bluuebunny/crossref_metadata_2025 huggingface dataset:
A Comparison of Function- and Affordance-Based Design
Authors: Wu Chunlong , Ciavola Benjamin , Gershenson John
Published: February 2014

Function-based design is the traditional approach in engineering design theory, proving useful and practical in many cases but showing limitations in others. Affordance-based design is an alternative approach that attempts to address some of function theory’s limitations by focusing attention on the interactions between systems. This paper compares function-based design with affordance-based design by examining their philosophies, tools, abilities, and suitability along a number of dimensions. We conclude that the approaches are compatible and suggest future work to realize their integration.
Automatic Reasoning for Defining Lathe Operations for Mill-Turn Parts
Authors: Eftekharian Ata A. , Fu Wentao , Manion Charlie , Campbell Matthew I.
Published: February 2014

With the increase in computer-controlled hybrid machining (e.g. mill-turn machines), one needs to discern what features of a part are created during turning (i.e. with a lathe cutter) versus those created by milling. Given a generic part shape, it is desirable to extract the turnable and non-turnable features in order to obtain feasible machining plans. A novel approach for automating this division and for defining the resulting turning operations in a hybrid process is proposed in this paper. The algorithm is based on identifying the dominant rotational-axis and performing several non-uniform lateral cross-sections to quickly generate the “as lathed” model. The part is then subtracted from the original model to isolate the non-turnable features. Next, resulting model and features are translated to a label rich graph and fed into a grammar reasoning tool to produce feasible manufacturing plans. The setup design is also studied against the tolerances specified by the designer. Performance of the algorithm has been tested on several examples ranging from simple to complex parts.
A Concurrent Search Algorithm for Multiple Phase Transition Pathways
Authors: He Lijuan , Wang Yan
Published: February 2014

The challenge of accurately predicting a phase transition in computer-aided nano-design is estimating the true value of transition rate, which is determined by the saddle point with the minimum energy barrier between stable states on the potential energy surface (PES). In this paper, a new algorithm for searching the minimum energy path (MEP) is presented. Unlike existing pathway search methods, the new algorithm is able to locate both the saddle points and local minima simultaneously. Therefore no prior knowledge of the precise positions for the reactant and product on the PES is required. In addition, the algorithm is able to search multiple transition paths on the PES simultaneously. In this method, a Bézier curve is used to represent each transition path. Starting from a single Bézier curve, multiple curves with ends connected can be generated during the search process. For each Bézier curve, the reactant and product states are located by minimizing the two end control points of the curve, while the transition pathway is refined by moving the intermediate control points of the curve in the conjugate directions. A curve subdivision scheme is developed so that multiple transition paths can be located. The algorithm is demonstrated by examples.
Torsional Vibration Detection Using High Sampling Rate and High Resolution Keyphasor Information
Authors: Luo Huageng , Chumai Roengchai , Peton Nicolas , Howard Brian , Menon Arun
Published: February 2014

Torsional vibration excitation in rotating machinery can cause system reliability issues or even catastrophic failures. Torsional vibration detection and monitoring becomes an important step in rotating machinery condition monitoring, especially for those machines driven by a variable frequency drive (VFD), a pulse width modulation motor (PWM), or a synchronous motor (SM), etc. Traditionally, the torsional vibration is detected by a phase demodulation process applied to the signals generated by tooth wheels or optical encoders. This demodulation based method has a few unfavorable issues: the installation of the tooth wheels needs to interrupt the machinery normal operation; the installation of the optical barcode is relatively easier, however, it suffers from short term survivability in harsh industrial environments. The geometric irregularities in the tooth wheel and the end discontinuity in the optical encoder will sometimes introduce overwhelming contaminations from shaft order response and its harmonics. In addition, the Hilbert Transform based phase demodulation technique has inevitable errors caused by the edge effect in FFT and IFFT analyses. Fortunately, in many industrial rotating machinery applications, the torsional vibration resonant frequency is usually low and the Keyphasor® and/or encoder for speed monitoring is readily available. Thus, it is feasible to use existing hardware for torsional vibration detection.

In this paper, we present a signal processing approach which used the Keyphasor/encoder data digitized by a high sampling rate and high digitization resolution analog-to-digital (A/D) convertor to evaluate the torsional vibration directly. A wavelet decomposition (WD) based method was used to separate the torsional vibration from the shaft speed, so that the time history of the torsional vibrations can be extracted without significant distortions. The developed approach was then validated through a synchronous motor fan drive and an industrial power generation system. Detailed results are presented and discussed in this paper.
Theory and Algorithms for L1 Fitting Used for Planar Datum Establishment in Support of Tolerancing Standards
Authors: Shakarji Craig M. , Srinivasan Vijay
Published: February 2014

We present the theory and algorithms for establishing a datum plane consistent with ASME Y14.5 standard definitions. Such a datum plane will correspond to a planar datum feature sampled with coordinate data that is weighted. The method uses a one-sided minimization search based on the L1 (L1) norm. We prove that the problem reduces to a simple minimization search between the weighted centroid and the convex hull. The practice of unweighted fitting works well enough when point sampling is controlled and can thus be made uniform (e.g., using a discrete point contact Coordinate Measuring Machine). However, we show by example that nonuniformly sampled points (arising from many new measurement technologies) coupled with unweighted fitting can lead to erroneous results. When needed, the algorithms presented also solve the unweighted cases simply by assigning the value one to each weight. Terse Mathematica code is included for the reader. The code is sufficient for constrained and unconstrained planar fitting as well as a 3-2-1 datum reference frame generation, which is also described in detail. We additionally prove convergence from the discrete to continuous cases of datum establishment as the point sampling becomes dense.
AWD Vehicle Dynamics and Energy Efficiency Improvement by Means of Interaxle Driveline and Steering Active Fusion
Authors: Vantsevich Vladimir V.
Published: February 2014

This paper presents a novel approach to improve both energy efficiency and lateral dynamics of an all-wheel drive (AWD) vehicle by means of active functional/operational fusion of a driveline system, which distributes power between the front and rear driving axles, and a steering system that steers the front driving wheels.

The paper starts by presenting the kinematic discrepancy factor, which is a normalized difference of the front and rear theoretical velocities that influences the wheel power distribution, as a mathematical function of the tire rolling radii in the driven mode, the gear ratios of the driveline system, and the steering angle of the front wheels. Using this function, the gear ratios from the transfer case to the front and rear wheels are determined to optimize vehicle energy efficiency by minimizing the kinematic discrepancy at the vehicle’s straight line motion and on a curve.

It is also analytically shown that the wheel power distribution leads to the variation of the circumferential force of the front wheels that significantly influences the magnitude and direction of the front wheel lateral force. Thus, the paper introduced the wheel power distribution between the driving axles as an instrument for controlling oversteer-understeer transition of a vehicle, i.e., controlling vehicle lateral dynamics.

Finally, the steering angle of the front wheels is considered and analyzed as an input of an active steering system to control the vehicle oversteer-understeer process in combination with the effect of the steering angle on the kinematic discrepancy factor. Longitudinal velocity control is added to constrain the lateral acceleration. Thus, the functional fusion of the active steering and driveline systems for enhancing both AWD vehicle energy efficiency and dynamics is introduced for the first time.
Structuring Engineering Design Courses to Motivate Students
Authors: Siddique Zahed , Hardré Patricia L.
Published: February 2014

The purpose of this study was to determine the effects of motivation in engineering design courses. In this study we present a structured approach to identify motivational gaps and instructional design to explicitly address motivational needs in a current course in mechanical engineering design. The SUCCESS framework (Hardré, 2009) has been proposed to assess the existing motivational components of the course, examine gaps in the course relative to its goals, and then propose motivating strategies to address those gaps. This paper presents the model and course description, along with the process and products of the analysis of the course to improve motivation for engagement and innovation.
Tolerance Analysis of Parallel Assemblies Using Tolerance-Maps® and a Functional Map Derived From Induced Deformations
Authors: Jaishankar Lupin Niranjan , Davidson Joseph K. , Shah Jami J.
Published: February 2014

This paper concerns about modeling tolerance accumulation in parallel assemblies using a spatial math model, the T-Map. In this paper, a specific case in 3D is discussed where an Accumulation Tolerance-Map is modeled when two parts arranged in parallel support a target part between the datum and the functional target feature. By understanding how much of variation from the supporting parts contribute to variations of the target feature, a designer can better utilize the tolerance budget when assigning values to individual tolerances.

When the parts are flexible, deformations are induced when parts in parallel are clamped together during assembly. The amount of deformations on the target part depends on the geometric manufacturing variations on the support parts in parallel assemblies. When parts are clamped stresses are induced in more than one direction depending on the type and amount of geometric variation on the supports. The next part of this paper relates the limit on the largest von Mises stress in the target part to the functional limits in tolerance allocation that must be set at the beginning of a tolerance analysis of parts in such an assembly by the designer. The last part of the paper shows the construction of a Functional Tolerance Map from the tolerance limits obtained from the relationship between von Mises stresses and tolerances on individual parts.
Synthesis of Stable Optimal Controls From Lyapunov Based Constraints
Authors: Koganti Prasanth B. , Udwadia Firdaus E.
Published: February 2014

This paper presents a simple approach to synthesize optimal controls from user prescribed positive definite functions. The synthesized controls minimize a user specified objective function which is a quadratic function of the control variables. The approach followed in this paper is inspired by recent developments in analytical dynamics and the observation that the Lyapunov criterion for stability of dynamical systems can be recast as a constraint to be imposed on the system. The approach used to obtain the fundamental equation of motion for constrained mechanical systems is extended to find control forces that minimize any user-specified quadratic function of the control forces while simultaneously enforcing the stability requirement as an additional constraint. This method can also be generalized to nonautonomous dynamical system described by first order nonlinear differential equations. We further explore the possibility of extending the approach to systems in which we do not have full state control.
Kinematic Modeling, Analysis and Control of Highly Reconfigurable Articulated Wheeled Vehicles
Authors: Alamdari Aliakbar , Zhou Xiaobo , Krovi Venkat N.
Published: February 2014

The Articulated Wheeled Vehicle (AWV) paradigm examines a class of wheeled vehicles where the chassis is connected via articulated chains to a set of ground-contact wheels. Actively- or passively-controlled articulations can help alter wheel placement with respect to chassis during locomotion, endowing the vehicle with significant reconfigurability and redundancy. The ensuing ‘leg-wheeled’ systems exploit these capabilities to realize significant advantages (improved stability, obstacle surmounting capability, enhanced robustness) over both traditional wheeled- and/or legged-systems in a range of uneven-terrain locomotion applications. In our previous work, we exploited the reconfiguration capabilities of a planar AWR to achieve internal shape regulation, secondary to a trajectory-following task. In this work, we extend these capabilities to the full 3D case — in order to utilize the full potential of kinematic- and actuation-redundancy to enhance rough-terrain locomotion.
Multi-Field Responsive Origami Structures: Preliminary Modeling and Experiments
Authors: Ahmed Saad , Lauff Carlye , Crivaro Adrienne , McGough Kevin , Sheridan Robert , Frecker Mary , von Lockette Paris , Ounaies Zoubeida , Simpson Timothy , Lien Jyh-Ming , Strzelec Rebecca
Published: February 2014

The use of origami principles to create 3-dimensional shapes has the potential to revolutionize active material structures and compliant mechanisms. Active origami structures can be applied to a broad range of areas such as reconfigurable aircraft and deployable space structures as well as instruments for minimally invasive surgery. Our current research is focused on dielectric elastomer (DE) and magneto active elastomer (MAE) materials to create multi-field responsive structures. Such multi-field responsive structures will integrate the DE and MAE materials to enable active structures that fold/unfold in different ways in response to electric and/or magnetic field. They can also unfold either as a result of eliminating the applied field or in response to the application of an opposite field. This concept is demonstrated in a folding cube shape and induced locomotion in the MAE material. Two finite element models are developed for both the DE and MAE materials and validated through physical testing of these materials. The models are then integrated to demonstrate multi-field responses of a bi-fold multi-field responsive structure. The bifold model is designed to fold about one axis in an electric field and a perpendicular axis in a magnetic field. Future modeling efforts and research directions are also discussed based on these preliminary results.
Classification and Type Synthesis of Deficient-DOF Parallel/Hybrid Compound Load Simulator With a Specified Load Pattern
Authors: Qu Yufeng , Yu Jingjun , Zong Guanghua , Bi Shusheng
Published: February 2014

A compound load simulator has drawn increasing attention due to the growing demand for testing of critical components in mechanical devices. However, its development is still limited owning to the shortage of corresponding design principle. Accompanied with the application of parallel mechanisms in a variety of multi-axis machine tools and motion simulators, it brings new inspiration to this field. Although existing six degree-of-freedom (DOF) parallel mechanisms such as Stewart platform can output multi-dimensional loads, it also produces the complexity of force control and inevitable collaborative error. Actually, it is enough to utilize deficient-DOF mechanisms for a majority of load patterns and practical engineering applications. Therefore, this paper mainly focuses on synthesizing deficient-DOF parallel/hybrid compound load simulators. Regular load types are summarized including one-dimensional generalized force and compound of them. Based on characteristics of each load type, DOF of the moving platform connecting to the component to be tested is determined through the mapping between force and displacement in rigid body motion. Current typical deficient-DOF parallel mechanism is enumerated to evaluate its load output characteristics. What is more important, a type synthesis procedure based on the graphic approach is presented to construct the configurations of parallel/hybrid mechanism corresponding to different compound load types, which may lead to useful load simulator configurations. The procedure also verifies that the graphic approach is a concise and effective method to synthesize the load simulators associated with a specified load pattern.
Post-Flutter Bifurcation Behavior in Long-Span Suspension Bridges
Authors: Arena Andrea , Lacarbonara Walter , Marzocca Pier
Published: February 2014

A linearized parametric continuum model of a long-span suspension bridge is coupled with a nonlinear quasi-steady aerodynamic model giving the aeroelastic partial differential equations of motion reduced to the state-space ordinary differential form by adopting the Galerkin method. Numerical time-domain simulations are performed to investigate the limit cycle oscillations occurring in the range of post-flutter wind speeds. Continuation tools are thus employed to path follow the limit cycles past the flutter speed where the Hopf bifurcation occurs. The stable post-flutter behavior, which can significantly affect the bridge by fatigue, terminate at a fold bifurcation. This result represents an important assessment of the conducted aeroelastic investigations. The stability range of the limit cycle oscillations is evaluated by carrying out sensitivity analyses with respect to the main design parameters, such as the structural damping and the initial wind angle of attack.
ROM of Primary Resonance Amplitude-Voltage Response of MEMS Cantilevers
Authors: Caruntu Dumitru I. , Luo Le , Martinez Israel , Fathelden Mostafa , Reyes Christian
Published: February 2014

This paper uses Reduced Order Model (ROM) method to investigate the amplitude-voltage response of MEMS cantilever resonators of linear thickness variation and constant width under AC voltage of frequency near half natural frequency of the resonator. The influences of nonlinearities resulting from AC voltage parametric excitation on the response of the structure are reported.
Experimental Vibro-Acoustic Transfer Path Analysis on Helicopters
Authors: Mucchi Emiliano , Vecchio Antonio
Published: February 2014

The Transfer Path Analysis (TPA) presented in this paper has been performed on the Agusta Westland AW-109 helicopter. A combination of laboratory measured FRFs and in-flight operational data has been gathered: while the structural and acoustic FRFs have been collected in a measurement campaign held at Politecnico of Milan employing the helicopter mock-up, the operational data, i.e. the paths acceleration, were obtained on the actual helicopter in a succeeding session that took place in the Agusta Westland factory. Since the data analysis has brought to light some corrupted data concerning the set of the structural FRFs, an attempt to perform the TPA using POLYMAX synthesized FRFs has been brought to completion with the aim of verifying at first the reliability of such an approach and then to assess whether this technique could be employed to substitute corrupted data with synthesized ones when the database occurred to be unreliable.
Study on Driver Distraction Indexes Using Biological Signals Applying Assessment of Information Display
Authors: Ohkura Michiko , Takahashi Nobumichi , Seki Hironori , Saito Yukou , Hasegawa Koyo
Published: February 2014

Driver distraction, which is one form of inattention, is a leading factor of vehicle crashes and near-crashes. Distraction occurs when a driver’s recognition of information needed to safely accomplish his driving task is delayed because some event, activity, object, or person within or outside the vehicle induces or shifts his attention away from the driving task.

To measure the distraction, driving performance indexes are commonly used. However, we employed biological signals to directly and quantitatively measure the distraction.

Our experiment results identified such useful biological indexes as EEG’s total power spectrum, beta wave ratio, ECG’s heart rate, and its LF/HF.

In this article, we introduce our trial in which we applied the index candidates to assess the information display positions.
Design for 1:2 Internal Resonances in In-Plane Vibrations of Plates With Hyperelastic Materials
Authors: Tripathi Astitva , Bajaj Anil K.
Published: February 2014

With advances in technology, hyperelastic materials are seeing increased use in varied applications ranging from microfluidic pumps, artificial muscles to deformable robots. They have also been proposed as materials of choice in the construction of components undergoing dynamic excitation such as the wings of a micro-unmanned aerial vehicle or the body of a serpentine robot. Since the strain energy potentials of various hyperelastic materials are more complex than quadratic, exploration of their nonlinear dynamic response lends itself to some interesting consequences. In this work, a structure made of a Mooney-Rivlin hyperelastic material and undergoing planar vibrations is considered. Since the stresses developed in a Mooney-Rivlin material are at least a quadratic function of strain, a possibility of 1:2 internal resonance is explored. A Finite Element Method (FEM) formulation implemented in Matlab is used to iteratively modify a base structure to get its first two natural frequencies close to the ratio 1:2. Once a topology of the structure is achieved, the linear modes of the structure can be extracted from the finite element analysis, and a more complete Lagrangian formulation of the hyperelastic structure can be used to develop a nonlinear two-mode model of the structure. The nonlinear response of the structure can be obtained by application of perturbation methods such as averaging on the two-mode model. It is shown that the strain energy potential for the Mooney-Rivlin material makes it possible for internal resonance to occur in such structures.
Post-Tsunami Evacuation Simulation Using 3D Kinematic Digital Human Models and Experimental Verification
Authors: Kakizaki Takao , Urii Jiro , Endo Mitsuru
Published: February 2014

A post-tsunami evacuation simulation using 3D kinematic digital human models (KDHs) and its experimental verification are addressed in the present study. Methods for carrying or assisting (transporting) injured people were experimentally investigated and the results were used for KDH data calibration to increase the accuracy of the simulations. It was found that, on flat ground, both the transit speed and the amount of time spent on intermittent rests were strongly affected by the load on the transporters. During ascent of stairways, the transit speed depended on the type of carry method being used, and decreased in the order saddleback carry, two-person arm carry and slightly injured walking. Several KDH evacuee motion primitives were developed for stairway ascent to a tsunami evacuation tower. The simulation results show that the evacuation time was affected by the number of evacuees and the congestion due to the transportation of injured people. The developed simulation techniques can be effectively utilized in the planning of tsunami tower evacuation and predicting related crowd behavior.
Dynamic Response of a Multi-Megawatt Wind Turbine Drivetrain Under Voltage Dips Using a Coupled Flexible Multibody Approach
Authors: Blockmans Bart , Helsen Jan , Vanhollebeke Frederik , Desmet Wim
Published: February 2014

High turbine reliability is of utmost importance to keep the cost of wind energy to a minimum. A considerable problem in this regard is that of premature drivetrain failures, which have plagued the wind turbine industry since its inception. Accurate prediction of the loads encountered by the drivetrain components during their lifetime is essential for reliable wind turbine design. Of particular interest are transient load events, which are expected to have a detrimental effect on the lifetime of drivetrain components, especially when they give rise to torque reversals. At the electrical side of the wind turbine, transient events worth investigating include grid faults, emergency stops and grid loss. Unlike previous research on the impact of these events, which typically uses simplified gearbox representations, this paper investigates the dynamic behavior of wind turbine drivetrains during grid faults using a coupled simulation of a flexible multibody model of a commercial multimegawatt wind turbine drivetrain and a Simulink model of a doubly fed induction generator (DFIG) and its controller. The mathematical modeling of the DFIG as well as the flexible multibody modeling of the drivetrain are described. Both gear and bearing forces on several components of the gearbox are examined during a symmetrical and asymmetrical voltage dip, and the influence of gearbox flexibility on these loads is assessed.
Optimizing Part Sourcing Strategies for Low-Volume, Long Life Cycle Products Using Second Sourcing and Part Hoarding
Authors: Prabhakar Varun J. , Allison Hannah , Sandborn Peter , Eriksson Bo
Published: February 2014

Long life cycle products, commonly found in aviation, medical and critical infrastructure applications, are often fielded and supported for long periods of time (20 years or more). The manufacture and support of long life cycle products rely on the availability of suitable parts, which over long periods of time, leaves the parts susceptible to supply chain disruptions such as suppliers exiting the market, allocation issues, counterfeit part risks, and part obsolescence.

Proactive mitigation strategies exist that can reduce the impact of supply chain disruptions. One solution to mitigating the supply chain risk is the strategic formulation of part sourcing strategies (optimally selecting one or more suppliers from which to purchase parts over the life of the part’s use within a product or organization). Strategic sourcing offers a way of avoiding the risk of part unavailability (and its associated penalties), but at the expense of qualification and support costs for multiple suppliers. An alternative disruption mitigation strategy is hoarding. Hoarding involves stocking enough parts in inventory to satisfy the forecasted part demand (for both manufacturing and maintenance requirements) of a fixed future time period. This excess inventory provides a buffer that reduces the effect of supply chain disruptions on the part total cost of ownership (TCO), but increases the total holding cost.

This paper presents a method of performing tradeoff analyses and identifying the optimal combination of second sourcing and hoarding for a specific part and product scenario. A case study was performed to examine the effects of hoarding on both single and second sourced parts. The case study results show that hoarding can contribute to a decrease in the cumulative TCO and a decrease in its variance.
A Gallery of Root Locus of Fractional Systems
Authors: Machado J. A. Tenreiro
Published: February 2014

The root locus (RL) is a classical tool for the stability analysis of integer order linear systems, but its application in the fractional counterpart poses some difficulties. Therefore, researchers have mainly preferred to adopt frequency based methods. Nevertheless, recently the RL was considered for the stability analysis of fractional systems. One first method is by tacking advantage of commensurable expressions that occur when truncating fractional orders up to a finite precision. The second method consists of searching the complex plane for solutions of the characteristic equation using a numerical procedure. The resulting charts are insightful about the characteristics of the closed-loop system that outperform the frequency response methods. Given the limited know how in this particular topic and the shortage of literature, this study explores several types of fractional-order transfer functions and presents the corresponding RL.
Development of an Integrated Product, Process and Material Information Model
Authors: Roy Utpal , Sarigecili Mehmet I.
Published: February 2014

There is a dire need for the development of an integrated information model for organizing and managing material and manufacturing related information, required for any product realization. In this paper, such an information framework for product, process and material modeling has been proposed to support the product’s form, function and behavior, its physical and functional decompositions, its design requirements and design rationale, and its material and process needs. A detailed, real-life case study of the water jet intensifier design system has been presented to show how this proposed framework could support, capture and utilize all necessary information required for the selection of the intensifier’s high-pressure cylinder material. The framework will also be able to provide sufficient information to quantify the eco-compatibility of products.
PCB Origami: A Material-Based Design Approach to Computer-Aided Foldable Electronic Devices
Authors: Sterman Yoav , Demaine Erik D. , Oxman Neri
Published: February 2014

Origami is traditionally implemented in paper of homogeneous material properties. This research explores the use of material with embedded electronics such as PCB (Printed Circuit Boards) as the medium for origami folding in order to create an interactive folding experience and to generate foldable objects with added functionalities. PCBs are produced as 2D shapes. By folding PCB arrays it is possible to create 3D objects that contain electronic functions. Conductivity, output devices (such as Light Emitting Diodes) and microcontroller computation can create an interactive folding experience, for user guidance and verification of the folding. We call this approach and methodology PCB Origami. The work presented in this paper describes two unique interaction and fabrication techniques for creating and folding electronic materials. We demonstrate prototypes and present verification/evaluation strategies for guiding the user through the folding process.
Multi-Stage Optimization of Wind Farms With Limiting Factors
Authors: DuPont Bryony L. , Cagan Jonathan
Published: February 2014

Larger onshore wind farms are often installed in phases, with discrete smaller sub-farms being installed and becoming operational in succession until the farm as a whole is completed. An extended pattern search (EPS) algorithm that selects both local turbine position and geometry is presented that enables the installation of a complete farm in discrete stages, exploring optimality of both incremental sub-farm solutions and the completed project as a whole. The objective evaluation is the maximization of profit over the life of the farm, and the EPS uses modeling of cost based on an extensive cost analysis by the National Renewable Energy Laboratory (NREL). The EPS uses established wake modeling to calculate the power development of the farm, and allows for the consideration of multiple or overlapping wakes.

A limiting factor is used to determine the size of wind farm stages: optimization stages based on the number of turbines currently available for development (representative of limitations in initial capital, which is commonly encountered in wind farm stage development). Two wind test cases are considered: a unidirectional test case with constant wind speed and a single wind direction, and a multidirectional test case, with three wind speeds and a defined probability of occurrence for each. The test case shown in the current work is employed on a 4000 km by 4000 km solution space. In addition, two different methods are performed: the first uses the optimal layout of a complete farm and then systematically “removes” turbines to create smaller sub-farms; the second uses a weighted multi-objective optimization over sequential, adjacent land that concurrently optimizes each sub-farm and the complete farm. The exploration of these resulting layouts indicates the value of full-farm optimization (in addition to optimization of the individual stages) and gives insight into how to approach optimality in sub-farm stages. The behavior exhibited in these tests cases suggests a heuristic that can be employed by wind farm developers to ensure that multi-stage wind farms perform at their peak throughout their completion.
Study on Method to Generate Wood Grain Pattern Representing Required Impression
Authors: Akiyama Ryo , Mori Takuya , Aoyama Hideki , Oya Tetsuo
Published: February 2014

Various approaches for generating wood grain patterns using computer graphics have been proposed so far. However, with such conventional methods, it is difficult to reproduce real wood grain patterns, as well as design wood grain patterns with impressions that reflect customer needs.

This paper proposes a new approach for generating wood grain patterns. For instance, it can generate virtual trees by simulating tree growth taking into consideration environmental conditions, model fine tree tissues and reflection properties at the wood surface, etc. By applying these modeled factors, more diverse and accurate wood grain patterns can be generated. The authors also propose a method of controlling the grain patterns generated based on Kansei to realize grain patterns that meet customer needs. By building the basic system of the proposed method, various grain patterns could be generated, and grain pattern impressions controlled.
Low Cost Mixed Reality System Using Projectors for Evaluation of Product Design (Shape and Function Structure)
Authors: Chinone Yuko , Aoyama Hideki , Oya Tetsuo
Published: February 2014

Three-dimensional models (CAD models) are constructed in the design processes of products because they are effective for design evaluation processes using CAE systems and manufacturing processes using CAM systems. However, mock-ups or prototypes are still required in the evaluation processes of designability and operability of products because the evaluation of the operations of real products is essential. It is however time-consuming and costly to make prototypes or to develop trial products for evaluation. For this problem, considerable studies have been conducted on the use of mixed reality technology by overlaying an image of the design model onto a physical model using a Head-Mounted Display (HMD) to evaluate the designability and operability of a product. Such technology reduces the need for making physical mock-ups (prototypes and trial products), but HMDs have drawbacks such as causing motion sickness and physical weight, bulkiness of the display, and high costs. In this paper, a method using projectors is proposed to establish mixed reality technology which does not have the drawbacks of HMDs. A mixed reality system was constructed according to the proposed method, and applied for evaluating designability and operability of products without physical mock-ups. In the mixed reality space built by the system, the functions of a product can be held in the hand as if they were real products.
A Computational Framework for Predicting the Motions of a Protein System From a Robot Kinematics Viewpoint
Authors: Arikawa Keisuke
Published: February 2014

There is an analogy between the kinematic structures of proteins and robotic mechanisms. On the basis of this analogy, we have so far developed some methods for predicting the internal motions of proteins from their three-dimensional structural data in protein data bank (PDB). However, these methods are basically applicable to a single protein molecule. In this study, we extended these methods to apply them to systems that consist of multiple molecules including proteins (protein systems), and developed a computational framework for predicting the motions of the molecules. The model used in this method is a type of elastic network model. In particular, proteins are modeled as a robot manipulator constrained by the springs (the dihedral angles on the main chains correspond to the joint angles). The interactions between molecules are also modeled as springs. The basic concept for predicting the motions is based on the analysis of structural compliance. By applying statically balanced forces to the model in various directions, we extracted those motions with larger structural compliance. To reduce the computational time, we formulated the method with the prospect of efficient computation including parallel computation. In addition, we developed a preparatory computer program implementing the proposed algorithms, and analyzed some protein systems. The results showed that the proposed computational framework can efficiently analyze large protein systems.
Solving Design Tasks in Engineering Using Object-Oriented Graph-Based Representations and Boolean Satisfiability
Authors: Münzer Clemens , Shea Kristina , Helms Bergen
Published: February 2014

Ever since computers have been used to support human designers, a variety of representations have been used to encapsulate engineering knowledge. Computational design synthesis approaches utilize this knowledge to generate design candidates for a specified task. However, new approaches are required to enable systematic solution space exploration. This paper presents an approach that combines a graph-based, object-oriented knowledge representation with first-order logic and Boolean satisfiability. This combination is used as the foundation for a generic, automated approach for requirement-driven computational design synthesis. Available design building blocks and a design task defined through a set of requirements are modeled in a graph-based environment and then automatically transferred into a Boolean satisfiability problem and solved, considering a given solution size. The solution is then automatically transferred back to the graph-based domain. The method is validated through the synthesis of automotive powertrains. The contribution of the paper is a new method that is both able to determine that an engineering task is solvable or not given a set of design building blocks and able to systematically explore the solution space.
Switchability in Discontinuous, Discrete Dynamical Systems
Authors: Luo Albert C. J.
Published: February 2014

Tin this paper, a theory for switchability and singularity of discontinuous, discrete dynamical systems. G-functions for the discrete dynamical systems are introduced through the boundary, and the necessary and sufficient conditions for the switchability of discrete mappings are presented.
Emotionally Acceptable Decision Making in Engineering
Authors: Fukuda Shuichi
Published: February 2014

Although there are many approaches to decision making, most of them are tools for a Closed World, they do not necessary provide a tool for decision making for such problems which many disciplines are related to and much heuristics or experience are called for.

Today, our world is expanding very quickly and the boundaries are disappearing very rapidly. In such an Open World, we need a wide variety of knowledge and experience to make a decision

And these pieces are not necessary obtained from the first. As we step forward, we find out what additional information is needed and we change our tracks to pursue better solutions.

And constraints also change with progress. In a Closed World, hard constraints remain hard all the way, but in an Open World, hard constraints may change to soft ones later.

Thus, how we can manage constraints and how we can postpone our decisions until we have necessary pieces of information are very important in decision making in an Open World.

This paper demonstrates that an AI approach provides a very versatile and useful tool for decision making in an open world by taking the case of producing welding procedure specification as an illustrative example.
Type Synthesis of Kinematically Redundant 3T1R Parallel Manipulators
Authors: Kong Xianwen , Chablat Damien , Caro Stéphane , Yu Jingjun , Gosselin Clément
Published: February 2014

A kinematically redundant parallel manipulator (PM) is a PM whose degrees-of-freedom (DOF) are greater than the DOF of the moving platform. It has been revealed in the literature that a kinematically redundant PM has fewer Type II kinematic singular configurations (also called forward kinematic singular configurations, static singular configurations or parallel singular configurations) and/or constraint singular configurations than its non-redundant counterparts. However, kinematically redundant PMs have not been fully explored, and the type synthesis of kinematically redundant PMs is one of the open issues. This paper deals with the type synthesis of kinematically redundant 3T1R PMs (also called SCARA PMs or Schoenflies motion generators), in which the moving platform has four DOF with respect to the base. At first, the virtual-chain approach to the type synthesis of kinematically redundant parallel mechanisms is recalled. Using this approach, kinematically redundant 3T1R PMs are constructed using several compositional units with very few mathematical derivations. The type synthesis of 5-DOF 3T1R PMs composed of only revolute joints is then dealt with systematically. This work provides a solid foundation for further research on kinematically redundant 3T1R PMs.
Determination of the Workspace of Parallel Manipulators Using a CAD Software and the Concept of Virtual Chains
Authors: Johnson Andrew , Kong Xianwen
Published: February 2014

Development of a new parallel manipulator can be very time consuming due to the traditional method of producing kinematic, dynamic and static calculation models and then evaluating them to determine aspects of the manipulator’s performance indices such as the mechanism’s workspace and singularity analysis. By extending the virtual chain approach to the type synthesis of parallel manipulators, this paper proposes a virtual-chain approach to the workspace analysis of parallel manipulators. This method is illustrated by producing and evaluating the workspace of several parallel robots including the well known DELTA robot by utilising the three-dimensional CAD software SolidWorks to produce a virtual prototype of a manipulator with an embedded virtual chain. The virtual chain represents the motion pattern of a manipulator’s end-effector and is very useful in the production of a graphical representation of the workspace of the manipulator. Using this approach, the link interferences and transmission indices can be easily taken into consideration in determining the workspace of a parallel manipulator.
Product Resynthesis as a Reverse Logistics Strategy for an Optimal Closed-Loop Supply Chain
Authors: Sane Chinmay , Tucker Conrad S.
Published: February 2014

With continued emphasis on sustainability-driven design, reverse logistics is emerging as a vital competitive supply chain strategy for many of the global high-tech manufacturing firms. Various original equipment manufacturers (OEMs) and multi-product manufacturing firms are enhancing their reverse logistics strategies in order to establish an optimal closed-loop supply chain through which they can introduce refurbished variants of their products back into the market. While a refurbished product strategy helps to mitigate environmental impact challenges as well as provide additional economic benefits, it is limited to an existing product market, possibly a subset of the existing market, and fails to commercialize/target new markets. In addition to refurbishing, the alternatives available for utilizing End-Of-Life (EOL) products are currently restricted to recycling and permanent disposal. In this work, the authors propose employing a new EOL option called “resynthesis” that utilizes existing waste from EOL products in a novel way. This is achieved through the synthesis of assemblies/subassemblies across multiple domains. The “newly” synthesized product can then be incorporated into the dynamics of a closed-loop supply chain. The proposed methodology enables OEMs to not only offer refurbished products as part of their reverse logistics strategy, but also provide them with resynthesized product concepts that can be used to expand to new/emerging markets. The proposed methodology provides a general framework that includes OEMs (manufacturers of the original product), retailers (distributors of the original product and collectors of the EOL products) and third-party firms (managers of the EOL products) as part of a closed-loop supply chain strategy. The proposed methodology is compared with the existing methodologies in the literature wherein a third-party supplies the OEM only with refurbished products and supplies products unsuitable for refurbishing to another firm(s) for recycling/disposal. A case study involving a multi-product electronics manufacturer is presented to demonstrate the feasibility of the proposed methodology.
Comparison of Different Methods to Control Constraints Violation in Forward Multibody Dynamics
Authors: Flores Paulo , Nikravesh Parviz E.
Published: February 2014

The dynamic equations of motion for constrained multibody systems are frequently formulated using the Newton-Euler’s approach, which is augmented with the acceleration constraint equations. This formulation results in the establishment of a mixed set of differential and algebraic equations, which are solved in order to predict the dynamic behavior of general multibody systems. It is known that the standard resolution of the equations of motion is highly prone to constraints violation because the position and velocity constraint equations are not fulfilled. In this work, a general review of the main methods commonly used to control or eliminate the violation of the constraint equations in the context of multibody dynamics formulation is presented and discussed. Furthermore, a general and comprehensive methodology to eliminate the constraints violation at the position and velocity levels is also presented. The basic idea of this approach is to add corrective terms to the position and velocity vectors with the intent to satisfy the corresponding kinematic constraint equations. These corrective terms are evaluated as function of the Moore-Penrose generalized inverse of the Jacobian matrix and of the kinematic constraint equations.
Dynamics of Drill Bits With Cutting Edges of Varying Parameters
Authors: Dombovari Zoltan , Stepan Gabor
Published: February 2014

In the metal cutting industry it is well known that milling processes can be stabilized by applying different strategies in order to destroy the pure single delay regeneration that arise in case of conventional milling tools when high material removal rates are used either at low or at high cutting speeds. To achieve this goal, variable pitch angle, variable helix angle and serrated tools are already available in the market and serve alternative solutions for process designers to enhance milling process stability. Regeneration can occur and can cause instability on the tip of the deep drilling equipment when the drill bit is driven across hard earth crust materials. This work shows that theories introduced for milling processes can be implemented to improve the stability properties of deep drilling processes, too. Unlike in case of most milling processes, however, the stability properties of deep drilling are affected by the longitudinal and the torsional vibration modes. In this paper, the geometrical and mechanical models are derived for drill bits with general shapes of cutting edges and it is shown that the two DOF dynamics can be described by distributed state dependent delay differential equations. The stability properties are characterized in stability diagrams that can help to select the optimal drilling process parameters.