bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of an Underactuated Finger With a Monolithic Structure and Largely Distributed Compliance
Authors: Steutel Peter , Kragten Gert A. , Herder Just L.
Published: March 2011

Many existing problems in conventional prosthetic fingers are related to the use of rigid links and kinematic joints and to the lack of adaptability of the finger. In this paper these problems are addressed by proposing a new design of a fully compliant underactuated prosthetic finger. First a general topology was defined. Subsequently a Pseudo Rigid Body method was used for a type synthesis and rough dimensional analysis in order to determine the conceptual design. In order to evaluate the grasping behavior of the conceptual design, four mock-ups were created. Detailed dimensional design was performed by a semi-automatic numerical analysis using a finite element method. A prototype based on this final design was manufactured and experimentally evaluated. It was found that the combination of underactuation and compliance is promising for the design of simple adaptive prosthetic fingers. As a result of the design process and the use of a predefined structure a fully compliant under-actuated finger with a monolithic structure and largely distributed compliance was obtained. The design shows potential of being applied in the field of prosthetics as well as robotic graspers.
A Simulation-Based Random Process Method for Time-Dependent Reliability of Dynamic Systems
Authors: Singh Amandeep , Mourelatos Zissimos P. , Nikolaidis Efstratios
Published: March 2011

Reliability is an important engineering requirement for consistently delivering acceptable product performance through time. As time progresses, a product may fail due to time-dependent operating conditions and material properties, and component degradation. The reliability degradation with time may significantly increase the lifecycle cost due to potential warranty costs, repairs and loss of market share. In this work, we consider the first-passage reliability, which accounts for the first time failure of non-repairable systems. Methods are available that provide an upper bound to the true reliability, but they may overestimate the true value considerably. This paper proposes a methodology to calculate the cumulative probability of failure (probability of first passage or upcrossing) of a dynamic system with random properties, driven by an ergodic input random process. Time series modeling is used to characterize the input random process based on data from a “short” time period (e.g. seconds) from only one sample function of the random process. Sample functions of the output random process are calculated for the same “short” time because it is usually impractical to perform the calculation for a “long” duration (e.g. hours). The proposed methodology calculates the time-dependent reliability, at a “long” time using an accurate “extrapolation” procedure of the failure rate. A representative example of a quarter car model subjected to a stochastic road excitation demonstrates the improved accuracy of the proposed method compared with available methods.
Novel XY Compliant Parallel Manipulators for Large Displacement Translation With Enhanced Stiffness
Authors: Hao Guangbo , Kong Xianwen
Published: March 2011

A novel XY compliant parallel manipulator (CPM) and a spatial double three-beam module both with distributed compliance are first proposed for large range of translation. Then, an improved XY CPM is proposed by combining the above XY CPM and a spatial double three-beam module in parallel. The normalized analytical models are further presented for the novel XY CPM, double three-beam module and improved XY CPM. It is shown that the improved XY CPM has the following merits: (1) large range of motion, constrained parasitic error motion, output-decoupling, maximal actuation isolation and minimal lost motion; and (2) large out-of-plane stiffness and no friction with base. The improved XY CPM may also be used as a building block to construct new spatial CPMs.
Dynamic Responses of Beam With Sloping Support Traversed by a Moving Mass
Authors: Yang Guolai , Yang James , Qiang Chen , Ge Jianli , Chen Qiang
Published: March 2011

This paper contributes to investigation on vibration analysis for cradle subjected to the moving barrel. The tipping part of the gun is simplified by a beam with sloping support traversed by a moving mass. The cradle structure is modeled by Euler-Bernoulli variable cross-section beam and the elevating strut is modeled by elastic supporting rod. The beam and supporting rod are discretized into finite elements, and then the main mass matrix, stiffness matrix, and damping matrix can be formulated. Gravity and inertial force are described by external nodal load vectors. The time-varying additional mass matrix, stiffness matrix, and damping matrix are derived. Numerical computation is conducted to analyze the effect of the barrel velocity on dynamic response of system, which can provide theoretical foundation to structural design of such system.
Integration of Resilience Perspective Into Sustainability Assessment of Biofuel Production
Authors: Mu Dongyan , Zhao Fu , Seager Thomas P. , Rao P. Suresh C.
Published: March 2011

The recent boom and collapse of the corn ethanol industry calls into question on the long-term sustainability of biofuels and traditional approaches to biofuel systems design. Compared with petroleum based transportation fuel production, biofuel production systems are so closely connected and heavily influenced by natural systems that they have to deal with high degrees of complexity, variability and unpredictability. Accordingly, a fundamental change in design philosophy is necessary for long-term viability of biofuel production. The new approach requires the system to be designed not for a narrowly defined efficiency (both economic and ecological), but for resilience (indicated by characteristics such as diversity, efficiency, cohesion and adaptability) to absorb unexpected disruptions and changes. Also, biofuel systems must be endowed with transformability to allow for “creative destruction” when current transportation fuels are eventually supplanted by new vehicle technologies and/or mode of transportation. This paper addresses important concepts in the design of coupled engineering-ecological systems (i.e. resilience, adaptability and transformability) that determine future system trajectories at multiple scales. In addition, several emerging biofuel conversion technologies are examined from a resilience perspective. It is suggested that the thermo-chemical conversion technologies may be preferable for biofuel production from resilience aspect. However, multiple technologies may increase the diversity and flexibility of the entire industry. This paper calls for the development of quantitative metrics for resilience assessment (similar to life cycle assessment for environmental sustainability) of industrial system, which are critical for integrating resilience into technology development and system design.
Topology Optimization of Compliant Mechanisms Using Hybrid Discretization Model
Authors: Zhou Hong
Published: March 2011

Hybrid discretization model for topology optimization of compliant mechanisms is introduced in this paper. The design domain is discretized into quadrilateral design cells. Each design cell is further subdivided into triangular analysis cells. This hybrid discretization model allows any two contiguous design cells to be connected by four triangular analysis cells no matter they are in the horizontal, vertical or diagonal direction. Topological anomalies such as checkerboard patterns, diagonal element chains and de facto hinges are completely eliminated. In the proposed topology optimization method, design variables are all binary and every analysis cell is either solid or void to prevent grey cell problem that is usually caused by intermediate material states. Von Mises stress constraint is directly imposed on each analysis cell to make the synthesized compliant mechanism safe. Genetic algorithm is used to search the optimum and avoid the need to choose the initial guess solution and conduct sensitivity analysis. The obtained topology solutions require no postprocessing or interpretation, and have no point flexure, unsmooth boundary and zigzag member. The introduced hybrid discretization model and the proposed topology optimization procedure are illustrated by two classical synthesis examples in compliant mechanisms.
Locomotion Strategies and Mobility Characterization of a Spherical Multi-Legged Robot
Authors: Wagenknecht Bryan , Apostolopoulos Dimi
Published: March 2011

Mobile robotics has seen a wide variety of mechanisms and strategies for motion in diverse terrain. Some robots employ rolling, some use legs for walking, some can hop, and some are capable of multiple of these modes. In this paper, we present the latest Robotic All-Terrain Surveyor (RATS) prototype as a unique design that can emulate a variety of locomotion modes by virtue of its geometric design and type of actuation. The novel robot has a spherical body the size of a soccer ball with 12 legs symmetrically distributed around its surface. Each leg is a single-DOF pneumatic linear actuator, oriented normal to the spherical body. Thorough investigation of this prototype’s mobility and actuation behavior has demonstrated the feasibility of tipping, hopping, and prolonged rolling locomotion by altering the actuation patterns of its legs. Here we summarize the experimental results of this characterization and present an understanding of the system’s performance limitations in an effort to draw insight for controlling its movements. We also discuss the effectiveness of RATS mobility strategies for varied terrains in light of initial testing on flat surfaces.
A Translator for Converting CAD Models to Second Life
Authors: Paul Ratnadeep , Anand Sam
Published: March 2011

Product Life-cycle Management (PLM) has been one of the single most important techniques to have been developed in the manufacturing industry. The increasing capabilities of internet and the ever increasing dependence of business entities on internet have led to the development of metaverses — internet-based 3D virtual worlds — which act as business platforms where companies display and showcase their latest products and services. This is in turn has led to a demand for development of methods for the easy transfer of data from stand alone PLM systems to the internet based virtual worlds. This paper presents the development of a translator which will transfer product data of 3D models created in CAD systems to an internet based virtual world. This translator uses a faceted-surface approach to transfer the product information. In this work CAD models were converted to a CAD-neutral data format, JT file format, and finally recreated in the metaverse Second Life (SL). Examples of models translated from JT to SL have been presented. A technique known as prim optimization, which increases the efficiency of the translation was also incorporated in the algorithm for the translator. Examples of prim optimization have been provided in the paper.
Parametric Instability in Metallic Bellows Subjected to Seismic Excitation
Authors: Kobayashi Nobuyuki , Kitada Keisaku , Sugawara Yoshiki
Published: March 2011

This paper investigates the parametric instability of a metallic bellows filled with fluid and subjected to the variance of dynamic internal pressure due to an earthquake. The axial stiffness of the bellows varies due to the variation in internal static fluid pressure, and this stiffness variation induces a parametric instability in the bellows. A finite element model describing a bellows connected to a pipe is developed to examine the question of whether parametric instability is excited in such bellows by earthquake motion, which is not the harmonic vibration. Numerical simulations and experiments were carried out using the acceleration recorded by past recorded actual earthquakes. We find that indeed parametric instability may appear in the bellows when the natural frequency of the pipe is close to the predominant frequency component of the earthquake, though the earthquake motion is not harmonic.
Probabilistic Design Optimization of Frequency Dispersion for Rotating Blades
Authors: An Liqiang , Wang G. Gary , Wang Zhangqi
Published: March 2011

In this paper, a probabilistic design optimization method based on finite element method is proposed to calculate the variability of design parameters subject to a specified dispersion of natural frequencies of rotating blades. The element stiffness and mass matrices are derived using a two-stage finite element method and numerical integration. Based on the perturbation technology, the sensitivity of the frequencies, as well as relationship between the frequency dispersion and the coefficient of variability (CV) of the design parameters can be obtained. Such sensitivity information is then used to convert the probabilistic design optimization problem into a deterministic optimization problem. Two case studies are given to illustrate the proposed method. From the results, it is concluded that rotation of blade changes the sensitivity of CV to the design parameters considered, and using the proposed method can transform the probabilistic constraints to deterministic constraints.
Investigation Into the Flexural Strength of a Material for Resin-Reinforced Rapid Prototyping Transtibial Sockets
Authors: Hsu L. H. , Lu C. T. , Huang G. F. , Chen J. T. , Yang H. S. , Shih H. S.
Published: March 2011

This investigation employed Taguchi experimental design method and ASTM three-point bending test to determine the parameters that influence the flexural strength of a material composed of a thin layer fabricated by a rapid prototyping (RP) machine and coated with a layer of unsaturated polyester resin (UPR). Since current rapid prototyping machines use a layer-based process to manufacture products, this will result in RP products liable to break along forming layers when bending load is applied. A type of resin-reinforced RP transtibial socket is proposed to strengthen the flexural strength so that the abrupt collapse can be prevented if a transtibial prosthetic socket made by an RP machine. This study proposed wrapping a layer of unsaturated polyester resin around a preliminary thin RP socket manufactured by a fused deposition modeling (FDM) machine to reinforce its flexural strength. Factors affecting the strength of the resin-reinforced RP socket include thickness and forming orientation of the preliminary RP socket, thickness of the UPR layer, and type of material used to make the preliminary RP socket. Employing Taguchi experimental design method and ASTM three-point bending test standard, the parameters that influence the flexural strength of the resin-reinforced RP prosthetic socket can be determined. Based on the appropriate parameters, including thickness of the RP layer and UPR layer, the RP material and RP fabricating orientation, the preliminary thin RP prosthetic sockets can be fabricated by an FDM machine. And the thin layer preliminary RP sockets were then wrapped with cotton socks and laminated UPR layer to form resin-reinforced RP sockets. To confirm the effectiveness of the resin-reinforced sockets developed in this study, a volunteer subject with unilateral left below-knee amputation is recruited to implement the experiment. The pressures at residual limb/socket interface were measured by using a pressure distribution measurement system and movement was captured by a motion analysis system while a volunteer patient wears the resin-reinforced RP socket. The experimental results demonstrated that the applicability of the proposed type of material and a resin-reinforced RP transtibial socket has been verified. A prosthetist may use the interface pressures exerting on stump and gait pattern during walking to assess the suitability of this type of RP socket based on clinical expertise. Further trial use and more subjects are needed to validate the durability of the proposed RP socket.
Development and Application of a Patent-Based Design Around Process
Authors: Hsu Yeh-Liang , Hsu Po-Er , Hung Yung-Chieh , Xiao Ya-Dan
Published: March 2011

This research proposes a patent-based design process by systematically integrating patent information, the rules of patent infringement judgment, strategies of designing around patents, and innovation design methodologies. The purpose of the process is to systematically generate new design concepts that are local variations of one of the concerned patents but does not infringe with existing patents. The basic idea is to consider patent infringement before engineering design concepts are actually generated. In this process, first the designer conducts standard patent analysis to identify the related patents to be designed around. Each patent is then symbolized by a “design matrix” converted from the technology/function matrix of the patent. A design-around algorithm is developed to generate a new design matrix that does not infringe with design matrices of existing patents. Then the new design matrix is transformed back into a real engineering design using the “contradiction matrix” in TRIZ. A computerized design-around tool based on the innovative patent-based design process is also developed.
Systematic Study of Kawaii Products: Relation Between Kawaii Feelings and Attributes of Industrial Products
Authors: Ohkura Michiko , Aoto Tetsuro
Published: March 2011

In Japan, the cute aesthetic is abused by many organizations and for many purposes including police mascots, and warning signs for dangerous areas. Although using cute to motivate and inform might seem strange, cute does offer potential. Dr. Cheok and his team at the National University of Singapore argued that Japanese ‘kawaii’ embodies a special kind of cute design, which reduces fear and makes dreary information more acceptable and appealing. Various Japanese kawaii characters such as Hello Kitty and Pokemon have become popular all over the world. However, since few studies have focused on kawaii attributes, we systematically analyze the kawaii interfaces themselves: kawaii feelings caused by such attributes as shapes, colors, and materials. Our aim is to clarify a method for constructing a kawaii interface from the research results. Kawaii might be one important kansei value for future interactive systems and industrial products of Asian industries. We previously performed experiments and obtained interesting tendencies about such kawaii attributes as shapes, colors, and sizes. Although questionnaires are the most common form of kansei evaluation, they suffer from such demerits as linguistic ambiguity, the possibility of mixing the intensions of experimenters and/or participants into the results, and interruption of the system’s stream of information input/output. Thus, to compensate for these demerits, we examined the possibility with biological signals. In this article, these experiments and their results are outlined.
Hand-Held Computing Devices for Industrial Applications: Some Case Studies
Authors: Jiang Pingyu , Cao Wei , Zhu Qiqi , Fu Yingbin , Jia Feng
Published: March 2011

This paper deals with an approach to the modes and methods of using hand-held computing devices in industry. The basic concepts and cross-platform computing models related to the hand-held computing devices are described firstly. Then three key and fundamental enabling technologies, including sampling real-time data, implementing interoperations with different database, and supporting collaborative activities, are presented in detail so as to use such mobile devices for potential industrial applications. Thirdly, five typical cases of using hand-held computing devices in design, manufacturing and logistic are studied in depth. Through analyzing and discussing the cases, four viewpoints are put forward: (1) using hand-held computing devices to supporting industrial activities is feasible; (2) hand-held computing devices play an important role in collecting, querying, scanning and simply processing data; (3) integrating hand-held computing devices with desktop computing devices together is needed if a huge number of data are involved in industrial applications; (4) hand-held computing devices will be used more widely and deeply in the future.
Design and Optimization of a Spatial Hybrid Motion System
Authors: Ouyang P. R. , Cargnello Steven
Published: March 2011

In this paper, a spatial hybrid motion system is developed that integrates two types of motions through one compliant mechanism: a macro motion driven by a DC servomotor and a micro motion driven by a PZT actuator. A unique feature of the developed hybrid motion system is the elimination of interaction between the macro motion and micro motion. Three issues are addressed in this study: (1) the design principle and implementation of the hybrid motion system; (2) the kinematic analysis and dynamic analysis; and (3) the optimization design of the hybrid motion system. For the micro motion, the five-bar topology of a mechanical amplifier is used to increase amplifying ratio and improve dynamic performance of the system. Finite element analysis results verify the design principle of the parallel architecture for the hybrid motion system.
Using a Singularity Locus to Exhibit the Number of Geometric Inversions, Transitions and Circuits of a Linkage
Authors: Myszka David H. , Murray Andrew P. , Schmiedeler James P.
Published: March 2011

The identification of motion characteristics and assembly circuits is fundamental in creating a workable mechanism. A circuit defect prevents a mechanism from moving between desired positions. This paper extends the established methods for analyzing multi-degree-of-freedom platforms to gain insight on single-actuated linkages. Specifically, from a plot of the singularity locus projected onto the input joint space, the number of singularities, number of geometric inversions and circuit regimes are revealed. The input/output motion of the linkage can be inferred from the locus. The methodology to produce the singularity locus is general and does not rely on geometric insights of a particular mechanism. By using the locus, desired operational features can be readily identified, such as a fully rotatable crank. Unique motion characteristics, such as a greater than 360° non-rotatable crank, can be also be detected. Further, it is observed that transition linkages serve as bounds between the regions of circuit change.
Multidisciplinary Co-Simulation of All-Terrain Crane With the Hydro-Pneumatic Suspension and Multi-Bridges Steering System
Authors: Qin Gang , Wu Jinglai , Zhang Yunqing , Chen Liping
Published: March 2011

Hydro-pneumatic suspension and multi-bridges steering system, which can meet the demands of ride comfort and steering maneuverability of the crane by their excellent nonlinear stiffness and damping characteristics and innovative control technology in their electro-hydraulic rear axle steering system, is used for construction industry vehicles widely. Such systems have great influences on controllability, steering stability, driving comfort and safety of a vehicle. Such a complex system includes mechanical multi-body, hydraulic, and control components which are influenced each other. However, few previous works concerned the coupling effects from multidisciplinary view, in general just single domain detail model are built and studied. This paper presents a detailed 5 axle all-terrain crane with hydro-pneumatic suspension and multi-bridges steering system consisting of the mechanical parts of suspension and steering multi-body model with ADAMS, suspension and steering hydraulic model that contain cylinder, control valve, and hydraulic pipes, etc., and the control strategy are built with AMESim software. A co-simulation is carried out to study the handling and stability of the vehicle affected by the hydro-pneumatic suspension and electro-hydraulic steering system. Some typical handling maneuvers, such as cornering steering releasing test and pylon slalom course of test are carried out by co-simulation to evaluate the control strategy of the steering and hydro-pneumatic suspension performance numerically. Comparisons between measured data and simulation results validate the correctness of the model.
Optimal Electronic Pricing With Uncertain Parameters
Authors: Sadjadi Seyed Jafar , Shishebori Davood
Published: March 2011

Electronic commerce plays an important role in many business activities, operations, and transaction processing. The recent advances on e-businesses have created tremendous opportunities to increase profitability. We present an optimal pricing and marketing planning where the primary objective function is to maximize the total profit. The proposed method of this paper considers different input parameters in uncertain regions and we provide a lower and upper bounds for the objective function of mathematical model with uncertain state. The paper is supported with a numerical example to demonstrate the implementation of the proposed method.
On the Dynamic Properties of Flexible Parallel Manipulators in the Presence of Payload and Type 2 Singularities
Authors: Briot Sebastien , Arakelian Vigen
Published: March 2011

It is known that a parallel manipulator at a singular configuration can gain one or more degrees of freedom and become uncontrollable. In our recent work [1], the dynamic properties of rigid-link parallel manipulators, in the presence of Type 2 singularities, have been studied. It was shown that any parallel manipulator can pass through the singular positions without perturbation of motion if the wrench applied on the end-effector by the legs and external efforts is orthogonal to the twist along the direction of the uncontrollable motion. This condition was obtained using symbolic approach based on the inverse dynamics and the study of the Lagrangian of a general rigid-link parallel manipulator. It was validated by experimental tests carried out on the prototype of a four-degrees-of-freedom parallel manipulator. However, it is known that the flexibility of the mechanism may not always been neglected. Indeed, for robots, joint flexibility can be the main source contributing to overall manipulator flexibility and can lead to trajectory distortion. Therefore, in our second paper [2], the condition of passing through a Type 2 singularity for parallel manipulators with flexible joints has been studied. In the present paper, we expand information about the dynamic properties of parallel manipulators in the presence of Type 2 singularity by including in the studied problem the link flexibility and the payload. The suggested technique is illustrated by a 5R parallel manipulator with flexible elements (actuated joints and moving links) and a payload. The obtained results are validated by numerical simulations carried out using the software ADAMS.
Fuzzy Decision Support in the Early Phases of the Fuzzy Front End of Innovation in Product Development
Authors: Achiche Sofiane , Appio Francesco Paolo
Published: March 2011

The innovation process may be divided into three areas: the fuzzy front end (FFE), the new product development (NPD) process, and commercialization. Every NPD process has a FFE in which products and projects are defined. Companies tend to begin the stages of FFE without a clear definition and analysis of the process to go from opportunity identification to concepts, and often they even abort the process or start over. Koen’s Model for the FFE is composed of 5 different phases, the first two being Opportunity Identification and Opportunity Analysis, which are the focus of this paper. Furthermore, several tools can be used by designers/managers in order to improve, structure and organize their work during the FFE. However, these tools tend to be selected and used in a heuristic manner. Additionally, some tools are preferred and more effective during specific phases of the FFE; hence an economic evaluation of the cost of their usage is very critical and there is also a need to characterize them in terms of their influence on the FFE. This paper focuses on decision support for managers/designers in their process of assessing the cost of choosing/using tools in the core front end activities, namely Opportunity Identification and Opportunity Analysis. This is achieved by analyzing the Influencing Factors (Firm context, Industry context, Macro environment) along with data collection from managers followed by the automatic construction of fuzzy decision support models (FDSM) of the discovered relationships. The decision support focuses upon the estimate investment needed for the use of tools during the 2 phases cited above. The generation of FDSMs is carried out automatically using a specialized genetic algorithm applied to learning data obtained from 5 experienced managers from 5 different companies. The automatically constructed FDSMs accurately reproduced the managers’ estimations using the learning data sets and were very robust when validated with hidden data sets.
Integration of System-Level Design and Analysis Models of Mechatronic System Behavior Based on SysML and Simscape
Authors: Cao Yue , Liu Yusheng , Paredis Christiaan J. J.
Published: March 2011

Model Based Systems Engineering (MBSE) provides a new method for the design of mechatronic systems with increasing complexity. However, different from other complex systems, the behavior of mechatronic systems is characterized best in terms of continuous dynamics and therefore it is not easy for the designer to evaluate it based on static design models. In this study, a method for integrating system-level design and analysis models of mechatronic system behavior is presented. A set of stereotypes is defined based on the Simscape modeling language to support explicit modeling of continuous dynamics in SysML. Simulation models are then introduced into SysML to support analyzing the system dynamics behavior with the help of simulation in Simscape. Finally, the system dynamics model and simulation model in SysML are integrated with the analysis model in Simscape through a bidirectional model transformation based on a triple graph grammar (TGG). The model transformation facilitates automatic model consistency and traceability. Also, the system dynamics behavior can be simulated automatically for verification and validation. The proposed method is implemented and illustrated with a simple example.
An Energy Based Method for Wear Analysis of a CrCoMo-UHMWPE and DLC-UHMWPE Couples for Hip Prosthesis
Authors: Rodri´guez-Lelis J. M. , Maza-Valle C. A. , Lo´pez y Rodri´guez A. R. , Ruiz-Domi´nguez D. , Abu´ndez-Pliego A. , Garci´a-Lozano J. L.
Published: March 2011

In this work, a model to evaluate the abrasive wear between two semi-cylindrical entities is presented. The entities represent the average roughness radius, of the contact surfaces formed between the femoral head and acetabular cup of a hip prosthesis. The contact couples employed in this work are CrCoMo-UHMWPE and DLC-UHMWPE. Here three different interference distances were employed: 1, 2.5 and 40 percent of the mean radius roughness of the UHMWPE. The energy method proposed here determines the maximum contact stresses, from where the maximum point of distortional energy is obtained. This is then linked to the geometry of the cylindrical entity, which then gives the initial failure point. Subsequent similar calculations provide with the trajectory of the wearing path. The percentage of the abrasive wear obtained from this method was compared to Archard’s method. It was noted that the percentage of Archard’s wear is a ten in million part from the total volume, while that the percentage of Energy’s wear is between 2.760% and 7.055%, when an interference distance S = 0.5 μm, was employed. It was also found that the CrCoMo-UHMWPE couple exhibited 22.84% of volume lost compared with the 2.95% of the DLC-UHMWPE couple.
Early Introduction of Robust Design Into the Engineering Curriculum
Authors: Platanitis George , Pop-Iliev Remon
Published: March 2011

Normally, there is very little opportunity for first-year engineering students to practice robust design techniques given the relatively simple nature of their projects, and they are not exposed to any robust design activity and Design of Experiments (DOE) methodologies until their third year. How can junior engineering students gain a sense of the robustness of their designs? Will the resulting product still be acceptably functional if used in non-ideal environments? The purpose of this paper is to introduce a potential assignment to supplement this need at the first-year level. Introduced as a bonus assignment in Fall 2009, students were charged with the task of designing an aircraft wing by choosing parameter setting combinations that would provide the maximum Lift-to-Drag ratio, simulating results theoretically that would be obtained in a wind-tunnel experiment, while including random noise. All necessary facts and equations were given, leaving students with the task of running calculations and employing Taguchi methods to select an optimal set of parameters. While few students chose to undertake the assignment, those that did it found the application interesting and useful. Example results for this robust design assignment, including final parameter selections for the optimal wing design, are presented in this paper, along with factors where students have shown weaknesses.
Robust Optimization Exploration Using NURBs-Based Metamodeling Techniques
Authors: Steuben John , Turner Cameron J.
Published: March 2011

Non-uniform rational B-splines (NURBs) demonstrate properties that are highly conductive to performing metamodeling for engineering design purposes. Previous research has resulted in the development of algorithms capable of fitting NURBs metamodels to design spaces of many input variables and performance indicies, and performing various discreet optimizations upon these metamodels. In the present research we expand upon this basis by illustrating the development of robust optimization algorithms that leverages the unique properties of NURBs metamodels. This optimization is conducted in a general fashion by considering both optimality and various robustness metrics as global or local model properties, and illustrates the tradeoffs between them using a novel graphical approach. The appeal of this approach is demonstrated by a series of test functions of one performance index and one or two performance indicies. A case study in designing composite structures of specific stiffness, of four and five design variables, follows. We proceed to discuss the future of NURBs metamodeling techniques and the potential for considering model properties besides optimality and robustness during optimization.
A Bayesian Framework for Predicting Cutomer Need Distributions
Authors: Takai Shun , Yang Tae G. , Cafeo John A.
Published: March 2011

Predicting future customer needs is critical when selecting a concept for a new product. Customer need prediction is challenging because customer needs may change as external factors that influence needs change over time. This paper proposes a Bayesian framework to predict future distribution of customer needs by incorporating forecasts of external factors and their corresponding accuracies. The framework is demonstrated by an illustrative example in which designers predict future distribution of a customer need (“Fuel Efficient”) based on forecast of an external factor (gasoline price index) and the accuracy of the forecast. The benefit of incorporating forecasts of the external factor on concept selection and a sensitivity analysis of concept selection on the accuracy of the forecast are demonstrated in the illustrative example.
An Approach to Modeling Customer Preference Uncertainty by Applying Bootstrap to Choice-Based Conjoint Analysis Data
Authors: Razu Swithin S. , Takai Shun
Published: March 2011

Analysis of customer preferences is among the most important tasks in a new product development. How customers come to appreciate and decide to purchase a new product affects the products market share and therefore its success or failure. Unfortunately, when designers select a product concept early in the product development process, customer preference response to the new product is unknown. Conjoint analysis is a statistical marketing tool that has been used to estimate market shares of new product concepts by analyzing data on the product ratings, rankings or concept choices of customers. This paper proposes an alternative to traditional conjoint analysis methods that provide point estimates of market shares. It proposes two approaches to model market share uncertainty; bootstrap and binomial inference applied to choice-based conjoint analysis data. The proposed approaches are demonstrated and compared using an illustrative example.
A Comparison of Case-Based Reasoning and Regression Analysis Approaches for Cost Uncertainty Modeling
Authors: Banga Karan , Takai Shun
Published: March 2011

This paper presents cost uncertainty modeling for a concept selection using case-based reasoning (CBR) and compares this method with the regression analysis approach. During the product development stage, a number of decisions must be made under uncertainty, including selection of an ideal product concept. The cost of a concept, i.e., the cost of the final product developed from a concept, is a key factor influencing the choice of an ideal concept. The CBR approach creates a knowledge base (or database) containing past cases, defines a new case, retrieves cases similar to the new case, and adapts the solution of the retrieved cases to the new case. This paper illustrates the proposed approach using automobiles as an example.
An Engineering-to-Biology Thesaurus for Engineering Design
Authors: Nagel Jacquelyn K. S. , Stone Robert B. , McAdams Daniel A.
Published: March 2011

Engineering design is considered a creative field that involves many activities with the end goal of a new product that fulfills a purpose. Utilization of systematic methods or tools that aid in the design process is recognized as standard practice in industry and academia. The tools are used for a number of design activities (i.e., idea generation, concept generation, inspiration searches, functional modeling) and can span across engineering disciplines, the sciences (i.e., biology, chemistry) or a non-engineering domain (i.e., medicine), with an overall focus of encouraging creative engineering designs. Engineers, however, have struggled with utilizing the vast amount of biological information available from the natural world around them. Often it is because there is a knowledge gap or terminology is difficult, and the time needed to learn and understand the biology is not feasible. This paper presents an engineering-to-biology thesaurus, which we propose affords engineers, with limited biological background, a tool for leveraging nature’s ingenuity during many steps of the design process. Additionally, the tool could also increase the probability of designing biologically-inspired engineering solutions. Biological terms in the thesaurus are correlated to the engineering domain through pairing with a synonymous function or flow term of the Functional Basis lexicon, which supports functional modeling and abstract representation of any functioning system. The second version of the thesaurus presented in this paper represents an integration of three independent research efforts, which include research from Oregon State University, the University of Toronto, and the Indian Institute of Science, and their industrial partners. The overall approach for term integration and the final results are presented. Applications to the areas of design inspiration, comprehension of biological information, functional modeling, creative design and concept generation are discussed. An example of comprehension and functional modeling are presented.
Experimental Validation of an Elastically Averaged Binary Manipulator for MRI-Guided Prostate Cancer Interventions
Authors: Proulx Sylvain , Miron Genevie`ve , Girard Alexandre , Plante Jean-Se´bastien
Published: March 2011

Polymer-based binary robots and mechatronics devices can lead to simple, robust, and cost effective solutions for Magnetic Resonnace Image-guided (MRI) medical procedures. A binary manipulator using 12 elastically averaged air muscles has been proposed for MRI-guided biopsies and brachytherapies procedures used for prostate cancer diagnostic and treatment. In this design, radially-distributed air muscles position a needle guide relatively to the MRI table. The system constitutes an active compliant mechanism where the compliance relieves the over-constraint imposed by the redundant parallel architecture. This paper presents experimental results for repeatability, accuracy, and stiffness of a fully functional manipulator prototype. Results show an experimental repeatability of 0.1 mm for point-to-point manipulation on a workspace diameter of 80 mm. Manipulator average accuracy is 4.7 mm when based on the nominal (uncalibrated) model and improves to 2.1 mm when using a calibrated model. The estimated stiffness at the end-effector is ∼0.95 N/mm and is sufficient to withstand the needle insertion forces without major deflection. Needle trajectories during state change appear to be primarily driven by the system’s elastic energy gradient. The study shows the manipulator prototype to meet its design criteria and to have the potential of becoming an effective and low-cost manipulator for MRI-guided prostate cancer treatment.
Optimal Location of the MR Fluid Segments in the Partially Treated Magnetorheological Fluid Sandwich Beam
Authors: Rajamohan Vasudevan , Sedaghati Ramin , Rakheja Subhash
Published: March 2011

A design optimization methodology is presented to maximize the modal damping factor of a partially treated MR sandwich beam. Modal strain energy approach has been implemented in the finite element model developed for a partially treated MR sandwich beam to derive the modal damping factor at each node. Two different configurations of a partially treated MR sandwich beam are considered including a beam with a cluster of MR fluid segments and a beam with arbitrarily located MR fluid segments. The significance of the location of MR fluid segments on the modal damping factor is investigated under different end conditions. The design optimization problem is formulated by combining the finite element method with optimization based on genetic algorithm (GA) to identify the optimal location of the MR fluid segments to maximize the modal damping factor for the first five modes individually under various end conditions. The results suggest that the optimal location of the MR fluid treatment is strongly related not only to the end conditions but also to the mode of vibration.
Modular Product Configuration: An Automatic Tool for Eliciting Design Knowledge From Parametric CAD Models
Authors: Raffaeli Roberto , Cicconi Paolo , Mengoni Maura , Germani Michele
Published: March 2011

The offer of tailored products is a key factor to satisfy specific customer needs in the current competitive market. Modular products can easily support customization in a short time. Design process, in this case, can be regarded as a configuration task where solution is achieved through the combination of modules in overall product architecture. In this scenario efficient configuration design tools are evermore important. Although many tools have been already proposed in literature, they need further investigation to be applicable in real industrial practice, because of the high efforts required to implement system and the lack of flexibility in products updating. This work describes an approach to overcome drawbacks and to introduce a product independent configuration system which can be useful in designing recurrent product modules. To manage configuration from the designer perspective, the approach is based on Configurable Virtual Prototypes (CVP). In particular, the definition of geometrical models is analyzed providing a tool for eliciting and reusing knowledge introduced by parametric template CAD models. Semantic rules are used to recognize parts parameterization and assembly mating constraints. The approach is exemplified through a case study.
Design of an Instrumented Lathe Tool Post for Vibration Monitoring Studies
Authors: Steuben John , Andersen Ken , Ostrum Chris , Turner Cameron J.
Published: March 2011

The research presented here details the development of an instrumented lathe tool post which has potential use in conducting a wide range of vibration monitoring studies, including condition-based maintenance or prognostic health management. The system developed allows for the modular mounting of instruments in differing configurations on an industry-standard tool post, which was developed in collaboration with a first-year graduate class in sensors and signals at the Colorado School of Mines. Data acquisition and the development of an interactive data analysis tool used for post-processing is discussed using results from a case study obtained by turning 304 stainless steel on a shop lathe. It is shown that chatter can be detected using a novel bi-level FFT approach at low computational cost. Potential future applications for the developed system are introduced, including real-time tool condition analysis and the development of a fully instrumented machine shop.
Workspace Computation and Analysis of a Planar 2-DoF Translational Tensegrity Mechanism
Authors: Chen Samuel , Arsenault Marc
Published: March 2011

Tensegrity mechanisms are interesting candidates for high-acceleration robotic applications since their use of cables allows for a reduction in the weight and inertia of their mobile parts. In this work, a planar two-degree-of-freedom translational tensegrity mechanism that could be used for pick and place applications is introduced. The mechanism uses a strategic actuation scheme to generate the translational motion as well as to ensure that the cables remain taut at all times. Analytical solutions to the direct and inverse kinematic problems are developed and the mechanism’s workspace boundaries are computed in both the actuator and Cartesian spaces. The influence of the mechanism’s geometry on the size and shape of the Cartesian workspace are then studied. Based on workspace size only, it is found that the optimal mechanism geometry corresponds to a relatively large ratio between the length of the struts and the width of the base and end-effector.
Forced Vibrations of Circular Plates: From Periodic to Chaotic Motions
Authors: Touze´ Cyril , Thomas Olivier , Amabili Marco
Published: March 2011

A numerical study of the transition from periodic to chaotic motions in forced vibrations of circular plates, is proposed. A pointwise harmonic forcing of constant excitation frequency Ω and increasing values of the amplitude is considered. Perfect and imperfect circular plates with a free edge are studied within the von Ka´rma´n assumptions for large displacements (geometric non-linearity). The transition scenario is observed for different excitation frequencies in the range of the first eigenfrequencies of the plate. For perfect plate with no specific internal resonance relationships, a direct transition to chaos is at hand. For imperfect plate tuned so as to fulfill specific internal resonance relations, a coupling between internally resonant modes is first observed. The chaotic regime shows an attractor of large dimension, and thus is studied within the framework of wave turbulence.