system health degradation with evolvingly updated design model parameters, which enables the application of failure prognosis for system health management. One case study is used to demonstrate the efficacy of the proposed approach for system health management.
Extension of the Kinematics-Based Method for Predicting the Motion of Proteins
Authors: Arikawa Keisuke
Published: January 2015

On the basis of an analogy between the kinematic structures of proteins and robotic mechanisms, we have so far developed methods for predicting the internal motion of proteins from three-dimensional structural data in the protein data bank (PDB). With these methods, we model proteins as serial manipulators constrained by springs, and calculate the structural compliance of the protein model. In this study, toward more practical purposes, we reformulate and extend the existing methods by broadening the definition of structural compliance and reducing the number of variables for expressing the conformation of the model. The broadening is performed by separating the parts whose deformations are evaluated from those where forces are applied. This separation allows the calculation of the effective forces causing deformation in other specified parts. We also reduce the number of conformation variables from the consideration based on the algebraic structure of the basic equations. The size of the matrix whose inverse must be calculated is thus minimized, and the computational cost is reduced. We verify the effectiveness of these extensions by analyzing the PDB data of some proteins.
Rotor Dynamics in Design of a High Speed Cryogenic Pump for Geo Stationary Launch Vehicles
Authors: Jammi Srinivasa R.
Published: January 2015

On January 5th 2014 the Indian Space Research Organization successfully launched its Geo Stationary Launch Vehicle with an indigenous Cryogenic engine. One of the main design aspects is in its rotor dynamics to predict the peak amplitude unbalance whirl and the speed at which it occurs. This engine has several key technologies, one of them specifically is coupled rotors, viz., Turbine, Hydrogen Pump and Oxidizer supported on seven nonlinear rolling element bearings and several seals all mounted in a flexible casing. The conventional beam model initially adopted failed to predict the speed at which peak unbalance response occurs.

The rotor system was first developed in a solid model to determine the critical speeds of the rotor alone considering its 40000 rpm centrifugal loads with bearings treated as linear. Then, unbalance whirl of this rotor system was developed by codes specially developed for this purpose. The rolling element bearings are found to be highly nonlinear with large bearing radial forces at critical speeds. An iterative procedure was developed to match the bearing force and unbalance whirl to determine peak amplitude response speeds. Subsequently, seals and the influence of casing and internal pressures were accounted in the analysis. This paper describes the advanced rotor dynamic design of this pump.
Workspace and Joint Space Analysis of the 3-RPS Parallel Robot
Authors: Chablat D. , Jha R. , Rouillier F. , Moroz G.
Published: January 2015

The Accurate calculation of the workspace and joint space for 3 RPS parallel robotic manipulator is a highly addressed research work across the world. Researchers have proposed a variety of methods to calculate these parameters. In the present context a cylindrical algebraic decomposition based method is proposed to model the workspace and joint space. It is a well know feature that this robot admits two operation modes. We are able to find out the set in the joint space with a constant number of solutions for the direct kinematic problem and the locus of the cusp points for the both operation mode. The characteristic surfaces are also computed to define the uniqueness domains in the workspace. A simple 3-RPS parallel with similar base and mobile platform is used to illustrate this method.
Dynamic Analysis of a 3-RRR Parallel Robot With Joint Clearances Using Natural Coordinates
Authors: Zhang Xuchong , Zhang Xianmin
Published: January 2015

A general computational methodology for modeling and analysis of planar rigid multibody systems with multi clearance joints is presented. The contact points are important for contact detection, natural coordinate system is implemented to describe the rigid links in order to reduce the amount of calculation. The Lankarani-Nikravesh continuous contact-impact model is used to evaluate the contact force, in which energy dissipation in the form of hysteresis damping is considered. The improved Coulomb’s friction force model is used to describe the friction phenomenon between the joint components. Numerical results for 3-RRR mechanism with revolute clearance joints are presented and discussed. This methodology is further compared with the widely used reference coordinate system, the numerical simulation results show that the presented method is an effective and new method to predict the dynamic characteristics of planar mechanical systems with clearance joints.
Motion Control of Three Link Underactuated Manipulator by Bifurcation Control
Authors: Yabuno Hiroshi , Endo Kazuya
Published: January 2015

Motion control of a three link underactuated manipulator, whose first joint has an actuator and a sensor and second and third joints do not have actuator or sensor, is theoretically proposed without feedback control with respect to the motion of the free links. By using high-frequency vertical excitation, so called Kapitza pendulum is stabilized at the upright position without state feedback control. The phenomenon can be regarded as a subcritical pitchfork bifurcation. On the other hand, it is known that the horizontal excitation causes supercritical pitchfork bifurcation in a pendulum. Also, the inclination of excitation from the horizontal and vertical directions produces the perturbation of the complete supercritical and subcritical pitchfork bifurcations, respectively. In this paper, we apply the method of multiple scales to obtain the averaged equations governing the motion of the free links. We perform the bifurcation analysis of the free links and clarify the equilibrium points in the free links and their stability. Then, we propose a strategy to swing up the free links and to stabilize them at the upright position by actuating the perturbation of the pitchfork bifurcations based on the change of the inclination of excitation.
Investigation of Numerical Performance of Partitioning and Parallel Processing of Markov Chain (PPMC) for Complex Design Problems
Authors: Lin Po Ting , Chou Yu-Cheng , Manuel Mark Christian E. , Hsu Kuan Sung
Published: January 2015

Divide-and-conquer strategies have been utilized to perform evaluation calculations of complex network systems, such as reliability analysis of a Markov chain. This paper focuses on partitioning of Markov chain for a multi-modular redundant system and the fast calculation using parallel processing. The complexity of Markov chain is first reduced by eliminating the connections with low transition probabilities associated with a threshold parameter. The transition probability matrix is then reordered and partitioned such that a worse-case reliability is evaluated through the calculations in only the diagonal sub-matrices of the transition probability matrix. Since the calculations of the sub-matrices are independent to each other, the numerical efficiency can be greatly improved using parallel computing. The numerical results showed the selection of threshold parameter is a key factor to numerical efficiency. In this paper, the sensitivity of the numerical performance of Partitioning and Parallel-processing of Markov Chain (PPMC) to the threshold parameter has been investigated and discussed.
A Framework for Hybrid Cells That Support Safe and Efficient Human-Robot Collaboration in Assembly Operations
Authors: Morato Carlos W. , Kaipa Krishnanand N. , Liu Jiashun , Gupta Satyandra K.
Published: January 2015

In this paper, we present a framework to build hybrid cells that support safe and efficient human-robot collaboration during assembly operations. Our approach considers a representative one-robot one-human model in which a human and a robot asynchronously work toward assembling a product. Whereas the human retrieves parts from a bin and brings them into the robot workspace, the robot picks up parts from its workspace and assembles them into the product. Using this collaboration model, we explicate the design details of the overall framework comprising three modules — plan generation, system state monitoring, and contingency handling. We provide details of the virtual cell and the physical cell used to implement our framework. Finally, we report results from human-robot collaboration experiments to illustrate our approach.
Nonlinear Forced Vibration of Carbon Nanotubes Considering Thermal Effects
Authors: Askari Hassan , Esmailzadeh Ebrahim , Younesian Davood
Published: January 2015

Nonlinear forced vibration of carbon nanotubes is investigated. The Euler-Bernoulli beam theory in conjunction with Eringen’s theory is considered and the thermal effect is incorporated into the formulation of the governing equation. The Winkler model is assumed for the foundation of carbon nanotube and the Galerkin method is performed to find the nonlinear ordinary differential equation of system based on the assumed boundary conditions. The multiple times scale is applied to investigate the forced vibration of carbon nanotubes. The effect of different parameters, namely, temperature variations and carbon nanotube length changes on the amplitude of oscillation of carbon nanotube are studied. It is found that the linear natural frequency of system increases by increasing the temperature and subsequently, the oscillation amplitude will decrease.
Helical Kirigami-Inspired Centimeter-Scale Worm Robot With Shape-Memory-Alloy Actuators
Authors: Zhang Ketao , Qiu Chen , Dai Jian S.
Published: January 2015

The worm-like robots are capable of imitating the amazing locomotion of the long and thin creature. This paper presents a novel centimeter-scale worm robot inspired by a kirigami-fold which is a variation of origami with helical motion. The body structure is extracted from the kirigami structure and its motion characteristics are analyzed in terms of kinematic principles. This leads to identification of the capability of the segmented worm robot with integrated parallel kirigami structures to imitate contracting motion, omega-shaped bending motion and twisting motion of the locomotion in nature. A prototype of the worm robot with three segments is fabricated with paper-made body structure and actuated by shape-memory-alloy (SMA) coil springs. The robot is lightweight and can be used in confined environments for detection and inspection. The study creates a new approach of integrating SMA actuators in origami-enabled parallel kinematic structures for the development of compliant and miniaturized robots including the presented worm robot.
Differentiating Bending From Folding in Origami Engineering Using Active Materials
Authors: Lauff Carlye , Simpson Timothy W. , Frecker Mary , Ounaies Zoubeida , Ahmed Saad , von Lockette Paris , Strzelec Rebecca , Sheridan Robert , Lien Jyh-Ming
Published: January 2015

Origami engineering — the use of origami principles in engineering applications — provides numerous opportunities to revolutionize the way we design, manufacture, assemble, and package products and devices. By combining origami principles with active materials, we can create reconfigurable products and devices that can fold and unfold on demand. In origami, the folded medium is paper, yet many engineering applications require materials with finite thickness to provide the necessary strength and stiffness to achieve the desired functionality. In such applications, it is important to distinguish between bending and folding so that we understand the differences in material behavior when actuated. In this paper, we propose definitions for bending and folding for materials used in engineering applications. The literature is reviewed in detail to provide context and support for the proposed definitions, and examples from our own research with active materials, specifically, magneto-active elastomers (MAE) and dielectric elastomers (DE), are used to illustrate the subtle, yet important, differences between bending and folding in materials with finite thickness.
Constraint Satisfaction Approach to the Design of Multi-Component, Multi-Phase Alloys
Authors: Galvan Edgar , Malak Richard J. , Gibbons Sean , Arroyave Raymundo
Published: January 2015

The development of new materials must start with an understanding of their phase stability. Researchers have used the CALPHAD method to develop self-consistent databases encoding the thermodynamics of phases. In this forward approach, thermo dynamic conditions (processing conditions such as composition, temperature, pressure, etc.) are mapped to equilibrium states. In this research, we are instead interested in the inverse problem of mapping a set of desired phase constitutions to the set of thermodynamic conditions that give rise to them. Recently, search and optimization techniques have been used to determine thermodynamic conditions that yield a particular phase stability state (point-to-point mapping). In this research, we focus on a more general problem: mapping of specific regions in multi-dimensional phase constitution spaces to ranges in values of thermodynamic conditions(set-to-set mapping). In the context of search theory, we are interested in finding all solutions to a Continuous Constraint Satisfaction Problem (CCSP). The problem is typically multi-dimensional, highly nonlinear, and, importantly, contains non-isolated solutions (the solution is ranges of values rather than finite points). Numerical methods for finding all solutions to CCSPs typically rely on branch-and-prune methods, which interleave branching with pruning steps. These methods are mainly designed to address CCSPs with isolated solutions and would be inefficient if applied to the problem at hand. In this work, we describe a novel algorithm to search the thermodynamic phase field for the full set of thermodynamic conditions that result in user-specified phase constitutions. The approach combines techniques from computational materials science, evolutionary computation, and machine learning to approximate the non-isolated solution set to the CCSP. We investigate the performance of the algorithm on an Fe-Ti binary alloy system using ThermoCalc with TCFE7 database. For this system, the algorithm is able to generate solutions with low error rates.
A Unified Concept for the Graph Representation of Constraints in Mechanisms
Authors: Müller Andreas , Shai Offer
Published: January 2015

There are two established approaches to represent constraints: the body-bar (BB) and the bar-joint (BJ) graph that can be used in machine theory. They are referred to as topological graphs as they describe the relation between members of a mechanism. It is known, however, that in many cases these graphs are not unique. Hence any method for kinematic analysis or mobility determination that is based on these topological graphs is prone to failures.

In this paper a generalized and unified concept for the representation of constraints in mechanisms is introduced. It is first shown in which situations BB and BJ representations fail to correctly represent the mechanism. The novel constraint graph is then derived starting from the most general model of constrained rigid bodies. It is shown how BB and BJ graphs result as special cases. Therefore the new graph representation is called the ‘mixed graph’. It is further shown how this novel mixed constraint graph allows for computation of the correct generic (topological) mobility, and thus overcomes the problems of BB and BJ representations.
6x6 UGV: Stochastic Dynamics Fundamentals for Mobility Estimation
Authors: Gray Jeremy P. , Vantsevich Vladimir V. , Opeiko Alexandre F.
Published: January 2015

Stochastic modeling for mobility estimation has vastly improved through recent research and the advancements in technology, but those advancements haven’t fully been applied to full vehicle mobility control and on-line (real time) analysis of each driving wheel’s contribution and influence.

This paper presents an analysis of fundamental mobility dynamics implemented into advanced stochastic estimation methodologies. Based on this analysis, the paper formulates: (i) developed on-line mobility criteria in stochastic conditions from one wheel to full vehicle with six driving wheels in which the contribution of every wheel can be estimated, and (ii) terrain characterization and agile vehicle dynamics information to estimate UGV mobility in real time.

This analysis enables on-line mobility estimation for UGVs to make control changes as the event of poor terrain conditions occur (or before it) rather than after the event, causing the vehicle to then optimize its reaction to regain control. These fundamental applications for mobility control in stochastic conditions enable today’s one wheel modeling solutions to be applied to the full vehicle.
The Impact of Sustainability on Consumer Preference Judgments of Product Attributes
Authors: Goucher-Lambert Kosa , Cagan Jonathan
Published: January 2015

Despite significant interest from consumers, sustainable products often struggle to find success in the marketplace. This failure is often attributed to the perception that consumers remain unwilling to sacrifice product attributes such as form, function, or price in order to adopt a product whose environmental impact is less than that of a competing product. This work aims to better understand how knowing a product’s environmental impact affects preference for that product’s disparate attributes. Three products of various complexities are explored through a conjoint analysis experiment that uncovers consumer preference for discrete form, function and price attributes. In this work, single use spoons, reusable water bottles, and home washing machines were used for analysis. These three products were decomposed into form, function, and price attributes that were varied at discrete levels. After a form-only ratings-based conjoint analysis study was conducted to find high, medium, and low preference form designs for each participant, two separate form-function-price discrete choice studies were conducted for each of the three products. These two discrete choice trials were identical in all aspects except in the second trial participants were provided with calculated environmental impact values for all design configurations; the presented environmental impact information was a dependent variable based on a Life Cycle Analysis calculation using the current product configuration being shown to the participant. Results show that when participants are provided with this additional piece of information, their preference for form, function, and price attributes of a product is greatly impacted. In particular we find that the importance of functional attributes increases in the context of environmental impact metrics, while the importance of form decreases and the importance of price decreases modestly.
Nonlinear Dynamics of Piezoelectric Cantilever Energy Converters Through Perturbation Theory and Experimental Analysis
Authors: Varoto Paulo S. , Mineto Andreza T.
Published: January 2015

It is known that the best performance of a given piezoelectric energy harvester is usually limited to excitation at its fundamental resonance frequency. If the ambient vibration frequency deviates slightly from this resonance condition then the electrical power delivered is drastically reduced. One possible way to increase the frequency range of operation of the harvester is to design vibration harvesters that operate in the nonlinear regime. The main goal of this article is to discuss the potential advantages of introducing nonlinearities in the dynamics of a beam type piezoelectric vibration energy harvester. The device is a cantilever beam partially covered by piezoelectric material with a magnet tip mass at the beam’s free end. Governing equations of motion are derived for the harvester considering the excitation applied at its fixed boundary. Also, we consider the nonlinear constitutive piezoelectric equations in the formulation of the harvester’s electromechanical model. This model is then used in numerical simulations and the results are compared to experimental data from tests on a prototype. Numerical as well as experimental results obtained support the general trend that structural nonlinearities can improve the harvester’s performance.
Customer Needs Extraction Using Disability Simulation for Purposes of Inclusive Design
Authors: Armstrong Jessica , Stone Rob , Cox Latane
Published: January 2015

Current product design methodologies are not conducive to creating inclusive products (products that meet the needs of persons with and without disabilities). In this paper, empathic design principles and modular product design strategies are explored as part of a novel approach to inclusive design. A disability simulation suit is used to test if empathically derived customer needs from persons without disabilities can serve as a proxy for the customer needs of persons with disabilities. This data collection methodology both increases the safety and ease by which customer needs can be gathered and gives designers an empathic design experience with the products they develop. This paper presents the techniques involved in and the preliminary data regarding the collection of customer needs on known product pairs. These product pairs perform the same function, but one is designed inclusively and one is not. Prior work on module identification from customer need statements is extended to specifically address the design of inclusive products. As part of larger research, this data will be used to make generalizations about the customer needs for inclusive products within the context of modular product design to create inclusive design guidelines, which will reduce the effort and expense involved in creating inclusively designed products.
A Qualitative Failure Analysis Using Function-Based Performance State-Machines for Fault Identification and Propagation During Early Design Phases
Authors: DeStefano Charlie B. , Jensen David C.
Published: January 2015

In a time when major technological advancements are happening at incredible rates and where demands for next-generation systems are constantly growing, advancements in failure analysis methods must constantly be developed, as well. Performance and safety are always top concerns for high-risk complex systems, and therefore, it is important for new failure analysis methods to be explored in order to obtain more useful and comprehensive failure information as early as possible, particularly during early design phases when detailed models might not yet exist. Therefore, this paper proposes a qualitative, function-based failure analysis method for early design phases that is capable of not only analyzing potential failure modes for physical components, but also for any manufacturing processes that might cause failures, as well. In this paper, the proposed method is first described in general and then applied in a case study of a proposed design for a nanochannel DNA sequencing device. Lastly, this paper discusses how more advanced and detailed analyses can be incorporated into this approach during later design phases, when more failure information becomes available.
Development of Underactuated Mechanical Fingers Based on Anthropometric Data and Anthropomorphic Tasks
Authors: Robson Nina , Allington James , Soh Gim Song
Published: January 2015

This paper describes a systematic method for the kinematic synthesis of one degree-of-freedom robotic fingers that incorporate multi-loop kinematic structures with second order task specifications, such that the fingers do not violate normal direction and curvature constraints imposed by contact with objects. We show how to use these contact and curvature effects to formulate the synthesis equations for the design of a planar index finger, based on anthropomorphic back-bone chain and anthropomorphic task. The prototype of the finger is described in the end of the paper.

It is important to note, that the theoretical foundation presented in this paper, assists in solving some of the open problems of the field, providing preliminary results on the synthesis of one degree-of-freedom kinematic chains, based on human’s finger dimensions and novel task specifications that incorporate curvature constraints, with future applications in grasping and object manipulation.
Integrity Diagnosis Method of Bolted Joint Based on Time Fluctuation of Reflection Intensity Caused by Nonlinear Wave Modulation
Authors: Tanaka Takashi , Masuda Arata , Sone Akira
Published: January 2015

This study presents the integrity diagnosis method of the bolted joint based on nonlinear wave modulation. When the structure that has the contact interface is vibrating at low-frequency, the contact interface is tapping and clapping due to low-frequency vibration. In this condition, the scatter characteristics, such as wave transmissivity and reflectivity, of high-frequency waves in vicinity of the contact interface are fluctuated in synchronization with low-frequency excitation because of the contact acoustic nonlinearity. The time fluctuation of reflection intensity, which expresses the reflectivity in the specific location, of high-frequency waves at the contact interface is given as the reflection intensity map which plots time-spatial map. In this paper, experiment using the beam specimen which has single bolted joint is conducted to examine the performance of the evaluation index based on the fluctuation amplitude of reflection intensity.
Optimized NURBS Based G-Code Part Program for High-Speed CNC Machining
Authors: Kanna Sai Ashish , Tovar Andres , Wou Jason Soungjin , El-Mounayri Hazim
Published: January 2015

This work presents the automation of high-accuracy CNC tool trajectory planning from CAD to G-code generation through optimal NURBs surface approximation. The proposed optimization method finds the minimum number of NURBS control points for a given admissible theoretical cord error between the desired and manufactured surfaces. The result is a compact part program that is less sensitive to data starvation than circular and spline interpolations with potential better surface finish. The proposed approach is demonstrated with the tool path generation of an involute gear profile.
Procedural Generation of Vegetation for a Virtual Test Track
Authors: Berssenbrügge Jan , Stöcklein Jörg , Koza Andre , Gräßler Iris
Published: January 2015

Advanced driver assistant systems (ADAS) are increasingly being tested during simulated test drives in a test and training environment based on a driving simulator, in order to reduce the number of extensive real test drives. The need for numerous virtual test drives in the driving simulator requires to model detailed and realistically appearing 3D models of real test tracks. A manual reproduction of real tracks is a cumbersome and time-intensive task.

In previous work, we have introduced a method to create virtual test tracks with minimized manual effort using data from various sources, such as navigation systems, digital elevation models, aerial images, digital landscape models etc. [1]. However, these virtual test tracks still do not appear very realistic to the test driver, since no detailed vegetation was generated by that method.

In this paper, we propose an approach to enrich a virtual terrain with authentic vegetation. The aim is to increase the perceived realism of the landscape, in order to provide the same input for the sensors of an ADAS under test in the driving simulator as on the real track. The requirement is to automate the vegetation generation as far as possible and to support real-time rendering of the generated very complex 3D model, which is crucial for a usable sensor feed.

The basis for the generation of vegetation in this work is data from digital landscape models. These data define where areas like woodlands and agricultural zones are located in geographic coordinates. These areas are refined by a color detection, which is applied to the corresponding aerial images, in order to identify various tree and plant species. Based on the application of a procedural rule system the actual plants are then placed in the refined areas. The rule system imitates the natural growth behavior of plants and is based on terrain characteristics like gradient, direction of a slope, or competition for resources. By combining terrain data, color detection on aerial images, and procedural rules, a planting method is developed to generate natural looking vegetation.

The implementation prototype of our approach, based on the Unity3D game engine, which supports an easy creation of complex sceneries, showed that it is possible to create vegetation for a virtual test track with minimal manual effort. By placing vegetation at realistic locations, considering natural spread of plants, the perceived realism of the scene was improved. A performance analysis showed that even with the generated vegetation, interactive frame rates are achievable.
A Constraint Stabilization Method for Time Integration of Constrained Multibody Systems in Lie Group Setting
Authors: Müller Andreas , Terze Zdravko
Published: January 2015

The stabilization of geometric constraints is vital for an accurate numerical solution of the differential-algebraic equations (DAE) governing the dynamics of constrained multibody systems (MBS). Although this has been a central topic in numerical MBS dynamics using classical vector space formulations, it has not yet been sufficiently addressed when using Lie group formulations. A straightforward approach is to impose constraints directly on the Lie group elements that represent the MBS motion, which requires additional constraints accounting for the invariants of the Lie group. On the other hand, most numerical Lie group integration schemes introduce local coordinates within the integration step, and it is natural to perform the stabilization in terms of these local coordinates. Such a formulation is presented in this paper for index 1 formulation. The stabilization method is applicable to general coordinate mappings (canonical coordinates, Cayley-Rodriguez, Study) on the MBS configuration space Lie group. The stabilization scheme resembles the well-known vectors space projection and pseudo-inverse method consisting in an iterative procedure. A numerical example is presented and it is shown that the Lie group stabilization scheme converges normally within one iteration step, like the scheme in the vector space formulation.
Origami-Based Self-Folding Structure Fabrication Based on 3D Printing on Polystyrene Films
Authors: Deng Dongping , Chen Yong
Published: January 2015

Self-folding structures have unique advantages such as reconfiguration capability during their usage. Such advantages can be beneficial for a wide variety of applications including biomedical and electronics products. However, how to fabricate and actuate self-folding structures is still an ongoing research topic. In the paper a simple fabrication approach based on a 3D printing process is presented for the fabrication of self-folding structures that can be actuated using a constrain-based thermo responsive mechanism. A self-folding structure fabricated by our method is an origami sheet with multiple layers. The middle layer of the origami sheet is a pre-strained polystyrene film, which can have a large shrinkage when exposing to heat. Both its upper and bottom surfaces are covered with desired patterns in cured plastic resin. A foldable hinge is achieved by using the cured resin to constrain the shrinkage of the film on one side while the other side of the film is exposed to the heating environment. A model of the related folding mechanism is developed. Based on it, a hinge structure design method is presented for a given folding angle. Various experiments are performed to verify the folding control of designed self-folding structures. Possible applications of the developed self-folding structures are also demonstrated and discussed.
Curing Temperature Study for Curl Distortion Control and Simulation in Projection Based Stereolithography
Authors: Xu Kai , Chen Yong
Published: January 2015

Polymerization shrinkage and thermal cooling effect have been identified as two major factors leading to the curl distortion in the Stereolithography (SLA) process. In this paper, the curing temperatures of built layers in the mask image projection based Stereolithography (MIP-SL) process are investigated using a high-resolution infrared (IR) camera. The curing temperatures of built layers using different exposure strategies including varying exposure time, grayscale levels and mask image patterns have been studied. The curl distortions of a test case based on various exposure strategies have been measured and analyzed. It is shown that, by decreasing the curing temperature of built layers, the exposure strategies using grayscale levels and mask image patterns can effectively reduce the curl distortion. In addition to curl distortion control, the curing temperature study also provides a basis for the curl distortion simulation in the MIP-SL process.
Development of an ADL Assistance Apparatus for Upper Limbs and Evaluation of Muscle and Cerebral Activity
Authors: Tanaka Eiichirou , Saegusa Shozo , Iwasaki Yasuo , Yuge Louis
Published: January 2015

We developed an assistance apparatus for upper limbs for patients who can control their finger but they cannot lift up their arms themselves, for example myopathy and hemiplegic patients. The mechanism of assistance is utilized the differential gears to lose the weight and volume of the mechanical arm. That enabled us to configure three motors to drive two DOFs (Degrees of freedom) for the shoulder and one DOF for the elbow around the root of the mechanical arm. This arm has two support trays, for wrist and upper arm. Furthermore, to realize other ADL (activities of daily living) motions (for instance, eating, writing, putting on makeup, wiping his/her face, and so on) them selves, we proposed to control the device using the targeted posture map for the mechanical arm. To be able to choose the appropriate input for each patient, various input interfaces, for example, joy-stick, push buttons, sensor glove using bending sensors, and so on, are equipped.

In general, even though a human behaves an atonic motion, the maximum voluntary contraction (%MVC) outputs at least from 5 to 10%. The usage of this apparatus is to move the user’s upper limbs with dependence completely, and the purpose of this apparatus is to decrease the value of %MVC up to approximately 10%. Therefore, in this paper, the muscles of the user were evaluated with the ratio of %MVC. To confirm the effectiveness of assistance ability, we measured muscle activity while using the device, and compared the %MVC data between using the device or not. As a result, the activity decreased up to 80%, and the effectiveness of this device could be confirmed.

Finally, to expand the usage of this apparatus to encompass Neuro-Rehabilitation as well, we measured cerebral activity while using the device for rehabilitation with a near-infrared spectroscopy (NIRS). Then we compared the data from using the device or not, and input motion from a third person. By using this device, the cerebral activity decreased especially when the target motion was complex. However, when the subject input the motion themselves, the cerebral activity increased more than when the data is input by a third person, especially, when the target motion was complex. Therefore, for use in Neuro-Rehabilitation, we found it is important the subject input the target motion him/herself.