bluuebunny/crossref_metadata_2025 huggingface dataset:
An FMS Control Structure: Data Modeling and Execution Components
Authors: Jeon Joongnam , Smith Jeffrey S.
Published: February 2021

This paper describes the data modeling and execution components of a flexible manufacturing system (FMS) control model. The execution unit operates based on the organizational and operational information that describes an FMS. We have developed a unified machine model for the various kinds of machines and controllers. The layout and connection of them are represented in Port Connection Graph (PCG). The operational information is represented in the Process Flow Graph (PFG) and Task Flow List (TFL). For the execution unit, the thread concept of the concurrent system has been adopted in order to implement a manufacturing process where multiple parts can be manufactured simultaneously. Specially, the database unit is interfaced to the internet such that the manager or customers can access the database tables through a web browser. These control components work directly with a decision-making model described in the literature. Used together, the components can be combined into a fully functional FMS control system. An implementation in a full-scale FMS laboratory is described.
Computer Aided Dimensional Analysis and Scale Modeling
Authors: Zargar Yasir S. , Farhang Kambiz
Published: February 2021

In this paper a computer program for dimensional analysis and scale modeling is presented. The program can be utilized to develop the scaling law and the simlitude requirenments for any physical system. The scaling law and the simlitude requirenments are then utilized to generate the scale factors. Proper use of this program can save considerable amount of time for any scientist working in the area of dimensional analysis and scale modeling.
Adaptive Slicing of Heterogeneous Solid Models for Layered Manufacturing
Authors: Kumar Vinod , Kulkarni Prashant , Dutta Debasish
Published: February 2021

A novel feature of Layered Manufacturing, an emerging manufacturing technology, is that it enables fabrication of heterogeneous objects (multi-material and functionally graded interiors). In our earlier work, we developed new modeling schemes (called heterogeneous solid models) for representing these heterogeneous objects by capturing both geometry and material information. One of the crucial steps for fabricating these heterogeneous objects in LM is adaptive slicing, a fundamental process planning task. In this paper, we describe how the heterogeneous solid models can be adaptively sliced to aid in the LM fabrication of heterogeneous objects.
Advanced FMEA Using Meta Behavior Modeling for Concurrent Design of Products and Controls
Authors: Kmenta Steven , Ishii Kosuke
Published: February 2021

This paper presents the use of Advanced Failure Modes and Effects Analysis (AFMEA) as a methodology for the concurrent design of electro-mechanical products and their control systems. The past two years have seen the extension of AFMEA to simulate dynamic changes of device operations using meta-behavior modeling. This approach can help engineers identify failure modes associated with controls and their interaction with physical systems and drive system design toward more reliable solutions. The proposed method uses behavior modeling to map control functions to physical entities and identifies failure modes as the departure from intended control functions. AFMEA provides a framework for controls and hardware developers to discuss and understand the relationship between sub-systems, controls, and overall system performance. An example of a power generation system illustrates how AFMEA applies to the early stages of layout and controls design.
Preserving Design Intent in Data Integration Between Virtual Prototyping and CAD Systems
Authors: Jayaram Sankar , Jayaram Uma , Kreitzer Robert
Published: February 2021

State of the art CAD/CAM technology enables the capture of user design intent through the use of assembly constraints, features, parameters, etc. However, due to the large size of the CAD models, engineers are using other virtual prototyping methods for visualization and complete assembly analysis. Constraint and parameter information is lost in the transfer of models from the CAD system to the virtual prototyping systems. In virtual prototyping systems, users typically have tools to modify the location of an assembly component. In order to maintain model validity, procedures need to be developed to transfer these modifications back to the CAD system while maintaining the design intent of the original CAD user. In other words, how do we take information about changes to absolute or relative location and orientation of a component and transform this to updated constraint and parametric information in the original CAD model?

In this paper, we address this need to update the constraints and parametric information of a CAD model based on location and orientation changes communicated from a virtual prototyping system. After analyzing and categorizing the assembly constraints in a typical feature-based CAD system, we propose a methodology to decide what information needs to be updated, and a procedure to update the information — all based on the original design intent captured in the constraints. The results of a test case to validate the methodology are also presented.
High-Lift Optimization Design Using Neural Networks on a Multi-Element Airfoil
Authors: Greenman Roxana M. , Roth Karlin R.
Published: February 2021

The high-lift performance of a multi-element airfoil was optimized by using neural-net predictions that were trained using a computational data set. The numerical data was generated using a two-dimensional, incompressible, Navier-Stokes algorithm with the Spalart-Allmaras turbulence model. Because it is difficult to predict maximum lift for high-lift systems, an empirically-based maximum lift criteria was used in this study to determine both the maximum lift and the angle of attack at which it occurs. Multiple input, single output networks were trained using the NASA Ames variation of the Levenberg-Marquardt algorithm for each of the aerodynamic coefficients (lift, drag, and moment). The artificial neural networks were integrated with a gradient-based optimizer. Using independent numerical simulations and experimental data for this high-lift configuration, it was shown that this design process successfully optimized flap deflection, gap, overlap, and angle of attack to maximize lift. Once the neural networks were trained and integrated with the optimizer, minimal additional computer resources were required to perform optimization runs with different initial conditions and parameters. Applying the neural networks within the high-lift rigging optimization process reduced the amount of computational time and resources by 83% compared with traditional gradient-based optimization procedures for multiple optimization runs.
A Comparison of Flashover Theories
Authors: Kim Hyeong-Jin , Lilley David G.
Published: February 2021

In structural fires, flashover is characterized by the rapid transition in fire behavior from localized burning of fuel to the involvement of all combustibles in the enclosure. Major parameters affecting flashover are fire growth rate, ventilation opening area, and room area. A comparison of flashover theories is undertaken using the Thomas, Babrauskas and the FASTLite theories, concentrating on the similarities and differences between the theories in their assessment of the major parameters affecting flashover.
Mixed Convective Heat Transfer From Rotating Spheres
Authors: Heydari Ali , Firoozabadi Bahar , Fazelli Hamid
Published: February 2021

This paper presents an analysis of flow and heat transfer over a rotating axsisymmetric body of revolution in a mixed convective heat transfer along with surface conditions of heating or cooling as well as surface transpriation. Boundary-layer approximation reduces the elliptic Navier-Stokes equations to parabolic equations, where the Keller-Cebeci method of finite-difference solution is used to solve the resulting system of partial-differential equations. Comparison of the calculated values of the velocity and temperature profiles as well as the shear and the heat transfer coefficients at the surface for the case of a sphere with the available literature data indicate the model well predicts the boundary-layer flow and heat transfer over a rotating axsisymmetric body.
Laser-Beam Fusion of Predeposited Metal Powder for Layered Manufacturing: Modeling, Simulation, and Experiment
Authors: Yevko Vladimir , Zak Gene , Park Chul B. , Coyle Tom W. , Benhabib Beno
Published: February 2021

Current commercial Rapid Prototyping (RP) systems can be used for fabricating layered models for subsequent creation of fully-dense metal parts using investment casting. Due to increased demand for shortened product development cycles, however, there exists a demand to rapidly create functional fully-dense metal parts without hard tooling. A possible solution to this problem is direct layered Rapid Manufacturing (RM) of such parts, for example, via laser-beam fusion of the metal powder. The RM process proposed herein is based on this approach. It involves selective laser-beam scanning of a predeposited metal-powder layer, forming fully-dense claddings, as the basic building block of individual layers.

This paper specifically addresses only one of the fundamental issues of the proposed RM process, namely the fabrication of single claddings. Our theoretical investigation of the influence of the process parameters on cladding’s geometrical properties employed thermal modeling and computer process simulation. Numerous experiments, involving fabrication of single claddings, were also carried out with varying process parameters. Comparisons of the process simulations and experimental results showed good agreement in terms of overall trends.
Reliabilist Approach of Arched Tubes
Authors: Shakourzadeh Hossein , Djeni Jean-Claude , Braibant Vincent , Patou Pascal
Published: February 2021

Understanding spring back for the arched tubes constitutes a major problem for every tube manufacturer. Even when the allowable fluctuations are limited to tenth of degrees, angular fluctuations of several degrees are usually observed. This indicates the importance of the problem. The aim of this study is to understand the role of materials in determining spring back characteristics of bent tubes. The first stage of the work thus consists in finding analytical, semi-analytical, numerical or even empirical models in order to formulate the spring back. These models are then validated by experimental tests. In second stage, an analysis of sensitivity is carried out in order to determine the influence of various parameters like the geometry, the process or material.
Sound Insulation Analysis of a Resin Composite Material Using the Homogenization Method
Authors: Yuge Kohei , Ejima Susumu
Published: February 2021

We propose a numerical method to predict the noise transmission loss of a resin composite cover, which considers the effect of the shape and the material properties of the microscopic reinforcements in a resin-composite. The mean material properties of the material are calculated with the homogenization method and the acoustic structural coupling analysis is made with the obtained material constants. The calculated results show that the sound insulation levels are affected seriously by the shape or rate of the reinforcements in the material, which suggests that the present method can be a good numerical method to determine the reinforcements in a resin to improve the sound insulation ability.
A Pattern Search-Based Algorithm for Three-Dimensional Component Layout
Authors: Yin Su , Cagan Jonathan
Published: February 2021

A pattern search-based algorithm is introduced for efficient component layout optimization. The algorithm is applicable to general layout problems, where component geometry can be arbitrary, design goals can be multiple and spatial constraint satisfactions can be of different types. Extensions to pattern search are introduced to help the algorithm to converge to optimal solutions by escaping inferior local minima. The performance on all of the test problems shows that the algorithm runs one-to-two orders of magnitude faster than a robust simulated annealing-based algorithm for results with the same quality. The algorithm is further extended to solve a concurrent layout and routing problem, which demonstrates the ability of the algorithm to apply new pattern strategies in search and to include different objective functions in optimization.
Optimum Topology of Embossed Ribs in Stamped Plates
Authors: Soto Ciro A. , Yang Ren Jye
Published: February 2021

This paper presents a methodology to compute the optimum topology of embossed ribs (also known as beads) in stamped plates. The pattern and orientation of embossed ribs are determined using topology optimization techniques as introduced by Bendsøe and Kikuchi (1988). The particular characteristics of embossed ribs in membrane and pure bending deformations are considered in the analysis model to closely simulate their structural behavior. What makes this approach unique is that the optimum solution is made of two materials, one with orthotopic properties which is optimally distributed within a second material with isotropic properties that model the non-ribbed plate. An example of a vehicle fuel tank is included to illustrate the potential use of this methodology.
Applications of Mating Conditions in Assembly Sequence Planning Task
Authors: Dulyapraphant Pongsak , Ozsoy Tulga
Published: February 2021

Because of their intuitive interface, mating conditions have been prevalently used in assembly modelling. Besides their use for modelling purposes, other type of information, such as spatial relationships between parts and local degrees of freedom, can be directly derived from mating conditions. This information in turn can be used in various engineering analysis applications, such as kinematics analysis or automatic tolerance chain generation for tolerance analysis. In this paper, application of mating conditions in an assembly sequence-planning task is investigated. The proposed approach mainly engages the mating information represented in the CAD assembly model to automatically generate sequence plans based on the minimization of the number of assembly directions.
On the Application of Tensor Product Solids in Heterogeneous Solid Modeling
Authors: Marsan Anne , Dutta Debasish
Published: February 2021

With the development of layered manufacturing (LM) technologies, engineers are now able to build objects which are composed of multiple materials and/or have varying material properties throughout. These so called heterogeneous objects can be described by heterogeneous solid models, which contain information about the boundaries of the object, as well as material properties. In this paper we show how tensor product solids, which are the 3D extension of tensor product surfaces, can be used to model material properties within the framework of a heterogeneous solid model. We then show how a heterogeneous solid model which makes use of tensor product solids can be used in reverse engineering and process planning for LM.
Robust Design by Support of CAT Tools
Authors: Söderberg Rikard
Published: February 2021

This paper describes how currently available tools for computer aided tolerancing (CAT), can be used in a two step procedure to increase the robustness of a design and when allocating proper tolerances.

The first step is to increase geometric robustness by minimizing the number of parameters controlling a critical characteristic. This is closely related to the philosophy behind axiomatic design, see Suh (1990) and is performed during concept design. In this step, the CAT tool is used to analyze the general stability and sensitivity of an assembly in order to detect the sources of variation, KC:s, on an overall product characteristic, PKC. This step is performed with equal tolerances applied to all geometrical part features, which enables the designer to detect geometrical couplings and evaluate general assembly robustness.

The second step is to assign tolerances on the final geometry. This is done with respect to final geometrical sensitivity, manufacturing capability and manufacturing cost and is performed during detail design. At this stage, the final variation of overall product characteristics may be simulated, and part tolerances may be adjusted with respect to final sensitivity and cost. If loss functions for the PKC:s are available, the total quality level of a concept may be analyzed.
Concurrent Design Implementing Aesthetic Factors
Authors: Yoshimura Masataka , Yanagi Hisaichi
Published: February 2021

In order to obtain product designs which maximize their appeal to users, a concurrent product design method is proposed in which aesthetic factors are implemented during conventional product design. Subjective attributes, corresponding to aesthetic factors, are evaluated concurrently with analytically obtained objective attributes of the product’s characteristics. The interaction of these subjective and objective attributes, as it relates to the product’s utility and manufacturing cost, is clarified. Then, the solution which has the minimum ratio of manufactured cost relative to the user’s expected product price is selected as the optimum design solution. Applied examples pertaining to robot designs are given, to demonstrate these methodologies.
Computer-Aided Linear Tolerance Analysis and Optimal Tolerance Distribution for Cylindrical Machined Parts
Authors: Tsai Jhy-Cherng , Shih Chin-Ming
Published: February 2021

Quality and cost are among the most important concerns for a product. While tolerance is one of the typical metrics for quality, it is a trade-off between tolerances and costs in product development though the two factors often conflict with each other. This paper describes a systematic approach to compute linear tolerance accumulation for cylindrical parts by machining operations based on the tolerance chart. A computer-aided tolerance chart system is developed to assist the construction of the corresponding tolerance chart and the computation of accumulated linear tolerances for a given process plan. Tolerance distribution to each machining operation by optimization techniques is also investigated. The goal is to minimize machining cost subject to constraints on tolerance accumulation and process capability. It shows that the machining cost of a sample part with the worst-case tolerance analysis can be reduced by 39%, compared to that by experience, and can be further reduced if statistical tolerance analysis applies.
The Design for Assembly Guidelines Transform a Product Innovation From a Loser to a Winner
Authors: Myszka David H.
Published: February 2021

Several manufacturer’s are witnessing soaring profits as a result of cost reductions derived from Design for Manufacturing and Assembly (DFMA) analyses. These successes are prompting others to turn to more refined computer models of product assemblies. However, much can be gained from a very routine analysis, using nothing more than the basic Design for Assembly (DFA) guidelines. These gains can be realized at a mere fraction of the resources needed for the computer models. This method of analysis is especially appealing to engineers whose time constraints require careful selection of design activities.

This paper argues that DFMA analysis does not need to be an elaborate modeling process to produce significant cost improvements. This point is illustrated with an example of a redesign of a cooking range door. A manual review of the DFA guidelines turned a design innovation from a loser into a winner. Success stories from such informal analyses should promote greater implementation across industries that are hesitant in adopting DFMA practices.
Design for Mass Customization by Developing Product Family Architecture
Authors: Tseng Mitchell M. , Jiao Jianxin
Published: February 2021

Mass customization is becoming an important agenda in industry and academia alike. This paper deals with mass customization from a product development perspective. A framework of design for mass customization (DFMC) by developing product family architecture (PFA) is presented. To deal with tradeoffs between diversity of customer requirements and reusability of design and process capabilities, DFMC advocates shifting product development from designing individual products to designing product families. As the core of DFMC, the concept of PFA is developed to assist different functional departments within a manufacturing enterprise to work together cohesively. A PFA describes variety and product families and performs as a generic product platform for product differentiation in which individual customer requirements can be satisfied through systematic decisions of developing product variants. Based on such a PFA, the DFMC framework provides a unifying integration platform for synchronizing market positioning, soliciting customer requirements, increasing reusability, and enhancing manufacturing scale of economy across the entire product realization process.
Condition Monitoring Methodology for Manufacturing and Design
Authors: Tumer Irem Y. , Wood Kristin L. , Busch-Vishniac Ilene J.
Published: February 2021

Part production requires constant monitoring to assure the effective manufacturing of high-quality components. The choice of monitoring methods can become a crucial factor in the decisions made during and prior to manufacturing. In an ideal world, designers and manufacturers will work together to interpret manufacturing and part data to assure the elimination of faults in manufacturing. However, manufacturing still lacks mathematically robust means of interpreting the manufacturing data so that a channel of communication can be established between design and manufacturing. To address part production concerns, we present a systematic methodology to interpret manufacturing data based on signals from manufacturing (e.g., tool vibrations, part surface deviations). These signals are assumed to contain a fingerprint of the manufacturing condition. The method presented in this paper is based on a mathematical transform to decompose the signals into their significant modes and monitor their changes over time. The methodology is meant to help designers and manufacturers make informed decisions about a machine and/or part condition. An example from a milling process is used to illustrate the method’s details.
Industrial Application of the Method “Early Determination of Product Properties”
Authors: Lindemann Udo , Stetter Ralf
Published: February 2021

Nothing is more critical for the success of a project than a design flaw that remains undetected until the product is in production or even handed over to the customer. In order to prevent the negative effects of undetected flaws, the method “early determination of product properties” has been developed at the Chair of Design at the Technische Universität München. In this paper the introduction of the method in a mid-size industrial company and the first resulting tool, the Parameter Checklist, are described. The presented research started with a detailed analysis of the product development process in the industrial company. In order to introduce a complex method in an industrial company, many aspects of the situation of the designers, from existing tools and procedures to the designers’ capabilities have to be considered. Because of this, the method was divided into distinct ideas, stages and tools, and compared individually to the situation given. On this basis a first methodical tool was developed, intended to support designers while using the method.

The tool called Parameter Checklist supports designers in planning analyses (e.g. tests with physical prototypes, finite element analyses) and in interpreting the results of these analyses. Furthermore, by using the tool, a database is filled that provides enough information to reconstruct the described analyses. In contrast with conventional testing instructions, the Parameter Checklist contains an explicit description of the model, in some respects found to be important, and a list of the influencing parameters. This is the basis for both a simple but conscious form of analysis planning and a more thorough interpretation of the analysis results.
The Chain Metrics Method for Identifying Integration Risk During Concept Design
Authors: Cunningham Timothy W. , Whitney Daniel E.
Published: February 2021

Two critical milestones that must be achieved during concept design are 1) definition of a product architecture that meets performance, producibility, and strategic objectives, and 2) estimation of the integration risk in each candidate concept. This paper addresses these issues by introducing the chain method for illustrating the structure of function delivery in a concept in a simple pictorial way. The chains method helps design teams to understand the advantages or disadvantages of using a modular or an integral product architecture. A set of metrics is proposed that can be used to compare different concepts and rank their integration risk. An example drawn from the aircraft industry is used to illustrate the method.
Optimal Experimental Setpoint Determination in Systems With Multiple Output Responses
Authors: Rai Sudhendu
Published: February 2021

This paper describes a methodology for determining input setpoints in engineering systems to simultaneously optimize multiple conflicting output responses. Orthogonal arrays are used to design experiments and capture experimental data. A nonlinear regression model using the mean value of each output response is obtained using MARS (Multivariate Adaptive Regression Splines). A multiobjective optimization method based on adaptive simulated annealing is then employed for generating global Pareto-optimal setpoints. Different conflicting objectives are traded-off against each other on the Pareto-optimal frontier to obtain the best setpoints. Two classes of experiments are discussed; one in which there are only two objectives and it is possible to visualize the entire Pareto-optimal curve and the other when the number of objectives are greater than three when it is no longer possible to visualize the entire Pareto-optimal hypersurface. The approach is also extended to include nonlinear models of signal-to-noise ratios that provide setpoints that are robust with respect to noise in the Taguchi sense. Several setpoint determination problems from the xerographic domain are presented to illustrate the overall approach.
Interoperability of Assembly Analysis Applications Through the Use of the Open Assembly Design Environment
Authors: Angster Scott , Lyons Kevin , Hart Peter , Jayaram Sankar
Published: February 2021

The emergence of high performance computing has opened up new avenues for the design and analysis community. Integrated Product/Process Design techniques are allowing multi-functional teams to simultaneously optimize the design of a product. These techniques can be inhibited, however, due to software integration and data exchange issues. The work outlined in this paper focuses on these issues as they relate to the design and analysis of electro-mechanical assemblies. The first effort of this work is the creation of an open environment, called the Open Assembly Design Environment. The goal of this environment is to integrate the otherwise disparate assembly design tools using a central control system and a common set of data. These design tools include virtual reality based design systems, computer-aided design systems, design for assembly systems and process planning systems. This paper outlines the overall goals of the project, presents the architecture designed for the system, describes the interfaces developed to integrate the systems, and discusses the data representation requirements for a system integrating a virtual reality system with computer-aided design systems.
A Data Approach to Tracking and Evaluating Engineering Changes
Authors: Cohen Tal , Fulton Robert E.
Published: February 2021

Changes are common during any stage of a product life cycle. There are local changes that do not influence other elements of a product. However, there are other changes that can influence different aspects of the product. Consequences of these changes, unless properly anticipated, and accounted for, can be costly. Therefore, it is highly desirable to obtain a mechanism that will be able to anticipate and evaluate product change consequences.

The first task in anticipating and evaluating change consequences is to represent them. The complexity of engineering models makes their representation to be rich and semantic. Information data models like EXPRESS provide tools for modeling products. However, the current EXPRESS and other information models do not have a generic methodology to support contextual change representation and propagation.

In this paper a methodology called Change FAvorable Representation – C-FAR is presented. C-FAR uses an existing product information model to facilitate change representation, propagation, and qualitative evaluation. The EXPRESS schema’s main elements are entities, relations among entities, and attributes that describe the entities.

C-FAR facilitates change and change evaluation to the attribute level.

C-FAR has been evaluated using case studies in structural analysis, and bumper design. Results show that C-FAR is capable of representing change and provides a reasonable qualitative evaluation of the change consequences.
Development of a Methodology for Cost Estimation in Robot Assembly
Authors: Tischner Oliver , Soni A. H.
Published: February 2021

The developments in today’s industries put the companies under increasing pressure concerning time and costs. This forces them to, among other measures, rationalize and automates the manufacturing systems, including the assembly systems. To reduce the risks of investments and enhance the investment planning, accurate calculation methodologies for assembly planning systems are necessary. There are a number of ways to lay out an assembly system. An assembly system may be designed for a manual operation, an automatic operation, or a flexible operation. Industrial robots are extensively used in such flexible assembly systems. Production volume and cost per assembled part depend heavily on how such a flexible cell is designed and on the robot being used. Boothroyd and Dewhurst have proposed an approach to arrive at evaluating robot integrated assembly cells. This approach is based on the manipulation of the part before presenting it for an assembly and the number of robot arms in the assembly cell. It does not account for the flexibility (number of robot axes, specific types of robots) the various industrial robots offer. Consequently, any evaluation made on this basis is expected to provide inaccurate answers.
Evaluation of Power Loss of the Rubber V-Belt CVT
Authors: Chen T. F. , Sung C. K.
Published: February 2021

This paper proposes a systematic method for the evaluation of power loss of rubber V-belt continuously variable transmissions (CVT). By observing the interaction between belt and sheaves, the entire belt may be divided into four regions. They are free span, wedging-in, adhesion, and wedging-out regions. Therefore, each region possesses a distinct motion characteristic. Herein, power loss is categorized into speed and torque losses. Since speed loss contributes less than 4% of the total power loss in most operating conditions, only torque loss is considered. The mechanisms causing torque loss may be attributed to the hysteresis of belt bending, compression and shear, and friction due to radial motion of the belt. These loss mechanisms are studied on the basis of motion characteristics in each region. Parameters for loss mechanisms are then analyzed to identify their contributions to the system efficiency. These parameters include external load, rotating speed and wedge angle of the pulley, speed ratio, pre-tension, and thickness and tooth profile of the belt. In addition, an experimental study is performed for verification of the proposed analytical approach.
Web-Based Interactive Cam Design
Authors: Larson Jonathan E. , Cheng Harry H.
Published: February 2021

We have developed a Web-based interactive cam design package under the programming paradigm of the CH language environment. This package was initially developed as a teaching and learning tool for educational use in an undergraduate Computer-Aided Mechanism Design course. Because the system is Web-based and implemented through a client/server model with the user interface through the Web browser, it is easy to use and maintain. The system can also be used to solve practical engineering cam design problems with two follower motion types of translation and oscillation. The system can be used to generate cam profile, position, velocity, and acceleration histories of the follower. Once a cam/follower system is designed, animation of the cam/follower system can be performed. At the end of the design, the CNC code for manufacturing the designed cam can also be produced through our Web-based cam design system. The package consists of a number of modules including various Web pages, common gateway interface (CGI) programs, and a CH program called cam which performs the necessary computation for cam design. Two different versions of the cam design package have been designed and implemented. One runs the cam design program on the client machine as a CH applet, and the other runs the cam design program on the Web server though CGI. In this paper, details of design and implementation of Web-based cam design package will be described. Two application examples with different motion types for the follower will be used to illustrate features of the applet-based and CGI-based implementation schemes.
A Virtual Reality Teleoperator Interface for Assembly of Hybrid MEMS Prototypes
Authors: Alex Joseph , Vikramaditya Barmeshwar , Nelson Bradley J.
Published: February 2021

In this paper we describe a teleoperated microassembly workcell that integrates a VRML-based virtual microworld with visual servoing micromanipulation strategies. Java is used to program the VRML-based supervisory interface and to communicate with the microassembly workcell. This provides platform independence and allows remote teleoperation over the Internet. A key aspect of our approach entails the integration of teleoperation and visual servoing strategies. This allows a supervisor to guide the task remotely, while visual servoing strategies compensate for the imprecisely calibrated microworld. Results are presented that demonstrate system performance when a supervisor manipulates a microobject remotely. Though Internet delays impact the dynamic performance of the system, teleoperated relative parts placements with submicron precision is successfully demonstrated.
Analytical Dynamics of Unrooted Multibody-Systems With Symmetries
Authors: Pfister Felix M. J. , Agrawal Sunil K.
Published: February 2021

The objectives of this paper are to (i) exploit the structure of Euler-Liouville equations for multibody systems and separate the external and internal aspects of motion, (ii) specialize these equations to systems with special mass and geometric properties such as holonomoids and orthotropoids, (iii) apply the results to special orthotropoids, the spheroidal linkages of Wohlhart, and write their equations of motion in a simple and elegant manner.
Naturally-Transitioning Rate-to-Force Control
Authors: Williams Robert L. , Murphy Mark A.
Published: February 2021

The Naturally-Transitioning Rate-to-Force Controller (NTRFC) for manipulators is presented. In free motion rate control is provided, while in contact the same rate commands are proportional to the force exerted on the environment by the manipulator. The transition between free motion and stable contact with the environment requires no changes in control mode or gains and hence is termed natural. The NTRFC has been experimentally implemented and shows great promise. This paper demonstrates the NTRFC concept and provides a basis for its modeling and design.
A Simple Algorithm for Controlling Manipulators
Authors: Yue Liming , Pasic Hajrudin , Williams Robert L.
Published: February 2021

This article presents a simple algorithm for control of manipulators. An n-input, n-output nonlinear system with n(2n+1) parameters can be simplified to a linear system with only n2 parameters. The control performance of the system using the simplified model are compared with that using the exact model. Simulations show that the simplified model approximates the exact model well. The simulation results are also compared with those of another method from the literature. It is demonstrated that the manipulator controlled by the current algorithm has better response and is simpler.
Algebraic Motion Approximation With NURBS Motions and its Application to Spherical Mechanism Synthesis
Authors: Ge Q. Jeffrey , Larochelle Pierre M.
Published: February 2021

In this work we bring together classical mechanism theory with recent works in the area of Computer Aided Geometric Design (CAGD) of rational motions as well as curve approximation techniques in CAGD to study the problem of mechanism motion approximation from a computational geometric viewpoint. We present a framework for approximating algebraic motions of spherical mechanisms with rational B-Spline spherical motions. Algebraic spherical motions and rational B-spline spherical motions are represented as algebraic curves and rational B-Spline curves in the space of quaternions (or the image space). Thus the problem of motion approximation is transformed into a curve approximation problem, where concepts and techniques in the field of Computer Aided Geometric Design and Computational Geometry may be applied. An example is included at the end to show how a NURBS motion can be used for synthesizing spherical four-bar linkages.
A Dual Ellipse Is a Cylindroid
Authors: Ghosal Ashitava , Ravani Bahram
Published: February 2021

In this paper, we take a relook at two-degree-of-freedom instantaneous rigid body kinematics in terms of dual numbers and vectors, and show that a dual ellipse is a cylindroid. The instantaneous angular and linear velocities of a rigid body is expressed as a dual velocity vector, and the inner product of two dual vectors, as a dual number, is used. We show that the tip of a dual velocity vector lies on a dual ellipse, and the maximum and minimum magnitude of the dual velocity vector, for a unit speed motion, can be obtained as eigenvalues of a positive definite, symmetric matrix whose elements are the dual numbers from the inner products. From the real and dual parts of the equation of the dual ellipse, we derive the equation of a cylindroid (Ball,1900).
A New Method of Task Specification for Spherical Mechanism Design
Authors: Tse David M. , Larochelle Pierre M.
Published: February 2021

In this paper we present a novel method for motion generation task specification for spherical mechanisms. This is accomplished with a new methodology for determining the optimal design sphere and the orientations on this design sphere for a finite set of desired spatial positions. In addition, we include a modification to the method which enables the designer to require that one of the n desired spatial positions be exactly preserved. The result is that designers can now specify spherical mechanism motion generation tasks without having to introduce into the design space an artificial design sphere. They are now free to work in unconstrained three-dimensional space. The application of this new task specification technique is discussed in a design case study.
Accurate Determination of Object Position From Imprecise Data
Authors: Gupta Krishna C. , Chutakanonta Puckpol
Published: February 2021

The problem of accurate determination of object position from imprecise and excess measurement data arises in kinematics, biomechanics, robotics, CAD/CAM and flight/vehicle simulator design. Several methods described in the literature are reviewed. Two new methods which take advantage of the modern matrix oriented software (e.g. MATLAB, IMSL, EISPACK) are presented and compared with a “basics” method. It is found that both of the proposed decomposition methods (I: SVD/QR and II: SVD/QS) give better absolute results than a “basic” method available from the text books. On a relative basis, the second method (SVD/QS Decomposition) gives slightly better results than the first method (SVD/QR Decomposition). Examples are presented for the cases when the points chosen are nearly dependent and when the independent points have small random errors in their coordinates.
Kinematic Fixturing With Respect to a Plane Using Contact Sensing
Authors: Nederbragt Walter W. , Ravani Bahram
Published: February 2021

This paper presents a method for determining the location of geometric elements that compose the external features of referencing fixtures. Since in most applications parts that are handled in robotic work-cells are on a worktable or a floor, this paper focuses on fixture geometries that reside on a plane of known location. The location of the unknown geometric elements are found using contacts to the geometric elements and spatial constraints between the geometric elements. Geometric equations for contacts between lines, planes, points, spheres, and cylinders are derived. Spatial constraint equations are also derived. An algorithm is given for locating the geometric elements that form the fixture. The algorithm uses the contact equations and spatial constraint equations to locate the geometric elements. To illustrate the use of this algorithm, two examples are described in detail.
The Topological Structure Code Permutation Group Method of Polyhedral Solid for Identification of Kinematic Chains Isomorphism
Authors: Liu Chuan-He , Yang Ting-Li
Published: February 2021

This paper puts forward a new method for identification of kinematic chains isomorphism, which is called the topological structure code permutation group method of polyhedral solid. It can be put into practice by means of computer, and it is exact, dependable, quick and efficient. When isomorphism of two kinematic chains is identified by the method, it only need determine whether one permutation can be found out or not between topological structure codes of the two kinematic chains, or determine whether adjoint codes of the two topological structure codes are equal or not, it need not find out a symmetry group at all. It applies to all kinds of non-separable closed kinematic chains that don’t contain compound hinges.

In this paper, a new concept called polyhedral solid is put forward, the polyhedral solid model is given, and a theorem that describes the relation of faces, vertices, edges and geometric solids of a connected graph is given and proved. This paper expounds the definitions and general forms of the topological structure code and its adjoint code, the methods and rules of coding, the procedure of generating them. It also expounds and proves the beingness, accuracy and the uniqueness of the topological structure code and its adjoint code and the necessary and sufficient condition and criteria of kinematic chains isomorphism as well. The algorithm and some typical examples for identification of kinematic chains isomorphism are given.
Establishment of Numeric Atlas and Synthesis for Planar 4-Bar Path Generator
Authors: Wu Chen , Chu Jinkui
Published: February 2021

Planar 4-bar crank-rocker mechanism is exampled to demonstrate how to establish a numeric atlas on the base of a new concept of basic dimensional type, which is originated by utilizing two discoveries that two groups of harmonic characteristic parameters of dimensional type (HCPDT) will have identical amplitude values but contrary phase values when (1) their corresponding dimensional type are identical but with normal and reverse assembling manner respectively, or when (2) length exchange of b (coupler) and c (rocker) occurs, resulting in such two dimensional types as (a,b,c,d) and (a,c,b,d) with the same assembling manner. Such a numeric atlas is composed of basic dimensional types of crank-rocker mechanism and their corresponding HCPDT. In fact, the two discoveries are also used to reveal inherent law of 4-bar curve cognate mechanisms.
Getting Around Corners: Transmission of Forces With Given Mechanical Advantage
Authors: Jensen Preben W.
Published: February 2021

When forces are to be transmitted in mechanical devices the mechanical advantage (M.A.) is often prescribed. The M.A. can be prescribed in up to two positions together with the corresponding crank angle. Forces can also be directed around obstacles with prescribed M.A.
Conception of Balanced Spring Mechanisms
Authors: Herder Just L.
Published: February 2021

Statically balanced mechanisms are well known in various appearances of counterweighed beams, and systems where undesired mass is balanced by means of compensation springs. Similarly, springs can be designed to balance other springs. Besides the application of spring force compensation, many other kinds of mechanisms can benefit from the concept of balanced spring mechanisms. This paper introduces a lucid and logical methodology for the conception of statically balanced spring mechanisms. Based on constancy of system potential energy, a set of elementary rules is derived for the modification of a standard configuration with idealized springs. A number of examples are included to illustrate the versatility of the methodology, and to demonstrate the application potential of balanced spring mechanisms in general mechanical engineering.
Closed-Form Inverse Kinematic Solution of Triple Octahedron Variable Geometry Truss Manipulators
Authors: Xu Li Ju , Duan Yang , Yang Sui Xian
Published: February 2021

In this paper the triple-octahedron variable geometry truss manipulator is presented and its inverse displacement analysis in closed form is studied, Input-output displacement equation in one output variable is derived. The solution procedure is given in detail. A numerical example is presented for illustration.
The Synthesis of Planar Parallel Manipulators With a Genetic Algorithm
Authors: Boudreau Roger , Gosselin Clément M.
Published: February 2021

This paper presents a genetic algorithm approach for the synthesis of planar three-degree-of-freedom parallel manipulators. A genetic algorithm is an optimization method inspired by natural evolution. As in nature, the fittest members of a population are given better chances of reproducing and transmitting part of their genetic heritage to the next generation. This leads to stronger and stronger generations which evolve towards the solution of the problem. For the applications studied here, the individuals in the population consist of the thirteen architectural parameters of the manipulators. The algorithm optimizes these parameters to obtain a workspace as close as possible to a prescribed working area. For each individual of the population, the geometric description of the workspace can be obtained. The algorithm then determines the intersection between the prescribed workspace and the actual workspace, and minimizes the area of the regions that do not intersect. The method is applied to two planar three-degree-of-freedom parallel manipulators, one with prismatic joints and one with revolute joints.