bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multi-Scale Design for a Robust Hydrogen Storage Tank
Authors: Ruderman Alex M. , Patel Jiten , Kumar Abhishek , Allen Janet K. , Choi Seung-Kyum
Published: July 2010

The current research proposes an integrated framework for product design that incorporates simulation-based tools into the early design stage to achieve optimum multi-scale systems. The method to determine the appropriate mesostructure-property relations for the internal material structures of the system is through a topology optimization technique and a multi-scale design process. Specifically, the Reliability-based Topology Optimization (RBTO) and the simulation-based multi-attribute design method are integrated into an Inductive Design Exploration Method (IDEM). The RBTO method is contributed to determine of optimal topologies at the meso-scale. The simulation-based multi-attribute design method is considered for decision support process of the macro-scale systems. The IDEM offers the capability for concurrent design on multiple scales providing an approach for integration of the other two methods. An example of the developed multi-scale design framework is presented in terms of a hydrogen storage tank used in hydrogen fuel cell automotive applications. The multi-scale tank design will feature a high strength mesostructured wall resulting in a large weight reduction.
Designing a Service-Learning Design Project for a First-Year Engineering Course
Authors: Williams Christopher B. , Terpenny Janis P. , Goff Richard M.
Published: July 2010

The creation of an appropriate, meaningful design experience for a first-year engineering design course is challenging as the instructor must balance resource constraints with broad learning objectives and a diverse, and often very large, enrollment. In this paper, the authors present the task of developing a design project for a first-year engineering course as a problem of design. Following a structured design process, the authors articulate the requirements for a successful first-year design project including: learning objectives that are appropriate for a multi-disciplinary group of first-year students and common budgetary and time constraints. Several project alternatives are generated and evaluated in a conceptual design phase. In their description of the embodiment and detail design phases, the authors present the implementation of the selected project concept: ROXIE (“Real Outreach eXperiences In Engineering”). The ROXIE project, a service-learning themed project, tasks first-year students with serving as design consultants to not-for-profit community partners. Through this partnership, students are able to practice principles and tools of design methodology and project management. Preliminary survey data and excerpts of student reflection essays are provided as a means of supporting the instructors’ project selection.
Effect of Geared Transmissions on Electric Vehicle Drivetrains
Authors: Ren Qinglian , Crolla David A. , Morris Adrian
Published: July 2010

The paper describes some simple modelling to investigate whether there are potential benefits to incorporating a geared transmission in electric vehicle driveline. The overall conclusion is that considerable benefits in energy consumption are available if a continuously variable gearbox system is incorporated; performance improvements of 6 to 19.2% are predicted over a range of European, USA and Japanese driving cycles. Furthermore, the use of a much simpler, two speed gearbox an improve performance significantly — by for example 9.2% over the NEDC cycle — although similar improvements are not predicted over other driving cycles. Overall, the results suggest not only that direct benefits in terms of energy reductions are obtainable, but also that significant reductions in motor and driveline sizing may be an alternative approach to exploiting the introduction of a transmission system.
Simulation and Optimization of Gear Form Grinding
Authors: Rosa Francesco , Gorla Carlo
Published: July 2010

Nowadays, the basic requirements of gear transmissions are not limited only to the more usual ones (like resistance, reliability ...), but often include also good efficiency and low vibration and noise emissions. Supporting structures, gear macro and micro geometry and textures are the key-points in the design of a geared system that fulfil the latter two requirements. The expected results can be obtained only if the gears actually meet the design specifications: this is one of the main reasons for the improvement and the optimization of the finishing processes, like shaving and grinding. A great deal of work has been done on defining the gear tooth flank topology that minimizes gear transmission error and consequently its noise emission, but usually, the practical realization of this micro-geometry is not taken into account. The actually available axes of the grinding machines and their laws of motion limit, in fact, the obtainable flank topology, and then it is often difficult to determine the optimal machine tool settings. In the paper, first it is presented a method to simulate gear form grinding with a disk tool; then a strategy to determine the combination of tool geometry and axes’ motions that best fulfil the gear design geometrical requirements is presented and discussed.
How Cultural Characteristics Influence Design Processes: An Empirical Study
Authors: Gautam Vivek , Blessing Lucienne
Published: July 2010

Product development increasingly involves designers with different cultural backgrounds. This paper describes an investigation into the effects of these different backgrounds on the design process. An empirical study is carried out under participation of designers drawn from industrial practice in Germany, India and China. They are observed while solving a given design problem in a laboratory setting. The recorded design processes are analyzed with a focus on cultural characteristics, which were derived from literature. The paper focuses on the following design activities: analyzing problem and requirements, working on sub-functions, deriving selection criteria, and improving solutions. The results indicate that the design processes are different and that these differences can be linked to the characteristics of culture.
Reliability-Based Design Optimization Using Enhanced Dimension Reduction Method With Variable Sampling Points
Authors: Yook Sunmin , Lee Gabseong , Yoon Sang-Joon , Park Jae-Yong , Choi Dong-Hoon
Published: July 2010

Reliability-Based Design Optimization (RBDO) is an effective method to handle an optimization problem constrained by reliability performance. In spite of its great benefits, one of the most challenging issues for implementing RBDO is associated with very intensive computational demands of Reliability Analysis (RA). Moreover, an accurate and efficient RA method is indispensible to apply RBDO to practical engineering design problems. Among various RA methods, an enhanced Dimension Reduction (eDR) method is the most popular one due to the high computational efficiency. It is very desirable to obtain an accurate and efficient RA result by using the minimum number of sampling points. But, it is difficult to determine it. That is because it depends on the nonlinearity of a constraint from approximating a model and the degree of uncertainty from integrating a design factor. In this research, eDR method with variable sampling points has been studied and proposed to resolve the early mentioned difficulties. The main idea of the suggested method is to employ a different number of axial sampling points for each random design factor. It is according to the nonlinearity of a constraint and the degree of uncertainty of each random design factor. For each random variable, it begins to use three points first and decides to stop or increase the axial sampling points based upon the proposed criteria in this study. In case of increasing sampling points, it is incremented by one sampling point and ended up five sampling points at most. As it shown in the result, the efficiency of eDR method with variable sampling points for each random variable is superior to the one with fixed sampling points without sacrificing any accuracy. Through the three representative RA problems, it is verified that the proposed RA method generates the result 26.5% more efficiently on average than the conventional eDR method with fixed sampling points. Furthermore, the Performance Measure Approach (PMA) was used to evaluate the performance of RBDO using the new RA method. For the comparison, three mathematical and one engineering RBDO problems were solved by both eDR method with variable sampling points and conventional one with fixed sampling points. Finally, the comparison results clearly demonstrate that RBDO using the suggested RA method is superior to the conventional one in terms of accuracy and efficiency.
Ensemble of Meta-Models Based on Local Error Measure Using Cross-Validation
Authors: Park Dohyun , Lee Yongbin , Choi Dong-Hoon
Published: July 2010

Many meta-models have been developed to approximate true responses. These meta-models are often used for optimization instead of computer simulations which require high computational cost. However, designers do not know which meta-model is the best one in advance because the accuracy of each meta-model becomes different from problem to problem. To address this difficulty, research on the ensemble of meta-models that combines stand-alone meta-models has recently been pursued with the expectation of improving the prediction accuracy. In this study, we propose a selection method of weight factors for the ensemble of meta-models based on v-nearest neighbors’ cross-validation error (CV). The four stand-alone meta-models we employed in this study are polynomial regression, Kriging, radial basis function, and support vector regression. Each method is applied to five 1-D mathematical examples and ten 2-D mathematical examples. The prediction accuracy of each stand-alone meta-model and the existing ensemble of meta-models is compared. Ensemble of meta-models shows higher accuracy than the worst stand-alone model among the four stand-alone meta-models at all test examples (30 cases). In addition, the ensemble of meta-models shows the highest accuracy for the 5 test cases. Although it has lower accuracy than the best stand-alone meta-model, it has almost same RMSE values (less than 1.1) as the best standalone model in 16 out of 30 test cases. From the results, we can conclude that proposed method is effective and robust.
Gaming and Interactive Visualization for Education: A Multi-Disciplinary and Multi-University Collaborative Project
Authors: Xu Yunjun , Miekas Charles , Siddique Zahed , Ling Chen , Chowdhury Sagar , Geng Xiaojun
Published: July 2010

Most people are more perceptive to the geometric rather than the symbolic representation of information. In engineering disciplines, visualization combined with game characteristics can provide an essential mode to facilitate students’ understanding of important and abstract concepts, and improve students’ willingness to learn. In this project, game characteristics are introduced into course module design, but different from commercially available games in that the level of the contents and assessment tools in this project are meaningful to teachers, students, and parents. This paper focuses on the design of the Gaming and Interactive Visualization for Education system. Specifically, some initial design results from the three universities for three different courses plus the development of evaluation system will be presented. The system is expected to (1) offer interactions with gaming scenarios that can excite emotions, (2) provide an engaging learning experience of understanding engineering concepts by allowing students to visualize and interact with 3-D objects in a game scenario, (3) employ situated learning by exposing students to the type of challenges they will face in industry, and (4) fit better with the learning styles of the majority of engineering students.
A Preliminary Study of Novice and Expert Users’ Decision-Making Procedures During Visual Trade Space Exploration
Authors: Wolf David , Simpson Timothy W. , Zhang Xiaolong Luke
Published: July 2010

Thanks to recent advances in computing power and speed, designers can now generate a wealth of data on demand to support engineering design decision-making. Unfortunately, while the ability to generate and store new data continues to grow, methods and tools to support multi-dimensional data exploration have evolved at a much slower pace. Moreover, current methods and tools are often ill-equipped at accommodating evolving knowledge sources and expert-driven exploration that is being enabled by computational thinking. In this paper, we discuss ongoing research that seeks to transform decades-old decision-making paradigms rooted in operations research by considering how to effectively convert data into knowledge that enhances decision-making and leads to better designs. Specifically, we address decision-making within the area of trade space exploration by conducting human-computer interaction studies using multi-dimensional data visualization software that we have been developing. We first discuss a Pilot Study that was conducted to gain insight into expected differences between novice and expert decision-makers using a small test group. We then present the results of two Preliminary Experiments designed to gain insight into procedural differences in how novices and experts use multi-dimensional data visualization and exploration tools and to measure their ability to use these tools effectively when solving an engineering design problem. This work supports our goal of developing training protocols that support efficient and effective trade space exploration.
Effects of Case Depth, Side-Face Carburizing and Helix Angle on Residual Stress and Bending Fatigue Strength of Case-Carburized Helical Gears
Authors: Miyachika Kouitsu , Ando Kazuaki , Xue Wei-Dong , Nordin Imaduddin Helmi Bin Wan
Published: July 2010

This paper presents a study on effects of case depth, side-face carburizing and helix angle on the residual stress and the bending fatigue strength of case-carburized helical gears. The carbon content of each element of the FEM gear models due to carburizing was obtained. A heat conduction analysis and an elastic-plastic stress analysis in the case-carburizing process of helical gears were carried out by the three-dimensional finite-element method, and then residual stresses were obtained. Effects of the case depth, the side-face carburizing, the helix angle and the face width on the residual stress of case-carburized helical gears were determined. Bending fatigue tests were carried out for case-carburized helical gears and S-N curves and bending fatigue limit loads were obtained. Effects of the case-depth, the side-face carburizing and the helix angle on the bending fatigue strength of the case-carburized helical gear were determined.
An Elastic Exoskeleton for Assisting Human Running
Authors: Cherry Michael S. , Kota Sridhar , Ferris Daniel P.
Published: July 2010

This paper presents the design and preliminary evaluation of an elastic lower-body exoskeleton (eExo). Human legs behave in a spring-like fashion while running. We selected a design that relied solely on material elasticity to store and release energy during the stance phase of running. The exoskeleton included a novel knee joint with a cam and a Bowden cable transferring energy to and from a waist-mounted extension spring. We used a friction-lock clutch controlled by hip angle via a pneumatic cylinder to release the cable during swing phase for free movement of the leg. The design also incorporated a composite leaf spring to store and release energy in the distal portion of the exoskeleton about the foot and ankle. Preliminary test data for our target subject showed that his typical leg deflection was 0.11 m with leg stiffness of 16 kN/m while running at 3.0 m/s. We used these values to set the desired stiffness (60±15% of the normal leg stiffness, or 9.6±2.4 kN/m) and deflection (0.11 m) of the exoskeleton. We created simplified multi-body and full finite element quasi-static models to achieve the desired system stiffness and validate our results, respectively. The final design model had an overall stiffness of 7.3 kN/m, which was within the desired range. We fabricated a single-leg prototype of the exo–skeleton that weighed 7.1 kg. We tested the exoskeleton stiffness quasi-statically and found a stiffness of 3.6 kN/m. While running, the exoskeleton provided ∼30% of the total leg stiffness for two subjects. Although the stiffness was lower than desired, the fabricated prototype demonstrated the ability of a quasi-passive exoskeleton to provide a significant portion of an individual’s leg stiffness while running.
Design Language for Airplane Geometries Using the Unified Modeling Language
Authors: Bo¨hnke Daniel , Reichwein Axel , Rudolph Stephan
Published: July 2010

The design language allows the construction of a variety of airplan designs. The syntax of the design language relies on the standardized Unified Modeling Language (UML) and consists of an object-oriented vocabulary (i.e. points, lines, profiles, wings, etc.) comparable to building blocks, and design rules (i.e. building laws) which represent the building knowledge used. In the terminology of graph-based design languages, the building blocks are the information objects which represent the static aspects of the design because they represent indivisible design entities. They are represented as UML classes and instances and their interrelation forms an object-oriented class hierarchy. The design rules represent the dynamic aspects of the design and express the building knowledge as stepwise activities. Finally, a production system (i.e. a specific rule set) is able to create an airplane geometry and generates design variants through manual modifications of the production system.
Modeling and Analysis of Flexible-Wheel Suspension Concept
Authors: Cao Dongpu , Khajepour Amir , Song Xubin
Published: July 2010

Flexible-wheel (FW) suspension concept has been recently proposed and regarded to be one of the novel technologies for future ground vehicles as well as planetary surface rovers. The FW concept generally integrates stiffness/damping components within an airless tire and wheel unit, to offer considerably potential benefits in decoupled ride and handling, compact and lightweight design, enhanced traction, road-holding, road-friendliness, driving safety and fuel efficiency. This study attempts efforts to develop generalized models for fundamental stiffness and damping properties of the FW suspension concept. Based on the generalized models, suspension properties are analyzed for two different FW design configurations. The generalized analytical formulations of the suspension properties of conceptual FW suspension designs would serve as a preliminary theoretical foundation for the development of FW suspension systems for future vehicle applications.
A Variable Spring Using a Tensegrity Prism
Authors: Azadi Mojtaba , Behzadipour Saeed , Faulkner Gary
Published: July 2010

Prestressable pin jointed structures are statically indeterminate but kinematically they can be either overdeterminate or indeterminate. Tensegrities are special cases of the latter class. Although, all prestressable structures have variable stiffness that can be controlled by prestress, it is only a subgroup of them such as tensegrities that make effective variable stiffness springs. An N-gon tensegrity prism is investigated as a basis for making a variable stiffness spring called Tensegrity Prism spring. The appropriate deflection direction is found and force-displacement and stiffness equations of a translational tensegrity prism spring with n bars are found. In addition, the main characteristics of a variable tensegrity prism spring and the methods that improve them are discussed.
Hierarchical Optimization-Based Approach for Two-Dimensional Rectangular Layout Design Problems
Authors: Fujita Kikuo , Kawamoto Masayuki
Published: July 2010

This paper proposes a hierarchical optimization-based approach for two-dimensional rectangular layout design problems. While decomposition-based optimization has been a key approach for the complicated design problems under the trend of multidisciplinary design optimization, it has focused on continuous ones. While various approaches for layout design have been developed, they are based on any evolutionary algorithm for effectively handling its combinatorial nature. This paper aims to bring a new paradigm by combining decomposition-based optimization and evolutionary algorithms toward solving complicated layout design problems. In the approach, the Pareto optimality of subsystem-level layout against the optimality of system-level layout is extracted through two-level hierarchical formulation. Then, a computational design algorithm is developed. It represents the layout topology with sequence-pair and the shape of each subsystem or component with the aspect ratio, and optimizes them with genetic algorithms. The Pareto optimality of sub-levels is handled with multi-objective genetic algorithms, in which a set of Pareto are simultaneously generated. Top-level and sub-level layout problems are coordinated through exchange of preferable ranges of shapes and layout. An implemented approach is applied to an example problem for demonstrating its performance and capability.
An Extended Hierarchical Statistical Sensitivity Analysis Method for Multilevel Systems With Shared Variables
Authors: Liu Yu , Yin Xiaolei , Arendt Paul , Chen Wei , Huang Hong-Zhong
Published: July 2010

Statistical sensitivity analysis (SSA) is an effective methodology to examine the impact of variations in model inputs on the variations in model outputs at either a prior or posterior design stage. A hierarchical statistical sensitivity analysis (HSSA) method has been proposed in literature to incorporate SSA in designing complex engineering systems with a hierarchical structure. However, the original HSSA method only deals with hierarchical systems with independent subsystems. Due to the existence of shared variables at lower levels, responses from lower level submodels that act as inputs to a higher level subsystem are both functionally and statistically dependent. For designing engineering systems with dependent subsystem responses, an extended hierarchical statistical sensitivity analysis (EHSSA) method is developed in this work to provide a ranking order based on the impact of lower level model inputs on the top level system performance. A top-down strategy, same as in the original HSSA method, is employed to direct SSA from the top level to lower levels. To overcome the limitation of the original HSSA method, the concept of a subset SSA is utilized to group a set of dependent responses from lower level submodels in the upper level SSA. For variance decomposition at a lower level, the covariance of dependent responses is decomposed into the contributions from individual shared variables. To estimate the global impact of lower level inputs on the top level output, an extended aggregation formulation is developed to integrate local submodel SSA results. The importance sampling technique is also introduced to re-use the existing data from submodels SSA during the aggregation process. The effectiveness of the proposed EHSSA method is illustrated via a mathematical example and a multiscale design problem.
System Dynamics Through Graphical Dimensional Analysis
Authors: Tadepalli Srikanth , Wood Kristin L.
Published: July 2010

Dimensional analysis is a powerful tool used commonly to develop functional relations between variables affecting a physical system. Known for its versatility in incorporating several different energy domains, the method has allowed for dimensional manipulation of diverse parameters. However, the dimensional combinations developed have been, for the most part, strictly confined to static and time invariant systems. Expanding on the process we introduce a graphical approach to dimensionally model dynamic systems for design. Continuing this extension, we present a graphical and topological combination to illustrate the applicability of dimensional analysis as a state equation generation tool. This tool is comparable to conventional differential element analysis in system dynamics, but provides a systematic and visual approach to design modeling. Further, this exposition acts as a learning instrument where complex engineering equations are derived and interpreted through visual perception similar to a block diagram or flow chart. A dynamic system, in the form of a compressed air–water rocket, is also evaluated in this paper for elucidation.
Material Property Characterization of Costal Cartilage Using AFM Indentation
Authors: Tripathy S. , Berger E. J.
Published: July 2010

Costal cartilage is one of the load bearing tissues of the rib cage. Literature on the material characterization of the costal cartilage is limited. Atomic force microscopy has been extremely successful in characterizing the elastic properties of articular cartilage, but no studies have been published on costal cartilage. In this study AFM indentations on human costal cartilage were performed and compared with macro scale indentation data. Spherical beaded tips of three sizes were used for the AFM indentations. The Hertz contact model for spherical indenter was used to analyze the data and obtain the Young’s modulus. The costal cartilage was found to be almost linearly elastic till 600 nm of indentation depth. It was also found that the modulus values decreased with the distance from the junction. The modulus values from macro indentations were found to be 2-fold larger than the AFM indentation modulus.
Computational Nonlinear Vibration Analysis of Gear Pairs Using a Three-Dimensional Model
Authors: Eritenel Tugan , Parker Robert G.
Published: July 2010

This work investigates the nonlinear vibration of gear pairs, where the nonlinearity is due to portions of gear teeth contact lines losing contact (partial contact loss). The gears are modeled as rigid bodies that admit motion in six degrees of freedom. A network of distributed stiffnesses models the nonlinear gear contact. The distributed stiffness scheme is obtained by discretizing the kinematic contact lines into segments, each with the possibility of losing contact. Whether these segments are actually in contact or not is determined by the gear deflections and tooth modifications. The modeling is verified with finite element analysis and experimental measurements from the literature. The combination of a translational and a tilting spring is proven to be identical to the distributed stiffness model. This equivalent representation of the mesh identifies a nonlinear tilting mesh stiffness that accompanies the well-known translational gear mesh stiffness typically modeled by a single spring. Modal analysis reveals a mesh tilting vibration mode where this spring dominates, in addition to the mesh deflection vibration mode. Computational dynamic analysis of a helical gear pair near the natural frequencies of the mesh tilting and deflection modes exhibit nonlinear vibrations. Both cases involve nonlinearity due to partial contact loss where only part of a nominal contact line loses contact at an instant.
Incorporating the Option Value of Product Family Variants in Material and Process Selection
Authors: Johnson Michael D. , Nanda Amlan
Published: July 2010

In the modern competitive environment, firms have to offer a variety of products to their customers in a cost effective manner. One way of achieving this goal is through the use of product platforms and product families. The choice of product materials and manufacturing processes has a significant effect on the ability to derive variants from these product platforms and families. Unfortunately, most economic analyses of materials selection rarely include the effect on the product family, and if they do they are viewed as static and passive investments. In reality, the decision to produce an additional variant is a “right, but not an obligation” — it can be viewed as a real option. A methodology to value the option of producing a follow-on variant product for an a posteriori (or bottom up) product family is proposed. This method uses inputs that are readily available for most product development teams. An automotive instrument panel beam case study is used to illustrate the method. Results from the case study show that while the follow-on variant option did not affect the relative economic preference of the materials, the value of the options associated follow-on variants accounted for a significant portion of total development project value. Valuations performed using both the binomial and Black-Scholes methods did not show significant differences between the methods. Material and manufacturing process characteristics are shown to have an effect on follow-on variant option value. The product lifetime and annual production volume of the follow-on variant are shown to have significant effects on option value. Initial variant product lifetime and underlying asset risk are shown to have less of an effect on option value.
Vibration Modes of Helical Planetary Gears
Authors: Eritenel Tugan , Parker Robert G.
Published: July 2010

This paper examines the vibration modes of single stage helical planetary gears in three dimensions with equally spaced planets. A lumped-parameter model is formulated to obtain the equations of motion. The gears and shafts are modeled as rigid bodies with compliant bearings at arbitrary axial locations on the shafts. A translational and a tilting stiffness account for the force and moment transmission at the gear mesh interface. The modal properties generalize those of two-dimensional spur planetary gears; there are twice as many degrees of freedom and natural frequencies due to the added tilting and axial motion. All vibration modes are categorized as planet, rotational-axial, and translational-tilting modes. The modal properties are shown to hold even for configurations that are not symmetric about the gear plane, due to, for example, shaft bearings not being equidistant from the gear plane. Computational modal analysis are performed to numerically verify the findings.
Optimal Throwing Motion Planning for a Biped Human Mechanism
Authors: Kim Joo H. , Xiang Yujiang , Yang Jingzhou James , Abdel-Malek Karim , Arora Jasbir S.
Published: July 2010

An optimal motion planning formulation of throwing for a biped human mechanism is proposed as an extension of a previous study. The unique characteristics of the throwing task—highly redundant, highly nonlinear, and highly dynamic—are addressed in this presentation within the framework of multibody dynamics and optimization. To generate physically feasible throwing motions in a fully predictive method without input reference, rigorous dynamic models are associated with the constraints. Given the target location and the object mass, the algorithm outputs the motion, required actuator torques, release parameters, balance criterion, and ground reaction forces. Overarm and sidearm throwing motions are generated as optimal solutions, which demonstrate valid kinematic and kinetic cause-effect relations.
Variable Fidelity Modeling as Applied to Trajectory Optimization for a Hydraulic Backhoe
Authors: Moore Roxanne A. , Paredis Christiaan J. J.
Published: July 2010

Modeling, simulation, and optimization play vital roles throughout the engineering design process; however, in many design disciplines the cost of simulation is high, and designers are faced with a tradeoff between the number of alternatives that can be evaluated and the accuracy with which they are evaluated. In this paper, a methodology is presented for using models of various levels of fidelity during the optimization process. The intent is to use inexpensive, low-fidelity models with limited accuracy to recognize poor design alternatives and reserve the high-fidelity, accurate, but also expensive models only to characterize the best alternatives. Specifically, by setting a user-defined performance threshold, the optimizer can explore the design space using a low-fidelity model by default, and switch to a higher fidelity model only if the performance threshold is attained. In this manner, the high fidelity model is used only to discern the best solution from the set of good solutions, so computational resources are conserved until the optimizer is close to the solution. This makes the optimization process more efficient without sacrificing the quality of the solution. The method is illustrated by optimizing the trajectory of a hydraulic backhoe. To characterize the robustness and efficiency of the method, a design space exploration is performed using both the low and high fidelity models, and the optimization problem is solved multiple times using the variable fidelity framework.
Temple of Zeus: A Micro Replica
Authors: Das Aditya N. , Murthy Rakesh
Published: July 2010

A miniature replica of “Temple of Zeus” has been built on a 1cm2 silicon die. The micro components have been fabricated on SOI (silicon-on-insulator) wafer using photolithography patterning and DRIE (deep-reaction-ion-etching) process. These micro components have been picked up and manipulated using a vacuum micro needle mounted on a high precision microassembly robot. After alignment the components are bonded to the silicon substrate using epoxy adhesive. A spherical sapphire lens has also been mounted on a micro tower made of silicon. This lens acts as a light source which illuminates the micro temple by diffusing a ray of light onto it. This micro replica of “Temple of Zeus” and other micro structures as well, have been built as a part of research on automated 3D microassembly at ARRI’s Texas Microfactory which demonstrates the versatility in developing robust, cost efficient and heterogeneous microsystems of future.
On the Concept of Mobility Used in Robotics
Authors: Mu¨ller Andreas
Published: July 2010

This paper summarizes the concept of mobility used for holonomic and non-holonomic mechanisms. The mobility of mechanisms is considered from a geometric viewpoint starting with the variety generated by the constraint mapping as configuration space. While the local (finite) mobility is determined by the dimension of the configuration space, the differential mobility may be different. This is so for singular configurations, but also at regular configurations of underconstrained mechanisms. Overconstrained mechanisms are identified as those comprising manifolds of regular configurations that are critical points of the constraint mapping. The considerations include non-holonomic mechanisms. For such mechanisms the configuration space is the integral manifold of the kinematic constraints. Different types of singularities are discussed for non-holonomic mechanisms.
The Part Count Tool (PACT) for Concept Selection
Authors: Parashar Tarang , Grantham Lough Katie , Stone Robert B.
Published: July 2010

This paper presents a part count tool that automates the consideration of manufacturing cost during the conceptual design phase by predicting part count for a particular product concept. With an approximate number of parts per product in the conceptual design phase, the designer can estimate the cost associated with the product. On the basis of the cost, the designer can make changes according to budget requirements. The part count tool will also aid in ranking the design concepts by number of components for a product. This tool utilizes existing automated concept generation algorithms to generate the design concepts. It extracts the available data from the Missouri S&T Design Repository to compute an average number of parts per component type in the repository and then calculates an average part count for new concepts. This data can subsequently be used by designers to estimate product cost. The part count tool also uses an algorithm to determine how to connect two non compatible components through the addition of mutually compatible components. While emphasis is placed on the average parts per product in evaluating designs, the overall functional requirement of the product is also considered.
Fabrication and Strength-Based Design of a Meso Forceps
Authors: Aguirre M. E. , Hayes G. , Yuangyai C. , Frecker M. , Adair J. , Antolino N.
Published: July 2010

A novel fabrication process and design optimization method for a mesoscale forceps is presented. This work is part of a larger research effort to design and fabricate nanoparticulate enabled surgical instruments using an iterative fabrication-design technique. The current paper focuses on the fabrication of thick (∼hundreds of microns) two dimensional parts with large aspect ratios (length/width > 20). The paper also describes an optimization method that accounts for manufacturing requirements and material strength. The process begins with the fabrication of an array of molds on refractory substrates using a modified UV lithography technique. In parallel, engineered ceramic nanocolloidal slurries are prepared for gel-casting into the molds. Mold infiltration takes place via a squeegee technique adapted from screen printing with excess slurry removed using an ethanol bath. Finally, the photoresist molds are removed via pyrolysis, and ceramic parts sintered to full density. Employing this manufacturing technique for the compliant micro forceps design is advantageous because a large number of parts can be produced with large aspect ratios, sharp edges (∼ 1 μm), and a resolution of 2 μm. An optimization algorithm, using ANSYS optimization module, is formulated to determine the effect of dimensional parameters and material strength on the optimal design and predicted performance of the compliant meso forceps. Three ultimate strength values are separately implemented as a stress constraint in our optimization problem. Results conclude that our manufacturing process is capable of producing meso scale forceps considering the anticipated ultimate strength at this scale.
Comparison of Torque and Coupler-Driven Four-Bars as Solutions to Planar Four Position and Spherical Four Orientation Tasks
Authors: Perkins David A. , Murray Andrew P.
Published: July 2010

This work presents a comparison between two actuation methods for planar and spherical four-bar mechanisms. The first is actuation by a torque applied at either of the fixed pivots. The second actuation method uses a linear actuator connected between ground and the coupler. For any four position task, planar or spherical, a one parameter set of dyads is found that may be used to guide the body through the four positions. Any two of these dyads, when coupled, define a potential four-bar solution to the task. A sampling across the set of all possible mechanisms that solve the four position task may be compared by analyzing the internal static loads of the four-bar mechanisms. The comparison was conducted to determine if coupler-driven four-bars have reduced internal loading when compared to torque-driven mechanisms. Four position tasks were used for comparison of mechanisms designed for the same task, under the assumption that the optimal torque-driven mechanism would have a different set of kinematic parameters than the optimal coupler-driven mechanism.
Development of a Haptic Modeling and Simulation System for Handheld Product Design and Evaluation
Authors: Wang Jinling , Lu Wen F.
Published: July 2010

In this paper, a haptic modeling and simulation system is developed to assist handheld product design. With haptic feedback, users could create, interact and evaluate the virtual product directly and intuitively without producing the physical prototype. This saves the cost and reduces time-to-market, which is especially meaningful for the rapidly changing handheld mobile devices. To provide a comfortable and accurate operation, a virtual vibration actuator is devised to add into the touch screen. Unlike the previous research that mainly focuses on the design of the product shape, the proposed system also models the interaction between the user (finger) or tool (pen) and handheld device (button/screen). To obtain realistic simulation and replace the physical prototype, the complex shape and deformation of the finger are considered when calculating the feedback force. A computational efficient collision detection method for complex shape objects is proposed to tackle the challenge of a high update rate of more than 1 kHz for real-time realistic haptic rendering. Moreover, the proposed system incorporates the haptic modeling of vibration interaction and menu interface design into the product design simulation system. A case study of handheld device design is used to illustrate the proposed system.
Shape Sensing for Soft Robotic Manipulators
Authors: Trivedi Deepak , Rahn Christopher D.
Published: July 2010

Soft robotic manipulators are continuum robots made of soft materials that undergo continuous elastic deformation and produce motion with a smooth backbone curve. These manipulators offer significant advantages over traditional manipulators due to their ability to conform to their surroundings, move with dexterity and manipulate objects of widely varying size using whole arm manipulation. Theoretically, soft robots have infinite degrees of freedom (dof), but the number of sensors and actuators are limited. Many dofs of soft robots are not directly observable and/or controllable, complicating shape sensing and controlling. In this paper, we present two methods of shape sensing for soft robotic manipulators based on a geometrically exact mechanical model. The first method use s load cells mounted at the base of the manipulator and the second method makes use of cable encoders running through the length of the manipulator. Simulation results show an endpoint localization error of less than 3% of manipulator length.
Path Planning in Topologically Evolving Planar Environments
Authors: Eftekharian Ata A. , Ilies¸ Horea T.
Published: July 2010

The task of planning a path between two spatial configurations of an artifact moving among obstacles is an important problem in many geometrically-intensive applications. Despite the ubiquity of the problem, the existing approaches make specific limiting assumptions about the geometry and mobility of the obstacles, or those of the environment in which the motion of the artifact takes place. In this paper we propose a powerful approach for 2D path planning in a dynamic environment that can undergo drastic topological changes. Our algorithm is based on a potent paradigm for medial axis computation that relies on constructive representations of shapes with R-functions that operate on real-valued half-spaces as logic operations. Our approach can handle problems in which the environment is not fully known a priori, intrinsically supports local and parallel skeleton computations for domains with rigid or evolving boundaries, and appears to extend naturally to 3D domains. Furthermore, our path planning algorithm can be implemented in any commercial geometric kernel, and has attractive computational properties. The capability of the proposed technique are explored through several examples designed to resemble highly dynamic environments.
Relationship Conflict and Feeling Communication in Design Teams
Authors: Roschuni Celeste , Oehlberg Lora , Beckman Sara , Agogino Alice M.
Published: July 2010

Collaborative design team members use feeling language in their communications with one another, dubbed feeling communications, as they negotiate their interpersonal relationships and task, process and relationship conflict to achieve successful outcomes. In this paper, we examine the use of feeling communications by design teams in a new product development class at UC Berkeley, how their use of feeling communications relates to the levels of conflict experienced by the teams throughout the semester, and how both relate to team performance. From this study, it appears that high-performing and low-conflict teams tend to use high levels of feeling communications. High-conflict teams also use high levels of feeling communications, but often suppress its use when given feedback on their process. Medium-conflict teams appear to initially produce less feeling communication, but build up to a normal level over the course of the project. These results are based on our study of 1,926 messages sent by 13 teams in the Fall 2008 class, and present promising avenues for further exploration.
An Human-Robot Interaction Control Architecture for an Intelligent Assistive Robot
Authors: Ficocelli Maurizio , Nejat Goldie , Jhin Greg Minseok
Published: July 2010

As the first round of baby boomers turn 65 in 2011, we must be prepared for the largest demographic group in history that could need long term care from nursing homes and home health providers. The development of socially assistive robots for health care applications can provide measurable improvements in patient safety, quality of care, and operational efficiencies by playing an increasingly important role in patient care in the fast pace of crowded clinics, hospitals and nursing/veterans homes. However, there are a number of research issues that need to be addressed in order to design such robots. In this paper, we address one of the main limitations to the development of intelligent socially assistive robots for health care applications: Robotic control architecture design and implementation with explicit social and assistive task functionalities. In particular, we present the design of a unique learning-based multi-layer decision making control architecture for utilization in determining the appropriate behavior of the robot. Herein, we explore and compare two different learning-based techniques that can be utilized as the main decision-making module of the controller. Preliminary experiments presented show the potential of the integration of the aforementioned techniques into the overall design of such robots intended for assistive scenarios.
Integration of Supply Chain Decisions at the Conceptual Design Stage: A Repository Enabled Decision Tool
Authors: Chiu Ming-Chuan , Gupta Saraj , Okudan Gu¨l E.
Published: July 2010

A supply chain connects product suppliers, manufacturers, as well as customers with the goal of managerial efficiency. Meanwhile, product design emphasizes the engineering efficiency of a product. Both supply chain management and product design have been drawing attention from numerous researchers. However, there has been only limited research on the integration of product design and supply chain. Despite this fact, there is significant potential for synergy in the integration of engineering and supply chain management, as well as managerial concepts into product design. In the paper, we present a methodology to form this synergistic connection. The methodology presented first generates functional requirements of a product. A design repository is then utilized to synthesize potential components of all sub-functions, providing multiple options for the potential conceptual designs. These concepts are screened by using a Design for Assembly (DfA) index and then a Design for Supply Chain (DfSC) index to select the best concept. An example from the bicycle industry is presented to demonstrate the benefit of supply chain considerations at the conceptual design phase.