bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermochemical Stability of Sulfur Compounds in Fuel Cell Gases Related to Fuel Impurity Poisoning
Authors: Sasaki Kazunari
Published: June 2008

Since sulfur compounds are the major poisons of fuel cell systems, equilibrium concentrations of minor sulfur-based impurities in fuel cell fuels are thermochemically calculated in the temperature range between 400°C and 1000°C. As sulfur-based impurities in fuel cell gases, H2S(g), elementary sulfur, inorganic sulfur compounds, mercaptans, alkyl (di-)sulfides, thiophenes, and related compounds have been taken into account. Various types of fuels are also considered, including H2, H2–CO, CO, CH4, biogas, liquidified petroleum gas, gasoline, kerosene, and diesel fuel. Among the 21 kinds of sulfur-based typical impurities considered, H2S(g) is the most stable sulfur-based species. COS(g) can also coexist, but even in CO-rich gases and in hydrocarbon-based fuels, COS concentration in equilibrium is one order or a few orders of magnitude lower than H2S concentration. Other sulfur compounds, such as CH4S(g) at intermediate temperatures and HS(g) and SO2(g) at high temperatures, are also expected to coexist but their concentrations are less than 1ppb (parts per billion) assuming thermochemical equilibrium.
Preparation of a 3DOM Ni–YSZ Anode With a Dense YSZ Thin Electrolyte Layer for Solid Oxide Fuel Cells
Authors: Munakata Hirokazu , Otani Masashi , Kanamura Kiyoshi
Published: June 2008

A three-dimensionally ordered macroporous (3DOM) Ni–yttria stabilized zirconia (YSZ) anode with a YSZ thin electrolyte layer was developed by a colloidal crystal templating method in order to lower the operating temperature of solid oxide fuel cells due to a high and uniform electrochemical interface that originated from a 3DOM structure. In the present study, 2μm polystyrene beads were used as the template. The anode structure was strongly influenced by the pH of the suspension, and it was optimized to 1.8 according to the zeta-potential measurement and scanning electron microscope observation. The 3DOM anode and thin electrolyte layer were simultaneously formed by sintering the deposit that was obtained by filtering two kinds of suspensions by turns. Here, we successfully obtained a 3DOM anode with high porosity of 72% and a 3μm thin YSZ layer on it, which was favorable in reducing both electrolyte and polarization resistances.
Interconnection and Sealing Using Silver Metal for Honeycomb SOFCs
Authors: Wang Zhenwei , Shimizu Satoshi , Yamazaki Yohtaro
Published: June 2008

An interconnection and sealing method used for stacking the electrolyte-supported honeycomb solid oxide fuel cells (SOFCs) is presented. The honeycombs were made of 3mol% yttria partially stabilized zirconia and 8mol% yttria stabilized zirconia with 3×3 channels. The size of each channel was 5×5mm2 and 20mm long. The thickness of the channel walls is 1mm. The electrode materials were Ni-cermet and lanthanum strontium manganite. Newly designed metal plates with insulation layers were used for the interconnection and gas sealing between the honeycomb single cells. An open circuit voltage (OCV) of 2.19V was obtained at 800°C using a two-cell stack. A small amount of OCV reduction was observed during a thermal cycling. However, the high values of the OCVs and the stable current indicated preferable electric connections, and lower gas leakage. The successful test shows that the interconnection and sealing method with the proposed interconnect plates is promising for honeycomb SOFC stacks.
Modelling of a Flexible Quadrirotor Helicopter
Authors: Mouhingou Alexis , Azouz Naoufel
Published: June 2008

This paper describes the dynamical modelling for the simulation of the quadrirotor Helicopter in order to see the influence of the flexibility on the dynamical model. We consider a quadrirotor Helicopter like a multibody systems constituted of the flexible and rigid substructures interconnected by of articulation joint. We use the variationnal Lagrangian approach to define the equations governing the motion. Deformations modes are used to represent elastic deformations of the substructure relative to a body reference frame. The displacement functions shape of the flexible components is obtained by a finite element discretization technique. The numerical application is related to the quadrirotor XSF developed in the LSC (Laboratory of Complex Systems).
Performance of Asymmetrically Heated Extended Surface With Temperature Dependent Thermal Conductivity
Authors: Aziz A.
Published: June 2008

The effect of temperature dependent thermal conductivity on the performance of an asymmetrically heated extended surface which is commonly encountered in compact heat exchangers is studied both analytically and numerically. The surface is assumed to extend between two primary surfaces at different temperatures and to operate in a convective environment. The nonlinear differential equation governing the thermal performance of the extended surface is solved by carrying out a perturbation analysis in which the perturbation parameter is the dimensionless measure of thermal conductivity variation with temperature. Two-term analytical solutions for the temperature distribution and the convective heat dissipation are presented. The problem is also solved numerically for a range of conventional fin parameter, thermal asymmetry parameter, and thermal conductivity-temperature variation parameter to assess the accuracy of the perturbation solutions. Graphical results illustrating the effect of these parameters on the temperature distribution, heat transfer rates from the end primary surfaces, and the total heat transfer from the extended surface are provided and discussed. For the thermal conductivity variations encountered in compact heat exchangers, the two-term perturbation solutions are accurate with 2% of the numerical solutions.
Cable-Suspended Robotic Contour Crafting System
Authors: Bosscher Paul , Williams Robert L. , Bryson L. Sebastian , Castro-Lacouture Daniel
Published: June 2008

This paper introduces a new concept for a contour crafting construction system. Contour crafting is a relatively new layered fabrication technology that enables automated construction of whole structures. The system proposed here consists of a mobile contour crafting platform driven by a translational cable-suspended robot. The platform includes an extrusion system for laying beads of concrete as well as computer-controlled trowels for forming the beads as they are laid. This system is fully automated and can be used to construct concrete structures rapidly and economically. The novel attributes of this system enable significant improvements over other proposed contour crafting systems, including easier portability, lower cost, and the potential to build much larger structures. This paper presents the kinematics and statics of the proposed system, and uses the reachable workspace of the robot as well as the corresponding cable tensions to approximate the maximum size structure that can be built using this manipulator.
Solving Jacobian Matrix of Parallel Manipulators With Linear Driving Limbs by Using CAD Variation Geometric Approach
Authors: Lu Yi , Hu Bo
Published: June 2008

The velocity Jacobian matrix and the force Jacobian matrix are important index for kinematics, singularity and dynamics analyses of parallel manipulators. A novel computer variation geometric approach is proposed for solving the velocity Jacobian matrix and the force Jacobian matrix of parallel manipulators with linear driving limbs, as well as the determinant of Jacobian matrix. First, basic computer variation geometry techniques and definitions are presented for designing the simulation mechanisms, and several simulation mechanisms of parallel manipulators with linear driving limbs are created. Second, some velocity simulation mechanisms are created and the partial derivatives in Jacobian matrix are solved automatically and visualized dynamically. Based on the results of the computer simulation, the velocity Jacobian matrix and force Jacobian matrix are formed and the determinant of Jacobian matrix is solved. Moreover, the simulation results prove that the computer variation geometry approach is fairly quick and straightforward, and is accurate and repeatable. This project is supported by NSFC No. 50575198.
Simulation Research on Dynamics of Belt Conveyor System
Authors: Song Weigang , Wen Bangchun , Liu Huijuan
Published: June 2008

With the magnification of the belt conveyor, dynamic analysis and dynamic design have become indispensability means in the design of belt conveyor. In this article, we build the finite-element model of the starting and stopping process, which bases on the multi-driving belt conveyor system, and the dynamic calculation method of multi-driving system basing on power tracing. According to the reasonable starting curve, we start the first driving/drive, and then the rest drives trace the first driving in order. We bring forward the starting curve of trapezium acceleration from the existing S-curve. We develop the dynamic analysis software of belt conveyor and test the correctness of its calculation and software by the computer simulation of the actual system. The method had been applied in the system design of 7.6 km belt conveyor in Jincheng city, Shanxi province.
The Singularity Analysis of 3-RPS Parallel Manipulator
Authors: Li Yanwen , Huang Zhen , Wang Lumin
Published: June 2008

This paper firstly introduces a kinematic principle of singularity. It is a sufficient and necessary condition to identify singularity. Using the condition this paper systematically studies the singularity of 3-RPS parallel manipulator. A simple singularity equation is derived and the complete singularity loci in the three-dimensional space are illustrated. In order to analyze the singularity property and verify the correctness of the derived equation the line-geometry and the constraint screw theory are used. Some important singularity properties and the distribution characteristics are presented.
Mobility and Position Analysis of a Novel 3-DOF Translational Parallel Mechanism
Authors: Zeng Daxing , Huang Zhen , Zhang Linlin
Published: June 2008

This paper presents the mobility analysis, the inverse and forward displacement analysis, and workspace of a novel 3-DOF 3-RPUR parallel manipulator. Closed-form inverse displacement solutions are obtained by the Denavit-Hartenberg method. The forward displacement problem is analyzed by using the continuation method and proved applying the result of the inverse displacement analysis. The workspace of the mechanism is also obtained. A numerical example is given in the paper.
Semantic Representations for Configurable Enterprise Systems
Authors: Ni Qianfu , Yarlagadda Prasad K. D. V. , Lu Wen Feng
Published: June 2008

Due to the variation of business practices from one company to another and the lack of flexibility to support different business practices, enterprise systems need to be customized based on the requirements of individual companies. Customization is one the major activities in the enterprise system implementation. It is mainly a process of redesigning and redeveloping functions of an enterprise information system for a particular company. The extra time required for customization definitely stretches the deployment cycle and increases the implementation cost. It is also a barrier that hampers companies to change their business practices for new business opportunities. Therefore, technologies for developing configurable enterprise systems with flexibility to adapt to business practices in different companies are gaining the attention of solution vendors and researchers. In this research, semantic representations were developed for configurable enterprise systems. These representations can enhance the flexibility of enterprise systems and make enterprise systems able to be rapidly tailored for different companies. The core of the concept is to decouple various logics from systems and represent the logics in a semantic manner. To achieve semantic representations, XML-based declarative language has been developed for representing a diversity of logics. The paper elaborates semantic representations of information entities, entity relationships, functional components and graphical environments. A business process management system based on the semantic representations is also briefly presented.
Generating Spiral Paths for Sculptured Surfaces Machining
Authors: Yao Zhiyang
Published: June 2008

To machine sculptured surfaces, ball end mills are mainly used to reach the final surface finish requirements. During machining, the cusp height is one of the major factors defining the final surface finish smoothness. A cutter path that maintains a high cutting efficiency as well as a constant cusp height is desired. Spiral curves, with the property of not requiring extra linkage segments between two adjacent arms can be used to generate a smooth cutter path. In this paper, a geometric algorithm for generating spiral cutter paths for ball end milling in machining sculptured surfaces is presented.
A Sensitivity Analysis of Shot Peening Parameters
Authors: Elbella Abdalla , Rami Vishal , Hogirala Jyothi
Published: June 2008

Shot peening process is largely used for surface treatment of metallic components with the aim of increasing surface toughness and extending fatigue life. The fatigue strength of the component can be improved by inducing compressive residual stress in the surface and subsurface layers by the shot peening process. Numerical simulation of the shot peening process is an important tool that is used to aid in understanding the effects of the process parameters on intended goal of attaining the optimum residual stress profile and maximum process gain. In this paper an elasto-plastic finite element model is used for the shot peening process. The process parameters that are varied in this analysis are: the shot diameter, shot speed, number of shots at a given time (coverage) and target material. The analysis is carried out for two different materials, namely, steel and aluminum. An Explicit finite element code (ABAQUS) is used to perform this task. These parameters have different effects on the resulting residual profile and the results of the study showed that by adjusting these parameters, the most effective residual stress profile could be obtained.
Two Novel Spherical 3-DOF Parallel Manipulators With Circular Prismatic Pairs
Authors: Li Qinchuan , Chen Qiaohong , Wu Chuanyu , Hu Xudong
Published: June 2008

Two novel spherical 3-DOF (degrees of freedom) parallel manipulators with circular prismatic pairs are proposed. One is 3-PC(RR)N parallel mechanism, where PC denotes a circular prismatic pair, (RR)N denotes two revolute pairs whose axes intersect at a common point N. The other is 3-PCRNS parallel mechanism. All the revolute axes in three limbs intersect at a common point N. The three circular prismatic pairs can be actuated. Mobility and singularity of this mechanism is analyzed via screw theory. Due to the circular prismatic pair, the rotational DOF of the moving platform about the z axis is decoupled from the other two rotational DOFs.
BB-ATC: Analytical Target Cascading Using Branch and Bound for Mixed-Integer Nonlinear Programming
Authors: Michalek Jeremy J. , Papalambros Panos Y.
Published: June 2008

The analytical target cascading (ATC) methodology for optimizing hierarchical systems has demonstrated convergence properties for continuous, convex formulations. However, many practical problems involve both continuous and discrete design variables, resulting in mixed integer nonlinear programming (MINLP) formulations. While current ATC methods have been used to solve such MINLP formulations in practice, convergence properties have yet to be formally addressed, and optimality is uncertain. This paper describes properties of ATC for working with MINLP formulations and poses a solution method applying branch and bound as an outer loop to the ATC hierarchy in order to generate optimal solutions. The approach is practical for large hierarchically decomposed problems with relatively few discrete variables.
Analysis of Three Degree of Freedom 6×6 Tensegrity Platform
Authors: Baker Antoin , Crane Carl D.
Published: June 2008

The mechanism studied in this paper is a three degree of freedom 6×6 tensegrity structure. A tensegrity structure is one that balances internal (pre-stressed) forces of tension and compression. These structures have the unique property of stabilizing themselves if subjected to certain types of disturbances. The structure analyzed in this paper consists of two rigid bodies (platforms) connected by a total of six members. Three of the members are noncompliant constant-length struts and the other three members consist of springs. For typical parallel mechanisms, if the bottom platform is connected to the ground and the top platform is connected to the base by six compliant leg connectors, the top platform will have six degrees of freedom relative to the bottom platform. However, because three of the six members connecting the two platforms are noncompliant constant-length struts, the top platform has only three degrees of freedom. The primary contribution of this paper is the analysis of the three degree of freedom tensegrity platform. Specifically, given the location of the connector points on the base and top platforms, the lengths of the three noncompliant constant-length struts, and the desired location of a point embedded in the top platform measured with respect to a coordinate system attached to the base, all possible orientations of the top platform are determined.
Immune-Based Fault Diagnosis Method for Gas Valve
Authors: Shao Jiye , Wang Rixin , Gao Jinbo , Xu Minqiang
Published: June 2008

Negative selection principle based on the natural immune system makes it possible to develop a new fault diagnosis technique. This paper investigates a fault diagnosis method for the gas valve of the reciprocating compressor based on the negative selection algorithm. The negative selection algorithm combining the clonal selection principle with the mutation theory is used to produce the detectors representing one fault by the sample indicating normal. The detectors representing abnormal are used to perform the fault detection and recognition. The preprocessing using discrete fourier transform to extract the characteristic frequency interval makes the method more efficient and reliable. Experimental data of three kinds of fault from the vibration signal of the gas valve of the reciprocating compressor is used to test the method. The results prove that this method is very efficient.
Optimally Unstable Underactuated Gripper: Synthesis and Applications
Authors: Birglen Lionel , Gosselin Cle´ment M.
Published: June 2008

This paper presents the synthesis of optimally unstable two-phalanx underactuated fingers. The method to obtain a design unable to grasp almost any object under normal conditions is presented. The technique relies on the careful analysis of the grasp-state plane and equilibrium curve associated to two-phalanx underactuated fingers. First, results of the analysis of the grasp-state plane are recalled. Second, unstable configurations and paradoxical equilibrium are presented. Then, the synthesis of optimally unstable fingers is detailed. Finally, applications of these unstable fingers are proposed.
An Introduction to the Analysis of Linkage-Driven Compliant Underactuated Fingers
Authors: Birglen Lionel
Published: June 2008

This paper presents an analysis of a two-phalanx linkage-driven underactuated finger with substantial compliance in all the joints of the system. The primary goal of the paper is to illustrate with an example, the theoretical issues faced in designing compliant underactuated fingers. To this aim, a two-phalanx linkage-driven underactuated finger is analyzed throughout the paper to clarify the concepts presented. First, a method to compute the contact forces generated by compliant underactuated fingers is presented and discussed. Finally, the self-mobility of the finger is discussed and a method to predict if this mobility will converge to a stable grasp or not is presented. The paper presents an exemplified theoretical analysis whose layout provides very useful insights for the design of compliant underactuated fingers and emphasizes the challenges to be met in order to design successful prototypes.
IGM-Mechanism Encyclopaedia and the Digital Mechanism Library as a Knowledge Base in Mechanism Theory
Authors: Corves Burkhard , Niemeyer Ju¨rgen , Kloppenburg Johannes
Published: June 2008

The Institute of Mechanism Theory and Machine Dynamics of RWTH Aachen University houses a large collection of more than 200 mechanisms and models. Partly they are used to illustrate and visualize kinematic basics and methods taught to students. Furthermore these models are also used as a basis for mechanical designers looking for a solution to their motion tasks in different machinery such as packaging or processing machines. These models span a wide arch from historic models showing e.g. sewing machines from the late 19th century, typewriters from the early 20th century and acrylic glass models still used today in university lectures where they are placed on the overhead projector. With the swift development of the internet as the major base for information retrieval, new ideas about knowledge presentation have come up. Today it is obvious that fast and easy access to information is a major success factor in most areas both economics and science and is therefore of eminent importance. New developments in information technology and related software have created new possibilities for the presentation of scientific knowledge also in mechanism theory [1]. In this paper the IGM-Mechanism Encyclopaedia and the Digital Mechanism Library will be presented. Both use the possibilities of the internet to make basic and specific knowledge for the analysis and synthesis of mechanisms available to a broad public.
Design of a Dual Piezoelectric Controlled Electrohydraulic Actuator
Authors: Axtell W. Michael , Rocheleau David N.
Published: June 2008

This research is concerned with the design, modeling, and testing of a dual piezoelectric controlled electro-hydraulic actuator for use in camless engine applications. The design utilizes two piezoelectric actuated spool valves located on either side of a piston to effectively control the volume and timing of pressurized oil entering and exiting the piston chamber. A system model relating spool displacement to piston displacement was created and tested within Matlab/Simulink. To demonstrate the design, a bench top prototype was created and programmed using Matlab/Simulink, dSpace, and ControlDesk. Testing was conducted using both time domain and frequency analysis. All test results indicate a close correlation between the prototype and the final system model.
A Six Degree-of-Freedom Haptic Device Based on the Orthoglide and a Hybrid Agile Eye
Authors: Chablat Damien , Wenger Philippe
Published: June 2008

This paper is devoted to the kinematic design of a new six degree-of-freedom haptic device using two parallel mechanisms. The first one, called orthoglide, provides the translation motions and the second one, called agile eye, produces the rotational motions. These two motions are decoupled to simplify the direct and inverse kinematics, as it is needed for real-time control. To reduce the inertial load, the motors are fixed on the base and a transmission with two universal joints is used to transmit the rotational motions from the base to the end-effector. Two alternative wrists are proposed (i), the agile eye with three degrees of freedom or (ii) a hybrid wrist made by the assembly of a two-dof agile eye with a rotary motor. The last one is optimized to increase its stiffness and to decrease the number of moving parts.
A Comprehensive Theory of Type Synthesis of Fully Parallel Platforms
Authors: Rico Jose´ M. , Cervantes-Sa´nchez J. Jesu´s , Tadeo-Chavez Alejandro , Pe´rez-Soto Gerardo Israel , Rocha-Chavarria Juan
Published: June 2008

This contribution presents a comprehensive theory for the type synthesis of fully parallel platforms. The theory deals with both types of platforms, 6 D.O.F. parallel platforms and lower mobility platforms. The theory is based on an analysis of the subsets and subgroups of the Euclidean group, SE(3). It is likely that the theory can be also developed based on an analysis of the subspaces and subalgebras of the Lie algebra, se(3), of the Euclidean group, SE(3).
Pattern-Based Reasoning in Critical Parameter Management (CPM) for Rapid Redesign
Authors: Chen Li , Li Simon
Published: June 2008

Critical Parameter Management (CPM) is an emerging area in engineering design owing to the motivation from Design for Six Sigma. Introduced in this paper is the exploration of CPM to support rapid redesign of evolutionary products in the context of mass customization. Along this line, a model-based CPM method that utilizes and leverages matrix patterns to support rapid redesign is presented, discussed and illustrated through the use of a redesign example as a case study. In particular, proposed in this paper is the pattern-centric CPM approach to rapid redesign based on “case → scenario → pattern → strategy → roadmap” reasoning mechanism. The results show that the proposed method enables one to rapidly reconfigure or customize the existing design of a given model as well as the promising future of this emerging research. This work represents an extended effort to complement our ongoing research on developing decomposition-enabled techniques to support model-based rapid redesign.
Reliability-Based Design Using Saddlepoint Approximation
Authors: Du Xiaoping
Published: June 2008

Reliability-based design optimization is much more computationally expensive than deterministic design optimization. To alleviate the computational demand, the First Order Reliability Method (FORM) is usually used in reliability-based design. Since FORM requires a nonlinear transformation from non-normal random variables to normal random variables, the nonlinearity of a constraint function may increase. As a result, the transformation may lead to a large error in reliability calculation. In order to improve accuracy, a new reliability-based design method with Saddlepoint Approximation is proposed in this work. The strategy of sequential optimization and reliability assessment is employed where the reliability analysis is decoupled from deterministic optimization. The accurate First Order Saddlepoint method is used for reliability analysis in the original random space without any transformation, and the chance of increasing nonlinearity of a constraint function is therefore eliminated. The overall reliability-based design is conducted in a sequence of cycles of deterministic optimization and reliability analysis. In each cycle, the percentile value of the constraint function corresponding to the required reliability is calculated with the Saddlepoint Approximation at the optimal point of the deterministic optimization. Then the reliability analysis results are used to formulate a new deterministic optimization model for the next cycle. The solution process converges within a few cycles. The demonstrative examples show that the proposed method is more accurate and efficient than the reliability-based design with FORM.
Uncertainty Analysis With Probability and Evidence Theories
Authors: Du Xiaoping
Published: June 2008

Both aleatory and epistemic uncertainties exist in engineering applications. Aleatory uncertainty (objective or stochastic uncertainty) describes the inherent variation associated with a physical system or environment. Epistemic uncertainty, on the other hand, is derived from some level of ignorance or incomplete information about a physical system or environment. Aleatory uncertainty associated with parameters is usually modeled by probability theory and has been widely researched and applied by industry, academia, and government. The study of epistemic uncertainty in engineering has recently started. The feasibility of the unified uncertainty analysis that deals with both types of uncertainties is investigated in this paper. The input parameters with aleatory uncertainty are modeled with probability distributions by probability theory, and the input parameters with epistemic uncertainty are modeled with basic probability assignment by evidence theory. The effect of the mixture of both aleatory and epistemic uncertainties on the model output is modeled with belief and plausibility measures (or the lower and upper probability bounds). It is shown that the calculation of belief measure or plausibility measure can be converted to the calculation of the minimum or maximum probability of failure over each of the mutually exclusive subsets of the input parameters with epistemic uncertainty. A First Order Reliability Method (FORM) based algorithm is proposed to conduct the unified uncertainty analysis. Two examples are given for the demonstration. Future research directions are derived from the discussions in this paper.
Coupling Degree of Mechanism and Its Application
Authors: Xiong Jing , Yang Ting-Li , Yang Xiangdong , Yang Dongchao , Chen Ken
Published: June 2008

The kinematic and dynamic analysis of an spatial multi-loop mechanism especially parallel mechanism is significant but always complex. Based on the topological structure of mechanisms, this paper proposes the concept of coupling degree of mechanism systematically, and applies it to the criterion of basic kinematic chains(BKCs) and other problems. The relation between topology, kinematics and dynamics of parallel mechanisms is established, and then it is achieved to quantitatively describe the analysis complexity of a parallel mechanism and to obtain its simplest solving path, according to its topological structure. The preliminary method for unified modeling of the topology, kinematics and dynamics of parallel mechanisms is proposed, using BKC as the basic analysis unit. Some suggestions for optimization and selective preference of parallel mechanisms are also presented.
Geometric Width Control in Topology Optimization Using Level Set Method and a Quadratic Energy Functional
Authors: Chen Shikui , Wang Michael Yu
Published: June 2008

A variational approach to geometric width control in topology optimization is presented in this paper. Different from conventional topology optimization approaches which only consider optimizing performance-describing objective functions, a quadratic energy functional governing the feature characteristic of geometric width is employed. In this manner, the geometric feature of the designed structure as well as its functional performance is accounted for. In addition, the quadratic energy function can be seamlessly integrated into the level set model that represents the geometry of the structure implicitly. The approach is demonstrated with benchmark examples of structure optimization and compliant mechanism optimization. The preliminary results show that this method is capable of generating strip-like (or beam) designs with specified feature width, which is a highly desirable characteristic and uniquely distinguishes the proposed method.
On Global Aspects of Real Newton’s Method in Synthesis of Linkages
Authors: Xie Jin , Yan Kaiyin , Chen Yong
Published: June 2008

Nonlinear equations arise from the synthesis of linkages. Newton’s method is one of the most accessible and easiest to implement of the iterative root-finding algorithms for these equations. As a discrete deterministic dynamical system, Newton’s method contains subsystems which have highly random motion. In a so-called chaotic zone, there is a rapid interchange between the basins of attraction for each root of the equation. Choosing initial points from such chaotic zone, one can obtain a certain number of roots or possible all of them under the Newton’s method. In this paper, how to locate the chaotic zones is addressed following the global analysis of real Newton’s method. It is show that there exist four chaotic zones for a general 4th degree polynomial. As an example, the equation derived from exact synthesis for five positions is solved.
A Simple Method for Inverse Kinematic Analysis of the General 6R Serial Robot
Authors: Shi Zhi Xin , Luo Yu Feng , Hang Lu Bing , Yang Ting Li
Published: June 2008

Because the solution to inverse kinematics problem of the general 5R serial robot is unique and its assembly condition has been derived, a simple effective method for inverse kinematics problem of general 6R serial robot or forward kinematics problem of general 7R single-loop mechanism is presented based on one-dimension searching algorithm. The new method has the following features: (1) Using one-dimension searching algorithm, all the real inverse kinematic solutions are obtained and it has higher computing efficiency; (2) Compared with algebraic method, it has evidently reduced the difficulty of deducing formulas. The principle of the new method can be generalized to kinematic analysis of parallel mechanisms.
Modular Method for Kinematic Analysis of Parallel Manipulators Based on Ordered SOCs
Authors: Shi Zhi Xin , Luo Yu Feng , Yang Ting Li
Published: June 2008

Based on the new viewpoint of structural decomposion that any multi-loop mechanism are made up of by a series of ordered single opened chains(SOCs), a new method for kinematic analysis of parallel manipulators, i.e, the SOCs modular method has been presented in the paper. The new method has the following features: (1) The dimensions of sets of the nonlinear kinematic analysis equations are reduced to the minimum, and the kinematic analysis equation often contains only one unknown variable for most parallel manipulators generally applied now. Accordingly, all the real solutions to forward kinematics problem of parallel mechanisms can be easily obtained by using one-dimension searching algorithm; (2) Compared with algebraic method, it has evidently reduced the difficulty of deducing formulas; (3) Compared with homotopy continuation method, it has higher computing efficiency.
Topological Synthesis of Shell Structures
Authors: Kormeier Thomas , Rudolph Stephan
Published: June 2008

Currently available tools for classical topology optimization of structures have proven valuable in conceptual design. These tools may provide design direction very early in the design cycle. However, the results subsequently need to be interpreted and translated by an engineer into a consistent CAD-model. This research focuses on the topological design synthesis of shell structures, which is being carried out using a design language approach. The aim of this approach is to automatically generate, modify and optimize an abstract representation of the design. This representation is automatically translatable into a CAD-model and will thus lead to an optimization process that offers a valid structural CAD-model as result. Design languages serve in this context as a computable abstraction of design representation and synthesis by use of rule-based information processing mechanisms. These rules (also called design patterns), are applied to generate and modify the topology of the design representation. Design patterns contain the engineers know-how and best-practice. The computerized execution of design patterns in a design compiler yields a powerful topology modification tool. As prototype application, the synthesis of shell structures is presented in this work. The automation mechanisms and the information flow through design synthesis, model generation, design analysis and evaluation are outlined. A discussion on the future application of design patterns for knowledge-based structural optimization is derived from the shown examples.
A General Geometric Method for Identifying Singular Configurations of One-DOF Planar Mechanisms
Authors: Di Gregorio Raffaele
Published: June 2008

The importance of finding singular configurations (singularities) of mechanisms has become clear since the interest of the scientific community for parallel architectures arose. Regarding the singularity analysis, the main interest has been devoted to architectures with more-than-one degree of freedom (dof) without realizing that one-dof mechanisms are commonly used and deserve the same attention. This paper addresses the singularity analysis of one-dof planar mechanisms. A general method for implementing this analysis will be presented. The presented method relies on the possibility of giving geometric conditions for any type of singularity. It can be used to generate systems of equations to solve either for finding the singularities of a given mechanism or to synthesize mechanisms that have to match specific requirements about the singularities.
Multidisciplinary Information Management for the Mechatronic Engineering of Assembly Systems
Authors: Qi Zhiliang , Scha¨fer Christian , Klemm Peter
Published: June 2008

The mechatronic engineering of assembly systems is a multidisciplinary engineering process. In each engineering discipline one or more engineering tools are applied to support the discipline-specific engineering tasks. These engineering tools manage the engineering data separately and in different formats. Reuse and consistency of these engineering data across the whole development process is a main problem in today’s mechatronic engineering of assembly systems. This paper presents an approach of an extensible multidisciplinary information system in order to manage and share the engineering data in the entire engineering of assembly systems.
SphinxCAM-Pro|E: Computer-Aided Modeling and Manufacturing of Spherical Mechanisms Via the Web
Authors: Larochelle Pierre M. , Schuler Jason M. , Ketchel John S.
Published: June 2008

In this paper we present a web-based computer-aided design modeling and manufacturing methodology for spherical mechanisms. Our purpose is to facilitate the analysis, dynamic simulation, and manufacture of one degree of freedom spherical four-bar mechanisms. First, a brief review of some of the current computer-aided design (CAD) software for spherical four-bar mechanisms, e.g. SPHINX, SPHINXPC, ISIS, and OSIRIS is presented. These software packages provide the three-dimensional visualization and computational capabilities necessary to design spherical four-bar mechanisms. However, to date no readily available and effective tools exist to aid in the modeling and manufacture of spherical mechanisms. Next, the kinematics of spherical four-bar mechanisms are reviewed as they pertain to their geometric modeling and manufacture. Finally, we present our web-based implementation of a computer-aided modeling, simulation, and manufacturing methodology for spherical four-bar mechanisms called SPHINXCAM-Pro|E. SPHINXCAM-Pro|E, when used with the CAD tools mentioned above, facilitates the design, dynamic simulation, prototyping, and manufacture of spherical four-bar mechanisms.
The Mobility Analyses of Some Classical Mechanism and Recent Parallel Robots
Authors: Huang Zhen , Xia Ping
Published: June 2008

The paper once again deals with the mobility analysis methodology of mechanisms based on constraint screw. It is a very important subject in mechanism theory lasting about 150 year. Firstly, the paper introduces some background and then the methodology. The paper focuses on analysis of some “paradoxical mechanisms”, including classical mechanism and modern parallel mechanisms, such as Bennett mechanism, Delta robot, Tsai’s CPM mechanism and so on. All the results prove that for the difficult mobility problem the analysis procedures are quite simple and convenient, and will easily be held by numerous mechanical engineers. The complicated problem is solved only by using a pencil, a sheet of paper and just for a few minutes.
Design and Development of Two Concepts for a 4 DOF Portable Haptic Interface With Active and Passive Multi-Point Force Feedback for the Index Finger
Authors: Lelieveld Mark J. , Maeno Takashi , Tomiyama Tetsuo
Published: June 2008

This research aims to develop a portable haptic master hand with 20 degrees of freedom (DOF). Master hands are used as haptic interfaces in master-slave systems. A master-slave system consists of a haptic interface that communicates with a virtual world or an end-effector for tele-operation, such as a robot hand. The thumb and fingers are usually modeled as a serial linkage mechanism with 4 DOF. So far, no 20 DOF master hands have been developed that can exert perpendicular forces on the finger phalanges during the complete flexion and extension motion. In this paper, the design and development of two concepts of a portable 4 DOF haptic interface for the index finger is presented. Concept A is a statically balanced haptic interface with a rolling-link mechanism (RLM) and an integrated constant torque spring per DOF for perpendicular and active force feedback. Concept B utilizes a mechanical tape brake at the RLM for passive force feedback. The systematic Pahl and Beitz design approach is used as an iterative design method.
An Ergonomic Assessment System Using a Digital Hand for Designing Handheld Information Appliances
Authors: Endo Yui , Kanai Satoshi , Kishinami Takeshi , Natsuki Miyata , Kouchi Makiko , Mochimaru Masaaki
Published: June 2008

Recently, as handheld information appliances, such as mobile phones, PDAs, have widely spread, the development of these appliances should pay more attention in their ergonomic design. However, the user tests for developing the “ergonomic” appliances are usually done by many real subjects testing a variety of these physical mockups, and the process of these tests usually requires the expensive cost and has to take a long time. So, we propose a software system of an automatic ergonomic assessment system for designing handheld information appliances by integrating the digital hand model with the product model of the appliance. Our system has the following four feature functions for ergonomic assessment: 1) Generation of kinematically and geometrically accurate digital hand models with rich dimensional variation, 2) automatic evaluation of the grasp posture stability by estimating the force-closure and the grasp quality, 3) automatic evaluation of ease of the finger motion in operating the user interface, 4) aiding the designers to re-design the housing shapes and user-interfaces in the product model. In this paper, we describe the 1) and 2) of the above functions. Moreover, we also describe the verification results of our system by comparing estimated grasp postures and these stability given from the system with the ones from experiments by real subjects.
Presentation of the Lifework of Kurt Hain: Pioneer of Applied Kinematics in Germany
Authors: Kerle Hanfried , Brix Torsten , Modler Karl-Heinz
Published: June 2008

Dr.-Ing. E.h. Kurt Hain was born 1908 in Leipzig and died 1995 in Braunschweig. He was a pioneer of applied kinematics in Germany. He also visited American universities four times starting in 1957. He wrote 13 books and about 380 articles on nearly all partial fields of kinematics. This paper tries to give a complete survey of his lifework and describes a national research approach to preserve his heritage for future generations of mechanical engineers.
Modeling of Electrodynamic Suspension Systems
Authors: Kim Nam Ho , Ge Long
Published: June 2008

Characteristics of magnetic–levitation system are studied using dynamic models that include motion–dependent lift, drag, slip, and roll motions. In addition, the contact constraint between the vehicle and the track is modeled using the penalty method. Unknown numerical parameters are identified using the optimization technique. The numerical tests are focused on the damping characteristic, stability in lifting and slip motions, the lifting efficiency compared with the concentric force, and contact with track.
On the Line Geometry of Finite Screw Systems and Point Displacements
Authors: Huang Chintien , Ravani Bahram
Published: June 2008

This paper unveils line-geometric foundations of finite displacement screw systems, with an emphasis on incompletely specified displacement of points. Linear line complexes are basic entities used in this research. Bisecting linear line complexes arising from finite displacements are proved to be subject to a reciprocal condition if a new definition of pitch of finite screws is defined. This definition was the one used to formulate finite screw systems. The relations among intersections of linear line complexes, screw systems, and varieties of lines are established in order to investigate finite screw systems. A novel treatment of point displacements allows us to visualize finite screw systems when they are formed by intersecting linear line complexes. This paper provides geometric insights into finite displacement screws and presents a new framework for the unification of finite and infinitesimal kinematics.
A General Formula of Degree-of-Freedom for Parallel Manipulators and Its Application
Authors: Yang Ting-Li , Sun Dong-Jin
Published: June 2008

This paper presents a new DOF formula for mechanism Its main feature is that the calculation of mobility has a single value for a given mechanism without the set of constraint equations, each of parameters in the formula can be correctly determined by simple symbol operation. The formula shows the map relationship between DOF and topological structure of a mechanism. It is embodied in the following aspects: (1) Dimension type: so that topological structure of a mechanism can be represented by symbols. (2) Orientation and location characteristic matrix: so that rank of a mechanism can be calculated by symbolic operation. (3) Orientation and location characteristic equation of serial mechanism and its symbolic operation. (4) Orientation and location characteristic equation of parallel mechanism and its symbolic operation. (5) The DOF calculation based on orientation and location characteristic equations of serial and parallel mechanisms. The DOF formula presented in this paper has already been used for topological analysis and synthesis of parallel mechanisms and its advantages has been proven.