bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of a Camless Engine Valve Actuator With Mechanical Feedback
Authors: Bucknor Norman K.
Published: July 2009

Fully flexible engine valve actuation systems are enablers for improvements in engine fuel consumption and power delivery, as well as the implementation of advanced combustion strategies like homogeneous charge compression ignition (HCCI). Hydraulically actuated valve actuation systems provide the greatest operating flexibility but have generally required precision flow control (i.e., servovalves) for viable operation while consuming more power than conventional cam-driven valvetrains. This paper describes an electrohydraulic fully flexible engine valve actuator with a mechanical feedback linkage between the engine valve and the spool in the hydraulic flow control valve. This feedback linkage is intended to simplify the control of the engine valve motion and eliminate the need for servovalve-class performance in the hydraulic control valve. The feedback mechanism reduces the control effort needed to operate the flow control valve since the spool position is not solely a function of the control input. With the assistance of mechanical feedback, the flow through the control valve is throttled in proportion to the engine valve motion. Thus, while throttling losses are not eliminated, there is no excessive flow throttling. This will have a beneficial impact on the energy consumption of the actuator. For preliminary study and validation of the concept, a model of the actuator was developed using ADAMS mechanical system simulation software and AMESim hydraulic simulation software. Results for the combined mechano-hydraulic model are presented to illustrate potential performance benefits and pitfalls of the concept, including effects of dimensional tolerances in the flow control valve. The simulation data was also used to size an electromechanical actuator that would be used to the flow control valve in conjunction with the feedback mechanism.
Identification of Parameters in a System of Differential Equations Modeling Evolution of Infectious Diseases
Authors: Herna´ndez Alberto M. , Dulikravich George S. , Blower Sally , Colaco Marcelo J. , Moral Ramon J.
Published: July 2009

The objective of this project was to perform an inverse parameter identification study to determine parameter values in a system of ten ordinary differential equations modeling the prediction of the evolutionary spread of syphilis. The goal was to predict infant mortality rates due to syphilis by using this model and match them to actual field data collected in the United States from 1900 to 1970. The syphilis model was developed by the UCLA Disease Modeling Group. The model involves 23 unknown user-specified parameters, each with specified maximum and minimum possible values. An accurate ordinary differential equation system integration algorithm was used to numerically integrate these equations. A hybrid evolutionary optimization algorithm was then used to iteratively find the proper values of the 23 unknown parameters by minimizing the difference between the predicted and the actual values of annual infant mortality rates due to syphilis. The parameters were originally treated as constants, meaning that they did not vary in time. During this study, they were also considered as time-dependent by modeling them as second degree polynomials. The sexually active population in the original model was assumed linearly increasing with time. To improve on the results, an eight term Fourier series fit was performed on the actual evolution of the sexually active population data during period 1900–1970. It was found that treating the 23 parameters as constants yielded an average fit of the infant mortality rates. By treating the parameters as time-dependent the fit still appeared average, but the variations of mortality during certain periods were captured more accurately.
A Solid Modeler Approach for Extracting Cutter Workpiece Engagements in Milling
Authors: Aras Eyyup , Yip-Hoi Derek
Published: July 2009

This paper presents a Solid modeling methodology for finding Cutter Workpiece Engagements (CWEs) generated during 3+2 -axis machining (spindle can tilt) of free – form surfaces using a range of different types of cutting tools and tool paths. Swept volumes of the cutters are generated utilizing the envelope theory. For the CWE extractions the removal volumes of the cutter constituent surfaces are used. For this purpose the cutter surfaces are decomposed with respect to the tool feed direction and then they intersected with their removal volumes for obtaining the boundary curves of the closed CWE area. The CWE boundary curves are mapped from Euclidean space to a parametric space defined by the engagement angle and the depth-of-cut for a given tool geometry. The reported method has been implemented using a commercial geometric modeler (ACIS) which is selected to be the kernel around which the geometric simulator is built. The described geometric methodology is being developed as part of a Virtual Milling methodology that combines the geometric modeling aspects of milling material removal with the modeling of the process.
A Continuous Model for Protein Synthesis Using Artificial Power Law in Topology Optimization
Authors: Koh Sung , Liu Gunagjun , Zhu Wen-Hong
Published: July 2009

A continuous protein synthesis formulation based on the design principles developed for structural topology optimization is proposed in this paper. Unlike conventional continuous protein design methods, the Power Law-based (PL) design formulation proposed in this paper enables using any number of residue types to accomplish the goal of protein synthesis and hence provides a continuous protein design formulation applicable to any general protein design problems. Moreover, a discrete sequence with minimum energy can be synthesized by the PL design method as it inherits the feature of material penalization used for the topology optimization. Since a continuous optimization method is implemented to solve the PL design formulation, the entire design process is more efficient and robust than the conventional design methods employing a stochastic or enumerative search process. The performance of the PL design formulation is demonstrated by designing simple lattice protein models for which an exhaustive search can be carried out to identify the sequence with minimum energy. The comparison with the exchange replica method indicates that the PL design method is millions of times more efficient than the conventional stochastic protein design method.
A Comparative Study of the Formulations for Topology Optimization of Compliant Mechanisms
Authors: Deepak Sangamesh R. , Dinesh M. , Sahu Deepak , Jalan Salil , Ananthasuresh G. K.
Published: July 2009

The topology optimization problem for the synthesis of compliant mechanisms has been formulated in many different ways in the last 15 years, but there is not yet a definitive formulation that is universally accepted. Furthermore, there are two unresolved issues in this problem. In this paper, we present a comparative study of five distinctly different formulations that are reported in the literature. Three benchmark examples are solved with these formulations using the same input and output specifications and the same numerical optimization algorithm. A total of 35 different synthesis examples are implemented. The examples are limited to desired instantaneous output direction for prescribed input force direction. Hence, this study is limited to linear elastic modeling with small deformations. Two design parameterizations, namely, the frame element based ground structure and the density approach using continuum elements, are used. The obtained designs are evaluated with all other objective functions and are compared with each other. The checkerboard patterns, point flexures, the ability to converge from an unbiased uniform initial guess, and the computation time are analyzed. Some observations are noted based on the extensive implementation done in this study. Complete details of the benchmark problems and the results are included. The computer codes related to this study are made available on the internet for ready access.
Realization of a 6-DOF Manipulator With an Unconventional Topological Structure
Authors: Arikawa Keisuke
Published: July 2009

We propose a six-degrees-of-freedom manipulator with an unconventional topological structure. Because of the complex kinematic structure, it might seem that we cannot actually build such a manipulator. However, we show that we can construct a working model and control its hand configuration. First, we discuss the mobility of the proposed manipulator, and present the conditions imposed on the kinematic structure and the active joint selection. Then, we derive a numerical solution of the inverse kinematics problem by making the best use of the mechanical features, and present the simulation results of trajectory tracking of the hand configuration obtained using the solution. Next, under static equilibrium, we derive the conditions for the singular configurations, where the hand cannot support specific force moments. Finally, we construct an equivalent spherical joint that has a large movable range, and we present a working skeletal model of the proposed manipulator using the joints.
Prognostics of Machine Condition Using Energy Based Monitoring Index and Computational Intelligence
Authors: Samanta B. , Nataraj C.
Published: July 2009

A procedure is presented for monitoring and prognostics of machine conditions using computational intelligence (CI) techniques. The machine condition is assessed through an energy-based feature, termed as ‘energy index’, extracted from the vibration signals. The progression of the ‘monitoring index’ is predicted using CI techniques, namely, recursive neural network (RNN), adaptive neuro-fuzzy inference system (ANFIS) and support vector regression (SVR). The proposed prediction procedures have been evaluated through benchmark datasets. The prognostic effectiveness of the techniques has been illustrated through vibration dataset of a helicopter drivetrain system gearbox. The performance of SVR was found to be better than RNN and ANFIS for the dataset used. The results are helpful in understanding the relationship of machine conditions, the corresponding indicating feature, the level of damage/degradation and their progression.
Task-Space Control Design and Performance Evaluation for a 6DOF Stewart Nanoscale Platform
Authors: Li Chun-Chung , Ting Yung , Liu Yi-Hung , Lee Yi-Da , Chiu Chun-Wei
Published: July 2009

A 6DOF Stewart platform using piezoelectric actuators for nanoscale positioning objective is designed. A measurement method that can directly measure the pose (position and orientation) of the end-effector is developed so that task-space on-line control is practicable. The design of a sensor holder for sensor employment, a cuboid with referenced measure points, and the computation method for obtaining the end-effector parameters is introduced. A control scheme combining feedforward and feedback is proposed. The inverse model of a hysteresis model derived by using a dynamic Preisach method is used for the feedforward control. Hybrid control to maintain both the positioning and force output for nano-cutting and nano-assembly applications is designed for the feedback controller. The optimal gain of the feedback controller is searched by using relay feedback test method and genetic algorithm. In experiment, conditions with/without external load employed with feedforward, feedback, and feedforward with feedback control schemes respectively are carried out. Performance of each control scheme verifies the capability of achieving nanoscale precision. The combined feedforward and feedback control scheme is superior to the others for gaining better precision.
Novel Two-Stage Electrical Energy Generators for Highly-Variable and Low-Speed Linear or Rotary Input Motions
Authors: Rastegar Jahangir S. , Murray Richard T.
Published: July 2009

A novel class of two-stage, vibration-based electrical energy generators is presented for linear or rotary input motions in applications which the input speed is relatively low and varies significantly over time such as wind mills, turbo-machinery used to harvest tidal flows, devices for harnessing coastal wave energy, and the like. Current technologies use magnet-and-coil based electrical generators in such machinery. However, to make the generation cycle efficient, gearing or other similar mechanisms must be used to increase the input speed. Variable speed-control mechanisms are also usually needed to achieve high energy conversion efficiency. Additionally, in many applications, such as those where energy is to be harvested from very low frequency oscillations of a platform such as a buoy or a ship, the use of speed increasing mechanisms such as gearing or the like is impractical. In this paper, a novel class of two-stage electrical energy generators that could operate with very low speed and highly variable input rotations and/or oscillations is described. The first stage consists of simple linkage mechanisms, which are used to excite vibratory elements. These two-stage generators are designed to convert low-speed and highly variable input rotations and oscillations to relatively high and constant frequency vibratory motions, which are then used to generate electrical energy using mechanical to electrical energy conversion devices such as piezoelectric elements. The design of a number of such two-stage generators together with a discussion of their potential applications is presented.
A Comprehensive Metric for Comparing Time Histories in Validation of Simulation Models With Emphasis on Vehicle Safety Applications
Authors: Sarin H. , Kokkolaras M. , Hulbert G. , Papalambros P. , Barbat S. , Yang R.-J.
Published: July 2009

Computer modeling and simulation are the cornerstones of product design and development in the automotive industry. Computer-aided engineering tools have improved to the extent that virtual testing may lead to significant reduction in prototype building and testing of vehicle designs. In order to make this a reality, we need to assess our confidence in the predictive capabilities of simulation models. As a first step in this direction, this paper deals with developing a metric to compare time histories that are outputs of simulation models to time histories from experimental tests with emphasis on vehicle safety applications. We focus on quantifying discrepancy between time histories as the latter constitute the predominant form of responses of interest in vehicle safety considerations. First we evaluate popular measures used to quantify discrepancy between time histories in fields such as statistics, computational mechanics, signal processing, and data mining. Then we propose a structured combination of some of these measures and define a comprehensive metric that encapsulates the important aspects of time history comparison. The new metric classifies error components associated with three physically meaningful characteristics (phase, magnitude and topology), and utilizes norms, cross-correlation measures and algorithms such as dynamic time warping to quantify discrepancies. Two case studies demonstrate that the proposed metric seems to be more consistent than existing metrics. It is also shown how the metric can be used in conjunction with ratings from subject matter experts to build regression-based validation models.
Improving the Performance of Visual Steering Commands for Multi-Dimensional Trade Space Exploration
Authors: Congdon Christopher D. , Carlsen Daniel E. , Simpson Timothy W. , Martin Jay D.
Published: July 2009

Designers perform many tasks when developing new products and systems, and making decisions may be among the most important of these tasks. The trade space exploration process advocated in this work provides a visual and intuitive approach for formulating and solving single- and multi-objective optimization problems to support design decision-making. In this paper, we introduce an advanced sampling method to improve the performance of the visual steering commands that have been developed to explore and navigate the trade space. This method combines speciation and crowding operations used within the Differential Evolution (DE) algorithm to generate new samples near the region of interest. The accuracy and diversity of the resulting samples are compared against simple Monte Carlo sampling as well as the current implementation of the visual steering commands using a suite of test problems and an engineering application. The proposed method substantially increases the efficiency and effectiveness of the sampling process while maintaining diversity within the trade space.
Topology Synthesis of Compliant Systems With Embedded Actuators and Sensors
Authors: Trease Brian , Kota Sridhar
Published: July 2009

The basic premise of a compliant system is the integration of motion/force transmission via elastic deformation with embedded actuation and sensing. Current electromechanical systems are generally fashioned in the rigid-and-discrete paradigm where one first designs a rigid structure with mechanical joints and then adds actuators and sensors, with the design of controls only following as an afterthought. The objective of this research is a systems approach to synthesis of mechanism, structure, actuation, and sensing, thereby advancing from traditional mechanical design to automated compliant system design. In previous studies of compliant mechanisms and their synthesis, single-actuator mechanisms have primarily been considered, with the determination of the actuator’s type, orientation, size, and location occurring outside of the automated design synthesis, at the designer’s option. A new algorithmic framework is presented, in which structural topology and actuator/sensor placement are simultaneously synthesized for adaptive performance. Significantly, this is not a traditional ad hoc method; sensor and actuator placement affect structural topology and vice versa. This is a continuation of our previously reported actuation-placement work [1–2], updated here to include the sensor placement co-synthesis and new tasks in addition to shape change. The methods used include genetic algorithms, graph searches for connectivity, and multiple load cases implemented with linear finite element analysis. Fundamental metrics for the inclusion of embedded components in a multifunctional compliant system are developed and investigated. The essential framework for the integration of controls with compliant mechanisms is established. Specifically, the concepts of controllability and observability, as redefined for compliant systems, are proven as a successful starting point for the design of multifunctional, adaptive systems. These concepts refer to the unique system response for each component (actuator or sensor) it contains. Results are presented for several problems, focusing on the application of shape-morphing aircraft structures. Through examples and design studies, the metrics and the methodology demonstrate that multiple, optimally-placed components indeed offer performance benefits for mechanical systems, in terms of multifunctional execution. Finally, the extension of controllability to address the problem of single-point multidegree-of-freedom manipulation is performed to show the generalized use of the new methodology in benefitting the design of compliant systems.
A Large-Deflection Annulus-Shape Flexure Hinge Based on Curved Beams
Authors: Zhao Shanshan , Bi Shusheng , Yu Jingjun , Sun Minglei , Zhong Guanghua
Published: July 2009

A curved flexure element such as an initially-curved beam can deflect largely and facilely. Using curved flexure elements in compliant mechanisms allows the mechanism to move a longer distance or undergo a larger rotation angle stroke than using conventional notch flexures. This paper presents a novel large-deflection annulus-shaped flexure hinge covering multiple curved-beam flexure elements. It has been shown that geometric symmetry in the constraint arrangement relaxes some of the design tradeoffs, resulting in some improved performances of the flexure hinge. Additional fixed RCM characteristic of isosceles-trapezoidal flexure modules existed in this compliant joint further improve its accuracy. A master-motion pseudo-rigid-body model provides a simple and accurate method to analyze the force-deflection behavior of this new rotary flexure hinge. The accuracy of the model is verified by comparing outcomes to non-linear finite element analysis. The result shows the proposed rotary flexure hinge has a large stroke angle, a low axial and radial stiffness.
Euclidean Symmetry Detection From Scanned Meshes Based on a Combination of ICP and Region Growing Algorithms
Authors: Mizoguchi Tomohiro , Kanai Satoshi
Published: July 2009

Recently, meshes of engineering objects have been easily acquired by 3D laser or high-energy industrial X-ray CT scanning systems and they are widely used in product developments. For the effective use of scanned meshes in inspection, re-design, and simulation of the objects, it is important to reconstruct CAD models from the meshes. Engineering objects often exhibit Euclidean symmetries for their functionalities. Therefore, it is essential to detect such symmetries when reconstructing CAD models with compact data representations which are similar to the ones already defined in CAD systems. However, existing methods for reconstructing CAD models have not focused on detecting such symmetries. In this paper, we propose a new method that detects partial or global Euclidean symmetries, including translation, rotation, and reflection, from scanned meshes of engineering objects based on the combination of the ICP and the region growing algorithms. Our method can robustly and efficiently extract pairs of symmetric regions and their transformations under which the pair can be closely matched to each other. We demonstrate the effectiveness of the proposed method from experiments on various scanned meshes.
Flaw Detection Using Image Registration and Fusion Techniques
Authors: Zhou Yiqiang , Hoberock L. L.
Published: July 2009

The inspection of polished metal contoured surfaces, such as silverware pieces, is much more difficult than for a flat surface, considering the complex curved surface, reflections, and shadows. It is hard to detect flaws when they overlap with shadows and specular reflections, which is typically the case. In this paper, this problem is solved using image registration and image fusion techniques. A continuous-inspection system is developed to take two images sequentially under different lighting conditions when the object is passing under the camera. Shadows and reflections shift, while the flaws do not. From the differences of these two images, flaws can be distinguished from shadows and reflections, and the lost information due to specular reflections can be made up. Fused images without specular reflections were obtained, and a new feature based image registration algorithm is developed to compare these two fused images to detect the surface flaws.
Design Method of Optimum Number of Teeth for Vehicle Transmission Considering Human Aural Characteristics
Authors: Araragi Takayuki , Uenishi Yasuhiro , Hirogaki Toshiki , Aoyama Eiichi
Published: July 2009

The gear noise has been reduced by reducing the meshing transmission error to improve the gear noise up to now. However, it seems that there is no research that considers even human aural characteristic yet in this field. Therefore, we propose a new design method of the low noise gear, which according to human aural characteristic. The proposed technique is a gear design to control the frequency of the gear noise by changing number of tooth. First of all, human aural characteristic was researched in a special acoustic environment in the vehicle. Secondly, the characteristic of vehicle interior sound was investigated. Thirdly, the relationship between the number of teeth and the sound level of the gear noise was investigated. Finally, it was demonstrated that a proposed method was effective to design an advantageous number of gear teeth according to human aural characteristic. It was found that the proposed method of varying the number of teeth was effective for designing gears with optimal human aural characteristics.
The Design of Future Cars in a New Age of Architectural Competition
Authors: Gorbea Carlos , Fricke Ernst , Lindemann Udo
Published: July 2009

This paper presents how complex system architecture lifecycles, such as that of cars, follow a similar S-curve shaped path as that of individual technological innovations. By applying this theory we show that today’s automotive industry has started a new chapter of architectural competition with similarities to its early history from 1885–1915 when steam, electric and internal combustion engine cars were competing to dominate the automotive market. Taking a historical perspective, we find that firms that organize their development activities to focus on bringing about architectural innovation are better placed in succeeding in the future market until a new dominant architecture emerges. The architecture lifecycle framework used in this study is constructed by means of a performance index. The index scores the performance of 91 cars of various architectures based on five overall system variables: power, weight, maximum velocity, fuel efficiency and the manufacturer’s suggested retail price. Depicting architectural performance over time helps identify periods of architecture competition and dominance where historical agents to change can be identified. The key factors that brought about architectural competition in the early 1900’s involved a series of innovation breakthroughs in engine and fuel technologies. Today, a new wave of power train innovations is being triggered primarily by environmental regulatory demands to reduce vehicle emissions. Future research lies in presenting a methodology for selecting vehicle architectures early on in the product development cycle that are best suited for the market going forward based on a manufacturer’s goals and a cost-benefit analysis.
An Integrated Process Planning System Architecture for Machining and On-Machine Inspection
Authors: Zhao Yaoyao F. , Xu Xun W. , Xie Sheng Q. , Kramer Tom R. , Proctor Fred M. , Michaloski John L.
Published: July 2009

Inspection is an essential part of the entire manufacturing chain providing measurement feedback to the process planning system. Fully automated machining requires automatic inspection process planning and real-time inspection results feedback. As inspection process planning is still based on G&M codes containing low-level information or vendor-specific bespoke routines, inspection process planning is mostly isolated from machining process planning. With the development of new data model standards STEP and STEP-NC providing high-level product information for the entire manufacturing chain, it is achievable to combine machining and inspection process planning to generate optimal machining and inspection sequences with real-time measurement results feedback. This paper introduces an integrated process planning system architecture for combined machining and inspection. In order to provide real-time inspection feedback, On-Machine Inspection (OMI) is chosen to carry out inspection operations. Implementation of the proposed architecture has been partially carried out with a newly developed data model and interpreter software. A case study was carried out to test the feasibility of the proposed architecture.
Non-Linear Least-Square Optimization of Mechanisms Based on Levenberg-Marquardt Method
Authors: Sancibrian Ramon , De-Juan Ana , Viadero Fernando
Published: July 2009

One of the main problems to improve the convergence rate in deterministic optimization of mechanisms is to obtain the Hessian matrix. The required second-order derivatives are difficult to obtain or they are not available. Levenberg-Marquardt optimization method is a pseudo-second order method which means that uses the jacobian information to estimate the Hessian matrix. In this paper, the formulation to obtain the exact form of the jacobian matrix is presented and how can be implemented in the Levenberg-Marquardt method. This formulation gives a very effective method to optimize mechanism geometry considering a large number of prescribed positions and design variables. At the same time it is possible to have control over singularities and permits to compare the desired and generated path avoiding translation and rotation effects.
Gripping Efficiency of Simple Gripping Mechanism With Hinges
Authors: Ando Hiroki , Muramatsu Naoki
Published: July 2009

This paper discusses improvements in gripping efficiency of a simple gripping mechanism. The simple gripping mechanism has flexible fingers, and the multi-fingered gripper holds the gripped object by elastically deforming the fingers. The two-fingered gripper is formed by bending a narrow strip of thin elastic plate into an appropriate shape. It is simple in structure and is able to be easily miniaturized. The deformations of the gripper and gripped object are analyzed to ascertain its gripping efficiency. The two-fingered gripper is considered as a rigid frame whose both ends are fixed, and its deformation is analyzed. Since this structure is statically indeterminate, the virtual work method is used to analyze it. The gripped object is considered as two cantilever beams arranged parallel to each other, and its deformation is analyzed. Effectiveness of this analysis is verified in comparison between calculated results and experimental results. Moreover, by comparing gripping efficiency of the conventional structure of the simple gripping mechanism and the other three different structures with hinges, the effects of these differences between the node conditions on gripping efficiency are clarified.
Implementing Fuzzy Logic in the Control of a Biologically Inspired Robotic Cat Leg
Authors: Crawford Anthony L. , Edwards Dean B.
Published: July 2009

This research discusses the implementation of a fuzzy logic control system to drive the movement of a simplified cat leg model. The system’s movement in this paper addresses a planar motion where the model experiences a fixed horizontal velocity and a harmonic vertical displacement. The fuzzy logic (FL) controller applies membership functions to fuzzify the position and velocity errors and applies height defuzzification to generate the time dependant forcing function for the system’s horizontal and vertical governing equations. A PID controller is also applied as a benchmark for this research. Both controllers are optimized using the simplex method for which the FL controller performed just as well as the PID controller with more promise of accounting for the nonlinear influences that were neglected in this simplified cat leg model and requiring actuators with a lower required force range. This research provides the skeletal structure for which an effective total controller can be built on.
Adaptive Control of Object Path Tracking and Finger Tip Slippage in a Multi-Fingered Robotic System
Authors: Hadian Jazi Shahram , Keshmiri Mehdi , Sheikholeslam Farid
Published: July 2009

Considering slippage between finger tips and an object, adaptive control synthesis of grasping and manipulating an object by a multi-fingered system is addressed in this paper. Slippage can occur due to many reasons such as disturbances, uncertainties in parameters and dynamics. In this paper, using a novel representation of friction and slippage dynamics, a new approach is introduced to analyze the system dynamics. Then an adaptive controller with a simple update rule is proposed to ensure the bounded trajectory tracking and slippage control, and at the same time to compensate for parameter uncertainties including coefficients of friction. The performance of the proposed adaptive controller is shown analytically and studied numerically.
Parameter Normalization in Multibody Dynamics
Authors: Ebrahimi Saeed , Ko¨vecses Jo´zsef
Published: July 2009

In this paper, we introduce a novel concept for parametric studies in multibody dynamics. This is based on a technique that makes it possible to perform a natural normalization of the dynamics in terms of inertial parameters. This normalization technique rises out from the underlying physical structure of the system, which is mathematically expressed in the form of eigenvalue problems. It leads to the introduction of the concept of dimensionless inertial parameters. This, in turn, makes the decomposition of the array of parameters possible for studying design and control problems where parameter estimation and sensitivity is of importance.
Development Life Cycle and Tools for Data Exchange Specification
Authors: Morris K. C. , Goyal Puja , Frechette Simon
Published: July 2009

In enterprise integration, a data exchange specification is an architectural artifact that evolves along with the business. Developing and maintaining a coherent semantic model for data exchange is an important, yet non-trivial, task. A coherent semantic model of data exchange specifications supports reuse, promotes interoperability, and, consequently, reduces integration costs. Components of data exchange specifications must be consistent and valid in terms of agreed upon standards and guidelines. In this paper, we describe an activity model and NIST developed tools for the creation, test, and maintenance of a shared semantic model that is coherent and supports scalable, standards-based enterprise integration. The activity model frames our research and helps define tools to support the development of data exchange specification implemented using XML (Extensible Markup Language) Schema.
Implementing Mini Design Projects to Maximize the Quality of Design-Build Term Project Student Work
Authors: Platanitis George , Pop-Iliev Remon
Published: July 2009

Project-based learning is a widely adopted strategy and a preferred pedagogical tool in the undergraduate engineering curriculum. However, design-and-build engineering projects are open-ended, ill-defined, and quite complex so that students often feel quite overwhelmed by the imposed need to solve relatively challenging and practical problems within limited time and resources. Although there are virtually no right or wrong feasible design engineering project solutions, over the years, students’ design project submissions identify a number of students with mediocre design competencies. This indicates that there is a need for developing a pedagogical strategy designed for assisting the students in better preparing for undertaking the challenges of term design engineering projects. Hence, a special series of deliberately designed small-scale “mini” design projects has been developed to serve as “just-in-time” means for building-up the students’ skills required to successfully undertake the tasks of the respective larger-scale term design projects. This paper focuses on exploring this strategy and the different ways of its implementation into the engineering curriculum through three representative core design courses at the beginner, intermediate and advanced levels, respectively.
Zero-Load Friction at Nanowire-Silicon Interfaces
Authors: Manoharan Mohan , Haque Aman
Published: July 2009

The dominance of adhesive forces at the nanoscale implies that significant friction forces can be generated at the interface even with no externally applied normal load. We have nanofabricated an adhesion-friction force sensor to characterize friction in zinc oxide nanowires on silicon substrates. Experimental results show static friction coefficients for zero externally applied normal load can be as high as 45. This behavior is observed to be strongly influenced by the ambient conditions and we propose that the presence of molecularly thin moisture layers is responsible for the observed pseudo-static friction. The findings of this study will provide valuable input to nanoscale interfacial systems such as nanowires and nanotube based sensors and nanocomposites.
Design of a Single-Acting Constant-Force Actuator Based on Dielectric Elastomers
Authors: Berselli Giovanni , Vertechy Rocco , Vassura Gabriele , Parenti Castelli Vincenzo
Published: July 2009

The interest in actuators based on dielectric elastomer films as a promising technology in robotic and mechatronic applications is increasing. The overall actuator performances are influenced by the design of both the active film and the film supporting frame. This paper presents a single-acting actuator which is capable of supplying a constant force over a given range of motion. The actuator is obtained by coupling a rectangular film of silicone dielectric elastomer with a monolithic frame designed to suitably modify the force generated by the dielectric elastomer film. The frame is a fully compliant mechanism whose main structural parameters are calculated using a pseudo-rigid-body model and then verified by finite element analysis. Simulations show promising performance of the proposed actuator.
Design of a Screw Test Fixture via Computer-Aided Engineering
Authors: Straatsma Michael , Barletta Anthony , Schonning Alexandra
Published: July 2009

Biomet Microfixation is a biomedical engineering company specializing in craniomaxillofacial products. One of their main products is the manufacturing of screws. The current method of testing the pullout strength of the screws has been under investigation and it was determined that a new screw test fixture must be designed. The new method would exert an axial load to the screw adhered to a substrate. The design process for developing the fixture followed an iterative process including brainstorming, developing conceptual drawings, three dimensional computer-aided modeling, and computer-aided drafting. The final design was a three part device that allowed for easy and quick testing of the axial pullout strength of multiple screws. The design has been approved and is soon to be manufactured and utilized.
A Novel Micro Tensile Testing Instrument With Replaceable Testing Specimen of Gold and Aluminum by Parylene Passivation Technique
Authors: Lau Yung-Dong , Hocheng Hong , Chen Rongshun , Fang Weileun
Published: July 2009

This study has successfully demonstrated a novel tensile testing approach to mount a thin film test specimen onto a MEMS instrument using microfabrication processes. The MEMS instrument consists of a thermal actuator, differential capacitance sensor, and supporting spring. The thermal actuator applies a tensile load on the test specimen to characterize the Young’s modulus and the residual stress of the thin film. As compare with the existing approaches, the problems and difficulties resulting from the alignment and assembly of a thin film test specimen with the testing instrument can be prevented. Furthermore, the parylene passivation technique with the MEMS fabrication process allows the user to change the test materials easily. In application, the present approach has been employed to determine the Young’s modulus and the residual stress of Au and Al films.
Causal Design Knowledge Acquisition by Constructing BBN Through FCM
Authors: Kim Yun Seon , Kim Kyoung-Yun Joseph , Cheah Wooi Ping , Yang Hyung-Jeong
Published: July 2009

Managing design knowledge is an important concern for industry, including engineering. Engineering firms are facing pressures to increase the quality of their products, to have even shorter lead times and reduced costs. There is also a trend towards globalization resulting in complex supply chains and the need to manage teams that are not necessarily co-located. Design knowledge needs to be exchanged and accessed efficiently. Other motivations for managing design knowledge are to provide a trail for product liability legislation and to retain design knowledge and experience as engineering designers retire. Fuzzy Cognitive Map (FCM) is one of the main formalisms for modeling, representing and reasoning about causal knowledge. Despite the fact that FCM has been used extensively in causal knowledge engineering, there is a lack of methodology for the systematic construction of FCM. Although some techniques were used in the individual construction processes, these techniques were either not systematically documented or too specific to the problem at hand. FCM and Bayesian Belief Network (BBN) are two major frameworks for modeling, representing and reasoning about causal design knowledge. Despite their extensive use in causal design knowledge engineering, there is no reported work which compares their respective roles. This paper deals with three topics, which are systematic constructing FCM, a methodology for FCM-BBN conversion, and comparison FCM and BBN. BBN has a sound mathematical foundation and reasoning capabilities, also it has an efficient evidence propagation mechanism and a proven track record in industryscale applications. However, BBN is less friendly and flexible, and often very time-consuming to generate appropriate conditional probabilities. Thus, Fuzzy Cognitive Map (FCM) is used for the indirect knowledge acquisition, and the causal knowledge in FCM is systematically converted to BBN. Finally, we compare BBNs directly generated by domain experts and generated from FCM, with a realistic industrial example, a fuel nozzle for an aerospace engine.
A Framework for the Evaluation of Resource Efficiency in Automotive Embedded Systems
Authors: Persson Erik , Gustavsson Ha˚kan
Published: July 2009

This article discusses the resource utilization of embedded systems in the automotive industry. Traditionally, the major cost driver — or resource input — has been regarded as the hardware cost. Issues such as software development costs and maintenance costs have historically been neglected. In order to address this, the article embraces the more comprehensive view on resources that a resource can be regarded as anything which could be thought of as a strength or weakness of a given firm. In this article the major drivers of resource consumption are identified. The work has also included several interviews with employees in order to find empirical data of the embedded systems in vehicles. This paper proposes a method to evaluate the resource efficiency of user functions implemented through the embedded system. By the use of Data Envelopment Analysis — which has proven to be a useful method — the resource utilization of six user functions is evaluated. Future work of particular interest would be to perform a more extensive case study.
Effect of Electromechanical Coupling on the Young’s Modulus of Zinc Oxide Nanowires
Authors: Desai A. V. , Haque M. A.
Published: July 2009

The Young’s modulus of zinc oxide nanowires was measured to be significantly lower than bulk zinc oxide, which cannot be explained within the framework of existing theories. We propose that the strong electromechanical coupling in piezoelectric materials, such as zinc oxide, influences the measured mechanical properties. The asymmetric wurtzite crystal structure and the ionic nature of the molecular bonding result in internal electric fields during straining of the zinc oxide nanowire, which in turn lead to reduction in the measured modulus. In case of flexural deformation, additional electromechanical coupling is present due to the flexoelectric effect.
Efficient ZMP Formulation and Effective Whole-Body Motion Generation for a Human-Like Mechanism
Authors: Kim Joo H. , Xiang Yujiang , Bhatt Rajankumar , Yang Jingzhou , Chung Hyun-Joon , Patrick Amos , Arora Jasbir S. , Abdel-Malek Karim
Published: July 2009

An approach of generating dynamic biped motions of a human-like mechanism is proposed. An alternative and efficient formulation of the Zero-Moment Point for dynamic balance and the approximated ground reaction forces/moments are derived from the resultant reaction loads, which includes the gravity, the externally applied loads, and the inertia. The optimization problem is formulated to address the redundancy of the human task, where the general biped and task-specific constraints are imposed depending on the task requirements. The proposed method is fully predictive and generates physically feasible human-like motions from scratch; it does not require any input reference from motion capture or animation. The resulting generated motions demonstrate how a human-like mechanism reacts effectively to different external load conditions in performing a given task by showing realistic features of cause and effect. In addition, the energy-optimality of the upright standing posture is numerically verified among infinite feasible static biped postures without self contact. The proposed formulation is beneficial to motion planning, control, and physics-based simulation of humanoids and human models.
A Line Geometric Approach to Determining Displacements Based on Line Specifications
Authors: Kuo Wuchang , Huang Chintien
Published: July 2009

This paper presents a systematic approach to determining the displacements of a rigid body from line specifications. The underlying concept of the proposed approach pertains to screw theory and line geometry. We utilize the correspondence between a pair of homologous lines and a regulus and that between a screw and a linear line complex. In this paper, a displacement screw is obtained by fitting a linear line complex to two or more line reguli. When two exact pairs of homologous line are specified, we obtain a unique linear line complex, which determines the displacement screw correspondingly. When more than two pairs of homologous lines with measurement errors are specified, it becomes a redundantly specified problem, and a linear line complex that has the best fit to more than two reguli is determined. A numerical example with the specification of four pairs of homologous lines is provided.
Nano-Scale Impact Characteristics of Rough Surfaces in Humid Atmosphere With Full or Partial SAM Protection
Authors: Teodorescu Mircea , Theodossiades Stephanos , Rahnejat Homer
Published: July 2009

The impact dynamics of micro-scale mechanisms deviates from the classical theories applied to traditional macro-systems, This is because of multiplicity of forces acting in nano-scale contacts, which have negligible effect at the larger scale. A fundamental understanding of these forces and their interplay is required to advise design of such mechanisms based on fundamental physics. The paper highlights the significance of some of these forces and circumstances where their influence becomes significant.