bluuebunny/crossref_metadata_2025 huggingface dataset:
Full Rotatability of Stephenson Six-Bar and Geared Five-Bar Linkages
Authors: Ting Kwun-Lon , Wang Jun , Xue Changyu , Currie Kenneth R.
Published: July 2009

Full rotatability identification is a problem frequently encountered in linkage analysis and synthesis. The full rotatability of a linkage is referred to a linkage in which the input may complete a full revolution without the possibility of encountering a dead center position. In a complex linkage, the input rotatability of each branch may be different. This paper presented a unified and comprehensive treatment for the full rotatability identification of six-bar and geared five-bar linkages disregard the choice of input and output joints or fixed link. A simple way to identify all dead center positions and the associated branches is discussed. Special attention and detail discussion is given to the more difficult condition with the input given through a link or joint not in the four-bar loop or on a gear-link. A branch without a dead center position has full rotatability. Using the concept of joint rotation space, the branch of each dead center position, and hence the branch without a dead center position can be identified easily. The proposed method is simple and conceptually straightforward and the process can be automated easily. It can be extended to any other single-degree-of-freedom complex linkages.
An Improved Initial Population Strategy for Compliant Mechanism Designs Using Evolutionary Optimization
Authors: Sharma Deepak , Deb Kalyanmoy , Kishore N. N.
Published: July 2009

In this paper, an improved initial random population strategy using a binary (0–1) representation of continuum structures is developed for evolving the topologies of path generating complaint mechanism. It helps the evolutionary optimization procedure to start with the structures which are free from impracticalities such as ‘checker-board’ pattern and disconnected ‘floating’ material. For generating an improved initial population, intermediate points are created randomly and the support, loading and output regions of a structure are connected through these intermediate points by straight lines. Thereafter, a material is assigned to those grids only where these straight lines pass. In the present study, single and two-objective optimization problems are solved using a local search based evolutionary optimization (NSGA-II) procedure. The single objective optimization problem is formulated by minimizing the weight of structure and a two-objective optimization problem deals with the simultaneous minimization of weight and input energy supplied to the structure. In both cases, an optimization problem is subjected to constraints limiting the allowed deviation at each precision point of a prescribed path so that the task of generating a user-defined path is accomplished and limiting the maximum stress to be within the allowable strength of material. Non-dominated solutions obtained after NSGA-II run are further improved by a local search procedure. Motivation behind the two-objective study is to find the trade-off optimal solutions so that diverse non-dominated topologies of complaint mechanism can be evolved in one run of optimization procedure. The obtained results of two-objective optimization study is compared with an usual study in which material in each grid is assigned at random for creating an initial population of continuum structures. Due to the use of improved initial population, the obtained non-dominated solutions outperform that of the usual study. Different shapes and nature of connectivity of the members of support, loading and output regions of the non-dominated solutions are evolved which will allow the designers to understand the topological changes which made the trade-off and will be helpful in choosing a particular solution for practice.
Heat Transport in the Al Nanopowder
Authors: Ho C. Y. , Shih C. S. , Wen M. Y. , Ma C.
Published: July 2009

The heat transport in the Al nanopowder is experimentally investigated in this paper. The understanding for thermal behavior of the Al powder is advantageous to the advancement of the processing technologies such as laser cladding, laser sintering, powder metallurgy and its other applications. The powder is wrapped up in the slender tube made of insulating material. One end of the slender tube filled with powder is maintained at temperature 0°C and the other end is kept at 24°C. The temperature histories at two different locations in the slender tube are recorded using thermal couples. The results show that the temperature in the powder composed of nanoparticles descends more quickly than that in bulk material. The increase of pressure on the powders enhances the heat transfer.
A Cellular Automata Modeling Approach for Continuum Elastodynamics
Authors: Leamy Michael J.
Published: July 2009

This article details a physics-based Cellular Automata (CA) modeling approach for studying the dynamic response of a solid elastic continuum. The domain of interest is discretized into rectangular cellular automata and a rule set is developed for evolving each cell’s state based on its present state and its neighbors’ states. A cell’s state is comprised of its displacement and velocity components, and its external force. It is shown that the choice of rectangular cells yields discrete equations equivalent to the centered-difference finite difference (FD) approach. However, the discrete equations are arrived at from the ‘bottom up’ using local rules vice ‘top-down’ discretization of global partial differential equations. A further distinction between the two methods concerns the location of stresses and its impact on boundary conditions: the CA approach assigns stresses to the cell faces while the FD approach assigns stress collocated with displacement components at a single node. These differences may provide important perspective on modeling arbitrary geometry with a finite difference-like approach based on cell assembly, similar to finite element analysis. Implementation of the CA paradigm using autonomous, local cells fits naturally with object-oriented programming practices and lends itself readily to distributed computing. Results are provided for an example ground-shock simulation in which a differentiated Gaussian pulse on the surface of a half-space generates the expected pressure, shear, and surface waves. Comparisons to waves computed using a staggered-grid finite difference approach demonstrate very good agreement. In addition, the simulation results suggest that the CA approach may exhibit less ‘ringing’ as waves pass, and more symmetry in left-ward and right-ward moving waves.
A Novel Linear MEMS Capacitor With Triangular Electrodes and Nonlinear Structural Stiffness
Authors: Shavezipur Mohammad , Hashemi Seyed Mohammad , Khajepour Amir
Published: July 2009

MEMS parallel-plate tunable capacitors have high Q-factors and fast responses to the actuation and therefore are desired for RF applications. However, conventional designs have low tuning ratios and nonlinear capacitance-voltage (C-V) responses which are highly sensitive to the voltage change near pull-in. In this research, a novel structure for parallel-plate-based capacitors is introduced. The capacitor has electrodes with triangular shape and uneven supporting beams and is equipped with a set of middle beams which increases the structural stiffness of the capacitor as bias voltage increases. Because the asymmetric design alters the parallelness of the plates, the stiffness of each middle beam is added to the system at a different voltage causing a smooth increment in structural stiffness. To analyze the capacitor and optimize the design, an analytical model is developed to solve the coupled electrostatic-structural physics. The results of numerical simulations reveal that if the stiffness coefficients of supporting and middle beams are optimized, a highly linear C-V response is obtained. Moreover, since the structural rigidity is gradually increased with voltage, the sensitivity of the response to the voltage change is also improved and a higher tunability over 150% is achieved. The proposed design has a simple geometry and can be fabricated by a three-structural-layer process such as PolyMUMPs.
A Control-Oriented Two Zone Thermo-Kinetic Model of a Single Cylinder HCCI Engine
Authors: Tandra Varun , Srivastava Nilabh
Published: July 2009

Over the past two decades, homogeneous charge compression ignition engine technology (HCCI) has aroused a great deal of interest in the automotive sector owing to its ability to generate ultra-low exhaust emissions and to be fuel-flexible. The current work proposes a control-oriented two-zone thermo-kinetic model of such a single cylinder HCCI engine. Earlier control laws were derived by using single zone mathematical models of HCCI combustion; however, these models fail to accurately capture the combustion dynamics of an HCCI engine owing to the assumption of homogeneous composition and temperature in the cylinder. Certain multi-zone models of HCCI engines emphasizing the shortcomings of these single zone models have also been reported in literature. However, such models are far too complex and unwieldy for the development of fast and efficient controllers for HCCI engines. The present work outlines the modeling approach of a single-cylinder two-zone HCCI engine by incorporating the first law of thermodynamics and the temperature and concentration inhomogeneities. The results showed good conformity to those obtained from literature-based multi-zone models. A comparative analysis between the single zone and two-zone models, in the context of predicting cylinder pressures, exhaust gas temperatures, emission concentrations, and start of combustion (SOC), is also discussed.
Behavior-Form Double Directions Creative Conceptual Design Model and Its Quotient Space Implementation
Authors: Wang Yu-Xin , Li Yu-Tong , Wang Jian-Wei
Published: July 2009

This paper presents a novel indirect matching approach between the function layer and the form layer to enhance the capability for the FBS method to obtain the creative conceptual design results. Firstly, the basic operation actions set, which is composed of the basic operation actions obtained by decomposing each function in the lowest level of the function decomposition tree in the FBS model into the sub-functions, in the function layer is regrouped dynamically. This behavior regroup process has introduced the new design variables into the conceptual design process and leads the behavior creativity to produce. On the other hand, considering the multi-functions for each basic structure to have and representing these functions with the basic operation actions, then the basic operation actions set in the form layer is set up. Dynamic regrouping this set in the form layer, the new design variables has been introduced into the conceptual design process, and leads the form creativity to produce. Through the above behavior-form double directions creative process, the solution scope of the conceptual design is enlarged obviously. Therefore, the method present in this paper has enough capability to obtain the creative conceptual results. Furthermore, the model presented in this paper is represented with the quotient space mathematically. The case study has shown that in the function layer, through adjusting the attribute function, which determines the partition grain of the basic operation actions set in the function layer or in the form layer, the new behaviors can be generated.
A New Methodology for Computer Aided Design of Fine Porcelain Whiteware
Authors: Carfagni Monica , Governi Lapo , Meiattini Daniela , Volpe Yary
Published: July 2009

Fine porcelain products get their peculiar characteristics at the end of their thermal process. During the firing, the product is subjected to shrinkage and a considerable amount of the material mass becomes viscous, causing the product shape to be modified due to the own object weight. As the final object shape is a relevant characteristic for both usability and aesthetics of the commercial product, the activity purpose was to devise a methodology to automatically detect the raw product shape required to match a provided final geometry. Such a methodology has been implemented by means of commercial CAD/FEM tools and should be used in porcelain products design. The research consists of three parts. During the first one an extensive experimental campaign has been carried out in order to model the behavior of the heat treated material; by using the experimental data a numerical model of the material behavior has been built. In the second part the model reliability has been tested by means of a set of FE analysis. Such an analysis simulates the effects of stresses caused by the real industrial firing process. In the end, during the third part, inverse firing process FE simulations have been performed. These simulations will allow the designer to know the raw-product geometry, in order to obtain the expected finished product.
Decision Support for Strategic Redesign
Authors: Chamberlain Matthew K. , Allen Janet K. , Mistree Farrokh
Published: July 2009

Researchers have paid relatively little attention to the fact that most of what is considered design is more like redesign than original design. Redesign activities are characterized by an attempt to leverage experience, knowledge, and the capital that a company has already invested into existing engineering systems. In this paper, a method for undertaking strategic redesign is proposed and explained. This method includes support for designers making decisions in redesign problems when there exist systems to be leveraged and multiple new systems to be created. In addition, strategy is introduced to the problem through the consideration that new systems may not be offered all at once, as is often assumed in product family design research. In this paper, the aim of the designer is assumed to be a creation, through redesign, of a series of new systems with desirable and distinct performance levels. In addition, a plan is required to involve as little redesign effort throughout the life of the family of systems as possible. The proposed approach is based upon the concepts of Constructal Theory and previous work to create methods for the design of mass customized families of systems. In addition, two metrics are developed to represent considerations unique to redesign as opposed to original design. These metrics for redesign effort and commonality value are utilized in the overall objective formulation for the proposed approach to redesign. Through a simple redesign scenario involving a family of universal motors, it is shown that the overall approach proposed can lead the designer towards promising redesign plans involving leveraging of existing systems, but that the constructal-inspired approach in and of itself has certain limitations when applied to redesign.
Function Design Framework (FDF): Integrated Process and Function Modeling for Complex Systems
Authors: Nagel Robert L. , Stone Robert B. , Hutcheson Ryan S. , McAdams Daniel A. , Donndelinger Joseph A.
Published: July 2009

Functional models are representations of the energy, material and signal transformations that occur through the expected or normal operating condition of a product. As the complexity of products increases, there are often multiple dimensions to their operation in addition to their nominal operating state, e.g., crash protection systems in a car or laser leveling and stud finding combined in a single tool. Here system state is used to represent the different operational dimensions of a product, and a representation scheme that allows designers to fully explore system functionality of products with multiple system states is explored. Previous work in process and functional analysis is integrated to better represent complex systems with multi-dimensional system functionality. Process and functional modeling are integrated to produce a new function design framework supporting user-defined fidelity of hierarchical models for functional representation. An example modeling a complete automobile life cycle illustrates the development of integrated process and functional models within a complex system analysis.
Development of a Multibody Dynamics Ford Expedition Model for Vehicle Dynamics Analysis
Authors: Chan Brendan J. , Sandu Corina
Published: July 2009

In the area of automotive engineering, testing of actual vehicles in various operating conditions during transient maneuvers is a costly and time-consuming stage of any vehicle design. However, the use of virtual proving grounds for simulation of full vehicles helps to alleviate the high cost physically testing a vehicle before mass production. This paper presents a study where a multibody dynamics model of a 2003 Ford Expedition is created for the purpose of evaluating performance and behavior in vehicle dynamics simulations. By using a dynamic model, rollover analysis and yaw stability can be analyzed. In addition to that, the vehicle model can also be used to integrate different controllers for different subsystems of the vehicle such as steering, brakes, and power-train. Preliminary simulation results are presented for proof of concept of the model.
Analysis of Capstone Design Reports: Visual Representations
Authors: Westmoreland Sophoria , Grenier Ashley , Schmidt Linda C.
Published: July 2009

Engineers require effective written communication skills, including the appropriate presentation of mechanical design information in visual format. A study of 48 Capstone Design Reports submitted over a period 5 semesters gives insight into the choices students make when selecting visual representations for describing designs. Student choices reflect assignment requirements, student preference, student skill level, and perceived appropriateness of representation type. This study presents observations on the use of visuals in a set of Capstone Design Reports with particular emphasis on sketches.
Modular Design Method for Sustainable Life-Cycle of Product Family Considering Future Market Changes
Authors: Koga Tsuyoshi , Aoyama Kazuhiro
Published: July 2009

A modular design is effective method in order to keep coexistence of environmental consciousness and variety of product. However, the lifecycle time is very long, so that a market could change greatly in the meantime. This is one of the major reasons that a judgment of a good or bad modular structure is not easy for the designer. In order to solve this problem, two methodologies are required: (1) a prediction method of the change of the market in long life span of the product family, and (2) a design method of the life-cycle and module structure based on the predicted market change. The aim of this research is to develop a method of the ability to design the optimal modular structure considering life-cycle calculation based on the sales scenario defined by the plan and prediction of the sales of the line-up products in the product family. This paper assumed that the market change is modeled as a number of the sold product. Based on this assumption and change of the quantity of the sales products by the change of the customer requirements and the competitive products in market are modeled as a sales scenario of a product family. An example is validated for effectiveness of the proposed method based on the proto-type system.
On the Influence of Contact Geometry on Grasp Stability
Authors: Kragten Gert A. , Herder Just L. , Schwab A. L.
Published: July 2009

This paper demonstrates that the predicted grasp stability is highly sensitive to only small changes in the character of the contact forces. The contribution of the geometry and stiffness at the contact points to the grasp stability is investigated by a planar grasp with three contact points. Limit cases of zero and infinite contact curvatures, and finite to infinite contact stiffnesses are considered. The stability is predicted based on the approach of Howard and Kumar [1], and verified with multibody dynamic simulations. For rigid objects and fingers with only normal contact stiffness, the grasp stability is dominated by the contact geometry, whereas the local contact stiffness and preload have a minor effect. Furthermore, grasps with pointed finger tips are more likely to be stable than grasps with flat finger tips.
Condition-Monitoring Based on Structure-Borne Ultrasound Analysis
Authors: Albers Albert , Dickerhof Markus , Burger Wolfgang
Published: July 2009

Recent results in condition monitoring of machine elements by acoustic emission analysis are presented. A special method based on the evaluation of structure-borne noise emissions in the ultrasonic range is described. The ultrasound-signals caused by friction processes are captured by a broadband piezoelectric sensor and analyzed subsequently. The method has proven to be suitable for detecting the occurrence of friction between solid objects in a very reliable way. This leads to a variety of possible applications wherever occurrence of solid body friction has to be considered as an indication of failure or wear. In addition to tribometer tests, experiments with sliding bearings and slide ring seals are presented exemplarily. In both cases promising results were achieved. The significant difference of the presented method compared to other sound-based methods is in the nature of the analyzed signals: Harmonic waves of audible sounds or percussion-type stimulations are not evaluated but the portion of friction sounds emerging in the ultra-sonic range beyond audible frequencies. These friction sounds are widely unaffected by ambient noise and other sources of interference.
A Review of Recent Phase Transition Simulation Methods: Saddle Point Search
Authors: Alhat Devendra , Lasrado Vernet , Wang Yan
Published: July 2009

A review of saddle point search methods on a potential energy surface is presented in this paper. Finding saddle points on a complex potential energy surface is the major challenge in modeling and simulating the kinetics of first-order phase transitions. Once the saddle points have been identified and the activation energy for the transition is known, one can apply the kinetic Monte Carlo method to simulate the transition process. We consider some factors while reviewing the methods, such as whether the solution is global, the knowledge of the Hessian during the search, the capability to locate multiple saddle points and higher order saddle points, the kind of approximations used for potential energy surface, if any; and the convergence of the methods.
A Computational Method for Task Allocation and Coordination in a Distributed Design Environment
Authors: Johnson Jay , Wu Hao , Sifleet Todd , Fathianathan Meryvn
Published: July 2009

Managing the product realization process is a difficult endeavor in today’s global product development environment. Design project managers are required to form teams from geographically distributed designers as well as effectively manage the collaborative design process. In this paper, a computational method is proposed to aid design managers in allocating design tasks to geographically distributed designers and identify appropriate coordination mechanisms to manage the collaborative design process. The method involves three stages: i) arriving at an initial design task sequence using the design structure matrix through partitioning of design tasks into blocks of dependent, independent and interdependent tasks, ii) allocating of design tasks to design teams and the improvement of the design sequence accounting for the number of designers available and their competencies and iii) determination of design review meeting frequencies as a coordination mechanism for interdependent tasks using agent based modeling simulations.
A Robust Laser Interferometer (RLI) for Prognostics and Health Management (PHM)
Authors: Karchnak Martin F.
Published: July 2009

It is strongly suggested that consideration of the litany of reasons for the introduction of the Robust Laser Interferometer (RLI) measurement capability in Prognostics and Health Management (PHM) planning is a good idea. A ‘half dozen’ reasons for this suggestion are explored. They include the following observations supported by measurements with a highly reliable information content, experience and, in some situations, both. 1st - RLI provides quality non-contact, highly linear measurement of the wideband mechanical spectrum information, providing information for a large variety of operational, technical and management interest. 2nd - RLI provides more correct vibration information than contact accelerometer systems. 3rd - RLI provides more correct Acoustic Emissions (AE) information than contact AE systems, something particularly noteworthy for measurements in a noisy environment. 4th - The quality of the RLI information lessens (and sometimes eliminates) the need for approaches such as use of ‘multiple sensors with data fusion’ that are supported primarily because of sensing shortfalls. 5th - RLI is user friendly and can be employed in a variety of situations where contact sensing is ‘out-of-the-realm of choices’ or otherwise woefully vulnerable. 6th - The flexibility of RLI technology enables and, in all likelihood, invites new implementation concepts. The rationale and supporting data for each of the selected observations are briefly considered in this paper.
Identifying Feature Handles of Freeform Shapes
Authors: Song Yu , Vergeest Joris S. M. , Wiegers Tjamme
Published: July 2009

Trends, ergonomics and engineering analysis post more challenges than ever to product shape designs, especially in the freeform area. In this paper, freeform feature handles are proposed for easing of difficulties in modifying an existing freeform shape. Considering the variations of curvature as the footprint of a freeform feature(s), curvature analysis is applied to find manipulators, e.g. handles, of a freeform feature(s) in the shape. For these, a Laplacian based pre-processing tool is proposed first to eliminate background noise of the shape. Then least square conformal mapping is applied to map the 3D geometry to a 2D polygon mesh with the minimum distortions of angle deformation and non-uniform scaling. By mapping the curvature of each vertex in the 3D shape to the 2D polygon mesh, a curvature raster image is created. With image processing tools, different levels of curvature changing are identified and marked as feature point(s) / line(s) / area(s) in the freeform shape. Following the definitions, the handles for those intrinsic freeform features are established by the user based on those feature items. Experiments were conducted on different types of shapes to verify the rightness of the proposed method. Different effects caused by different parameters are discussed as well.
An Approach to Modeling Integrated Product Teams
Authors: Crowder Richard M. , Sim Y. W. , Payne Terry , Robinson Mark , Jackson Helen , del Carmen Romero Ternero Maria
Published: July 2009

This paper considers an agent-based approach to organizational modeling within the engineering design domain. It is widely recognized that interactions between individual designers, between (and within) integrated product teams (IPTs), together with the nature of design tasks have a significant impact upon how well a task can be performed, and hence the quality of the resultant product. In order for organizations to gain a full understanding of design team interactions within IPTs, we propose the use of multi-agent systems to model the behaviors and cognitions of team members, and to explore the applicability of different agent-theoretic approaches that could augment current team practices. In this paper we discuss the background to the work and the identifications of individual, and team variables. The paper concludes by discussing the computational model of a small IPT, which has been implemented using JADE, and the initial results are presented.
Parallel Implementation of Particle Swarm Optimization (PSO) Through Digital Pheromone Sharing
Authors: Kalivarapu Vijay K. , Winer Eliot H.
Published: July 2009

In this paper, a parallelization model for PSO through sharing of digital pheromones between multiple particle swarms to search n-dimensional design spaces is presented. Digital pheromones are models simulating real pheromones produced by insects for communication to indicate a source of food or a nesting location. Particle swarms search the design space with digital pheromones aiding communication within the swarm to improve search efficiency. Digital pheromones have demonstrated the capability of searching design spaces within PSO in the previous work by authors in both single and coarse granular parallel computing environments. Multiple swarms are simultaneously deployed across various processors in the coarse granular scheme and synchronization is carried out only when all swarms achieved convergence. This was done in an effort to reduce processor-to-processor communication and network latencies. With an appropriate parallelization scheme, the benefits of digital pheromones and swarm communication can potentially outweigh the network latencies resulting in improved search efficiency and accuracy. A swarm is deployed in the design space across different processors to explore this idea. Each part of the swarm is made to communicate with each other through an additional processor. Digital pheromones aiding within a swarm, communication between swarms is facilitated through the developed parallelization model. In this paper, the development and implementation of this method together with benchmarking test cases are presented.
A Survey of Assembly Planning Based on Intelligent Optimization Algorithms
Authors: Liu Jihong , Zeng Sen
Published: July 2009

Assembly planning is one of the NP complete problems, which is even more difficult to solve for complex products. Intelligent optimization algorithms have obvious advantages to deal with such combinatorial problems. Various intelligent optimization algorithms have been applied to assembly sequence planning and optimization in the last decade. This paper surveys the state-of-the-art of the assembly planning methods based on the intelligent optimization algorithms. Five intelligent optimization algorithms, i.e. genetic algorithm (GA), artificial neural networks (ANN), simulated annealing (SA), ant colony algorithm (ACO) and artificial immune algorithm (AIA), and their applications in assembly planning and optimization are introduced respectively. The application features of the algorithms are summarized. At last, the future research directions of the assembly planning based on the intelligent optimization algorithms are discussed.
The Systematic Design of a Layered Manufacturing Process for the Realization of Metallic Parts of Designed Mesostructure
Authors: Williams Christopher B. , Mistree Farrokh , Rosen David W.
Published: July 2009

Recognizing the need for an improved cellular material manufacturing process, the authors follow a systematic design method (posed by Pahl and Beitz) to address the inherent limitations imposed on designer freedom by existing manufacturing techniques. After identifying unique requirements of a cellular material manufacturing process, several solution principles are systematically generated following functional decomposition, working principle ideation, the formulation of working structures (via morphological matrices), and a preliminary selection exercise. Following preliminary embodiment, a principal solution is identified through the formulation and solution of a selection Decision Support Problem. As a result of this design effort, a novel layered manufacturing process capable of realizing metallic cellular materials (specifically, the three-dimensional printing of metal oxide parts followed by a thermal-chemical conversion postprocess) is realized. Another result of this design process is the insight gained from the systematic requirements-driven (or “application-pull”) design of a layered manufacturing process.
Issues on Aesthetic Shapes Perception for the Development of New Design Tools
Authors: Bordegoni Monica , Cugini Umberto
Published: July 2009

Exploring how to enhance and assist the design process with the support of new Information and Communication Technologies is a growing field of research. The analysis of the design processes of aesthetic shapes highlights open issues that make the processes inefficient and generate some questions about how to improve the process performances. Examples of questions are: how to generate more and better ideas, how to become more creative and how to exploit at best people know-how. The research presented in this paper reasons about issues related to aesthetic shapes perception and proposes some solutions at the basis of future design tools based on new ways of working and new ways of interaction.
Automatic Shutter Control System for Home Care Using Local-Loop Approach
Authors: Chen Chao Hung , Lin Hsiung Cheng , Liu Ying Chu , Hsu Wei Chung , Chang Shin-Ming
Published: July 2009

With increasing population of elder people around the world, the demand of home care system such as sufficient sunlight supplier from natural resource is getting much attention in recent years. This paper has proposed a microprocessor (8051) based automatic shutter action control system using 4-speed controlled DC motor. The proposed system can keep sunlight moderate as desired in the indoor room. Real practical performance results are presented to demonstrate the effectiveness of the proposed approach in term of robust, simple, flexible and efficient performance.
Contour-Crafting-Cartesian-Cable Robot System Concepts: Workspace and Stiffness Comparisons
Authors: Williams Robert L. , Xin Ming , Bosscher Paul
Published: July 2009

Contour crafting (CC) is a new technology that is proposed for construction. Formerly we presented a cable-suspended robot to implement CC technology with Cartesian motion. The current paper proposes an improved Contour-Crafting-Cartesian-Cable (C4) robot. Although the new concept is preferable in structural design, here we compare the original and improved C4 robot concepts with regard to kinematics, workspace, and stiffness.
Response Control in Fluid-Smart Structure Interaction
Authors: To C. W. S.
Published: July 2009

A formulation with computational procedure for the response control in fluid-smart structure interaction is presented. It exploits the features of the smart triangular shell finite elements developed earlier by the author and his associate, the double asymptotic approximation for fluid-structure interaction of Geers, and the finite element-cum-boundary element method that was proposed by To and O’Grady. To provide a better understanding of the interplay between the structural responses and the applied voltage of the piezoelectric layers, computed results of a three-layered simply-supported plate structure were presented. It was observed that significant deformation reduction can be achieved with applied voltage indicating that with the smart shell finite elements desired deformation at chosen locations of the submerged system can be specified.
Accuracy Enhancement of Flexible Fourbar Mechanisms via the Curvature-Based Finite Element Method
Authors: Kuo Y. L. , Cleghorn W. L.
Published: July 2009

The paper investigates accuracy enhancement of flexible four-bar mechanisms via the curvature-based finite element method. Conventionally, the displacement-based method is usually applied to solid mechanics, and it needs more elements or high-degree polynomials to obtain highly accurate solutions. The curvature-based method assumes a polynomial to approximate a curvature distribution, and the expressions are investigated to obtain the displacement and rotation distributions. During the process, the boundary conditions associated with displacement, rotation, and curvature are imposed, which leads the great reduction of the number of degrees of freedom which are required. The numerical results demonstrate that the errors obtained by applying the curvature-based method are much smaller than those by applying the displacement-based method, based on the comparison of the same number of degrees of freedom.
ANSLC Artifitial Neural Strain Life Curves
Authors: el Dsoki Chalid , Hanselka Holger , Kaufmann Heinz , Ro¨big Andreas
Published: July 2009

A durable design for linear flow split sheet components requires suitable methods and transferability criteria which are not yet available for dentritic structures. Knowledge of the cyclic material behaviour is essential for this. For this reason, the cyclic material parameters are determined as a function of the product’s properties (level of deformation, microstructure, surface finish, residual stresses) and different loading parameters. However, since the determination of the cyclic parameters is associated with considerable experimental effort and costs, a cost-effective and easy method is sought to determine these parameters. A very promising approach for this is the application of artificial neural networks (ANN) [1, 2, 3, 4, 5] since they have the ability to generate the influences on the fatigue strength from the manufacturing and environmental parameters using sensibly selected input parameters. They offer the possibility to access acquired knowledge and to thus construct a multidimensional map based on a few tests.
Design of Perfectly Static-Balanced One-DOF Planar Linkage With Revolute Joint Only
Authors: Lin Po-Yang , Shieh Win-Bin , Chen Dar-Zen
Published: July 2009

A systematic methodology for the design of a statically balanced, single degree-of-freedom planar linkage is presented. This design methodology is based on the concept of conservation of potential energy, formulated by the use of complex number notations as link vectors of the linkage. By incorporating the loop closure equations, the gravitational potential energy of the system can be simplified as the function of the vectors of all ground-adjacent links. The balance of the gravitational potential energy of the system is then accomplished by the elastic potential energy of a zero free-length spring on each ground-adjacent link of the linkage. As a result, spring constants and installation configurations of the ground-attached springs are obtained. Since the variation of the gravitational potential energy of the linkage at all configurations can be fully compensated by that of the elastic potential energy of springs, this methodology provides an exact solution for the design of a general spring balancing mechanism without auxiliary parallel links. Illustrations of the methodology are successfully demonstrated by the spring balancing designs of a general Stephenson-III type six-bar linkage and a Watt-I type six-bar linkage with parallel motion.
Kinematic Analysis of the Vertebra of an Eel Like Robot
Authors: Chablat Damien
Published: July 2009

The kinematic analysis of a spherical wrist with parallel architecture is the object of this article. This study is part of a larger French project, which aims to design and to build an eel like robot to imitate the eel swimming. To implement direct and inverse kinematics on the control law of the prototype, we need to evaluate the workspace without any collisions between the different bodies. The tilt and torsion parameters are used to represent the workspace.
Mobility and Geometrical Analysis of a Two Actuated Spoke Wheel Robot Modeled as a Mechanism With Variable Topology
Authors: Wang Ya , Ren Ping , Hong Dennis
Published: July 2009

In this paper, the mobility and geometrical analysis of a novel mobile robot that utilizes two actuated spoke wheels is presented. Intelligent Mobility Platform with Active Spoke System (IMPASS) is a wheel-leg hybrid robot that can walk in unstructured environments by stretching in or out three independently actuated spokes of each wheel. First, the unique locomotion scheme of IMPASS is introduced and the definitions of the coordinate systems are developed to describe the kinematic configurations. Since this robot is capable of utilizing its metamorphic configurations to implement different types of motion, its topology structures are classified into different groups based on the cases of ground contact points. For each contact point case, the mobility analysis is performed using the conventional Gru¨bler and Kutzbach criterion. However, as for the cases in which the structure is overconstrained, the Modified Gru¨bler and Kutzbach criterion based on reciprocal screws are implemented to obtain the correct number of degrees of freedom. Line geometry is adopted to assist in the process. Additionally, the geometrical constraint equations of the robot are derived. The results in this work lay the foundation of the future research on inverse and forward kinematics, instantaneous kinematics, dynamics analysis and motion planning of this unique locomotion robot.
Three-Dimensional Kinematic Analysis of a Two Actuated Spoke Wheel Robot Based on Its Equivalency to a Serial Manipulator
Authors: Ren Ping , Wang Ya , Hong Dennis
Published: July 2009

In this paper, the inverse and forward kinematics of a novel mobile robot that utilizes two actuated spoke wheels is presented. Intelligent Mobility Platform with Active Spoke System (IMPASS) is a wheel-leg hybrid robot that can walk in unstructured environments by stretching in or out three independently actuated spokes of each wheel. First, the unique locomotion scheme of IMPASS is introduced. Then the configuration of the robot when each of its two spoke wheels has one spoke in contact with the ground is modeled as a two-branch parallel mechanism with spherical and prismatic joints. An equivalent serial manipulator of the 2-SP mechanism with the same degrees of freedom is proposed to solve for the inverse and forward kinematic problems. The relationship between the physical limits of the stroke of the spokes (effective spoke length) and the limits of its equivalent degree of freedom is established. This approach can also be expanded to deal with the forward and inverse kinematics of other configurations which has more than two ground contact points. Several examples are used to illustrate the method. The results obtained will be used in the future research on the motion planning of IMPASS walking in unstructured environment.
Optimization of Hydro-Pneumatic Suspension of All-Terrain Crane Based on ADAMS
Authors: Cai Fuhai , Wang Xin , Gao Shunde , Zhao Fuling
Published: July 2009

Characteristic of All-Terrain Crane (ATC) is introduced in this paper and the working principle of Hydro-Pneumatic Suspension (HPS) in ATC is also discussed. The development status and tendency are summarized, through which we can see there is a large technology gap between China and Western Europe. An optimization method to HPS based on ADAMS is introduced in the paper. Based on ADAMS, a single bridge HPS of All-Terrain Crane virtual prototype is built and the function of HPS is accomplished with the standard hydraulic components. By the method of Design of Experiments (DOE), the dynamics optimization of HPS is carried out based on the analysis of the affecting factors after optimization variables are chosen. At last the result indicates that the dynamics characteristic of optimized model performs better than the former one and the present method can be used as a structural optimization reference.
Optimization Design of a Spatial Six-Degree-of-Freedom Parallel Manipulator Based on Genetic Algorithms and Neural Networks
Authors: Zhang Dan , Gao Zhen
Published: July 2009

Optimizing the performances of parallel manipulators by adjusting the structure parameters can be a difficult and time-consuming exercise especially when the parameters are multifarious and the objective functions are too complex. Artificial intelligence approaches can be investigated as the effective criteria to address this issue. In this paper, genetic algorithms and artificial neural network are implemented as the intelligent optimization criteria of global stiffness and dexterity for spatial six degree-of-freedom (DOF) parallel manipulator. The objective functions of global stiffness and dexterity are calculated and deduced according to the kinetostatic model. Neural networks are utilized to model the solutions of performance indices. Multi-objective optimization is developed by Pareto-optimal solution. The effectiveness of the proposed methodology is proved by simulation.
The Development of an Incrementally Loaded Finite Element Model of the Whole Skin Locomotion Mechanism: Discovering the Relationship Between Its Shape and Motion
Authors: Lahr Derek , Hong Dennis
Published: July 2009

The Whole Skin Locomotion (WSL) robotic platform is a novel biologically inspired robot that uses a fundamentally different locomotion strategy than other robots. Its motion is similar to the cytoplasmic streaming action seen in single celled organisms such as the amoeba. The robot is composed of a closed volume, fluid filled skin which generally takes the shape of an elongated torus. When in motion the outer skin is used as the traction surface. It is actuated by embedded smart material rings which undergo cyclical contractions and relaxations, generating an everting motion in the torroidially shaped skin. To better understand, design, and optimize this mechanism, it is necessary to have a model of the skin, fluid, and actuators and their interactions with the environment. This paper details the first steps in the development of a non-linear finite element (FE) model which will allow us to study these interactions and predict the shape and motion of the robot under various actuation strategies. A simple membrane element model is introduced from literature and is modified such that an incremental loading strategy can be employed. Finally, an underlying physical mechanism is introduced which could possibly describe the relationship between the shape of and pressure within the membrane skin and motion of the whole skin locomotion robot.
Layered Depth-Normal Images for Complex Geometries: Part Two — Manifold-Preserved Adaptive Contouring
Authors: Wang Charlie C. L. , Chen Yong
Published: July 2009

We present an adaptive contouring approach to generate contour surface from solid models represented by Layered Depth-Normal Images (LDNI) sampled in three orthogonal directions. Our contouring algorithm builds an octree structure for mesh generation in a top-down manner: starting from the bounding box of a LDNI solid model, the cells are recursively subdivided into smaller sub-cells based on the topology and geometry criteria of refinement until both of the requirements, the topology in cell is simple and the geometry approximation error is less than a user defined tolerance, are satisfied. The subdivision also stops when the processed cells reach the finest resolution of LDNI models. In order to overcome the topology ambiguity inside a cell that leads to the occurrence of non-manifold entities, we analyze the possible inside/outside configurations of cell-nodes and exploit two strategies to generate manifold-preserved mesh surfaces. Moreover, the most time-consuming step of our contouring algorithm — the construction of octree structure can be easily parallelized to run under a computer framework with multiple-processors and shared memory. Several examples have been tested in the paper to demonstrate the success of our method.