bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinematic Analysis and Prototyping of a Partially Decoupled 4-DOF 3T1R Parallel Manipulator
Authors: Richard Pierre-Luc , Gosselin Cle´ment M. , Kong Xianwen
Published: June 2008

A four-degree-of-freedom (DOF) 3T1R parallel manipulator is presented in this paper. This manipulator generates the family of so-called Scho¨nflies motions, SCARA motions or 3T1R motions, in which the moving platform can translate in all directions and rotate around an axis of a fixed direction. The kinematic analysis of this architecture is presented, including the study of the constraint singular configurations, kinematic singular configurations and the determination of the workspace. A prototype (the Quadrupteron) is also presented and demonstrated. The characteristics of the proposed prototype are: (a) there is no constraint singularity, (b) its input-output equations are partially decoupled, (c) its kinematic singular configurations can be expressed using an equation in the angle of rotation of the moving platform and are thus easy to avoid at the design stage, and (d) its forward displacement analysis requires the solution of a univariate quadratic equation and can therefore be solved efficiently.
Visual Representations as an Aid to Concept Generation
Authors: Attaluri Vivek , McAdams Daniel A. , Stone Robert B. , De Crescenzo Andrea
Published: June 2008

This paper describes our initial efforts to develop a 3D visualization tool that is part of an overall effort to create a Concept Generator, an automated conceptual design tool, to aid a designer during the early stages of the design process. The use of CAD software has diversified into various disciplines that have made use of simulation and software modeling tools for reasons that range from improving accuracy in design, reduction in lead times, and simple visualizations. The impacts of CAD software have been beneficial in industry and education. Described in this paper is the use of low-memory VRML models to represent components. These low memory models have been created to achieve several goals that complement the overall objectives of the concept generator. One key goal is that the concept generator be accessible via the web, thus the need for low-memory and low-data models. Additionally, as the concept generator is intended for usage during early conceptual design, the 3D visualization tool allows the creation of models upon which basic manipulations can be performed so that a designer can get an initial feel of the structure that his product is going to take. Our research has enabled us to create a basic visualization tool which, while similar in nature to most other CAD software tools, is unique, in that it represents the link, as a visual interface, between a formulated concept and the designer. The paper presents the research problem, an overview of the architecture of the software tool and some preliminary results on visual representations as an aid to concept generation.
Product Platform Problem Taxonomy: Classification and Identification of Benchmark Problems
Authors: Allada Venkat , Choudhury Abhijit K. , Pakala Padmavathi K. , Simpson Timothy W. , Scott Michael J. , Valliyappan Somasundaram
Published: June 2008

Many companies are using product platform concepts to gain economies of scale and to identify new market opportunities. Though the area of product platforming continues to be actively investigated by both industry and academia, there is no comprehensive classification scheme that can provide a clear picture of the existing problems and possible future research directions. Hence, in the present paper, we introduce a broad taxonomy that classifies product platform problems based on the product development stages. This can serve as a basis to: (1) Extract and categorize problems from research literature; (2) Identify potential extensions and/or new problems that have not been addressed in the literature; and (3) Identify existing problem sets and/or develop new problem sets for benchmarking purposes. We introduce a Conditions and Assumptions Code (CAC) scheme and use it in the identification of benchmark problems as well as in analyzing two classes of evaluation methods adopted for the platform problems: metrics-based and optimization-based. Thus, we have not only categorized existing problems but also identified possible future research problems in each of the categories. This categorization serves as a navigation tool to understand the progress made in this field so far and to identify new research directions.
Spreadsheet-Based Design and Analysis of Mechanisms
Authors: Cheetancheri Kabileshkumar G. , Cheng Harry H.
Published: June 2008

A spreadsheet based mechanism analysis and animation system is presented in this article. The system is developed in Excel using Ch, an embeddable C/C++ interpreter, and Ch Mechanism Toolkit. It allows users to develop and solve complicated planar mechanism problems conveniently using an easy to use Excel spreadsheets as the front end. Users can input the required data to define a mechanism in an Excel spreadsheet and execute script files associated with the work cells. The spreadsheet based system can be used for kinematic and dynamic analysis, graphical plotting, and animation for four-bar, crank-slider, fivebar, and sixbar linkages. Examples are provided to illustrate its ease of use. The source code and demos are available for downloading from the internet.
Conformance Testing for XML-Based STEP Conceptual Models
Authors: Jardim-Gonc¸alves Ricardo , Onofre Se´rgio , Agostinho Carlos , Steiger-Garc¸a˜o Adolfo
Published: June 2008

ISO10303 STEP has been acknowledged by most of the industrial companies as the most important family of standards for the integration and exchange of product data under the manufacturing domain. The incremental use of XML as an effective format for STEP data exchange has increased the number of implementations of Application Protocols in global networked business environments, where organizations are willing to establish collaborative business practices integrating product data and business information. STEP defines a conformance testing methodology that, although developed for the validation of product data, can be extended to application in these hybrid industrial business environments. This paper proposes an innovative XML-based framework to implement it. The results have been validated under a real industrial scenario in the scope of an international research project.
High Accuracy Laser Scanned View Registration Method for Reverse Engineering Using a CMM Generated CAD Model
Authors: Jamshidi Jafar , Mileham Antony Roy , Owen Geraint Wyn
Published: June 2008

Complete CAD modelling by 3D digitizers comprises of full coverage scanning of the part from a number of views in the Reverse Engineering process. Different scanned views are required to be registered into a cohesive coordinate system to generate a practical CAD model. In this paper a high accuracy registration method is introduced in which the preregistered views, obtained by a conventional registration method are used as a base for fine registration. This is based on the relationships of the scanned views in the Laser Scanned model and the scanned features created by the Coordinate Measurement Machine. This method is most suitable for Reverse Engineering of precision parts with accurate and standard machined geometric features and complex but less accurate casting features. Experimental results of the method application on two components are presented.
Ruled Layer Generation Between Two Freeform Curves by Normal and Distance Matching
Authors: Samanta Kuntal , Koc Bahattin
Published: June 2008

A new curve matching method is proposed to generate non-self-intersecting and non-twisted ruled layers for application in diverse fields such as layered manufacturing, offsetting and multi-axis CNC machining. The method establishes point-to-point correspondence represented by a set of ruling lines between two directrices of the ruled surface. The directrices are given as non-self-intersecting, closed, at least C1 continuous, planar, B-spline curves. To match the points on the directrices, a heuristic optimization method developed with the objective is to maximize the sum of the inner products of the unit normals at the end points of the ruling lines and minimize the sum of the lengths of connecting ruling lines. The generated ruling lines can be used as cutter location data for multi-axis NC machining of ruled surfaces. Moreover, by subdividing the ruling lines into equal number of segments, one can construct a series of intermediate piecewise linear curves that represent the metamorphosis between the directrices. Implementation and examples are also presented.
Adapted Concept Generation and Computational Techniques for the Application of a Transformer Design Theory
Authors: Skiles Stewart M. , Singh Vikramjit , Krager Jarden , Seepersad Carolyn Conner , Wood Kristin L. , Jensen Dan
Published: June 2008

Transformers are a class of products with great potential in a number of markets and applications. These are systems that exhibit a change in state to facilitate new or enhanced product functionality. The historical children’s toys known as “transformers” provide a mental picture of this definition. Working examples are vertical lift aircraft that function as helicopters for take-offs but transform to propeller-driven airplanes for point-to-point travel. This paper builds on research into developing principles and design methodologies for the creation of transforming products. We summarize this research and demonstrate an approach for implementing Transformer Design Principles as part of an ideation and computational design process. An application to an Unmanned Aerial Vehicle (UAV-TACMAV) illustrates the utility of the approach.
Using Tolerance-Maps to Generate Frequency Distributions of Clearance for Pin-Hole Assemblies
Authors: Ameta Gaurav , Davidson Joseph K. , Shah Jami J.
Published: June 2008

A new mathematical model for representing the geometric variations of lines is extended to include probabilistic representations of 1-D clearance which arise from multidimensional variations of an axis, a hole and a pin-hole assembly. The model is compatible with the ASME/ANSI/ISO Standards for geometric tolerances. Central to the new model is a Tolerance-Map (T-Map), a hypothetical volume of points that models the 3-D variations in location and orientation for a segment of a line (the axis), which can arise from tolerances on size, position, orientation, and form. Here it is extended to model the increase in yield that occurs when maximum material condition (MMC) is specified. The frequency distribution of 1-D clearance is decomposed into manufacturing bias, i.e. toward certain regions of a Tolerance-Map, and into a geometric bias that can be computed from the geometry of multidimensional T-Maps. Although the probabilistic representation in this paper is focused on geometric bias and manufacturing bias is presumed to be uniform, the method is robust enough to include manufacturing bias in the future. Geometric bias alone shows a greater likelihood of small clearances than large clearances between an assembled pin and hole.
Optimal Tolerance Allocation of Automotive Pneumatic Control Valves Based on Product and Process Simulations
Authors: Lyu Naesung , Shimura Amane , Saitou Kazuhiro
Published: June 2008

This paper discusses a computational method for optimally allocating dimensional tolerances for an automotive pneumatic control valve. Due to the large production volume, costly tight tolerances should be allocated only to the dimensions that have high influence to the quality. Given a parametric geometry of a valve, the problem is posed as a multi-objective optimization with respect to product quality and production cost. The product quality is defined as 1) the deviation from the nominal valve design in the linearity of valve stroke and fluidic force, and 2) the difference in fluidic force with and without cavitation. These quality measures are estimated by using Monte Carlo simulation on a Radial-Basis Function Network (RBFN) trained with computational fluid dynamics (CFD) simulation of the valve operation. The production cost is estimated by the tolerance-cost relationship obtained from the discrete event simulations of valve production process. A multi-objective genetic algorithm is utilized to generate Pareto optimal tolerance allocations with respect to these objectives, and alternative tolerance allocations are proposed considering the trade-offs among multiple objectives.
Dynamic Testing and Model Validation of a Capture Mechanism for Rendezvous Between a Space Tether and Payload
Authors: Canfield Stephen L. , Norris Marshall A. , Knight Seth V. , Sorensen Kirk F.
Published: June 2008

Momentum eXchange Electrodynamic Reboost, or MXER, tether systems have been proposed to serve as an “upper stage in space” [1]. A MXER tether station would boost spacecraft from low Earth orbit to a high-energy orbit quickly, like a high-thrust rocket. Then, using the same principles that make an electric motor work, it would slowly rebuild its orbital momentum by pushing against the Earth’s magnetic field without using any propellant. One of the significant challenges in developing a momentum-exchange / electrodynamic reboost tether system is in the analysis and design of the capture mechanism and its effects on the overall dynamics of the system [2]. A capture mechanism that provides nearly passive operation is presented and described in [3] and led to the fabrication of a prototype article of this mechanism. This paper will describe the process of testing this prototype in a dynamically similar environment and validating an associated dynamic model. The primary contributions of this paper will be a description of the proposed capture mechanism concept and associated testing process and the validation of a dynamic model of this mechanism.
CAM Size Optimization Based on a Fatigue Life Model
Authors: Shakoor Mwafak M. , Ali Muhammad , Qamhiyah Abir , Flugrad Don R.
Published: June 2008

The cam fatigue life of the translating roller-follower system is studied for polynomial and cycloidal displacement functions. The stress distribution in the contact zone between the cam and the roller-follower is determined by using a computer program. The “volume under risk” where the stress field is higher than the endurance limit is determined. Ioannides-Harris (IH) theory is used on the ‘volume under risk’ and the expected fatigue life is calculated. The effects of cam base circle radius, follower offset, follower total lift and cam angular velocity on the fatigue life are studied. The primary design parameter governing the cam fatigue life is found to be the base circle radius. The fatigue life curve shows an improvement in the life up to a critical base circle radius value. Any further increase in the base circle radius appears as a decrease in the fatigue life.
Some Metrics and a Bayesian Procedure for Validating Predictive Models in Engineering Design
Authors: Chen Wei , Xiong Ying , Tsui Kwok-Leung , Wang Shuchun
Published: June 2008

Even though model-based simulations are widely used in engineering design, it remains a challenge to validate models and assess the risks and uncertainties associated with the use of predictive models for design decision making. In most of the existing work, model validation is viewed as verifying the model accuracy, measured by the agreement between computational and experimental results. However, from the design perspective, a good model is considered as the one that can provide the discrimination (good resolution) between design candidates. In this work, a Bayesian approach is presented to assess the uncertainty in model prediction by combining data from both physical experiments and the computer model. Based on the uncertainty quantification of model prediction, some design-oriented model validation metrics are further developed to guide designers for achieving high confidence of using predictive models in making a specific design decision. We demonstrate that the Bayesian approach provides a flexible framework for drawing inferences for predictions in the intended but may be untested design domain, where design settings of physical experiments and the computer model may or may not overlap. The implications of the proposed validation metrics are studied, and their potential roles in a model validation procedure are highlighted.
An Upper Ontology for Manufacturing Service Description
Authors: Ameri Farhad , Dutta Debasish
Published: June 2008

In today’s volatile market, manufacturing companies are increasingly adopting agile manufacturing strategies. Virtual Enterprise (VE) is one of the key enablers of the agile philosophy. Timely deployment of VE requires efficient communication between the potential members of VE through a common language. This work introduces Manufacturing Service Description Language (MSDL) as an ontology for representation of manufacturing services. MSDL provides the primitive building blocks required for description of a wide spectrum of manufacturing services. Description Logic is used as the knowledge representation formalism of MSDL in order to make it amenable to automatic reasoning.
RoboTrikke: Design, Modeling and Experimentation With a Robotic Trikke
Authors: Chitta Sachin , Karabas Mustafa , Galloway Kevin C. , Kumar Vijay
Published: June 2008

In this paper we present new experimental results for a novel underactuated system called the ROBOTRIKKE. The ROBOTRIKKE is a three-wheeled system that can be driven by periodic motion of its front steering wheel combined with rocking side-to-side motion of a robotic rider. We present two new generations of the ROBOTRIKKE including a ABS model made using Shape Deposition Manufacturing (SDM). We present modeling, simulation and experimental results for gait generation for the ROBOTRIKKE using a combination of periodic inputs for the steering axis and a rider. We show how a rocking motion (as used by human riders) can be used to improve the performance of the ROBOTRIKKE.
History of Mechanisms: The Odometer of the Mormon Trail
Authors: Howell Larry L.
Published: June 2008

The wagon odometer (or “roadometer”), designed, built, and implemented on the Mormon Trail, has generated much interest because of the documentation of the odometer’s design, the unusual circumstances under which it was developed, the impact it made on the settlement of the West, and the epic nature of the Mormon Exodus. This paper reviews first-person accounts documenting the odometer’s development, discusses the odometer’s impact, and reviews myths and misconceptions surrounding the odometer. In contrast to previous assumptions, this paper argues that enough information is provided from the accounts, combined with knowledge of gear design, to determine the actual gear sizes. Calculations and arguments are provided to support the idea that the gear diameters were 15 inches (38 cm) for the 60-tooth gear, 10 inches (25 cm) for the 40-tooth gear, and 1 inch (2.54 cm) for the 4-tooth gear.
A Lifecycle-Cost Model of Concept Testing
Authors: Takai Shun
Published: June 2008

This paper presents a lifecycle-cost model of concept testing, with and without learning. In the lifecycle-cost model, product lifecycle is divided into four stages: marketing, concept generation, prototyping, and product lifecycle after prototyping. Engineers minimize the expected lifecycle cost to find the optimum number of prototypes that engineers develop to test concepts. The optimum number of prototypes is a function of unit costs in these stages. The optimum number of prototypes depends not on the absolute cost of prototyping one concept, but on prototyping cost relative to the other stage costs. In the lifecycle-cost model with learning, engineers can more accurately choose good concepts that they test as prototypes once they gain experience in developing similar products or as they learn more effectively from their experiences. As engineers gain more experience or improve their learning capability, the optimum number of prototypes decreases.
Optimization of a PEM Fuel Cell System for Low-Speed Hybrid Electric Vehicles
Authors: Wishart Jeffrey D. , Dong Zuomin , Secanell Marc M.
Published: June 2008

Design optimization is performed by presenting a systematic method to obtain the optimal operating conditions of a Proton Exchange Membrane (PEM) fuel cell system targeted towards a vehicular application. The fuel cell stack model is a modified version of the semi-empirical model introduced by researchers at the Royal Military College of Canada and one that is widely used by industry. Empirical data obtained from tests of PEM fuel cell stacks are used to determine the empirical parameters of the fuel cell performance model. Based on this stack model, a fuel cell system model is built in MATLAB. Included in the system model are heat transfer and gas flow considerations and the associated Balance of Plant (BOP) components. The modified ADVISOR vehicle simulation tool is used to integrate the New York City Cycle (NYCC) drive cycle and vehicle model to determine the power requirements and hence the load cycle of the fuel cell system for a low-speed fuel cell hybrid electric vehicle (LSFCHEV). The optimization of the powerplant of this vehicle type is unique. The vehicle model has been developed in the work to describe the characteristics and performance of an electric scooter, a simple low-speed vehicle (LSV). The net output power and system exergetic efficiency of the system are maximized for various system operating conditions using the weighted objective function based on the load cycle requirement. The method is based on the coupling of the fuel cell system model with three optimization algorithms (a) sequential quadratic programming (SQP); (b) simulated annealing (SA); and (c) genetic algorithm (GA). The results of the optimization provide useful information that will be used in future study on control algorithms for LSFCHEVs. This study facilitates research on more complex fuel cell system modeling and optimization, and provides a basis for experimentation to verify the fuel cell system model.
Updating Belief in Concept Selection of a Public Project Using a Mathematical Model
Authors: Takai Shun
Published: June 2008

Acquiring information about uncertainty and updating belief before making the final decision are important steps in decision analysis. In this paper, a national laboratory (lab hereafter) uses decision analysis to choose the optimal project proposal for a public project submitted to the government. A project proposal consists of a system concept (system technology and specifications) and a budget. When choosing a project proposal, the lab may not know what might happen when the cost of the project exceeds the budget. If the cost only exceeds the budget for a small amount, the government may allow the project to continue. On the other hand, if the cost substantially exceeds the budget, the project may be cancelled. To assess this uncertainty, experts’ opinions are useful source of information. However, experts’ opinions may not always be available. This paper proposes a mathematical model to simulate the government’s actions and to update the lab’s belief about this uncertainty when experts’ opinions cannot be obtained. Information obtained from analyzing a mathematical model should help the lab update its belief and make better decisions.
Semantic Tolerance Modeling
Authors: Wang Yan
Published: June 2008

A significant amount of research efforts has been given to explore the mathematical basis for 3D dimensional and geometric tolerance representation, analysis, and synthesis. However, engineering semantics is not maintained in these mathematic models. It is hard to interpret calculated numerical results in a meaningful way. In this paper, a new semantic tolerance modeling scheme based on modal interval is introduced to improve interpretability of tolerance modeling. With logical quantifiers, semantic relations between tolerance specifications and implications of tolerance stacking are embedded in the mathematic model. The model captures the semantics of physical property difference between rigid and flexible materials as well as tolerancing intents such as sequence of specification, measurement, and assembly. Compared to traditional methods, the semantic tolerancing allows us to estimate true variation ranges such that feasible and complete solutions can be obtained.
Parametric and Topological Control in Shape Optimization
Authors: Chen Jiaqin , Shapiro Vadim , Suresh Krishnan , Tsukanov Igor
Published: June 2008

We propose a novel approach to shape optimization that combines and retains the advantages of the earlier optimization techniques. The shapes in the design space are represented implicitly as level sets of a higher-dimensional function that is constructed using B-splines (to allow free-form deformations), and parameterized primitives combined with R-functions (to support desired parametric changes). Our approach to shape design and optimization offers great flexibility because it provides explicit parametric control of geometry and topology within a large space of freeform shapes. The resulting method is also general in that it subsumes most other types of shape optimization as special cases. We describe an implementation of the proposed technique with attractive numerical properties. The effectiveness of the method is demonstrated by several numerical examples.
Inverse Kinematics Analysis of General 6R Manipulator Based on Groebner Basis-Sylvester Hybrid Method
Authors: Hang Lubing , Yang Tingli
Published: June 2008

In this paper we present a solution to the inverse kinematics problem for serial manipulator of general geometry. Using only seven equations which are consisted of Duffy’s four kinematical equations containing only three angles and three corresponding angles’ sincos identical equations instead of traditional fourteen equations, we reduce the inverse kinematics problem of the general 6R manipulator to a univariate polynomial with minimum degree based on Groebner-Sylvester method. From that, a conclusion can be drawn that the maximum number of the solutions is sixteen, generally. Also the mathematics mechanization method used in this paper can be extended to solve the other mechanism problem involving nonlinear equations symbolically.
Top-Down Benchmarking Approach for Estimating Cost of Concept
Authors: Ramesh Raghuram Puthali , Takai Shun
Published: June 2008

Due to the highly competitive nature of businesses today, cost estimation forms an important strategic process in making decisions about design and development of new products. The focus is on improving the quality and service of the product at ever reducing costs. In conceptual design phase, engineers need to estimate how much the final products developed from each concept may cost. Estimating cost of the final product is critical in selecting the optimal concept. Majority of the cost estimation techniques used in the industry today concentrate on the parametric estimation. Parametric estimation accurately predicts cost of the final product using historic data about cost drivers. However, if firms are developing new products different from their past product categories, historic data may not be a credible source for parametric cost estimation. In this paper, the authors proposed a top-down benchmarking approach in estimating cost of new products in conceptual design phase. The objective is to construct a cost distribution model for the final product developed from each concept.
Determination of the Interference Geometry Between Two Convex Objects
Authors: Luo Lianzhen , Nahon Meyer
Published: June 2008

The determination of the interference geometry between two arbitrary objects is an essential problem encountered in the simulation of continuous contact dynamics and haptic interactions. In these applications, with known material properties, the interbody contact force is only a function of the interference geometry between two objects. Here a theoretical basis and algorithms for the calculation of the interference geometry, such as overlap region, contact area and normal, and interference volume, are presented. Two methods to obtain the contact area and normal are analyzed: an area-weighted method and a best-fitting method. The geometric properties of the area-weighted method are presented and the degenerate cases related to both methods are discussed. Methods to calculate the application point of an interbody contact force are discussed. Some numerical simulation results are presented based on the implementation of the geometric algorithms, which are verified by comparison with hand calculation. The continuity of contact normal and its application point are demonstrated for a case in which the contacting objects smoothly move with respect to each other in the simulation.
Multi-Disciplinary Conceptual Modeling and Optimization With Uncertainty Effects Consideration
Authors: Liu Nan , Manoochehri Souran , Yu Chan
Published: June 2008

A multi-disciplinary modeling and design optimization formulation for uncertainty effects consideration is presented in this paper. The optimization approach considers minimization of uncertainty factors related to the overall system performance while satisfying target requirements specified in the form of constraints. The design problem is decomposed into two analysis systems; performance design and uncertainty effects analysis. Each design system can be partitioned into several subsystems according to the different functions they perform. Performance evaluation is considered by minimizing the variations between specified expected values of performance functions and their target values. Uncertainty effects analysis is defined by minimizing the ratio of the maximum variations caused by uncertainty factors over the expected function values. The entire problem has been treated as a multi-disciplinary design optimization (MDO) for maximum robustness and performance achievement. An electromechanical system is used as an example to demonstrate this optimization methodology.
Design and Fabrication of an Elastic Knee Orthosis: Preliminary Results
Authors: Cherry Michael S. , Choi Dave J. , Deng Kevin J. , Kota Sridhar , Ferris Daniel P.
Published: June 2008

When humans hop or run on compliant surfaces they alter the stiffness of their legs so that the overall stiffness of the leg-surface system remains the same. Adding a spring in parallel to the ankle joint incites a similar neuromuscular response; humans decrease their biological ankle stiffness such that the overall ankle stiffness remains unchanged. These results suggest that an elastic exoskeleton could be effective at reducing the metabolic cost of locomotion. To further increase our understanding of human response we have developed an elastic knee brace that adds a stiff spring in parallel to the knee. It will be used as a test platform in ascertaining the neuromuscular effects of adding a parallel knee spring while hopping on one leg. This paper focuses primarily on the mechanical design and implementation of our elastic knee orthosis. Results of the forthcoming studies of human subjects wearing this knee orthosis will be presented in a separate article that will focus on the biomechanics and the neuromuscular adaptations of the human body. Prior research found that the neuromuscular response to hopping on compliant surfaces was the same when running on compliant surfaces. We expect that our results from hopping with springs in parallel with the knee will also be applicable to running. This elastic knee brace represents the first phase of an ongoing research project to develop a passive compliant lower-body exoskeleton to assist in human running. It is expected that this research will benefit healthy individuals as well as those with disabilities causing decreased muscle function.
The Role of Modularized QFD in an Interdisciplinary Approach for System Concept Selection
Authors: Takai Shun
Published: June 2008

This paper discusses a role of modularized Quality Function Deployment (QFD) matrices in an interdisciplinary approach for system concepts selection. The approach uses a set of interdisciplinary tools that consists of marketing, accounting, value engineering and design engineering. When using modularized QFD matrices in the interdisciplinary approach, engineers specify target requirements before assessing how each output design requirements (e.g., system requirements) contributes to the achievement of input design requirements (e.g., customer requirements). Then engineers use their value of each output design requirement in QFD relationship matrices. By setting target requirements for each system module, engineers can freeze interactions between modules when modularizing QFD matrices. By using engineers’ value in QFD relationship matrices, engineer can allocate worth of system (for the customers) to system modules based on engineers’ value. The target cost of modules calculated from the allocated worth reflect both customers’ and engineers’ value.
Type Synthesis of Parallel Mechanisms With Multiple Operation Modes
Authors: Kong Xianwen , Gosselin Cle´ment M. , Richard Pierre-Luc
Published: June 2008

There are usually several motion patterns having the same DOF (degree of freedom). For example, planar motion, spherical motion, and spatial translation are motion patterns with 3-DOF. An f-DOF parallel mechanism with multiple operation modes is a parallel mechanism that can generate different motion patterns with f DOF. Up to now, no method has been proposed for the type synthesis of parallel mechanisms with multiple operation modes. This paper presents a general method for the type synthesis of parallel mechanisms with multiple operation modes. Using the proposed approach, 3-DOF parallel mechanisms with both spherical and translational modes, i.e., parallel mechanisms generating both the spherical motion pattern and the spatial translational motion pattern, are generated systematically. A large number of parallel mechanisms with both spherical and translational modes are obtained.
Customer Requirements Management: Methodology Selection and Deployment Guide
Authors: Beiter Kurt A. , Ishii Kosuke , Karandikar Harshavardhan
Published: June 2008

This paper describes strategies for clarifying the product definition early in the development phase by deploying the right mix of key methods and tools. The focus is on customer value chains, project priority, “voice of customer” acquisition, and requirements flow-down. The tools most effective for each development project differ depending on the nature of the product. The authors noticed that one can characterize the products in two axes: morphology (hardware vs. systems) and maturity (established vs. new), and mapped them into four quadrants. We analyzed over a dozen projects in different industries raging from electronics to industrial equipment, and observed how each sector required and utilized the key tools with different priority. The paper is a guide to efficient deployment of the methods and tools and shows that analysis using these tools contributes to the build-up and management of consensus amongst the product development team and increases the rate of project success. The proposed approach provides guidance on which key tools the project should focus on based on the morphology vs. maturity mapping and contribute to project planning and scheduling and resource allocation between the development tollgates. The paper includes two case studies that represent two ends of the spectrum in our characterization quadrants. We conclude by identifying three major areas of research opportunities in product definition: 1) amorphous products that combine hardware, software, and external infrastructure, 2) integration of solution elements of different forms, and 3) global platform design.
Spiral-Like Path Planning Without Gap for Material Deposition Processes
Authors: Eiamsa-ard Kunnayut , Liou F. W. , Ren Lan , Choset H.
Published: June 2008

Contour-parallel path, also called offset path, is a commonly used deposition strategy exploited by many deposition processes. This offset path has been studied vastly due to the potential of its applications. The majority of contour-parallel path research is found in robotics, CNC machining, and metal deposition. Even though curve offsetting has been extensively studied, there is virtually no algorithm that can produce a complete connected deposition path and can fill arbitrary shape cross sections entirely without gaps. This gap problem is similar to the uncut-region problem in CNC pocket machining. There are only few investigations on this uncut-region or gap problem even though the problem has long been recognized. A new strategy to divide regions and to plan the spiral-like deposition paths without gap based on contour-parallel paths is discussed in this paper. To prove the correctness and the usefulness of the proposed method, simulations and experiments are also discussed.
The Operation and Kinematic Analysis of a Novel CAM-Based Infinitely Variable Transmission
Authors: Lahr Derek F. , Hong Dennis W.
Published: June 2008

In this paper, the operation and analysis of a novel, highly configurable, infinitely variable transmission of the ratcheting drive type is presented. This particular drive uses a cam and a number of cam followers rotatably mounted to a carrier plate to generate an oscillatory motion in an equal number of planet gears. A number of indexing clutches are then used to rectify this motion into a rotational output. A full description of the mechanism, including its components, operation, and kinematic equations are presented. There are a number of inversions of this device, and their characteristics and limitations are discussed. In addition, a method is presented to select the most suitable inversion, gearing, and follower velocity for a given application.
Fault Detection With NURBs-Based Metamodels
Authors: Turner Cameron J. , Ajetunmobi Abiola M. , Crawford Richard H.
Published: June 2008

Developing the ability for a system to self-monitor its condition is a desirable feature in many modern engineering systems. This capability facilitates a maintenance-as-needed rather than a maintenance-as-scheduled paradigm, offering potential efficiency improvements and corresponding cost savings. By using continuously updated Non-Uniform Rational B-spline (NURBs) metamodels of system performance to monitor the system condition, the onset of incipient faults can be detected by comparison to a self-generated as-built system metamodel, providing a basis for determining off-normal operating conditions. This capability is demonstrated for three distinct fault conditions prevalent in brushless DC motors. The results show that this technique can be used to develop an as-built system metamodel, develop a current system model during system operation, and detect the presence of an incipient fault condition despite the compensation provided by a feedback control system.
Conceptual Synthesis of Compliance at a Single Point
Authors: Kim Charles , Moon Yong-Mo , Kota Sridhar
Published: June 2008

In this paper, we investigate a methodology for the conceptual synthesis of compliance at a single point based on a building block approach. The methodology lays the foundation for more general compliant mechanism synthesis problems involving multiple points of interest (i.e. inputs and outputs). In the building block synthesis, the problem specifications are decomposed into related sub-problems if a single building block cannot perform the desired task. The sub-problems are tested against the library of building blocks until a suitable building block is determined. The synthesized design is composed of an assembly of the building blocks to provide the desired functionality. The building block approach is intuitive and provides key insight into how individual building blocks contribute to the overall function. We investigate the basic kinematic behavior of individual building blocks and relate this to the behavior of a design composed of building blocks. This serves to not only generate viable solutions but also to augment the understanding of the designer. Once a feasible concept is thus generated, known methods for size and geometry optimization may be employed to fine tune performance. The key enabler of the building block synthesis is the method of capturing kinematic behavior using Compliance Ellipsoids. The mathematical model of the compliance ellipsoids facilitates the characterization of the building blocks, transformation of problem specifications, decomposition into sub-problems, and the ability to search for alternate solutions. The compliance ellipsoids also give insight into how individual building blocks contribute to the overall kinematic function. The effectiveness and generality of the methodology are demonstrated through a synthesis example. Using only a limited set of building blocks, the methodology is capable of addressing generic kinematic problem specifications.
Design for Mass Customization in the Early Stages of Product Development
Authors: Marion Tucker J. , Freyer Matthew , Simpson Timothy W. , Wysk Richard A.
Published: June 2008

This paper describes a method for the early stages of new product development that supports the conceptual design of modular, platform-based, and customizable components. The method includes up-front product planning encompassing definition of customer requirements, market segmentation, and competitive product analysis, ultimately leading to product specifications. The results from product planning are combined with tools for developing a product platform architecture with easily customizable customer interface components, which are based on well-defined interfaces. The method and tools are applied to a family of bactericidal door handle products. The major elements of the customizable door handle product architecture are defined, and several concepts are generated that utilize modularity, customization, and product platforms within a single design. The results are discussed in detail with specific comments on applying up-front planning and design tools in terms of modularity and customization for commercialization based on well-defined interfaces. Finally, we conclude with comments on the limitations of the method, proposed improvements, and future work.
Modeling Design Spaces With Discontinuous Variables Using NURBs HyPerModels
Authors: Turner Cameron J. , Crawford Richard H.
Published: June 2008

The vast majority of metamodeling demonstrations focuses on problems composed of continuous variables. However, important engineering design problems often include one or more discontinuous variables that require special attention. Previous work demonstrated the ability of Non-Uniform Rational B-spline HyPerModels to represent highly nonlinear functions composed of continuous variables. With minor modifications those capabilities can be extended to include functions defined by combinations of discontinuous input and output variables of different types, including discrete integer variables, feasibility variables and membership functions. Examples are used to demonstrate these modeling capabilities including applications developed from real engineering design problems such as the optimal positioning of a construction site crane and the optimal lay-up of a composite material I-beam.
Joint Coupling Design of Underactuated Grippers
Authors: Dollar Aaron M. , Howe Robert D.
Published: June 2008

This paper examines the nature of joint coupling in underactuated grippers for environments where object properties and location may not be well known. A grasper consisting of a pair of two-link planar fingers with compliant revolute joints was simulated as it was actuated after contact with a target object. The joint coupling configuration of the gripper was varied in order to maximize successful grasp range and minimize contact forces for a wide range of target object size and position. A normal distribution of object position was assumed in order to model sensing uncertainty and weight the results accordingly. The results show that proximal-distal joint torque ratios of around 0.6 produced the best results for cases in which sensory information available for the task was poor, and ratios of around 1.0 produced the best results for cases in which sensory information available for the task was good.
Computer Aided Synthesis of Piecewise Rational Motions for Spherical 2R and 3R Robot Arms
Authors: Purwar Anurag , Jin Zhe , Ge Q. J.
Published: June 2008

This paper deals with the problem of synthesizing piecewise rational spherical motions of an object that satisfies the kinematic constraints imposed by a spherical robot arm with revolute joints. The paper brings together the kinematics of spherical robot arms and the recently developed freeform rational motions to study the problem of synthesizing constrained rational motions for Cartesian motion planning. Using quaternion kinematics of spherical arms, it is shown that the problem of synthesizing the Cartesian rational motion of a 2R arm can be reduced to that of circular interpolation in two separate planes. Furthermore, the problem of synthesizing the Cartesian rational motion of a spherical 3R arm can be reduced to that of constrained spline interpolation in two separate planes. Due to the limitation of circular interpolation, for spherical 2R robot arm, only C1 continuous rational motions are generated. In this case, for applications that require C2 continuous motions, the paper presents a method for generating a C2 continuous joint motion that approximates a given C1 rational motion of the end-effector. For spherical 3R arm, C2 continuous rational motions are generated exactly.
Verve: A General Purpose Open Source Reinforcement Learning Toolkit
Authors: Streeter Tyler , Oliver James , Sannier Adrian
Published: June 2008

Intelligent agents are becoming increasingly important in our society in applications as diverse as house cleaning robots, computer-controlled opponents in video games, unmanned aerial combat vehicles, entertainment robots, and autonomous explorers in outer space. However, the broader adoption of intelligent agents is often hindered by their limited adaptability to new tasks; when conditions change slightly, agents may quickly become confused. Additionally, a substantial engineering effort is required to design an agent for each new task. This paper presents an adaptable, general purpose intelligent agent toolkit based on reinforcement learning (RL), an approach with strong mathematical foundations and intriguing biological implications. RL algorithms are powerful because of their generality: agents simply receive a scalar reward value representing success or failure, which greatly simplifies the agent design process. Furthermore, these algorithms can be combined with other techniques (e.g., planning from a learned internal model) to improve learning efficiency. The design and implementation of an open source RL toolkit is presented here as a step towards the goal of general purpose agents. Experimental results show learning performance on several tasks, including two physical control problems.
Rotating Range Sensor System for Obstacle Detection and Map Building
Authors: Park Hyunwoong , Lee Sooyong
Published: June 2008

This paper describes a new sensor system for improving the accuracy of the range information using multiple IR range sensors. Environment and obstacle sensing is the key issue for mobile robot localization and navigation. Laser scanners cover 180° and are accurate but too expensive. Radial range sensors such as laser scanners, IR scanners and Ultrasonic range sensor rings have blind spots so that a small obstacle not close enough to the sensor may be easily missed. It is necessary to develop a low cost sensor system which covers 360° with small blind spots. A sensor system with 12 IR range sensors is designed and implemented. The problem of the 2D sensor systems is, they measure the nearby obstacles on a plane where the sensors are located. In order to scan the environment vertically, a 2.5D sensor system is designed and the experimental result shows the effectiveness of the proposed sensor system.