bluuebunny/crossref_metadata_2025 huggingface dataset:
Self-Intersection Free and Topologically Faithful Slicing of Implicit Solid
Authors: Huang Pu , Wang Charlie C. L. , Chen Yong
Published: June 2012

We present a robust and efficient approach to directly slicing implicit solids. Different from prior slicing techniques that reconstruct contours on the slicing plane by tracing the topology of intersected line segments, which is actually not robust, we generate contours through a topology guaranteed contour extraction on binary images sampled from given solids and a subsequent contour simplification algorithm which has the topology preserved and the geometric error controlled. The resultant contours are free of self-intersection, topologically faithful to the given r-regular solids and with shape error bounded; therefore, correct objects can be fabricated from them by rapid prototyping. Moreover, since we do not need to generate the tessellated B-rep of given solids, our approach is memory efficient — only the binary image and the finest contours on one particular slicing plane need to be stored in-core. Our method is general and can be applied to any implicit representations of solids.
Analytical Model of the Efficiency of Spur Gears: Study of the Influence of the Design Parameters
Authors: Pleguezuelos Miguel , Pedrero Jose´ I. , Sa´nchez Miryam B.
Published: June 2012

An analytic model to compute the efficiency of spur gears has been developed. It is based on the application of a non-uniform model of load distribution obtained from the minimum elastic potential criterion and a simplified non-uniform model of the friction coefficient along the path of contact. Both conventional and high transverse contact ratio spur gears have been considered. Analytical expressions for the power losses due to friction, for the transmitted power and for the efficiency are presented. From this model, a complete study of the influence of some design parameters (as the number of teeth, the gear ratio, the pressure angle, the addendum modification coefficient, etc.) on the efficiency is presented.
A Design Methodology Based Process for Robotic Gripper Design
Authors: Streusand David B. , Turner Cameron J.
Published: June 2012

Designing effective end-effector tooling for robotic systems is necessary for all robotics applications. These tools, ranging from specialty items such as grinders and welders to more universal tools such as grippers, represent a critical component in the operations of a robotic system. Performance limitations of a robotic gripper impose performance limitations upon the operations of the system as a whole. By applying classical design methods to the design of a robotic gripper, a robotic gripper that meets the performance requirements and specifications of a system can be developed. This paper demonstrates the use of existing design methods to develop a band gripper design for Los Alamos National Laboratory and presents a robust design process that can yield satisfactory gripper designs. The developed gripper is subsequently tested and evaluated based on the project requirements and specifications to validate the design. The resulting gripper met or exceeded project design requirements and specifications.
Collinear-Type Statically Balanced Compliant Micro Mechanism (SB-CMM): Experimental Comparison Between Pre-Curved and Straight Beams
Authors: Tolou Nima , Estevez Pablo , Herder Just L.
Published: June 2012

The feasibility of collinear-type statically balanced compliant micro mechanism (SB-CMM) with pre-curved beams has been studied experimentally and compares to those with initially straight beams. The collinear-type SB-CMM is a near zero stiffness micro mechanism with a near zero actuation force in a finite range of motion. However, from the experimental data, it was found that the collinear-type SB-CMM are sensitive to fabrication errors, as a results negative or positive constant force instead of zero actuation force maybe obtained. For the case of pre-curved beams, the curvature can be tuned for better zero stiffness behavior. Further improvements in the concept are considered towards a robust design and reliable prototypes, such as optimization and accurate dimensioning and fabrication.
A Generalized Form of ToMFIR Approach to Fault Detection in Dynamic Systems
Authors: Liu Chun-Mei , Chen Wen
Published: June 2012

This paper is to develop a general form for Total Measurable Fault Information-based Residual (ToMFIR) approach to fault detection in dynamic systems. The ToMFIR is initially established for systems with a constant control input signal and a fault approaching to a constant. Practical systems satisfying the aforementioned conditions is few. That is why a generalized form is developed in this work. The definition of the ToMFIR is first introduced and the special case is also presented for the continuity of the statement. Based on a stable and linear time-invariant system, the general form of the ToMFIR is derived, and a practical DC motor example, with a PID controller, is used to demonstrate the effectiveness and robustness of the ToMFIR-based fault detection.
Importance of Correct Validation of Simulation Models
Authors: Kat Cor-Jacques , Els Schalk
Published: June 2012

This paper aims at demonstrating the importance of the correct validation of simulation models. Although correct model validation is often taken for granted, a large portion of published research does not pay adequate attention to this issue, resulting in models that are not adequate validated. The importance of validating the model for the correct parameters will be demonstrated by means of a case study which entails the modeling and experimental validation of a multi-leaf spring suspension system. Experimental measurements include the spring force as well as the forces acting at the suspension attachment points measured by two six component load cells. The six component load cells make it possible to validate the resultant force as well as its application point at the suspension attachment points. The result of the qualitative comparison of the experimental and model data shows the importance of validating the model against the parameters of interest. It also shows that extrapolating correlation results to other parameters may not be a good assumption in many situations.
A Novel and Flexible Design of Magnetostrictive Sensor for Strand/Rope Defect Inspection
Authors: Tse Peter W. , Liu X. C. , Wang X. J. , Wang D.
Published: June 2012

Steel strands and ropes are widely used to support heavy structures, such as bridges, buildings, lifts, and cable cars. They are also used in transmission lines to deliver power to cities as well as electrical trains. Failures occurring in strands/ropes may cause serious casualties and suspension of services. Therefore, it is of prime concern to provide advanced warnings prior to fatal failures. Magnetostrictive sensor (MsS) has become popular in generating and receiving desired ultrasonic guided waves to detect strand/rope defects. Conventional MsS usually uses hard sensing coils to generate the necessary dynamic magnet field to excite the desired guided waves for defect inspection. However, the hard coils are bulky and difficult to install on strands/ropes with different diameters. Such inflexibilities limit the use of MsS in many practical situations. This paper reports the design of a new type of MsS that uses innovative flexible coils, called flexible printed coil (FPC). The FPC is made of flexible film with the desired printed circuit pattern so that it can replace the conventional hard coils. The FPC-based MsS can be easily installed on or removed from the inspected strand/cable because of its flexible structure and the wrapped around type of mounting fashion. Moreover, the inspection performance of the new FPC-based MsS has been greatly increased because the FPC can be wrapped into multiple layers. The more the layers, the higher the wave energy can be emitted. The results obtained from the experiments conducted on seven-wire steel strand samples have proven the superior abilities of FPC than the conventional hard coils. The multi-layer FPC-based MsS has longer inspection range and higher sensitivity in detecting small cracks.
Transient Forward and Backward Whirl of Beam and Solid Rotors With Stiffening and Softening Effects
Authors: Rao J. S.
Published: June 2012

This paper describe the procedure of achieving unbalance response and stability of general accelerating solid rotor model rotors with variable cross-section on fluid film or rolling element bearings and seals with the casings mounted on foundations including stress stiffening and spin softening effects. The solid rotor analysis results are verified with beam analysis results wherever applicable.
Modal Analysis of Jointed Structures
Authors: Quinn D. Dane
Published: June 2012

Structural systems are often composed of multiple components joined together at localized interfaces. Compared to a corresponding monolithic system, these interfaces are designed to leave the load carrying capability of the system unchanged and the resulting effect on the system stiffness is minimal. Hence the mode shapes and frequencies of the dominant structural modes are relatively insensitive to the presence of the interfaces. However, the energy dissipation in such systems is strongly dependent on the joints. The microslip that occurs at each interface couples together the structural modes of the system and introduces nonlinear damping into the system, effectively altering the observed damping of the structural modes. This work develops equations of motion for a jointed structure in terms of the structural modal coordinates and implements a reduced-order description of the microslip that occurs at the interface between components. The interface is incorporated into the modal description of the system through an existing decomposition of a series-series Iwan interface model and a continuum approximation for microslip of a elastic rod. The developed framework is illustrated through a discrete three degree-of-freedom system.
An XYZ Parallel Kinematic Flexure Mechanism With Geometrically Decoupled Degrees of Freedom
Authors: Awtar Shorya , Ustick John , Sen Shiladitya
Published: June 2012

We present the constraint-based design of a novel parallel kinematic flexure mechanism that provides highly decoupled motions along the three translational directions (X, Y, and Z) and high stiffness along the three rotational directions (θx, θy, and θz). The geometric decoupling ensures large motion range along each translational direction and enables integration with large-stroke ground-mounted linear actuators or generators, depending on the application. The proposed design, which is based on a systematic arrangement of multiple rigid stages and parallelogram flexure modules, is analyzed via non-linear finite element analysis. A proof-of-concept prototype of the flexure mechanism is fabricated to validate its large range and decoupled motion capability. The analyses as well as the hardware demonstrate an XYZ motion range of 10 mm × 10 mm × 10 mm. Over this motion range, the non-linear FEA predicts a cross-axis error of less than 3%, parasitic rotations less than 2 mrad, less than 4% lost motion, actuator isolation less than 1.5%, and no perceptible motion direction stiffness variation. Ongoing work includes non-linear closed-form analysis and experimental measurement of these error motion and stiffness characteristics.
Design and Analysis of a Micro-Positioning Stage
Authors: Chen Jau-Liang , Chen Yan-Ming
Published: June 2012

The purpose of this research is trying to design a 6 degree-of-freedom micro-precision positioning stage with monolithic mechanism. It is hoped that this stage can reach 10 μm strokes along linear axis and with rotational angle no less than 50 μrad. The dimension of this positioning stage should be less than 200 mm × 200 mm × 50 mm. By using flexure hinge and piezoelectric actuator, this stage can achieve nanometer resolution. From the experimental results, it is found that the stage can achieve a maximum displacement of 29.3 μm in X axis; 11.94 μm in Y axis; and 6.74 μm in Z axis. The stage can also achieve a maximum rotation of 405.41 μrad around Z axis; 57.18 μrad around X axis; and 63.72 μrad around Y axis. With open loop control, we have shown that the minimum step for the stage is 110 nm in X-axis; 45 nm in Y axis; and 30 nm in Z-axis.
Exploiting Super-Harmonic Resonances of a Bi-Stable Axially-Loaded Beam for Energy Harvesting Under Low-Frequency Excitations
Authors: Masana Ravindra , Daqaq Mohammed F.
Published: June 2012

A research paradox currently lies in the design of miniaturized vibratory energy harvesters capable of harnessing energy efficiently from low-frequency excitations. To address this problem, this effort investigates the prospect of utilizing super-harmonic resonances of a bi-stable system to harvest energy from excitation sources with low-frequency components. Towards that objective, the paper considers the electromechanical response of an axially-loaded clamped-clamped piezoelectric beam harvester with bi-stable potential characteristics. By numerically constructing the voltage-frequency bifurcation maps of the response near the super-harmonic resonance of order two, it is shown that, for certain base excitation levels, the harvester can exhibit responses that are favorable for energy harvesting. These include a unique branch of large-orbit periodic inter-well oscillations, coexisting branches of large-orbit solutions, and a bandwidth of frequencies where a unique chaotic attractor exists. In these regions, the harvester can produce power levels that are comparable to those obtained near the primary resonance.
Kinematic Mapping and Calibration of the Thumb Motions for Teleoperating a Humanoid Robot Hand
Authors: Cui Lei , Cupcic Ugo , Dai Jian S.
Published: June 2012

Mapping and calibration from a human hand to a robot hand pose a challenge due to their differences in kinematic structures. This paper uses the CyberGlove® as the input device for telemanipulating an object with the thumb and the index finger of the Shadow® Dexterous Hand™, with the focus not only on the position but also on the orientation of the thumb fingertip because it is found through experiments conducted on the Shadow Hand that the calibration of tip position alone can lead to unacceptable grasping postures. This paper develops an experiment protocol and proposes a nonlinear optimization formulation that makes the normals of the surfaces of the thumb and index fingertips within the friction cone while subject to fingertip position constraint. The results are verified to be accurate enough to conduct the telemanipulation.
An Improved Size, Matching, and Scaling Method for the Design of Deterministic Mesoscale Truss Structures
Authors: Chang Patrick S. , Rosen David W.
Published: June 2012

Mesoscale truss structures are cellular structures that have support elements on the order of centimeters. These structures are engineered for high performance and have applications in industries where a high strength-to-weight ratio is desired. However, design of mesoscale truss structures currently requires some form of topological optimization that slows the design process. In previous research, a new Size, Matching and Scaling method was presented that eliminated the need for topological optimization by using a solid-body finite element analysis combined with a library of lattice configurations to generate topologies. When compared to topological optimization, results were favorable: design times were significantly reduced and performance results were comparable. In this paper, we present a modified Size Matching and Scaling design method that addresses key issues in the original method. Firstly, we outline an improve methodology. Secondly, we expand the library of configurations in order to improve lattice performance. Finally, we test the updated method and library against design examples.
About the FN Approximation to Fractional Neutron Transport Equation in Slab Geometry
Authors: Baleanu Dumitru , Kadem Abdelouahab
Published: June 2012

The neutron transport denotes the study of the motions and interactions of neutrons with materials. In given applications we need to know where neutrons are in an apparatus, what direction they are moving, and how fast they are going. In this manuscript the Legendre polynomial approximation method FN was applied to the one dimensional slab geometry neutron transport equation.
Fractional Order Constitutive Model of Geomaterials Under the Condition of Triaxial Test
Authors: Yin Deshun , Wu Hao , Cheng Chen , Chen YangQuan
Published: June 2012

Fractional calculus has been successfully applied to characterize the rheological property of viscoelastic materials, however, geomaterials were seldom involved in fractional order constitutive models (FOCM), and the issue of first loading and then unloading is rarely discussed through fractional calculus. It is considered that all materials are arranged in a queue and ideal solid and Newtonian fluid are located at both ends of the queue in FOCM. On the basis of FOCM, stress-strain relation under the condition of first loading and then unloading, besides creep, stress-relaxation and loading of constant strain rate are obtained. The stress-strain relation is utilized to fit triaxial test results of geomaterials under the corresponding conditions. The comparison between the test and fitting results reveals that FOCM can reasonably describe the stress-strain, stress-time or strain-time characteristics of geomaterials, which shows that fractional calculus is a good tool to constitutive model research of geomaterials.
Symbolic Algebra and Theorem Proving for Failure Criteria Reduction
Authors: Michopoulos John G. , Iliopoulos Athanasios
Published: June 2012

The present paper reports on recent efforts of utilizing symbolic computing for identifying failure criteria cross reducibility from the perspective of theorem proving. Utilizing equational theorem proving algorithms and Gro¨bner Basis polynomial theorem provers implemented in Mathematica we have proven a number of interesting theorems related to the area of structural failure criteria for anisotropic and particularly orthotropic materials. The main contribution of this work is the demonstration of the tremendous utility of symbolic algebra for engineering applications as well as the demonstration of the idea that all failure criteria presented in the literature up to know can be proven under certain conditions to be special forms of general criteria relating to the strain energy density function associated with material continua. Two specific examples are presented and discussed along with a theorem proving the existence of a dual form of all stress space based criteria to equivalent one expressed in strain space.
Functional Concept-Based Detection for Transformative Product Design
Authors: Choi Keunho , Kim Kyoung-Yun
Published: June 2012

Cross-disciplinary technologies are noticeable phenomena in modern products, as found in renewable energy and electric vehicle industries. However, current conceptual design tools have been limited to respond these cross-disciplinary technology products. One of remarkable characteristics in this technology change is transforming an existing product with multiple cross-disciplinary technologies. This paper presents a new product design paradigm, called Transformative Product Design (TPD), to respond this phenomenon. In TPD, transformation is a design process to produce a new product (i.e., transformative product) from a base product by adding and/or converting functions/features with reference products or technologies. To accomplish the transformation process, this paper develops a new Functional Concept-based Detection method. Also, the proposed functional concept-based detection method is described with a case study in the context of transformative product design process.
The Effect of Harmonic Helix Angle Variation on Milling Stability
Authors: Dombovari Zoltan , Stepan Gabor
Published: June 2012

The linearly varied helix tool is widely used in manufacturing industry and milling tools are available in the market with these special cutting edges. There were several attempts to introduce complex harmonically varied helix tools, but the manufacturing of sinusoid edges is extremely difficult and its effect on cutting dynamics is not clear yet. In this study a mechanical model is introduced to predict the linear stability of these special cutters. It is shown that these milling tools cause distribution in regeneration and the corresponding time periodic distributed delay differential equations are investigated by semi-discretization. This work points out how the harmonically varied helix cutters behave in case of high and low cutting speed applications.
Engineering Applicability of a Universal Design Performance Measure
Authors: Talley Austin , Crawford Richard H. , Talley Kimberly
Published: June 2012

Universal Design (UD) is defined as the creation of products and environments to be usable by all people, to the greatest extent possible, without the need for adaptation or specialization. There is a growing need for such products. However, many products are not accessible to all potential customers, arguably due to a lack of experience, design tools, and engineering methods for creating universally designed products. Currently, there are no industry standard design tools or methods to assist engineers in the universal design of products. The Center for Universal Design (North Carolina State University; Raleigh, NC) has created the Universal Design Performance Measure for Products (UDPMP), based on the seven principles of universal design, which is intended to assist industrial designers. This paper reports on research to evaluate the applicability of the UDPMP for assisting engineers in the universal design of consumer products. An experiment was conducted in which a group of practicing engineers analyzed three standard kitchen products (can opener, salad spinner, and corkscrew) to identify metrics that should be improved to create a UD version of these standard products. Half of the engineers, the test group, completed this exercise using the UDPMP, while the other half, the control group, did not use the tool. The results of the experiment show that the UDPMP assisted the engineers in the test group for a limited subset of the universal design principles. In particular, the test group identified reduction in force for the user as an important metric for universally designed products. The metrics generated in the experiment were most commonly linked with principle six of the UDPMP tool, i.e., “low physical effort.” The identified metrics were then physically measured for the standard products as well as for paired award-winning UD products to determine if the metrics were indeed improved in the UD product. Additionally, a comparison of functional models of the products was performed to identify any functional differences between each pair of standard and UD products. Improvement in metrics associated with low physical effort was verified for the UD products over the standard products, and added functionality was identified in the UD products that address these metrics. The research indicates that engineers who were given the UDPMP did generate more metrics that were improved in the UD versions of the products than engineers without the tool. While the UDPMP does assist engineers in certain aspects of UD design, it is clearly not a comprehensive tool for engineers. There is a need to develop tools and methods to promote UD by engineer designers of consumer products.
Optimal Trajectory Tracking Control With a 5R Parallel Robot
Authors: Coppola Gianmarc , Zhang Dan
Published: June 2012

This work examines the control characteristics of a 5R parallel robotic manipulator subjected to two control studies. Firstly, fundamental aspects of dynamics are presented. Then a brief review of Particle Swarm Optimization (PSO) and feedforward Neural Networks (NN) is undertaken. Subsequently, to tackle the challenging problem of controller parameter tuning for parallel robots in trajectory tracking scenarios, a multi objective optimization problem is formulated for automatic tuning using PSO. This offline method is comparatively evaluated to the Nelder-Mead (NM) sequential simplex optimization scheme. Several results are attained illustrating the strengths and weaknesses of this method for parallel robot control. Then, an adaptive NN model reference control scheme using PSO is proposed. This scheme is proposed as one possible way to take advantage of the strong properties of the PSO online. The scheme is tested and several observations are outlined.
An Experimental Evaluation of a Rule-Based Approach to Manufacturing Supplier Discovery in Distributed Environments
Authors: Ameri Farhad , McArthur Christian
Published: June 2012

Manufacturing supplier discovery in virtual environments is a computationally intensive task. Existing electronic marketplaces for manufacturing services, due to their syntactic and human-oriented approach in search, fail to build accurate connection between seller and buyers. Automation and intelligence are the two key requirements of web-based solution for efficient deployment of virtual supply chains. It was previously shown that an ontological approach, because of its semantic nature, yields more precise results compared to traditional techniques such as keyword search. While the proposed ontology, known as Manufacturing Service Description Language (MSDL), can sufficiently encode structural knowledge in the manufacturing domain, it doesn’t have the required level of expressivity for representing constraint knowledge. This paper introduces an extension to MSDL for formal representation of constraints and rules based on Semantic Web Rule Language (SWRL). To identify the rules and to evaluate the performance of the rule-based technique, an experimental approach is followed in this research.
A New Model for Wind Farm Layout Optimization With Landowner Decisions
Authors: Chen Le , MacDonald Erin
Published: June 2012

Current wind farm layout optimization research focuses on advancing optimization methods. The research includes the assumption that a continuous piece of land is readily available. In reality, wind farm development projects rely on the permission of landowners for success. When a viable wind farm site location is identified, local residents are approached for permission to build turbines on their land, typically in exchange for monetary compensation. Landowners play a crucial role on the development of a wind farm and some land parcels are more important to the success of the project than others. In order to advance the research on wind farm optimization, this paper relaxes the assumption that a continuous piece of land is available, developing a novel approach that includes landowners’ decisions on whether or not to participate in the project. The optimization results of this new approach show that, for a specific wind farm layout case, we can identify the most crucial landowners and the optimal positions of turbines prior to the negotiation process with landowners. Using this approach, a site developer can spend more resources on persuading these most-important landowners to take part in the project, or approach them in a personalized manner. This will ultimately increase the efficiency of wind farm projects, saving time and money in the development stages.
Detection of Cracks in Mistuned Bladed Disks Using Reduced Order Models and Vibration Data
Authors: Jung Chulwoo , Saito Akira , Epureanu Bogdan I.
Published: June 2012

A novel methodology to detect the presence of a crack and to predict the nonlinear forced response of mistuned turbine engine rotors with a cracked blade and mistuning is developed. The combined effects of the crack and mistuning are modeled. First, a hybrid-interface method based on component mode synthesis is employed to develop reduced order models (ROMs) of the tuned system with a cracked blade. Constraint modes are added to model the displacements due to the intermittent contact between the crack surfaces. The degrees of freedom (DOFs) on the crack surfaces are retained as active DOFs so that the physical forces due to the contact/interaction (in the three-dimensional space) can be accurately modeled. Next, the presence of mistuning in the tuned system with a cracked blade is modeled. Component mode mistuning is used to account for mistuning present in the un-cracked blades while the cracked blade is considered as a reference (with no mistuning). Next, the resulting (reducedorder) nonlinear equations of motion are solved by applying an alternating frequency/time-domain method. Using these efficient ROMs in a forced response analysis, it is found that the new modeling approach provides significant computational cost savings, while ensuring good accuracy relative to full-order finite element analyses. Furthermore, the effects of the cracked blade on the mistuned system are investigated, and used to detect statistically the presence of a crack and to identify which blade of a full bladed disk is cracked. In particular, it is shown that cracks can be distinguished from mistuning.
Mutibody Vehicle Dynamics Analysis Using an Explicit-Implicit Integrator With Subsystem Synthesis Method
Authors: Kim Sung-Soo , Jeong Wan Hee , Jo Junyoun , Wang Ji-Hyeun
Published: June 2012

This paper proposes an explicit-implicit numerical integration method in order to apply to multibody vehicle dynamics model based on a subsystem synthesis method. The subsystem synthesis method can provide effective means to independently analyze each subsystem with virtual reference body. In the proposed method, the explicit integration is used for solving the equations of motion for a base body, while the implicit integration is utilized for obtaining the solutions of the equations of motion for each subsystem. For the purpose of the application of the implicit formulas easily, a subsystem synthesis method with the Cartesian coordinates is developed. In order to show the application viability and effectiveness of the proposed method, an extensive comparative study has been performed through simulations. Then, the proposed method is compared to conventional implicit integration method applied to an overall system. When simulating the bump run of a multibody vehicle model with compliance effect such as bushing elements, the proposed method achieves about 2 times computational speed-up. Furthermore, the simulation study reveals that the larger the number of the attached subsystems is, the better the computational efficiency of the proposed method is than that of the conventional implicit integration method.
On Pure-Bending Non-Linear Plate Elements With Developable Surfaces
Authors: Dmitrochenko Oleg , Mikkola Aki
Published: June 2012

In this study, a new approach for generating beam and plate finite elements is proposed for a large-deformation and large-rotation dynamical multibody simulation of thin structures. The elements employ curvatures and/or torsions in the definition of generalized coordinates. This definition of element degrees of freedom is based on intrinsic properties of a spatial curve or a surface and it avoids longitudinal elongations of the beams and plates with associated high frequency vibrations, which helps to avoid problems during numerical simulation.
Flutter-Type Instability of a Beam Subjected to Coulomb Friction
Authors: Seo Yasuhiro , Kono Go , Yabuno Hiroshi
Published: June 2012

To analyze the excitation mechanism of self-excited oscillation in a beam which is in contact with a moving floor surface, we deal with a beam subjected to Coulomb friction and theoretically predict the occurrence of self-excited oscillation through flutter-type instability. We introduced an extensible continuum model, and derived its governing equations by special Cosserat theory, which allows for the extensibility of the beam to be considered and boundary conditions. The boundary conditions on the end of the beam are unique, because the end of the beam contacts with the moving floor surface. Then, we discretized the system, analyzed the linear stability, and indicated that the flutter-type instability in the beam is produced due to the Coulomb friction and the extension of the extensibility.
Optimum Design of Cantilevered Piezoelectric Harvester Based on Distributed Parameter Model
Authors: Alazemi Saad F. , Yigit Ahmet S. , Alhazza Khaled A.
Published: June 2012

In the past decade, there have been numerous studies which showed the feasibility of harvesting electrical energy from vibrating structures. The main goal of this study is first to generate a Finite Element (FE) model using ANSYS to verify an existing harvesting model. This FEM model can be used as a base for designing more complex harvesters. The second goal of this study is to optimize the parameters of a simple cantilever harvester to maximize the power generation from ambient mechanical energy. A distributed parameter model and its modal solution are used to identify the design variables through a parametric study. The results obtained using the distributed parametric model is compared with the results obtained using ANSYS. It is of interest to ensure adequate power generation under non-resonant conditions for a broad band excitation. The average power within a certain frequency range is used as the cost function to define optimization problem along with some geometric and physical constraints. We found that, in certain frequency ranges, the parameters can be optimized to generate maximum power. Having validated the methodology, work is in progress to design and optimize harvesters with complex geometries.
Decomposition of System Level Reliability-Based Design Optimization to Reduce the Number of Simulations
Authors: Villanueva Diane , Le Riche Rodolphe , Picard Gauthier , Haftka Raphael T. , Sankar Bhavani V.
Published: June 2012

It is computationally expensive to evaluate the overall system level reliability when several interacting failure modes are present. Therefore, it is even more expensive to optimize considering the system level reliability that accounts for the interactions between failure modes. In this paper, we decompose the system level reliability based optimization problem using surrogates into less expensive problems with fixed risk allocation for each failure mode. In addition, the fixed risk allocation problem is transformed from a purely probabilistic problem to a deterministic one through an iterative process of updating safety factors to limit the number of calls to evaluate the reliability. We found that the number of calls to the simulation to evaluate the system level reliability was reduced by 77% with this methodology.
FEM Modeling of a Rotor System With the Open Crack and Vibration Diagnosis (Case of the Anisotropic Support Stiffness)
Authors: Inoue Tsuyoshi , Nagata Nobuhiro , Ishida Yukio
Published: June 2012

This paper develops and improves the concise and general purpose oriented finite element rotating shaft model with an open crack for the quantitative analysis. Particularly, the case with the directional difference of the bearing support stiffness is focused. The theoretical analysis of both the natural frequency and the double-frequency vibration due to crack are performed. Both theoretical results are compared with the experimental results, and their quantitative agreement are confirmed.
Curve Decomposition Analysis for Fixed-Guided Beams With Application to Statically Balanced Compliant Mechanisms
Authors: Kim Charles
Published: June 2012

Statically balanced compliant mechanisms require no holding force throughout their range of motion while maintaining the advantages of compliant mechanisms. In this paper, a post-buckled fixed-guided beam is proposed to provide the negative stiffness to balance the positive stiffness of a compliant mechanism. To that end, a unique curve decomposition modeling method is presented to simplify the large deflection analysis. The modeling method facilitates parametric design insight and elucidates key points on the force-deflection curve. Experimental results validate the analysis. Furthermore, static balancing with fixed-guided beams is demonstrated for a rectilinear proof-of-concept prototype.
Embodiment of Emotions Through Wearable Technology
Authors: Ugur Secil , Bordegoni Monica , Wensveen S. G. A. , Mangiarotti Raffaella , Carulli Marina
Published: June 2012

Due to the huge impact of communication technologies, the meaning of social existence is changing towards the use of electronic devices as extensions of senses. While technology is becoming intimate, reaching farther into user’s lives than ever before, wearable technology has emerged as a new research field where technology is worn to provide a sensory interface. Through the integration of technology and garments, the research aims to discover new ways of creating wearables that provide new avenues for emotional expression and social interaction. Emotional embodiment through Wearable Technology can strengthen social bonds through a paradigm of increased emotional expression, understanding, and trust. To verify this hypothesis, a set of dynamic garments has been built by developing both virtual and real prototypes and performing user tests. This paper addresses to new scenarios of sensing, interacting, and interpreting emotions through Wearable Technology and its’ effects on the user’s perception.
Cognitive Multi-UAV Formation Flight: Principle, Low-Cost UAV Testbed, Controller Tuning and Experiments
Authors: Di Long , Chao Haiyang , Han Jinlu , Chen YangQuan
Published: June 2012

Cooperative UAV systems can have great advantages over isolated UAV systems, regarding application, safety, efficiency and many other perspectives. Motivated by challenges from practical multiple UAV formation flight, this paper presents our approaches towards cognitive formation flight. It introduces the principle ofmulti-UAV cognitive formation flight and the control structure utilized in our development, describes a low-cost UAV testbed developed by ourselves, and details the tuning procedures of the implemented multi-agent flight controller for stable and consistent formation flights. Different formation flight scenarios are also discussed and the experimental setup is presented including real-time issues and the formation flight test protocol. Routinized comprehensive flight test results are also shown at the end.
Formalizing Flow Relationships in Data Archival and Reuse for Product Design
Authors: Bohm Matt R. , Nagel Robert L.
Published: June 2012

This paper explores the relationship between primary and carrier flows for design knowledge archival and reuse. Often, it is noted that flows (especially when modeling materials and signals) through an engineered system are accompanied by supporting flows (often energies). These accompanying flows (termed carrier flows), while being important to the overall (or black box) functionality of the system, are often of lesser interest during functional modeling activities related to conceptual design. However, when modeling a system for archival and reuse, not capturing these flows could hinder some of the more creative leaps where flows once used as a carrier flow in a system are now identified as viable primary flows. When systems are modeled utilizing primary/carrier flow designations, it may be easier to search and locate analogous systems. From a knowledge reuse standpoint, the physical solutions to carrier flows in one system may also be the physical solutions to primary flows in another design scenario. To assist with modeling, known primary/carrier flow combinations are presented in this paper. Modeling, archival, and reuse are presented, and the potential to identify creative leaps is explored.
Vehicle Platooning: A Brief Survey and Categorization
Authors: Kavathekar Pooja , Chen YangQuan
Published: June 2012

In this paper, the vehicle platooning literature published between 1994 and 2010 is categorized and discussed. The paper includes a general introduction and overview of vehicle platooning and a technical description of the methodology. Recent trends in Vehicle Platooning are presented and discussed. The results are reviewed and the vehicle platooning literature is categorized into subcategories within the broader division of application focused and theory focused results. Issues and challenges faced in platooning are discussed.
Adaptive Bias Current Control in Active Magnetic Bearings for Energy Optimization
Authors: Ueno Satoshi , Sahinkaya M. Necip
Published: June 2012

This paper introduces an adaptive bias current control method for an active magnetic bearing (AMB). The bearing force is analyzed theoretically, and the dynamic performance of the magnetic bearing for various bias currents is discussed. Then power consumption is analyzed and the optimum bias current that minimizes power consumption is derived. A novel optimization method using a steepest descent method is proposed. This requires less computing power than the former optimization method using a recursive Fourier transform algorithm. Experimental results show that the optimized bias current can be achieved by the proposed method. However, the dynamics of the rotor is affected by the bias current variation. In order to overcome this problem, the effects of parameter errors are investigated and correction methods are introduced. Experimental results show that the rotor dynamics are not affected by the variable bias current if the parameters are corrected. Results are also presented for machine run-up and run-down.
Investigation of Restitution Coefficient and Spring-Damper Models for the Bouncing Ball Problem
Authors: Carbonelli Alexandre , Perret-Liaudet Joe¨l , Rigaud Emmanuel , Feki Mohamed-Sai¨d
Published: June 2012

The non linear system under study consists on the bouncing ball problem. Focusing on the n-T periodic solutions and the permanent contact motion, simulations performed underline the effect of spring-damper contact model in comparison with the classical restitution coefficient. Both approaches are implemented in an adimensional way. For the restitution coefficient approach, iterating maps are easy to obtain after some assumptions. On the contrary, the spring-damper model leads to transcendental equations needing the use of numerical continuation methods. The damping ratio is defined as a function of the restitution coefficient. The effect of the contact stiffness is studied. For high values of the contact stiffness, the spring-damper model has the same behavior as the restitution coefficient model as the impact duration gets shorter. Predictions of the two models diverge when the contact stiffness decreases. Results are illustrated by time histories and Poincare´ Maps of dynamic responses. This paper aims to be guideline to quantify the error made by making the assumptions required for a restitution coefficient model.
Improved PID Control Using an Adaptive Two-Input Single-Output Coarse/Fine Approach
Authors: Wood Eric , Nelson Carl A. , Koch Alyssa
Published: June 2012

In robotic manufacturing, the qualities of responsiveness (speed) and accuracy are both desirable, but these two goals tend to oppose each other. A theoretical model of an adaptive PID controller for robotic and other actuated mechanical systems is presented here in pursuit of these combined objectives. Emphasis is placed on rotational velocity control using multiple inputs to produce a single desired output. Shared control of the system between two motors is proposed such that dominance of each motor controller shifts smoothly as a function of error signal based on the kinematic combination of the motor inputs (continuously sliding modes). Performance and stability analyses are provided to illustrate the behavior of the system based on operating parameters.
Multifunctional Device for Assisting Unskilled People in Hand Movements Through the Haptic Point-Based Approach
Authors: Covarrubias Mario , Bordegoni Monica , Cugini Umberto
Published: June 2012

This paper describes a multifunctional haptic machine, a device that is used for assisting unskilled people in the assessment and training of hand movements. Sketching, hatching and cutting operations are assisted through the multifunctional device by using the haptic point-based approach. The device has enabled users to haptically interact with a 2D virtual template, which acts as a virtual tool path taking advantages of its force feedback capabilities. For sketching, hatching and cutting operations the haptic device is driven under the user movement and assisted through the Magnetic Goemetry Effect (MGE). Two configurations of the multifunctional device have been analyzed; the cartesian and the RR mechanism attached to the PHANTOM device. For sketching and hatching several pencils and pens colors are available. Regarding the cutting operation, a hot wire cutting tool can be replaced for cutting soft materials as expanded and extruded polystyrene foam. This paper discusses the design concept, kinematics and mechanics of the multifunctional haptic device. A brief test using the device in sketching, hatching and cutting operations is also given.
Generic Visual Simulation of Manufacturing Equipment
Authors: Dhaveji Ch. Sweta , Sparks Todd E. , Ruan Jianzhong , Liou Frank W.
Published: June 2012

Simulation of a machine is very important before laser metal deposition is performed, as a tool to check collision detection and validate deposition result. There are several kinds of machines that are used for laser deposition and hence there is a need for a generalized concept for visual simulation of various kinds of machines. This paper presents the research conducted on describing each machine configuration in a generic format. A parent–child list and a dependency list obtained from the machine configuration are utilized to form the generic format. Such a format can be used to describe linear and rotational motion of the machines parts. This method has been tested on various examples to demonstrate its robustness and efficiency.
Spinal Implant With Adjustable and Nonlinear Stiffness
Authors: Dodgen Eric R. , Howell Larry , Bowden Anton
Published: June 2012

The human spine is a complex mechanism composed of both passive and active components. The nonlinear stiffness of the passive components provides mechanical stability to the system. There is a need for spinal implants that have nonlinear stiffness to provide this stabilization if the spine loses stiffness through injury, degeneration, or surgery. There is also a need for spinal implants to be customizable for individual needs. This paper proposes contact-aided inserts to be used with the FlexSuRe™ spinal implant to create a nonlinear stiffness. Moreover, different inserts can be used to create different behaviors. To show this effect an elliptical contact surface is considered and the inserts are varied by changing the semi-major axis of the elliptical section. An analytical model is introduced for insert design, and the model is verified by comparing the models force-deflection profiles to a finite element model and tests of physical prototypes. The models and experiments demonstrate that it is feasible to create a spinal implant that has a nonlinear stiffness, and that different inserts can be used with the base implant to customize the behavior for individual needs. The analytical model developed is a tool available for implant design.