bluuebunny/crossref_metadata_2025 huggingface dataset:
Take-Home Mechatronics Control Labs: A Low-Cost Personal Solution and Educational Assessment
Authors: Stark Brandon , Li Zhuo , Smith Brendan , Chen YangQuan
Published: February 2014

Control theory, once described as the “Physics of the 21st Century,” is pervading to almost all subjects of higher learning. However, it is a difficult topic for many students, especially when introduced at the undergraduate lower level. Providing hands-on experience is often a great aid for teaching difficult concepts, but for control theory forcing a hands-on component can distract from the learning if the students are unprepared. An effective control theory laboratory curriculum builds on the foundations of statics and dynamics, circuit theory, signal processing and programming course-work. However, undergraduate students have a limited educational experience and are typically lacking in one or more of those foundations. Coupled with the unfamiliarity of the common equipment found in teaching labs, students often find themselves overwhelmed and struggle with the setups, limiting their exposure to the topic of control theory. Some industry and education companies have introduced extensive control workstations to bring integrated control theory to a teaching laboratory; however these systems are expensive and specialized, limiting their reach and effectiveness. In this paper, a low-cost mechatronics control theory personal laboratory setup with a proposed curriculum is developed for undergraduate students that addresses their uncertain foundation and improves accessibility by introducing portability to maximize the learning outcomes.
HRV Monitoring for Human Factor Research in UAS
Authors: Stark Brandon , Patel Tejal , Chen YangQuan
Published: February 2014

Though Unmanned Aerial System (UAS) operators have started to push for general acceptance into the National Airspace System (NAS), there remain significant and necessary areas of research. Despite the ‘Unmanned’ moniker, human factors serve a vital role in safe and robust operation. Numerous reports have placed human errors as significant factors in recent UAS incidents, leading many researchers to investigate a framework for analyzing these human factors that lead to incidents. In this paper, the use of Heart Rate Variability (HRV), as an indicator of operator pressure or cognitive load of a UAS operator, is considered. Furthermore, potential applications of HRV research are presented towards applying this new layer of human feedback information to adjust UAS operations to achieve a safer and more resilient UAS. This paper serves as an initial proposal for this bigger closed-loop thinking in UAS human factor research.
A Prediction Method of Wear on Tooth Surface for Spur Gears
Authors: Inoue Shotaro , Ikejo Kiyotaka , Nagamura Kazuteru , Seyama Natsuhiko , Nakagawa Shinya
Published: February 2014

Gear drives are widely used in various mechanical systems. Therefore, the understanding for the failure mode of gear tooth provides the improvement of various machines. The wear on the tooth surface is one of the important failure modes for the gear drives. The tooth wear changes its profile, and frequently increases gear vibration and noise. However, there are many unclear phenomena about the wear on the tooth surface for the gear drive. In this study, we investigated wear of spur gear using a power circulating-type gear testing machine, and measured the change in tooth profile of the test gears. Furthermore, we developed a computer program to predict the amount of the wear on the tooth surface for the spur gears. The method employs two equations. One is based on the wear theory under lubricated condition that was deduced by Soda. The other is derived from the ploughing wear model. Using these equations, the wear depth on the tooth surface is calculated with the contact stress, the sliding velocity, the oil film thickness, etc. The calculated value of the wear agreed with the experimental data.
Factors That Effect Motivation and Performance on Innovative Design Projects
Authors: Linnerud Blake , Mocko Gregory
Published: February 2014

For engineering companies striving to be competitive in today’s economy, it is essential that innovation is the crux of their strategy and decision making process. Engineering designers are constantly pushed to develop new and innovative solutions to design problems yet there has been little research on what actually motivates these designers, both intrinsically and extrinsically, to be innovative. Similarly, engineering students working on their capstone design project are pushed to develop solutions to innovative design problems. The purpose of this paper is to present the initial findings of an innovation survey of Mechanical Engineering students at Clemson University.

This paper will discuss the importance of innovation, the current state of innovation, the surveys that were created, the results of said survey, and how this information will be used going forward to improve performance and motivation in capstone design classes. The purpose of this survey is to determine which motivational factors engineering students perceive to be the most effective when working on innovative design projects. The initial results showed that (1) making an “A” grade in the class, (2) developing an “elegant” solution, and (3) making professional contacts with the industry sponsors were the three factors that most effectively promoted innovative design. Conversely, (1) impressing peers, (2) making professional contacts with the fellow students, and (3) winning cash prizes were the three factors that least effectively promoted innovative design.
Designing a System of Plug-In Hybrid Electric Vehicle Charging Stations
Authors: Khosrojerdi Amirhossein , Xiao Minting , Sarikprueck Piampoom , Allen Janet K. , Mistree Farrokh
Published: February 2014

In this paper we present a two-step approach for the design of a system of Plug-in Hybrid Electric Vehicle (PHEV) charging stations. Our approach consists of a simulation model and a mathematical model. The simulation model formulates the charging station’s ability to meet charging demand by using discrete event simulation. The mathematical model formulates the design decisions made when designing the charging stations, i.e. locations and configurations of charging stations, using the compromise Decision Support Problem (cDSP). Waiting time, service time, number of slots (chargers) and demand are key inputs for the simulation model. Output of the simulation model, which is the service level of the charging stations, is used as an input for the mathematical model. By compromising between maximizing the service level, maximizing the demand coverage, minimizing the installation cost for slots and minimizing distance between charging stations and demand nodes, design decisions are taken in the mathematical model. Our focus in this paper is on the method which is widely applicable. However the approach is presented and evaluated for a data set from Dallas County, Texas.
Utilizing Augmented Reality Technology for Crowd Pedestrian Analysis Involving Individuals With Disabilities
Authors: Stuart Daniel , Christensen Keith , Chen Anthony , Kim Yong , Chen YangQuan
Published: February 2014

This research explores how different compositions of Individuals with Disabilities (IwDs) affect the dynamics of crowd movement. In particular, we consider IwDs such as individuals on manual and electric wheelchair, with vision loss and other mobility impairments to better understand the impacts that the compositions of individuals with various types of disabilities will bring on the mobility of the crowd at various structural elements of a built environment such as hall way, door way, and stairwells. While currently available video tracking technologies provide options for primitive macroscopic and microscopic analysis of a crowd, they lack the ability to analyze detailed navigational information of each focused group such as IwDs with varying types of disabilities. This paper provides an approach that exploits ARToolKitPlus libraries and Power-over-Ethernet high speed cameras along with augmented reality elements to track navigational patterns at individual level in a crowd. Preliminary results demonstrate the feasibility of the proposed system to track individual tracking of navigational patterns.
Localization Phenomena of Nonlinear Vibrations in Three-Blade Wind Turbines
Authors: Ikeda Takashi , Harata Yuji , Takahashi Hisashi , Ishida Yukio
Published: February 2014

Vibration characteristics of three-blade wind turbines are investigated. The system is modeled by a coupled system of the flexible tower with two degrees of freedom and each blade with a single degree of freedom, and these blades are subjected to wind pressure which varies depending on the height from the ground. The vibrations of the three-blade wind turbines are theoretically analyzed to determine the natural frequency diagrams, frequency responses, stationary time histories and their FFT results. It is found that several peaks appear at the specific range of the rotational speed ω in the response curves because of both the wind pressure and the parametric excitation terms. In three-blade wind turbines, vibrations including predominant components of 3ω and its higher harmonics appear near these peaks. The response curves near the highest peak exhibit soft spring types due to the nonlinearities of the restoring moments of the blades. In the numerical simulations, “localization phenomena” in the blades, which vibrate at different amplitudes, are observed. The influence of an imperfection of the three blades is also examined.
Vibration of Bending-Torsion Coupled Resonance in a Rotor
Authors: Fujiwara Hiroyuki , Tsuji Tadashi , Matsushita Osami
Published: February 2014

In certain rotor systems, bending-torsion coupled resonance occurs when the rotational speed Ω (= 2π Ωrps) is equal to the sum/difference of the bending natural frequency ωb (= 2π fb) and torsional natural frequency ωθ(= 2πfθ). This coupling effect is due to an unbalance in the rotor. In order to clarify this phenomenon, an equation was derived for the motion of the bending-torsion coupled 2 DOF system, and this coupled resonance was verified by numerical simulations.

In stability analyses of an undamped model, unstable rotational speed ranges were found to exist at about Ωrps = fb + fθ. The conditions for stability were also derived from an analysis of a damped model. In rotational simulations, bending-torsion coupled resonance vibration was found to occur at Ωrps = fb − fθ and fb + fθ.

In addition, confirmation of this resonance phenomenon was shown by an experiment. When the rotor was excited in the horizontal direction at bending natural frequency, large torsional vibration appeared. On the other hand, when the rotor was excited by torsion at torsional natural frequency, large bending vibration appeared. Therefore, bending-torsion coupled resonance was confirmed.
A Methodology for Examining the Role of Adaptive Expertise on CAD Modeling
Authors: Johnson Michael D. , Ozturk Elif , Valverde Lauralee , Yalvac Bugrahan , McGary Prentiss , Peng Xiaobo
Published: February 2014

Computer-aided design (CAD) tools play a significant role in the modern product commercialization environment. As CAD and general CAx technology advances, it becomes more important to understand how engineers adapt their expertise to new environments and problems. This work examines a methodology consisting of a set of surveys, interviews, and exercises with a small group of practicing engineers to assess adaptive expertise (AE) and relate this AE to CAD modeling performance and procedures. Results detail AE survey results, a modeling and alteration exercise, and an exercise where engineers are asked to model a component using a CAD platform they are unfamiliar with. Interview and time use (from screen capture videos) results from this exercise are presented along with other data. Correlations among AE survey and interview variables and model analysis variables are presented. The epistemology dimension of the AE survey was found to be negatively correlated with both original modeling and alteration time. Overall modeling time in the different platform was positively correlated with the percentage of time a participant spent engaging in trial and error; modeling time in the different platform was negatively correlated with percentage of time spent doing actual modeling and the time spent thinking.
Vibration Control of Cylindrical Shell Panel With Shape Memory Alloy Actuators
Authors: Li Huiyu , Li Hua , Tzou H. S.
Published: February 2014

This paper studies the vibration control of cylindrical shell panel. Shape memory alloy (SMA) wires are adopted as actuators and neural network training method is applied to enable SMA to output desired force. The proposed SMA actuators are fixed on the cylindrical shell panel and generate contracting forces while be heated electronically. The SMA actuators need to generate forces opposite to the external loading, and thus they can suppress the effect of external force. However, as SMAs present nonlinear relationship between temperature and force, it is difficult to output the desired stress profile. In this research, the hysteresis characteristics of SMAs are fitted by neural networks. The neural network model of SMA plant model is established based on the temperature input and force output; and the inverse model is generated with the force as input and temperature as output. The desired forces are obtained based on these neural network models. To validate the effectiveness of SMA actuators, the vibration response of cylindrical shell panel is analyzed with modal expansion method. The modal response under the controlling of SMA actuators is calculated based on the modal dynamic equation. The results show that SMA actuators controlled by the neural network method are effective to suppress the vibration of cylindrical panel shell. Primary experiments were performed to verify the proposed neutral network method. The results show that the SMA wire actuator generated desired force profile while heating using the neutral network method.
Rationale-Based Patent Analysis for Corporate Product Design
Authors: Liang Yan , Liu Ying
Published: February 2014

Patents are well-recognized as valuable data source for product innovation, design and development. They contain rich information about design rationale (DR), technology development and so on. In this paper, we intend to discover design focuses, which refer to types of design that a corporation emphasizes on in innovations and R&D approaches. By analyzing invention features, we attempt to reveal distinct design focuses that corporations have targeted at. In our previous study, we have explored text mining to discover DR based on the proposed ISAL model (issue, solution and artifact layer) from patents. In this paper, we aim to design a rationale-based patent analysis approach to analyze technical focuses of corporations from a large volume of patents. In our proposal, DR information of each patent is firstly discovered and each patent is represented by a structured manner of issue, solution and artifact layers. A feature association-based approach is designed to measure connections between artifact features and highly related features are clustered into groups to represent the categories of invention and design focuses from a corporation perspective. A scoring function is then defined to categorize patents based on artifact feature groups. In experimental study, a case study using patents filed by Apple Inc. and RIM (Research In Motion) over a period of time was conducted to demonstrate the approach proposed. We reported our findings on issues like design topic clusters and design focuses involved in the inventions over time.
Design of the Second Spine: A Secondary Pathway to Transfer Loads From the Shoulders to the Pelvis
Authors: Park Joon-Hyuk , Stegall Paul , Zanotto Damiano , Vashista Vineet , Jin Xin , Agrawal Sunil K.
Published: February 2014

The Second Spine is a vest intended to prevent musculoskeletal injuries caused by heavy backpack loads, while also maintaining the range of motion of the wearer. The vest is formed by multiple segments between the shoulder and a pelvic belt. In normal “off” configuration, the segments are disconnected from each other and the vest is flexible providing full range of motion to the upper body. With the pull of a string in the “on” configuration, the vest becomes semi-rigid creating a secondary pathway to transfer loads between the shoulder and a pelvic belt.

The device was evaluated by a subject who walked on a treadmill while carrying a backpack load of 25% of his body weight (BW). Experiment results showed that the semi-rigid vest reduces the force exerted on the shoulders and induces a more erect posture. Muscle activations in the lower limbs indicate that loads were successfully transferred from the shoulders to the waist while bypassing the vertebral column. These results show that the device can be used to mitigate potential risks of musculoskeletal injuries caused from backpack loads.
Dimensional Synthesis of Planar Eight-Bar Linkages Based on a Parallel Robot With a Prismatic Base Joint
Authors: Soh Gim Song , Ying Fangtian
Published: February 2014

This paper details the dimensional synthesis for the rigid body guidance of planar eight-bar linkages that could be driven by a prismatic joint at its base. We show how two RR cranks can be added to a planar parallel robot formed by a PRR and 3R serial chain to guide its end-effector through a set of five task poses. This procedure is useful for designers who require the choice of ground pivot locations. The results are eight different types of one-degree of freedom planar eight-bar linkages. We demonstrate the design process with the design of a multifunctional wheelchair that could transform its structure between a self-propelled wheelchair and a walking guide.
Implicit Emotional Message Representation With 1/F-Fluctuation for Ambient Interface Application
Authors: Ito Teruaki
Published: February 2014

For remote communication, it is very hard to convey emotional message, or atmosphere of conversation to the opponent people who are located in a geographically difference place. For Email messages, emoticon, or face mark symbols are often used to express emotion, which works well to show emotion in an explicit way. Even though, the opponent face is show on the screen in remote video communication, emotional expression over the network is not similar to face-to-face meeting. In a face-to-face meeting, atmosphere of the conversation is shared in an implicit manner as opposed to the explicit explanation using words, sign, or pictures.

This research proposes an idea of implicit representation of emotional messages using light illumination [Lin, T.I. 2004; Vandewalle, G. 2010] with 1/f-fluctuation. It is reported that the 1/f-fluctuation makes a relaxed mental state. Therefore, ambient lighting with 1/f-fluctuation could provide a comfortable (and/or uncomfortable) atmosphere. In addition to this, this study aims to present emotional message in the illumination. In order to do so, four different types of 1/f-fluctuation pattern were created to represent four different types of typical human emotion, including joy, anger, pathos, and humor. The paper explains how the idea was implemented, using light illumination of four types of emotion based on the user experiments. According to some feasibility experiments, these four types of illumination were recognized to express each type of emotion. Applying emotional message representation with 1/f-fluctuation in the illumination of video conference speaker, implicit emotional message was presented during the conversation. Then the paper discusses the feasibility of the idea for ambient human interface.
Lyapunov Stability of Linear Fractional Systems: Part 2 — Derivation of a Stability Condition
Authors: Trigeassou Jean-Claude , Maamri Nezha , Oustaloup Alain
Published: February 2014

This paper, composed of two parts, addresses the stability of linear commensurate order fractional systems, Dn (X) = A X 0 < n < 1, using the infinite state approach. Whereas Part 1 has been dedicated to the definition of fractional systems energy, Part 2 deals with the derivation of a stability condition. When the eigenvalues of A are real, the modal representation shows that system energy is the sum of independent modal energies, so the derivation of a stability condition is straightforward in this case. On the contrary, when the eigenvalues are complex with positive real parts, unusual energy dynamics depending on initial conditions prevent direct derivation of a stability condition. Thus, an indirect method is proposed to formulate a stability condition in the complex eigenvalues case.
Axodes Analysis of the Multi DOF Parallel Mechanisms and Parasitic Motion
Authors: Chen Ziming , Ding Huafeng , Cao Wenao , Huang Zhen
Published: February 2014

The general motion of a spatial mechanism is a screw motion about an instantaneous screw axis (ISA). The locus of a series of ISAs will form a ruled surface, which can be called as an axode. For a spatial mechanism with only one degree of freedom (DOF), the ISAs or the axodes of the moving platform are unique. However, the axodes of the parallel mechanisms (PMs) with multi DOF are related to the specific motion which has various possibilities. In this paper, the ISAs of the multi DOF PMs are studied using the jacobian matrix which is changing with the configurations of the moving platform. The axodes of the multi DOF PMs with different inputs or outputs are obtained using this method. Based on the analyzed results, it is very clear that the general motions of the PMs are screw motions or rotations about a series of ISAs. In the end, the parasitic motion of the PMs is studied. For a PM, the parasitic motion will exist if the rotational freedoms are not rotations about a fixed point or axis.
High Aspect Ratio Au/Ni Coaxial Nanorod Arrays for Biosensing Applications
Authors: Hsu Che-Wei , Wang Gou-Jen
Published: February 2014

In this study, a novel fabrication method for high aspect ratio magnetic Au/Ni coaxial nanorod arrays is proposed. It is expected that the stiffness of the gold shell could be supported by the core nickel rod. Furthermore, a magnetic force can be employed to manipulate the motion of the coaxial nanorod arrays. The fabrication procedures include: AAO template preparation, working electrode coating, nickel electrodeposition, alumina etching, and gold-plating by an electroless nickel immersion gold (ENIG) process.

Experimental results demonstrated that the proposed method in this study could synthesize high aspect ratio magnetic Au/Ni coaxial nanorod arrays. The height of the synthesized coaxial nanorods is about 65.3 μm and the diameter of each nanorod is around 0.225 μm. Hence the aspect ratio is 290. The Au/Ni coaxial nanorod array was further used as a biosensor for the detection of glucose. The sensitivity of the proposed glucose biosensor was 225 μA/(mM·cm2) with a linear detection range of 27.5 μM to 1.38 mM. The sensitivity of the proposed Au/Ni coaxial nanorod array for glucose detection is the best among the reported works.
Study of the Lubricant Supply Arrangement in Non Recessed Hybrid Journal Bearing
Authors: Dwivedi Vijay Kumar , Chand Satish , Pandey K. N.
Published: February 2014

The present work is focused on the theoretical study of the performance of journal bearing operating under steady state condition, with particular emphasis on the influence of lubricant supply arrangements. In this paper the influence of the location of the grooves with respect to the load line and influence of groove dimensions on the performance parameter were investigated. The optimum location of the groove axis lies between 60° to 90° to the load line. It is also concluded that smaller groove length yielded lower load carrying capacity.
Optimum Solar-Powered HDH Desalination System for Semi-Isolated Communities
Authors: Abd El-Aziz Khalid M. , Hamza Karim , El Morsi Mohamed , Nassef Ashraf O. , Metwalli Sayed M. , Saitou Kazuhiro
Published: February 2014

For semi-isolated communities, fresh water may be scarce; however, brackish water or seawater can be easily accessed. This provides a drive to develop optimum-cost desalination system for such communities. This paper presents the optimization of a water-heated solar-powered humidification-dehumidification (HDH) desalination system with variable saline water flow rate. The design variables include the sizing of solar collector, storage tank and its internal heat exchanger, humidifier and dehumidifier. A program was developed to predict performance based on selected weather data file and optimize the system for minimum unit cost of produced fresh water. System cost is predicted via different first-order estimators. A tailored optimization technique is used and compared to a genetic algorithm procedure in the design optimization for local climate and market. A case study develops an optimum desalination plant for the Red Sea near the city of Hurgada and compared to previously developed system.
Positioning System for the Interaction With Virtual Shapes Through a Desktop Haptic Device
Authors: Covarrubias Mario , Bordegoni Monica , Cugini Umberto
Published: February 2014

The paper describes the results of a research activity on the design of a positioning system which includes both a physical 3-DOF and virtual platforms which carries out a Desktop Haptic Interface (DHI). The positioning system allows the user to interact with a virtual shape through a combination of linear and rotation motions, some of them driven by the user and some driven by the virtual shape. On the other hand, by rendering a physical 2D cross-section through the DHI permits the assessment of virtual prototypes of industrial products with aesthetic value. Typically, virtual objects are modified several times before reaching the desired design, increasing the development time and, consequently, the final product cost. The desktop haptic system (which includes the positioning system and the DHI) that we propose here, will reduce the number of physical mockups during the design process allowing designers to perform several phases of the product design process continuously and without any interruption. In particular the system is developed with the aim of supporting designers during the evaluation of the aesthetic quality of a virtual product.
Multiscale and Multifield Multiphysics of High Current Pulse Static Contact With Rough Surfaces
Authors: Michopoulos John G. , Young Marcus , Iliopoulos Athanasios
Published: February 2014

We are presenting a multi-field and multiscale theory leading to derivations of physical properties from surface topography and bulk material properties for the interface between two rough surfaces in contact activated by mechanical load and high current pulses. At the macro-scale our proposed model involves multi-field coupling of conduction and induction currents with heat conduction induced by Joule heating. The structural mechanics of the conducting materials are also considered. At the meso-scale and micro-scale the associated model contains an asperity based comprehensive model that leads to homogenized macro scale properties for the interface boundary. The mechanical pressure and the repulsion effect from electric current through the micro-contacts are accounted for as well. Numerical analysis results illustrate the dependence of the derived properties on the surface characteristics, external load and the electric current. Finally, the entire framework is applied to an actual conductor configuration of hollow cylinders under compression and a high current pulse to demonstrate the feasibility of the entire approach.
Principles on Collaborations in Cloud-Aided X (CLAX)
Authors: Lin Po Ting , Chou Yu-Cheng
Published: February 2014

In the past few years, the Computer-Aided Technologies, also known as Computer-Aided X (CAX) have been evolving to the Cloud. Cloud computing provides remote services with data storage, software, platform and infrastructure. The next-generation computing applications rely on the collaborations using the technologies of Cloud-Aided Technologies, or Cloud-Aided X (CLAX). The engineers and designers at various locations in different time zones can collaboratively and simultaneously work on a computing design project using CLAX. Issues such as security, conflict, storage, and online computing are inevitable. This paper presents the challenging problems in cloud-based collaborations and some principles for CLAX.
Towards Realization of Shape-Controlled Adaptable Buildings Following a Robotics Approach
Authors: Christoforou Eftychios G. , Müller Andreas , Phocas Marios C. , Matheou Maria , Arnos Socrates
Published: February 2014

Shape–controlled adaptable buildings constitute a major excursion from traditional architectural approaches with a potential for superior performance and enhanced flexibility compared to traditional fixed–shape building structures. A building concept is examined whose skeleton structure consists of a parallel arrangement of planar closed–loop n–bar linkages and it is covered with a flexible material. Shape adjustments involve coordinated reconfigurations of the constituent closed–chain mechanisms. Each individual linkage is equipped with one motion actuator as well as brakes installed on every joint. For the reconfigurations an “effective 4–bar” concept has been proposed that involves stepwise adjustments. Each step involves the selective locking of (n – 4) joints of each linkage so that it is effectively reduced to a single–DOF 4–bar mechanism the configuration of which can be adjusted using the available motion actuator. Appropriately planned control sequences can be used for a complete reconfiguration of the linkage. Motion planning is concerned with the generation of optimal control sequences while taking into account imposed limitations arising from the moving structure as well as the flexible envelop. This paper is a continuation of a prior work paying special attention to the envelop design. Simulation examples as well as an experimental study are used to demonstrate the feasibility of the concept and investigate relevant issues.
New Deployable Structures Based on an Elastic Origami Model
Authors: Saito Kazuya , Tsukahara Akira , Okabe Yoji
Published: February 2014

Traditionally, origami-based structures are designed on the premise of “rigid folding,” meaning that the facets and fold lines of origami can be replaced with rigid panels and ideal hinges, respectively. Rigid folding is an important factor in defining origami for mathematicians and geometricians. However, ideal rigid folding is impossible in real structures and every act of folding and unfolding is accompanied by elastic deformations. In this study, we focus on these elastic deformations in order to expand origami into a new method of designing morphing structures. We start by proposing a simple model for evaluating elastic deformation in nonrigid origami structures. In this model, the facets of origami are replaced with plates that are not only rigid but also elastic. This partially elastic origami model has a one-degree-of-freedom mechanism; therefore, its folding process can be described using rigid folding simulation techniques. In this process, the deformations of the elastic plates can be calculated and we can estimate the elastic energy through folding/unfolding. We then apply these methods to deployable plate models constructed of quadrilateral plates and hinges to design new deployable structures. Initial strain is introduced into the elastic parts of the partially elastic origami model and these parts function as actuators for deployment. Then, by using the finite element method, we conduct numerical simulations and confirm the deploying capabilities of the models.
Self Localization Using a 9DOF IMU Sensor With a Directional Cosine Matrix
Authors: Georgiou Evangelos , Morgan Peter L. , San Diego Jonathan , Dai Jian , Luck Michael
Published: February 2014

In the field of robotics, the most essential requirement for successful navigation is an accurate and numerically inexpensive method for self-localization. This paper presents a method that exploits the principles of directional cosines to setup a rotation matrix to deal with a closed loop PI feedback based model. The system uses a 9 degree of freedom (9DOF) sensor and exploits the benefits of the accuracy of a 3-axis gyroscope by leveraging the measurement of a 3-axis accelerometer and 3-axis magnetometer, which compensates and corrects the accumulative drift generated by integrating the gyroscope velocity measurements. The results show that the method is relatively accurate with a small level of error when compared to vision based glyph recognition and tracking methods for self-localization and is a sustainable method for removing accumulative drift.
Multibody Dynamics Modeling of Sand Flow From a Hopper and Sand Pile Angle of Repose
Authors: Wasfy Tamer M. , Ahmadi Shahriar G. , Wasfy Hatem M. , Peters Jeanne M.
Published: February 2014

An explicit time integration multibody dynamics code is used to create a three-dimensional model of sand. Sand is modeled using discrete cubical particles with appropriate normal contact force and tangential friction force models. The model is used to predict the sand angle of repose and flow rate during discharge from a conical hopper. A penalty technique is used to impose normal contact constraints (including particle-particle, particle-hopper and particle-ground contact). An asperity-based friction model is used to model friction. A Cartesian Eulerian grid contact search algorithm is used to allow fast contact detection between particles. The governing equations of motion are solved along with contact constraint equations using a time-accurate explicit solution procedure. Parameter studies are performed in order to study the effects of the particle size and the orifice’s diameter of the hopper on the angle of repose and sand flow rate. The results of the simulations are validated using previously published experimental results.
Generation of Planar Kinematic Chains With One Multiple Joint
Authors: Ding Huafeng , Yang Weijuan , Huang Peng , Ma Li , Kecskeméthy Andrés
Published: February 2014

It is very important to synthesize as many feasible kinematic structures of mechanisms as possible in the conceptual design of mechanisms. Besides simple joint mechanisms, multiple joint mechanisms are also widely used in various mechanical systems. This paper proposes an automatic method for the synthesis of planar multiple joint kinematic chains which are seldom addressed in literature. The bicolor topological graph and the bicolor contracted graph are adopted to represent the topological structures of multiple joint kinematic chains. The characteristic number string of bicolor topological graphs is proposed and used to detect efficiently isomorphism in the synthesis progress. A systematic method for the synthesis of kinematic chains with one multiple joint is proposed, and the whole families of multiple joint kinematic chains with up to 16 links and all possible degrees of freedom are obtained for the first time.
Dimensional Optimization of a Two-Arm Robot for Single-Site Surgery Operations
Authors: Drouin Christophe , Pourghodrat Abolfazl , Miossec Sylvain , Poisson Gérard , Nelson Carl A.
Published: February 2014

Unlike open surgery, minimally invasive surgery (MIS) involves small incisions through which instruments are passed to perform surgery. This technique is preferred since it reduces postoperative pain and recovery time. Laparoendoscopic single-site (LESS) surgery is the next step in MIS; a single incision is created instead of multiple access points for allowing the instruments to enter the peritoneal cavity. However, such minimally invasive techniques force the surgeon to perform more complex movements, hence the interest to use robotic systems. Design of robots for LESS is challenging to avoid collisions, reduce weight, and improve compactness while respecting the technical requirements (minimum forces, velocities). In this paper, we present the dimensional synthesis of a two-arm robot used for LESS. Each arm has a 2R-R-R architecture with link lengths optimized to respect the workspace constraints and maximize compactness while improving the performance in terms of forces and velocities (kinetostatic properties).
A Method for the Assessment of the Dynamic Performance of Neck Protection Devices
Authors: Galmarini Gianmarco , Gobbi Massimiliano , Mastinu Gianpiero , Previati Giorgio
Published: February 2014

In this paper a method for the evaluation of the dynamic performance of neck protection devices for motorcyclists is presented.

The research project involves both experimental and numerical activities.

An impulsive load is applied to the head of a 50th percentile male Hybrid III dummy while wearing a helmet by means of a pendulum of calibrated mass starting from a well-defined initial condition. The impact load and the load at the neck of the dummy are measured by means of two six axes load cells. Additionally, head linear and rotational accelerations are measured. The test procedure shows a very good repeatability and allows for the comparison of the force passing through the neck with and without neck protection devices.

Since neck protection devices should work in situations in which no relevant head injuries are present, the experimental parameters (pendulum mass and speed) are chosen to cause a high probability of injuries to the neck together with a low probability of damages to the head while wearing a standard helmet. Injury indices, found in the literature, have been used to determine the neck injury level.

A multibody model of the human neck, developed in Matlab™ SimMechanics™, is validated by using the data acquired during the tests.

A study of real-world crashes has allowed the identification of reference impact scenarios which have been simulated by using the multibody model.

The validated model is suitable to determine the chance that a motorcyclist would have significant neck injury with or without a neck protecting device.
Dynamic Analysis and Identification of Critical Points in the Superstructure of a Vehicle Through FE Modeling and Mobility Tests
Authors: Giagopoulos Dimitrios , Natsiavas Sotirios
Published: February 2014

A systematic methodology is applied, leading to an accurate prediction of the dynamic response and the location of critical points in the superstructure of a real military vehicle. First the vehicle superstructure is modeled numerically with the finite element method. The model is then updated through an experimental modal analysis procedure in a support-free state. Mobility tests are performed next in real operating conditions, aimed at recording the acceleration time histories at the connection points of the superstructure with the chassis. These accelerations are used as ground excitation to the model. The stresses developed under the specific loading conditions are evaluated. The critical points of the superstructure are selected, based on the level of the larger stresses developed. Finally, strain gauges are placed at the critical points of the superstructure and a new set of measurements is carried out, in order to experimentally verify the stress levels developed. Comparison of the numerical and experimental data verifies that the method applied is quite reliable, indeed.
The Rigid Origami Patterns for Flat Surface
Authors: Liu Sicong , Chen Yan , Lu Guoxing
Published: February 2014

Because of the internal mobility, rigid origami structures have great potential in engineering applications. In this research, a kinematic model of the rigid origami pattern is proposed based on the assembly of spherical 4R linkages. To ensure the rigid origami pattern with mobility one, the kinematic and geometric compatibility conditions of the kinematic model are derived. Four types of flat rigid origami patterns are obtained, including three existing types as well as a novel one called the supplementary type. To testify and display the mobile processes of the patterns, their simulation models are built accordingly.
A New Indirect Actuation Principle for Safe Physical Human-Robot Interactions
Authors: Esteveny Laure , Barbé Laurent , Bayle Bernard
Published: February 2014

Intrinsically safe mechanisms represent an innovative solution to develop physical human-robot interactions. These systems are characterized by low masses, inertia and torques. In this paper, an innovative actuation strategy is presented, focused on safety concerns. The system is first statically balanced to compensate gravity forces in any configuration. Our contribution then lies in the design of a mechanism that modifies the system balancing, making it possible to follow a planned trajectory or to remain in contact with a moving environment, without developing large forces. This principle is illustrated with an elementary one degree of freedom arm. The whole design procedure is described, so as to define properly the arm parameters for a given task. A closed loop position control strategy is then proposed in order to drive the mechanism. It uses a proportional-derivative controller with configuration dependent gains, whose efficiency is illustrated by trajectory following and interaction simulations.
The Homotopy-Analysis Approach for the Dynamical Study of a Microbeam Modeled on the Basis of the Strain-Gradient Theory
Authors: Belardinelli Pierpaolo , Lenci Stefano
Published: February 2014

The purpose of this work is to investigate the nonlinear dynamics of a slender microbeam, modeled within the framework of the strain-gradient elasticity, adopting the homotopy analysis method (HAM). The microbeam is fixed at both edges and a geometric nonlinearity is also present accounting for the axial stretch. To attain an accurate and reliable model, so that the error is spread smoothly over the domain, a Chebyshev approximation for the nonlinear electric actuation term is introduced. A reduced-order model for the governing equation of motion, represented by an high-order nonlinear partial differential equation, is obtained. Then, the single-degree-of-freedom model is studied to find an analytical approximated solution. The free vibrations of the beam are investigated and the effects of several parameters, such as the applied axial load, are analyzed. Particular attention is also paid to find the influence of the high-order length scale material parameters, introduced by the non-classical theory, that progressively modify the oscillating behaviour. The results on the nonlinear phenomena, show both an hardening and a softening behaviour, in competition between them, varying the beam parameters. A numerical solution, obtained by a 4th order Runge Kutta algorithm, is also proposed as a benchmark for the analytical results.
Topology Optimization of Nonlinear Metamaterials
Authors: Manktelow Kevin L. , Leamy Michael J. , Ruzzene Massimo
Published: February 2014

Optimal topology for periodic structures exhibiting nonlinearity is considered for two-dimensional plane stress systems. Optimal, in this context, refers to a design which maximizes the frequency shift (and thus bandgap shift) at the edge of the first Brillouin Zone for the acoustic branch. Parametric analyses and a genetic algorithm implementation identify topologies that produce large increases in complete bandgap width or group velocity variation. Analysis of Bloch wavemodes which produce large nonlinear frequency shifts reveals that the largest contributions to the frequency shift are primarily produced from localized strains in thin layers of compliant, nonlinear matrix material.
Multiobjective Optimization of a Railway Vehicle Dampers Using Genetic Algorithm
Authors: Mousavi Bideleh Seyed Milad , Berbyuk Viktor
Published: February 2014

Ride comfort, safety, wear and vehicle speed are the most important factors in evaluating the efficiency of railway transportation. In order to decrease the track access charges it is often desirable to run the vehicle at maximum allowed speed, while keeping an admissible amount of wear in system. This usually deteriorates the ride comfort and safety level during the operation. Therefore, an optimization problem to find a tradeoff value for vehicle speed and design parameters is inevitable. Since, ride comfort, safety and wear values are sensitive to primary and secondary suspensions’ damping parameters it is desirable to find the optimum values of such design variables. In this regard, the multiobjective optimization of railway vehicle dampers is considered to increase the cost-efficiency of railway operation. One car vehicle model with 26 degrees of freedom (DOF) along with a set of initial states, design parameters and operational conditions is explored here. All bodies are assumed to be rigid. Vehicle carbody and bogie frames supposed to have the full set of DOF in space. While, only lateral and yaw motions are considered for each wheelset. It is also assumed that wheelset roll angle is a function of the lateral displacement. Primary and secondary suspensions compromised of parallel linear springs and dampers in longitudinal, vertical and lateral directions which connect wheelsets to bogie frames, and bogie frames to carbody, respectively. Lagrange formalism is employed to obtain the system’s equations of motion. The nonlinear heuristic theory is chosen to relate creepages and the corresponding creep contact forces. The dynamic response of the system is obtained for different operational scenarios including ideal and imperfect tangent and curved tracks. Series-based functions are chosen to approximate the harmonic lateral track irregularities. Accelerations at carbody level, shift forces and wear number are used to evaluate the ride comfort, safety and wear, respectively. MATLAB genetic algorithm optimization routine is applied to perform the optimization. The Pareto sets and Pareto fronts obtained from this study provide the vectors of optimal design parameters corresponding to maximum admissible vehicle speed and guarantee the best tradeoff values for safety and comfort with threshold on wear for each operational scenario. Analysis of the obtained results gives insight into multiobjective optimized dynamic response of a railway vehicle and useful hints for designing adaptive bogie systems with the possibility to switch between optimal damping parameters value and provide the best operational efficiency.