bluuebunny/crossref_metadata_2025 huggingface dataset:
An Application of Parallel Singularity in Variable Stiffness Elements
Authors: Azadi Mojtaba , Behzadipour Saeed
Published: July 2009

Variable stiffness elements (VSE) or variable springs have wide applications in vibration control systems and robotics. In this work, the concept of a new VSE is introduced and the criteria for the design are explained. The new VSE is based on a special case of cable-driven mechanisms at a singular configuration and is called antagonistic variable stiffness element (AVSE). Singularity of the mechanism provides interesting characteristics for the AVSE such as zero elastic (passive) stiffness and fully controllable stiffness along the infinitesimal flex. Based on the given criteria, the possible configurations of the AVSE are found.
Assessing Functional and Shape Differentiation Within a Family of Products
Authors: Alizon Fabrice , Fu Jing , Simpson Timothy W. , Joshi Sanjay B. , Shooter Steven B.
Published: July 2009

Market differentiation strategies must identify competitive advantages when offering a line of products varying in features, price, quality, and/or aesthetics. Although this concept is well-known, many companies still have difficulties positioning their own products within their own product lines and against competitors. Few approaches combine two or more facets to answer the product differentiation problem. In this study, two novel indices are proposed to audit shape and functional differentiation within a family of products. The shape index appraises the shape similarity between the products upon digitization, while the functional assessment is based on functions characteristics of the product. Customers’ perception data is obtained experimentally and compared to these indices to validate the result. Pairs of products are evaluated, and the average scores are considered as the indices for a product family. A case study illustrates the usage of these two indices and performance of these tools as well. This approach can be used during detailed studies as well as early stages of the design process to help validate product family positioning.
Fundamental Strategies for System Optimization of Machine Product Designs
Authors: Yoshimura Masataka , Yoshimura Yu , Izui Kazuhiro , Nishiwaki Shinji
Published: July 2009

In machine product designs, a variety of characteristics such as product performances, manufacturing cost, and robustness of characteristics are evaluated, and the need for improvements is increasingly stringent over time. Such characteristics almost always have interrelationships, and systematic evaluation and optimization must be performed to obtain preferable product design solutions. To conduct effective system optimization, the complex interrelationships among characteristics that are included, and sometimes hidden, in the optimization problem, must be understood and dealt with. To construct optimization methodologies for such problems, these relationships must be clarified, and the characteristics simplified. Simplifying the characteristics makes the essence of the optimization problem clearer, and facilitates examining the interrelationships among the simplified characteristics during the optimization process. Based on the simplified characteristics, “priority relationships”, i.e., relationships among simplified characteristics that will be optimized first, and “conflicting relationships”, i.e., tradeoff relationships that will be simultaneously optimized, are obtained. Hierarchical optimization procedures develop naturally as the relationships among the simplified characteristics are clarified. This paper focuses on the priority relationships of characteristics in system optimization procedures. General and specific rules concerning priority relationships are presented, and these form the basis for the constructed optimization procedures. An applied example of a machine tool product design is presented to demonstrate the effectiveness of the proposed methodology.
Contact Analysis Between a Moving Solid and the Boundary of Its Swept Volume
Authors: Erdim Hu¨seyin , Ilies¸ Horea T.
Published: July 2009

The modeling of many practical problems in design and manufacturing involving moving objects relies on sweeps and their boundaries, which are mathematically described by the envelopes to the family of shapes generated by the moving object. In many problems, such as the design and analysis of higher pairs or tool path planning, contact changes between the moving object and the boundary of its swept volume become critical because they often translate into functional changes of the system under consideration. However, the difficulty of this task quickly escalates beyond the reach of existing approaches as the complexity of the shape and motion increases. We recently proposed a sweep boundary evaluator for general sweeps in conjunction with efficient point sampling and surface reconstruction algorithms that relies on our novel point membership classification (PMC) test for general solid sweeps. In this paper we describe a new approach that automates the prediction of changes in the state of contact between a shape of arbitrary complexity moving according to an affine motion, and the boundary of its swept set. We show that we can predict when and where such contact changes occur with only minimal additional computational cost by exploiting the data output by our sweep boundary evaluator. We discuss the problem and the associated computational issues in a 2D framework, and we conclude by discussing the extension of our approach to 3D moving objects.
Rational Using of Small Frontal Rigid Gear Couplings Type Gleason at Simple Direct and Differential Dividing and Geometrical Development of Smaller Size
Authors: Ungur Petru , Pop Petru A. , Gordan Mircea , Gordan Cornelia , Veres Mircea
Published: July 2009

This paper has presented two constructive solutions of rational using of frontal rigid gear couplings with spherical gear in circle arc type Gleason, knowing as curved frontal gear coupling, on small dimensions, ones for simple direct dividing and second for simple differential dividing, and geometrical development possibility of new family of frontal coupling and small size. The frontal gear coupling type Gleason are formed from two rings, one with concave gear and other with convex gear, being characterized by great twist moments of capacity transmission, realizing a precision angular position, fast central connection and assuring of optimal conditions for manufacturing of mass production and low cost. One new application of small frontal gear couplings was external diameter of O̸100mm and O̸120mm, assured a higher accuracy of angular location of ±2″ and a great carrying capacity for couplings by using of compound rest of lathe with ultra precision location. A second application has presented a new landing of simple direct and differential dividing using one or more pair of Gleason’s gear coupling due to construction of new indexing tables with ultra precision in metal cutting.
Intuition-Based Browsing Interaction Towards Emotional Design
Authors: Ito Teruaki
Published: July 2009

Emotional qualities such as the product’s aesthetics are regarded as critical factors in mature products. In the mean time, the products, whichever they are matured or not, must satisfy the functional requirements from the customers considering the technical constraints. For emotional designing, the designer’s view point towards the design object plays a very critical role. However, those views are not well taken care of in the conventional design support tools. The author proposed the idea of perspective browsing, where the designer’s viewpoint is represented as “Perspective”. There can be a variety of “Perspective” during the product designing process, and these are all dynamic. If “Perspective” is well taken care of, kept, and shared during the designing process, the designer’s thought can be well maintained, activated, and transferred to the product design. To verify the effectiveness of the idea, Intuition-based Browsing Interaction system, or IBI system has been designed to support a bicycle design and implemented as a software tool. The main module of IBI is composed of four sub-modules; namely, parts/component, size/shape, technical calculation, and 3D modeling. Basic user interface is implemented to control the design operation. However, intuitive user interface is wrapped over the basic interface so that the user can intuitively use the system as an idea generation support tool. Some modules have a function as a portal to other systems or modules. Parts/component module works with internal/external database and 3D modeling module works with external modeling software. Showing the interaction example for a bicycle design, this paper presents how IBI system supports the designer. Even though IBI is still a prototype system for bicycle design, perspective browsing can be recognized for designing process of a bicycle. The designer can freely access to the design object from different perspectives to modify, update, change, evaluate in an intuitive manner. The target user of IBI is not only limited to product designer, but also is aimed at the customer who use the bicycle. Therefore, the customers themselves can participate in the designing activities and contribute to create innovative design based on the emotional feelings and inspirations.
Instantiation and Manipulation of User-Defined Freeform Features
Authors: Langerak Thomas R.
Published: July 2009

One of the sub-topics of CAD research is the topic of feature-based design. Features are characteristic parts of a shape to which functional or parameter information can be attached. By using features in a design process, high-level interrogation and editing of a shape model is enabled. It is widely accepted that feature-based design methods should be able to handle user-defined features. Much work has been done on the definition of features and the management of feature definitions, but very little work has been done on the instantiation of these features on a target shape, especially in the domain of freeform shape. This paper discusses the current literature on freeform feature-based design and identifies the issues that play a role in the instantiation and manipulation of freeform features on target shapes. Also, a general methodology is proposed for the instantiation and manipulation of freeform features. Finally, an implementation of the proposed methods and some application examples are given.
Optimization of Engine Torque Management Under Uncertainty for Vehicle Driveline Clunk Using Time-Dependent Metamodels
Authors: Wehrwein Daniel , Mourelatos Zissimos P.
Published: July 2009

Quality and performance are two important customer requirements in vehicle design. Driveline clunk negatively affects the perceived quality and must be therefore, minimized. This is usually achieved using engine torque management, which is part of engine calibration. During a tip-in event, the engine torque rate of rise is limited until all the driveline lash is taken up. However, the engine torque rise, and its rate can negatively affect the vehicle throttle response which determines performance. Therefore, the engine torque management must be balanced against throttle response. In practice, the engine torque rate of rise is calibrated manually. This paper describes an analytical methodology for calibrating the engine torque, considering uncertainty, in order to minimize the clunk disturbance, while still meeting throttle response constraints. A set of predetermined engine torque profiles which span the practical range of interest, are used and the transmission turbine speed is calculated for each profile using a bond-graph vehicle model. The turbine speed quantifies the clunk disturbance. Using the engine torque profiles and the corresponding turbine speed responses, a time-dependent metamodel is created using principal component analysis and Kriging. The metamodel predicts the turbine speed response due to any engine torque profile and is used in a deterministic and reliability-based optimization which minimizes the clunk disturbance while still meeting the throttle response target. Compared with commonly used production calibration, the clunk disturbance is reduced substantially without negatively affecting the vehicle throttle response.
Microgrooves Enhanced AC Electrothermal Pumping for High Conductivity Microfluids
Authors: Du E. , Manoochehri Souran
Published: July 2009

This paper presents utilization of microgrooved structure in enhancing manipulation of high conductivity fluids with alternating current (AC) electrothermal mechanism with low electric voltage requirement (<10 V ). Two manipulation modes including bidirectional pumping and stationary state can be achieved by changing the electric frequency. Numerical simulations are performed and the effects on electrothermal driven fluid motion in grooved surface structure are investigated. The pumping capacity of several grooved profiles of rectangular, trapezoid and hybrid trapezoid are analyzed and compared. The theoretical analysis as well as the numerical simulation indicates that electrothermal driven micropumping and temperature rise can be controlled in these structures for optimum operations.
Sensitivity Analyses of FORM-Based and DRM-Based Performance Measure Approach for Reliability-Based Design Optimization
Authors: Lee Ikjin , Choi Kyung K. , Du Liu , Gorsich David
Published: July 2009

In a gradient-based design optimization, it is necessary to know sensitivities of the constraint with respect to the design variables. In a reliability-based design optimization (RBDO), the constraint is evaluated at the most probable point (MPP) and called the probabilistic constraint, thus it requires the sensitivities of the probabilistic constraints at MPP. This paper presents the rigorous analytic derivation of the sensitivities of the probabilistic constraint at MPP for both First Order Reliability Method (FORM)-based Performance Measure Approach (PMA) and Dimension Reduction Method (DRM)-based PMA. Numerical examples are used to demonstrate that the analytic sensitivities agree very well with the sensitivities obtained from the finite difference method (FDM). However, since the sensitivity calculation at the true DRM-based MPP requires the second-order derivatives and additional MPP search, the sensitivity derivation at the approximated DRM-based MPP, which does not require the second-order derivatives and additional MPP search to find the DRM-based MPP, is proposed in this paper. A convergence study illustrates that the sensitivity at the approximated DRM-based MPP converges to the sensitivity at the true DRM-based MPP as the design approaches the optimum design. Hence, the sensitivity at the approximated DRM-based MPP is proposed to be used for the DRM-based RBDO to enhance the efficiency of the optimization.
On the Ability of a Cable-Driven Robot to Generate a Prescribed Set of Wrenches
Authors: Bouchard Samuel , Gosselin Cle´ment M. , Moore Brian
Published: July 2009

This paper presents a new geometry-based method to determine if a cable-driven robot operating in a d-degree-of-freedom workspace (2 ≤ d ≤ 6) with n ≥ d cables can generate a given set of wrenches in a given pose, considering acceptable minimum and maximum tensions in the cables. To this end, the fundamental nature of the Available Wrench Set is studied. The latter concept, defined here, is closely related to similar sets introduced in [23, 4]. It is shown that the Available Wrench Set can be represented mathematically by a zonotope, a special class of convex polytopes. Using the properties of zonotopes, two methods to construct the Available Wrench Set are discussed. From the representation of the Available Wrench Set, computationally-efficient and non-iterative tests are presented to verify if this set includes the Task Wrench Set, the set of wrenches needed for a given task.
Three Dimensional Behavior of Fully Compliant Bistable Micromechanisms
Authors: Cherry Brian B. , Howell Larry L.
Published: July 2009

An improved understanding of the three-dimensional behavior of fully compliant bistable micromechanisms (FCBMs) would facilitate their appropriate implementation in applications such as threshold sensing arrays. A 3-D finite element model was developed to analyze the motion of a nominal FCBM design with various eccentric and off-axis loading conditions. Roll, pitch, and yaw rotations and Z-direction deflection results are presented for various loading conditions. Two distinct behaviors are discussed. Phenomenon 1 occurred when no off-axis loads were applied or when the magnitudes were small. Phenomenon 1 is characterized by shuttle motion with a relatively large pitch rotation. Phenomenon 2 occurred for larger magnitudes of off-axis loads, and was characterized by larger Z-direction deflections, lower actuation forces, and occasional loss of bistability.
Continuous Workspace Analysis, Synthesis and Optimization of Wire Robots
Authors: Bruckmann Tobias , Mikelsons Lars , Hiller Manfred , Schramm Dieter
Published: July 2009

Wire robots (also called Tendon-based parallel manipulators) use a movable end-effector which is connected to a machine frame by motor driven tendons. Since tendons can transmit only pulling forces, at least m = n + 1 cables are needed to tense a system having n degrees-of-freedom. The resulting redundancy gives m − n degrees-of-freedom in the wire force distribution, making workspace analysis a complex and computationally expensive task. Discrete methods are widely used to solve this problem, but their drawback is that intermediate points on the discrete calculation grid are neglected which may lead to false results. This paper provides detailed algorithms for continuous workspace analysis for wire robots which avoid the discretization and have additional advantages. Especially, it is easy to extend the analysis methods to methods usable for the workspace synthesis.
Sensitivity Analysis of Planar Parallel Manipulators
Authors: Caro Ste´phane , Binaud Nicolas , Wenger Philippe
Published: July 2009

This paper deals with the sensitivity analysis of planar parallel manipulators. A methodology is introduced to derive the sensitivity coefficients by means of the study of 3-RPR manipulators. As a matter of fact, the sensitivity coefficients of the pose of its moving platform to variations in the geometric parameters are expressed algebraically, the variations being defined both in Polar and Cartesian coordinates. The dexterity of the manipulator is also studied by means of the conditioning number of its normalized kinematic Jacobian matrix. As an illustrative example, the sensitivity of a symmetrical planar parallel manipulator is analyzed in detail. Finally, the accuracy of the manipulator is compared with its dexterity.
Stochastic Control for Self-Assembly of XBots
Authors: Ayanian Nora , White Paul J. , Ha´la´sz A´da´m , Yim Mark , Kumar Vijay
Published: July 2009

We propose a stochastic, decentralized algorithm for the self-assembly of a group of modular robots into a geometric shape. The method is inspired by chemical kinetics simulations, particularly, the Gillespie algorithm [1, 2] that is widely used in biochemistry, and is specifically designed for modules with dynamic constraints, such as the XBot [3]. The most important feature of our algorithm is that all modules are identical and all decision making is local. Individual modules decide how to move based only on information available to them and their neighbors and the geometric, kinematic and dynamic constraints. Each module knows the details of the goal configuration, keeps track of its own location, and communicates position information locally with adjacent modules only when modules in their vicinity have reconfigured. We show that this stochastic method leads to trajectories with convergence comparable to those obtained from a brute-force exploration of the state space. However, the computational power (speed and memory) requirements are independent of the number of modules, while the brute-force approach scales quadratically with the number of modules. We present the schematic of the modules, preliminary experimental results to illustrate the basic moves, and simulation results to demonstrate the efficacy of the algorithm.
Precision Circular Walking of Bipedal Robots
Authors: Muecke Karl J. , Hong Dennis W. , Lim Seungchul
Published: July 2009

Whenever bipedal robots need to make turns, the ability to walk stably and precisely along a circular curve of an arbitrary radius will be quite beneficial. This motivates us to derive new Zero Moment Point (ZMP) constraint equations with respect to a rotating coordinate frame, seek appropriate dynamic gaits based on them, and address the forward and inverse kinematics. After the relevant body and feet trajectories are fully prescribed, joint motions are determined using the inverse kinematics. A set of dynamic walking patterns including the transient are herein proposed and applied to an exemplificative case of turning locomotion. Conclusively, dynamic simulations prove the patterns to be successful even in the presence of distributed-mass and ground contact effects.
Improving Cost Effectiveness in an Existing Product Line Using Component Product Platforms
Authors: Farrell Ronald S. , Simpson Timothy W.
Published: July 2009

Previously, we introduced a new method for improving commonality in a highly customized, low volume product line using component product platforms. The method provides a bottom-up platform approach to redesign family members originally developed one-at-a-time to meet specific customer requirements. In this paper, we extend the method with an Activity-Based Costing (ABC) model to specifically capture the manufacturing costs in the product line, including the cost associated with implementing a platform strategy. The valve yoke example is revisited in this paper, the customized ABC model is defined, two design strategy alternatives are addressed, and the new method is used to determine which alternative is better at resolving the tradeoff between commonality, total cost, and product performance. The proposed method shows promise for creating a product platform portfolio from a set of candidate component platforms that is most cost-effective within an existing product line. The proposed method allows for arbitrary leveraging as it does not rely solely on the traditional vertical, horizontal, or beachhead strategies advocated for the market segmentation grid, and this is especially beneficial when applied to an existing product line that was develop one-at-a-time time such that artifact designs are inconsistent from one to another.
Basic Study on Trend Prediction for Style Design
Authors: Yoshida Shinya , Aoyama Hideki
Published: July 2009

With diversification of consumer taste, appearance shape together with functionality contributes to the appeal of a product vastly. Concept design and industrial design therefore serve as an important process in product development. These designs are difficult to perform based on theoretical backing, since appearance shape design is a creative activity which depends on a designer’s aesthetic sense strongly. When embodying a product shape, naturally design is determined not only by a designer’s sensitivity but by use and function of a product as well. It is also important to investigate designs desired by consumers, and reflect all of this in the product design. The ability to predict consumer taste trends therefore greatly aids product design. In this research, the prototype models of a product in trend every year were made by multiplying weights according to the number of a product sold in the past to calculate that the rate of exaggeration of prototype models of each year to all whole prototype models. The straight extrapolation of the Spline method was applied to the exaggeration vector, and the technique of predicting shapes preferred by consumers in the near future using that method was proposed. Moreover the eigenspace method was applied to similar product shapes to propose the technique of grasping the features of shape for every year by computing the eigenvalue and eigenvector of the coordinates of the points of the shapes as well as the technique of predicting shapes which consumers will prefer in the near future by using the Linear function of Moving Least Square method.
Dynamic Simulation of Topology-Varying Mechanisms by Replacing Local Modeling Units
Authors: Zhao Kai , Wang Hao , Chen Guanlong
Published: July 2009

Global simulation of mechanisms with time-varying topology is a tough task because the kinematic and kinetic equations of the whole system should be reformulated at each different topological stage, which increases the difficulty and decreases the efficiency. This paper proposes a new dynamics simulation approach of topology-varying mechanisms by replacing local modeling units. The interchangeability of unit models makes it possible to switch among different topologies automatically without rebuilding the system model. The topology-varying part of the system can be modeled as changeable modeling units, which leaves the other part as a settled one. Local replacement of changeable units will realize the reconfiguration of system model from one topological stage to another. This method has been used to analysis two typical kinds of mechanisms with time-varying topology: mechanism with “lock-unlock” process and with “opening-closing” loop. The simulation of the buffering motion in a forging manipulator is presented here as a case study, which proves the feasibility and efficiency of this new approach.
Agent Based Variation Propagation for Collaborative Top-Down Assembly Design
Authors: Zhang Shuting , Chen Xiang , Gao Shuming , Yang Youdong
Published: July 2009

The design of a complex mechanical product is usually a top-down process carried out by different teams or designers that are geographically distributed. A systematical variation propagation mechanism is very important to fully support such a design process. In this paper, based on the framework for collaborative top-down assembly design previously proposed by the authors, an agent based approach is presented for addressing variation propagation for collaborative top-down assembly design. The approach achieves variation propagation during the collaborative top-down assembly design through the interaction and cooperation of the agents located at the clients and server. To make the variation propagation automated and intelligent, four kinds of variation reasoning including hierarchical variation reasoning, engineering constraint variation reasoning, feature variation reasoning, and assembly constraint variation reasoning are identified, and the corresponding algorithms are developed and utilized. Meanwhile, a distributed assembly model is put forward to effectively support the design variation propagation for the collaborative top-down assembly design. The approach is implemented and a variation propagation example is given.
Integrating Motion Platforms With Unmanned Aerial Vehicles to Improve Control, Train Pilots and Minimize Accidents
Authors: Hing James , Oh Paul Y.
Published: July 2009

As the number of UAVs increase, the risk of accidental crashes also grows. A critical examination of these accidents reveals that human error is a major cause. This suggests a need to improve the remote piloting of UAVs. This paper explores the use of motion platforms to augment pilot performance. This approach follows studies on human factors performance and cognitive loading. The resulting design serves as a test bed to study UAV pilot performance, create training programs, and ultimately a platform to avoid UAV accidents.
Interval Extensions of Signed Distance Functions: Uniform Samplings and the Range of Associated Implicit Objects
Authors: Storti Duane , Ganter Mark
Published: July 2009

This paper considers the problem of inferring the geometry of an object from values of the signed distance sampled on a uniform grid. The problem is motivated by the desire to effectively and efficiently model objects obtained by 3D imaging technology that is now ubiquitous in medical diagnostics. Recently developed techniques for automated segmentation convert intensity to signed distance, and the voxel structure imposes the uniform sampling grid. While specification of the signed distance function throughout the ambient space would provide an implicit model that uniquely specifies the object, a set of uniformly sampled signed distance values may uniquely determine neither the distance function nor the shape of the object. Here we employ essential properties of the signed distance to construct upper and lower bounds on the allowed variation in signed distance in 1, 2, and 3 dimensions. The bounds are combined to produce interval-valued extensions of the signed distance function including a tight global extension and more computationally efficient local bounds that provide useful criteria for root exclusion/isolation.
Teaching Mechanics of Machines to Students of Automation Engineering
Authors: Galletti Carlo , Giannotti Elena
Published: July 2009

We present our experience with teaching an elective course in mechanics of machines to students of automation engineering. The subjects of the course are related to those of system and control engineering in order to emphasize relationships with core courses of the curriculum. The traditional organization of the course into classroom lectures is supported by a multibody simulation software and by the computer-laboratory work of teams of students. Students must build the multibody model of a mechanical system that satisfies given tasks. Then, they must use it as a facility to understand several matters that they have already studied in other courses, or that have been presented in our classroom activity. Satisfactory results require strong interactions with teachers.
Defining Specifications for Custom Products: A Bayesian Probabilistic Approach
Authors: Wang Yue , Tseng Mitchell M.
Published: July 2009

Defining product specifications to meet customers’ preferences is a crucial and challenging task for custom product design. An efficient specification defining method should take both product structures and customers’ preferences into consideration. Because customers’ preferences depend largely on factors such as product attributes and external parameters, conventional specification definition methods in deterministic form fall short of providing adequate approaches to represent and manipulate the probabilistic nature of customers’ preferences. They often suffer from low efficiency, lack of intelligence to adapt to different customers’ inputs, being unable to provide guidance to users who have little domain knowledge, etc. These technical issues have hindered the development of custom product design and mass customization. To solve these issues, Bayesian network is deployed to represent the product physical structure and the likelihood of the customers’ potential preferences among components. The specification defining is modeled as an uncertainty elimination process and an information theory based algorithm is applied to obtain customers’ target product configuration. The idea is to sequentially select the most relevant component for a customer to specify from the remaining components pool based on his previous step’s specification. An inference module is also proposed which can recommend possible product configurations to help customers find what they want quickly. Thus a customized 1-to-1 specification defining procedure is provided and the final configuration can converge to a customer’s target with fewer interactions between the customer and product design team. This paper explores the framework of product specification defining in uncertain domain and offers a new angle to advance design for mass customization (DfMC), and possibly the Design for Manufacturing in general.
Adaptive NC Path Generation From Massive Point Data With Bounded Error
Authors: Zhang Dongdong , Yang Pinghai , Qian Xiaoping
Published: July 2009

This paper presents an approach for generating curvature-adaptive finishing tool paths with bounded error directly from massive point data in three-axis CNC milling. This approach uses the Moving Least Squares (MLS) surface as the underlying surface representation. A closed-form formula for normal curvature computing is derived from the implicit form of MLS surfaces. It enables the generation of curvature-adaptive tool paths from massive point data that is critical for balancing the trade-off between machining accuracy and speed. To ensure the path accuracy and robustness for arbitrary surfaces where there might be abrupt curvature change, a novel guidance field algorithm is introduced. It overcomes potential excessive locality of curvature-adaptive paths by examining the neighboring points’ curvature within a self-updating search bound. Our results affirm that the combination of curvature-adaptive path generation and the guidance field algorithm produces high-quality NC paths from a variety of point cloud data with bounded error.
On the Mathematical Morphology Based Coupler-Curve Feature Extraction for the Purpose of Synthesis of Path Generating Mechanism
Authors: Xie Jin , Yan Hui , Chen Yong
Published: July 2009

To extract the features from a coupler curve is one of key issues in the synthesis of path generating mechanism. Fourier transformation is widely used at present. A new method of feature extraction, named mathematical morphology based method, emerges in resent years. Based on the essential operations of mathematical morphology, the shape spectrum (SS) of the coupler curve is computed. SS is rotation-scale-translation invariant. Therefore, as a means of describing coupler curve, it has possesses advantage over that based on Fourier transformation. In this paper, what kind information involved in SS of a curve is revealed. It is shown that the largest radius of internally tangent circle and the area inside of the curve can be inferred from its SS. This paper also shows that SS is without the information of the structure feature which is necessary to describe a nonsimple closed coupler curve. Eight-figure-shaped coupler curve is the simplest nonsimple closed curve. To describe such curve, three structure parameters of the curve should be involved besides that provided by SS of curve. A method using five numbers to describe and differentiate an eight-figure-shaped coupler curve is proposed in this paper. The five numbers can be obtained from its SS and the structure of the curve. A new formula to compute the similarity between two eight-figure-shaped couplers using the five numbers is presented.
Design and Control of an Omnibot Autonomous Vehicle
Authors: Bemis Steven , Riess Brian , Nokleby Scott
Published: July 2009

A design for autonomous control of a novel omni-directional platform is presented. This platform is to be used in conjunction with a robotic arm to further research of mobile-manipulator systems. This design differs from other omni-directional platforms that use omniwheels in that its drive axes do not intersect its geometric centre. The platform can be controlled autonomously through multiple sub-systems that have been designed including a closed-loop velocity controller, a localization system, an obstacle avoidance and collision detection system, a vision system, and a data routing system. These sub-systems communicate with a remote computer which plots the path and sends data to guide the platform. The closed-loop velocity controller provides feedback which can be used to analyze and correct the path of travel.
Synthesis of Grashof Four-Bar Mechanisms Using Particle Swarm Optimization
Authors: McDougall Robin , Nokleby Scott
Published: July 2009

A Particle Swarm Optimization algorithm (PSO) and Grashof criteria for a four-bar mechanism are used to develop a general Grashof four-bar mechanism synthesis routine. The use of the stochastic PSO algorithm to minimize the non-linear objective function removes the requirement for sequential parameter transforms and design constraints previously employed in tandem with traditional deterministic quasi-Newtonian optimization routines to achieve convergence on meaningful global minima which often artificially constrict the feasible solution set space under exploration. The performance of this implementation compares favourably with other mechanism synthesis algorithms, particularly as the number of specified precision points is increased.
Elicitation and Modeling of Customers’ Preferences in Industrial Design: A Comparative Study on Vehicle Front End
Authors: Dagher Antoine , Petiot Jean-Franc¸ois , Guyon Herve´
Published: July 2009

The understanding of customer preference, in relation to product attributes, is a key challenge in industrial design. It is based on preference measurement, which is a complex task, crucial for sound design decisions. In this paper, we study experimentally the influence of the preference elicitation method on the results of the test. For this, we designed a case study concerning the perception of vehicle’s front-end by a panel of subjects. Two different preference elicitation methods were used in the same session: direct rating on a scale, and pairwise comparison. Conjoint Analysis was used next to model the preference and to compute the part worth of the different design factors. Two conjoint methods were examined: rating based and choice based. The paper presents a comparison of the results of the different modeling with conjoint analysis, in order to assess the reliability and the validity of the models.
Optimal Kinematics Design of an Industrial Robot Family
Authors: O¨lvander Johan , Feng Xiaolong , Holmgren Bo
Published: July 2009

Product family design is a well recognized method to address the demands of mass customization. A potential drawback of product families is that the performance of individual members are reduced due to the constraints added by the common platform, i.e. parts and components need to be shared by other family members. This paper presents a formal mathematical framework where the product family design problem is stated as an optimization problem and where optimization is used to find an optimal product family. The object of study is kinematics design of a family of industrial robots. The robot is a serial manipulator where different robots share arms from a common platform. The objective is to show the trade-off between the size of the common platform and the kinematics performance of the robot.
The Effect of Sub-Wavelength Structure Morphology on Anti-Reflection Properties
Authors: Lin Hung-Yi , Tsai Jen-Hui , Chang Shuo-Hung , Wu Tung-Chuan , Wei Mao-Kuo
Published: July 2009

In this paper, we present a new thermal reflow method to transform photresist pillars into the shapes of spherical caps and month-eyes. We also investigated the effect of this sub-wavelength structure morphology on anti-reflection properties of these photoresist patterns. The diameter, the height, and the pitch of this regularly arranged pillar array were set at 200, 250, and 340 nm, respectively. After the thermal reflow, experimental results showed that the reflectivity of the heat-treated photoresist patterns can be reduced to approximately one fourth of that of the polished surface of the silicon wafer.
A Least-Squares Finite Element Formulation for Inverse Detection of Unknown Boundary Conditions in Steady Heat Conduction
Authors: Dennis Brian H.
Published: July 2009

A Least Squares Finite Element Method (LSFEM) formulation for the detection of unknown boundary conditions in steady heat conduction is presented. The method is capable of determining temperatures and heat fluxes in locations where such quantities are unknown provided such quantities are sufficiently overspecified in other locations. In several finite element and boundary element inverse implementations, the resulting system of equations becomes become rectangular if the number of overspecified conditions exceeds the number of unknown conditions. In the case of the finite element method, these rectangular matrices are sparse and can be difficult to solve efficiently. Often we must resort to the use of direct factorizations that require large amounts of core memory for realistic geometries. This difficulty has prevented the solution of large-scale inverse problems that require fine meshes to resolve complex 3-D geometries and material interfaces. In addition, the Galerkin finite element method (GFEM) does not provide the same level of accuracy for both temperature and heat flux. In this paper, an alternative finite element approach based on LSFEM will be shown. The LSFEM formulation always results in a symmetric positivedefinite matrix that can be readily treated with standard sparse matrix solvers. In this approach, the differential equation is cast in first-order form so equal order basis functions can be used for both temperature and heat flux. Enforcement of the overspecified boundary conditions is straightforward in the proposed formulation. The methods allows for direct treatment of complex geometries composed of heterogeneous materials.
Feature Mapping Automation for CAD Data Exchange
Authors: Hanayneh Leen , Wang Yiwen , Wang Yan , Wileden Jack C. , Qureshi Khurshid A.
Published: July 2009

Computer-aided design (CAD) data interoperability is one of the most important issues to enable information integration and sharing in a collaborative engineering environment. A significant amount of work has been done on the extension and standardization of neutral data formats in both academy and industry. In this paper, we present a feature mapping mechanism to allow for automatic feature information exchange. A hybrid semantic feature model is used to represent implicit and explicit features. A graph-based feature isomorphism algorithm is developed to support feature mapping between different CAD data formats.
Creative Stimulation in Conceptual Design: An Analysis of Industrial Case Studies
Authors: Howard Thomas , Culley Steve , Dekoninck Elies
Published: July 2009

When retrospectively analyzing the design process of a creative product, the creative leap or moment of inspiration is often described by the designer in an ‘idealized way’ [1]. There is little evidence within literature describing when the ideas behind promising concepts were conceived. This study tracks several real industrial design projects in the early conceptual design phase. The development and manipulation of ideas captured during the initial group brainstorm meeting are assessed in terms of the concepts at the following stage gate meeting. In addition, several different forms of stimulus were introduced to the different groups and compared to a control group. The results showed that the frequency of idea production remained virtually constant for the first 60 minutes. However, the number of ideas to form part of a concept at the stage gate meeting dropped markedly after the first 20 minutes. The frequency of appropriate ideas featuring within stage gate concepts increased with the introduction of stimuli, highlighting the positive effect of introducing stimuli.
Energy Characteristic State Model for Automated Conceptual Design of Hydraulic System
Authors: Ma Wenyong , Wang Delun , Ting Kwun-Lon
Published: July 2009

A new approach for automated conceptual design of hydraulic system is developed in this paper based on the energy characteristic state model. The energy characteristics of hydraulic systems are firstly represented by qualitative vectors, and the integral hydraulic systems are visualized as a set of subsystems with single-action for synthesis. Then, two categories of basic transformation units are defined from general hydraulic components, and the qualitative matrix representations for these basic transformation units are also established according to the function analysis. Finally, the conceptual design model for hydraulic system is established, in which the design processes of single-action subsystems are transformed into the decomposition of system-level matrices and the matching of component-level matrices. A design example is also given to illustrate the proposed approach.
A Growth Design Approach for Tolerancing
Authors: Huang Ke-Zheng , Ren Huai-Wei
Published: July 2009

Tolerancing is an essential part of a product design process. It is traditionally performed after the product structure has been determined. The product precision requirements may not be fully utilized for the decision making for selecting the best structure in the early stage of product design — the conceptual design phase. A growth design method has been proposed for product structure design and concurrent tolerancing, in which the product form and tolerance can be generated in the same way as an organism grows. The basic feature of biology, cell division, has been borrowed as the design guiding principle. Product conceptual model has been built as the basis of form and tolerance growth design. The relationship of product function, structure and tolerance was analysed to explain on what and how they act in product design process. Tolerance mathematic model expressed by screw parameters and expression model based on Technologically and Topologically Related Surface (TTRS) are described to execute the tolerance allocation. The automation selection of Datum reference frame (DRF) can facilitate the generation of tolerance. Finally, a prototype form design and tolerancing system has been implemented and applied to a dedicated fixture design to verify the validity of the growth design.
Application of an Emergent Design System to Artificial Hip Stem and Body in White
Authors: Sato Koichiro , Ujiie Yoshiki , Matsuoka Yoshiyuki
Published: July 2009

In early design processes, called conceptual and basic designs, diverse ideas must be obtained from a global solution search using the constraints from unclear design conditions. Thus, it is difficult to derive an adequate design solution for a design object with complicated conception because current methods to derive diverse solutions depend solely on designers’ experience and knowledge. Hence, it has been speculated that a method to derive diverse solutions globally will further improve the design environment. This study applies an emergent design system, which derives diverse solutions that can be applied to the early design process using the concept of emergence, to an artificial hip stem design and a Body In White (BIW:BIW is a car body frame) design. Then the effectiveness of the diverse solution derivation in this system was determined by comparing solutions derived from this system to the solution from the conventional optimization method for both application objects.
Performance Sensitivity Analysis of the Mesh-Free Random Grid Method for Whole Field Strain Measurements
Authors: Iliopoulos A. P. , Michopoulos J. G. , Andrianopoulos N. P.
Published: July 2009

In responding to the needs of the material characterization community, the recently developed mesh-free random grid method (MFRGM) has been exhibiting very promising characteristics of accuracy, adaptability, implementation flexibility and efficiency. In order to address the design specification of the method according to the intended application, in the present paper we are presenting a sensitivity analysis that aids into determining the effects of the experimental and computational parameters characterizing the MFRGM in terms of its performance. There are two sets of parameters that affect the performance characteristics of MFRGM for whole field strain measurement applications. The first set involves parameters associated with the characteristics of the experimental setup and the random grid applied on the specimen under measurement. The second set involves the computational characteristics of the mesh-free approximation and the solution (minimization) algorithms utilized. The performance characteristics of the MFRGM are mainly its accuracy, sensitivity, smoothing properties and efficiency. In the present paper we are presenting a classification of the first set of parameters as well as their relationship followed by the above mentioned sensitivity analysis to establish the influence trends in the performance characteristics with the intension to optimize the selection of the user controlled variables for a desired performance specification.