bluuebunny/crossref_metadata_2025 huggingface dataset:
Towards Dynamic Tolerance Analysis Using a Finite Element Formulation
Authors: Salomons Otto , Arentsen Elmer , Aarts Ronald , van Houten Fred
Published: December 2020

A theoretical framework is proposed by which the effect of tolerances can be analyzed. Especially it focuses on the influence of clearances on the dynamic behavior of mechanisms. As opposed to previous publications, where a bondgraph formulation was used, this paper uses a finite element formulation in order to simulate the dynamic behavior under the influence of tolerances and other physical effects. The finite element formulation that has been selected for this work has two major advantages when compared to a bondgraph formulation. The first important advantage is that the method is analytical to a great extent. As a result, no numerically derived derivatives will exist, hence not leading to numeric inaccuracies. The second advantage is that small numbers can be separated from large numbers allowing to separate tolerances from the nominal path, resulting in faster simulations. The paper describes how a geometric model, including its tolerances, can be transformed into a corresponding finite element model that on its part consists of submodels. Based on this model, simulations can be performed which can provide insight in the dynamic behavior of the mechanism. The paper details on how geometric tolerances (such as form, orientation, position as well as size and clearances), with the focus on clearances, can be accounted for in a finite element model.
Design and Optimization of Stamping Process to Improve Manufacturing Feasibility
Authors: Naceur H. , Guo Y. Q. , Batoz J. L.
Published: December 2020

In this paper, we present a numerical procedure combining a finite element inverse approach (I.A.) [10, 14–18] for the simplified analysis of the stamping process with a mathematical programming technique (BFGS method) to optimize some process parameters. Our objective is to optimize the quality of the final workpiece, by minimizing the risk of rupture and wrinkles. The design variables of the present problem are the drawbead restraining forces in relation with the Forming Limit Diagram (FLD). The optimization procedure associated to the analytical sensitivities analysis technique based on the adjoint method is applied for the square cup of Numisheet’93 and the Twingo dashpot cup proposed by RENAULT [32]. The satisfactory results demonstrate the usefulness of this automatic optimization procedure in the preliminary design of deep-drawing process.
Principles and Applications on Intelligent Optimization Design Approach Based on Compound Knowledge
Authors: Yao Jianchu , Zhou Ji , Yu Jun
Published: December 2020

This paper proposes a concept of an intelligent optimal design approach, which is organized by a kind of compound knowledge model. The compound knowledge consists of modularized quantitative knowledge, inclusive experience knowledge and case-based sample knowledge. By using this compound knowledge model, the abundant mathematical information of mathematical programming and the symbolic knowledge of artificial intelligence can be united together in this model. The intelligent optimal design model based on such a compound knowledge and the automatically generated decomposition principals based on it are also presented. This paper realized the object-orientated based decomposition of optimal model and integration of compound knowledge. Practically, our approach has been applied to the production planning, process schedule and optimization of production process of a refining & chemical work and a great profit was achieved. Specially, the methods and principles presented in this paper are adaptable not only to continuous process industry, but also to discrete manufacturing one.
Optimization of Machine System Designs Based on Decomposition and Hierarchical Ordering of Criteria and Design Variables
Authors: Yoshimura Masataka , Nomura Ryousuke
Published: December 2020

Designs of machine products routinely have so many characteristics to be evaluated that usual design optimization methods often result in an unsatisfactory local optimum solution. In order to overcome this problem, this paper proposes a design optimization method based on decomposition by substructuralization and subsequent hierarchical ordering, considering the both conflicting and cooperative relationships between the characteristics under evaluation. First of all, each characteristic is divided into simpler basic characteristics. The pool of design variables is also divided into smaller groups, according to specific design features. Next, the relationships between the basic characteristics and the divided design variables, as well as the relationships among the characteristics themselves, are systematically identified and clarified. Then, based on this clarification, and after setting a core characteristic derived from the primary performance characteristic for the product under consideration, an optimization strategy and detailed hierarchical optimization procedures are constructed. In this paper, the proposed method is applied to machine tool structures and transportation products.
A Practical Bundle Algorithm for Nonconvex and Nonsmooth Engineering Optimization and its Numerical Implementation
Authors: Wang-Zhou Hong , Zhong Yifang , Xiao Renbin , Du Xuan , Zhou Ji
Published: December 2020

An algorithm based on Lemarechal’s bundle method for nonsmooth and nonconvex engineering optimization is proposed. The convergence result is given and proved. The algorithm’s numerical implementation is discussed in detail. By the numerical methods proposed by this paper, most bundle methods could be used in practical engineering optimization. Finally, some numerical results are presented to show its efficiency.
Hierarchical Parallel Processes of Genetic Algorithms for Design Optimization of Large-Scale Products
Authors: Yoshimura Masataka , Izui Kazuhiro
Published: December 2020

A large-scale machine system often has a general hierarchical structure. For hierarchical structures, optimization is difficult because many local optima almost always arise, however genetic algorithms that have a hierarchical genotype can be applied to treat such problems directly. Relations between the structural components are analyzed and this information is used to partition the hierarchical structure. Partitioning large-scale problems into sub-problems that can be solved using parallel processed GAs increases the efficiency of the optimization search. The optimization of large-scale systems then becomes possible due to information sharing of Pareto optimum solutions for the sub-problems.
Automatic Calculation of Product Architecture Metrics Within a Solid Modeler
Authors: Line J. Kevin , Steiner Mark W.
Published: December 2020

The architecture of a product is defined as the scheme in which functions are mapped to physical components. Architecture has a strong impact on how a product satisfies design objectives. There are several ways to measure architecture, and one is implemented into a solid modeling program, that will do the quantification automatically. The software used is the I-DEAS solid modeling package, for which an internal program file was created to automatically perform the calculations. This program works by counting the parts that the user has created, then uses an internal I-DEAS function to find all of the joined parts. The program counts the joints and then prompts the user for the strength of each joint. With this information, an adjusted parts connectivity and average joint strength is calculated and can be used to evaluate the degree to which the architecture of a product is either integral or modular. Four case studies are presented that were used to evaluate the effectiveness of the program. Three of these yielded excellent results, but the final case study failed because of model input problems. With further development this program could be a very important design tool in the future.
The Impact of Reference Free Part Encapsulation (RFPE) on Design for Manufacturability With CNC Machining
Authors: Ahn Sung H. , Plancarte Juan , Wright Paul K.
Published: December 2020

The Reference Free Part Encapsulation (RFPE) is a workholding system which is designed to “free-up” the design space and greatly expand the possible range of the parts that can be designed and then machined. RFPE allows the machining of parts with thin spars and narrow cross-sections. Such parts are often difficult or impossible to hold with conventional vises or toe-clamps. Despite the increased capability of the RFPE technique, its influence on part warpage and part accuracy has not yet been sufficiently documented, and thus the experiments reported here have made a new contribution in this direction. 7075T6 aluminum (annealed) and ABS materials were machined with flat end mills, and deflections of the specimens were measured. The results were obtained in two categories i) without RFPE using conventional toe clamps ii) with RFPE. RFPE uses a bi-phase material (Rigidax™). In the conventional toe clamp set-up, the aluminum specimens showed increasing warpage with decreasing test-part dimension. When the molten fixturing material was applied, the warpage remained the same for the aluminum specimens. In the conventional toe clamp set-up, the ABS plastic showed almost no warpage after machining. However, warpage increased to a maximum of 0.04∼0.06 inch when the fixturing material was applied to the ABS specimens. The warpage is proposed to occur due to the relaxation of ABS’s anisotropic molecular chains during the heating and cooling process. In conclusion, warpage of thin aluminum parts was from machining-induced residual stress, but warpage of thin ABS parts was mainly from thermal residual stress developed during the RFPE process. Results presented in this paper indicate the amount of warpage that might be expected. These values could be used in CAD/CAM databases for DFM (Design For Manufacturing) checking.
Measuring Value of Prototypes During Product Development
Authors: Franck Christopher G. , Rosen David W.
Published: December 2020

Rapid prototyping has become a key factor in reducing the cost and time to market associated with new product development. Unfortunately a lot of the potential time and cost savings associated with rapid prototyping are lost due to the use of processes that are incompatible with the type of information needed by the designer at any given point in the product development process. A quantitative measure is proposed in this paper for the value of a prototype at any given point in the product development process, where value is defined as a function of benefit (information learned) of a prototype and the cost of the prototype. The value measure is utilized to suggest prototyping technologies to aid the designer in selecting appropriate technologies. Three different value metrics were developed: one based on the benefit-to-cost ratio, one on utility theory, and one on value theory. The value metrics are applied to an industrial example, a cash register till, and compared on their ability to suggest appropriate prototyping technologies along the design time-line.
A Proactive Approach to Integrated Synthesis of Components and Realization Systems
Authors: Yan Xiu-Tian , Borg Jonathan C. , Juster Neal P.
Published: December 2020

Product designers are under increasing pressure to reduce lead time, improve quality and reduce cost of a product. An important approach is to generate not only design solutions of a component, but also manufacturing models for the component at the same time so that a designer can make design decisions whilst having access to evolving “virtual” manufacturing system models. This paper presents such an approach that proactively supports designers to make informed design decisions, by revealing knowledge of component related manufacturing and assembly processes. Knowing the manufacturing and assembly implications of design decisions during design, designers are aided to avoid negative implications and promote positive ones. Based on the approach a Knowledge Intensive CAD (KICAD) prototype tool, named FORESEE has been developed. FORESEE allows designers to foresee and explore manufacturing and assembly consequences caused by design decisions, co-evolving during mechanical component design decision making. The paper presents an outline of the KICAD’s approach, its architecture, system requirements of such a system and its implementation. The application of the prototype is also demonstrated through a thermoplastic component design session.
Material Modeling for Shape Deposition Manufacturing of Biomimetic Components
Authors: Xu Xiaorong , Cheng Wendy , Dudek Daniel , Cutkosky Mark R. , Full Robert J. , Hatanaka Motohide
Published: December 2020

As our understanding of the principles underlying animal locomotion improves, we are inspired to apply them to robot design. This has traditionally been achieved through controls or discrete mechanical devices; however, new manufacturing methods, such as Shape Deposition Manufacturing (SDM), offer us the opportunity to develop mechanisms containing intrinsic mechanical properties tailored for function. To properly utilize SDM, we must develop a bridge between biology and design. As a first step, we have conducted relaxation and dynamic tests on the ablated metathoracic limb of the Blabems discoidalis cockroach and derived measures of stiffness and damping. We then tested an SDM-compatible polymer with similar viscoelastic properties. Comparison and understanding of the mapping between these two materials enables us to design and manufacture legs with stiffness and damping similar to those found in insects.
Wavelet-Based Surface Analysis for Form Feature Extraction
Authors: Sun Lei , Qamhiyah Abir
Published: December 2020

A new procedure for extracting form features from solid models with non-planar surfaces is presented in this paper. In the procedure, a surface is selected as the unit for feature representation, i.e. “feature primitive.” Three-dimensional wavelet transforms are applied to code and classify surfaces in a CAD model. Form features are then extracted by clustering the coded surfaces. Two wavelet bases, Harr and Daubechies with different vanishing moments, have been implemented. An example is presented to demonstrate the proposed procedure.
Layer Based Robot Machining for Rapid Prototyping
Authors: Song Y. , Chen Y. H.
Published: December 2020

Many useful methods have been applied to Rapid Prototyping (RP) technologies in recent years, and each of them has its own features. To solve the problem in large-scale prototyping, a robotic machining center with layer based algorithms is developed. Using STereoLithography (STL) file, the surfaces of a model are represented by triangles. Calculating the intersection between a series of parallel planes and the STL file, a STereolithography Contour (SLC) file of the model is generated where the model is represented as a series of contours on a set of parallel planes. Instead of using the popular RP technologies, traditional Computer Numerical Controlled (CNC) machining method is applied in machining each layer of the model. With visibility calculation, the thickness of each material layer is selected. When collision is detected for a point on the tool path, the orientation of the tool is modified. With the machining of a vase model, the effectiveness of the proposed algorithm is demonstrated. Errors of the robot machining system are analyzed by a Coordinate Measuring Machine (CMM) and a surface texture measuring machine.
Kinematic Analysis of Threaded Fastener Assembly in 3 Dimensions
Authors: Wiedmann Stephen L. , Sturges Robert H.
Published: December 2020

This work concentrates on a common assembly primitive, threaded fastener insertion, in an effort to determine the nature of contact between a bolt and nut during thread mating. Contact state models were created to constrain the motion of the bolt at 1 and 2-point contacts. By analyzing the depth of intersection of the bolt into the nut as well as the vertical movement of the origin of the bolt reference frame, we determined that there are three types of contacts states present: unstable two-point, quasi-stable two-point, stable three point. Though the unstable case remains to be deciphered, the parametric equations derived in this work can be used without modification to create a full spectrum of maps at any point in the history of a threaded assembly problem. We investigated 81 potential orientations, each of which has its own set of contact points. From this exhaustive examination, we are capable of detailing a contact state history and, from this, have the potential to develop a constraint network.
Qualitative and Imprecise Solid Modeling for Conceptual Shape Design
Authors: Shu Huilin , Liu Jihong , Zhong Yifang
Published: December 2020

The shape design of products is the primary activity of design process. The research on qualitative & imprecise solid modeling for computer-aided conceptual shape design is presented in this paper. At first, the requirements of shape representation for computer-aided conceptual shape design are emphatically discussed. Secondly, in the situation where the product information is deficient, the ideas of qualitative and imprecise solid modeling are presented to deal with qualitative and imprecise information in the phase of conceptual shape design. The aims are mainly to explore the representation and manipulation of product shapes, and to benefit designers to design shapes in the phase of conceptual design. Finally, a prototype system CACSD is briefly introduced to implement the relevant ideas.
Learning From Experience of Peers: An Empirical Study of Knowledge Sharing in a Product Design Community
Authors: Liang Tao , Leifer Larry J.
Published: December 2020

In this paper, we describe usage patterns of a design information database observed from four years of data, and discuss issues of learning through social and technology mediated interactions in a product design community. From the period of 1994 to 1999, an increasing amount of the design information in a project-based course at Stanford University has been captured in electronic format. This design information consists of design notes, drawings, reports, slide presentations, emails, vendor references, and even, in some cases, summaries of phone conversations, meeting minutes, and the like. The large corpus of captured information was made available to the project teams during each academic year on the assumption that one would be able to achieve better performance by building on and learning from experiences of peers. Because the data was all made available over a webserver, we were able to collect information on access to it We have thus had a chance to learn from studying the usage of a large body of captured design information. Preliminary analysis on the first two years of data was reported in DETC conference in 1998 (Liang, Cannon et al. 1998). Results from our current analysis show some interesting patterns of file utilization. Those patterns includes a surprising high ratio of access to process-related files, as opposed to product-related files; a temporal access pattern that closely matches project deliverables and milestones; and, an increased correlation between database usage and team-based performance over time.

The results from quantitative data analysis are augmented with qualitative user interviews. When interviewed, all engineers agreed that there could be a lot of benefits from learning from peer experiences. Nevertheless, physical and psychological barriers often prevent one from doing so. Physical barriers include distance, time, and organizational distance. Some psychological barriers include the perceived value of the archived information, and perceived effort of finding useful information. These pragmatic organizational learning issues arise from the fact that the teams were working on diverse projects and are all pressured by time and resources. We hypothesize that these real-world constraints of time and resources prohibited many learning opportunities to occur which would otherwise have been very productive and effective. This tension between learning and working is the backdrop of this learning experiment. We suggest that the patterns reported in this paper will be typical of a small product design consulting firm that has many fast-paced projects running in parallel.
State Library Materials Handling System Design: Part I
Authors: Derby Stephen , Simon Matthew P. , Puffer Raymond H. , Allen Mark A. , Shone Tristan M. , Winston Jeremy B. , Judd Van
Published: December 2020

This paper (part one of two) addresses the investigative efforts of the Center for Automation Technologies (CAT), Rensselaer Polytechnic Institute, into the requirements and processes of the New York State Talking Book and Braille Library (TBBL), and the describes the first several module concepts in the automation system designed to assist the TBBL staff in the processing of “talking books” (books on cassette). Part two discusses the remaining modules, system simulations, and conclusions.

The primary purposes for this modular system are 1. To assist the TBBL in meeting increased throughput demands and 2. To reduce work-related injury claims. The modules are designed to work individually (as to allow the possibility of similar libraries in other states purchasing modules as desired), and facilitate incremental implementation toward a complete system (for maximized benefit).

In this paper, the modules discussed are the BMC unloader (for which a patent application has been filed), the sorting and singulating module, the case orientation and latch opening module, a possible buffer module, and the automation-assisted rewind and inspection module.
Design of Angular Snap-Fits for Positive Interference Assembly
Authors: Sodhi Raj S. , Das Sanchoy
Published: December 2020

This article introduces a new design for a cantilever type snap-fit fastener. This new design is configured to provide a positive interference between the mating parts even in the assembled position. The legs are therefore not in a relaxed position at the end of assembly. This results in higher levels of alignment quality and part fit in a completed assembly. The positive interference is achieved by the use of angular legs as opposed to orthogonal legs in a traditional snap-fit. Issues of material strength, fastener geometry, part stiffness, attachment strategy and manufacturability are addressed in the paper.
Automated Initial-Population Generation for Genetic-Algorithm-Based Assembly Planning
Authors: Smith Gregory C. , Chen Shiang-Fong
Published: December 2020

Genetic algorithms show particular promise for automated assembly planning. As a result, several recent research reports present genetic-algorithm-based mechanical-product assembly planners. However, genetic-algorithm-based assembly planners require an initial assembly-sequence population, and search efficiency greatly depends upon input-population quality. State-of-the-art genetic-algorithm-based assembly planners use one of two techniques for generating an initial assembly-sequence population: use a user-supplied assembly-sequence set or use a randomly generated assembly-sequence set. Generating a user-supplied initial population requires a substantial amount of manpower. Using a randomly generated initial population reduces search efficiency. As a result, we propose an algorithm for automatically generating an initial assembly-sequence population. Our algorithm calculates component assembly complexity and uses both component assembly complexity and component connectivity to automatically generate a valid assembly-sequence population. Using automatically generated initial populations, we achieve search efficiencies comparable to search efficiencies achieved when using user-supplied initial assembly-sequence populations, while eliminating manpower required to generate user-supplied assembly sequences.
Assembly Configurations of Planar Multi-Loop Mechanisms With Kinematic Limitations
Authors: Foster David E. , Cipra Raymond J.
Published: December 2020

This paper examines the problem of identifying the assembly configurations (ACs), also called circuits, of planar multi-loop mechanisms with kinematic limitations, such as joint limits, link interference, collision with stationary obstacles, and workspace limitations. First, a method is given to describe numerically the satisfaction or violation of these kinematic limitations, and then this is applied to find the ACs of mechanisms with kinematic limitations. The method is valid for mechanisms with one or two degrees of freedom, and is illustrated with two examples.
Finite-State-Machine Representations for Mechanisms and Chains With Variable Topologies
Authors: Yan Hong-Sen , Liu Nien-Te
Published: December 2020

This paper provides a novel representation for the topological structures of mechanisms and chains with variable topologies. The concept is finite state machines. Graphs are traditional representations of mechanism topologies and have the advantages of easily observing. Finite state machine is proposed for expressing the changes of input links and operating stages. The double-dwell slider-crank mechanism is applied as an example to illustrate the proposed representations. These representations are useful for analyzing the characteristics of topology structures of mechanisms and chains with variable topologies. And, the result of this work can be extended for synthesizing mechanisms and chains with variable topologies.
Solving the Kinematics of Planar Mechanisms by Dixon Determinant and a Complex-Plane Formulation
Authors: Wampler Charles W.
Published: December 2020

This paper presents a general method for the analysis of any planar mechanism consisting of rigid links connected by revolute and slider joints. The method combines the complex plane formulation of Wampler (1999) with the Dixon determinant procedure of Nielsen and Roth (1999). The result is simple to derive and implement, so in addition to providing numerical solutions, the approach facilitates analytical explorations. The procedure leads to a generalized eigenvalue problem of minimal size. Both input/output problems and the derivation of tracing curve equations are addessed.
A Method for Representing the Configuration, and Analyzing the Motion of Complex Cable-Pulley Systems
Authors: Hong Dennis W. , Cipra Raymond J.
Published: December 2020

In this paper a systematic way of representing complex cable-pulley mechanism configurations and a method to analyze and synthesize the motion of these cable-pulley devices is presented. The cable-pulley system model that is being considered is composed of three basic elements which are pulleys, blocks, and cables. A configuration table is used to identify the constraint equations by systematically defining the connections between the cables, pulleys, and blocks. The basic strategy is to use the constraint equations to generate the relationship between each variable and a subset of the variables identified as the inputs. The number of input variables is equal to the total number of variables minus the number of independent constraints. This choosing of the set of inputs is done in conjunction with a row reduction process on the system of constraint equations which identifies the number of inputs and ultimately generates the relationships of each variable to the input(s). Examples are given to illustrate the procedure.
Configuration Estimation of Gough-Stewart Platforms Using Extended Kalman Filtering
Authors: Fasse Ernest D. , Wavering Albert J.
Published: December 2020

This paper develops extended Kalman filtering algorithms for a generic Gough-Stewart platform assuming realistically available sensors such as length sensors, rate gyroscopes, and accelerometers. The basic idea is to extend existing methods for satellite attitude estimation. The nondeterministic methods are meant to be a practical alternative to existing iterative, deterministic methods for real-time estimation of platform configuration.
A Study of Vibration in Caliper-Disc Brake Systems With Surface Roughness Effects: Part B — Inclusion of Surface Roughness Effects in the Equations of Motion and Results
Authors: Meinhardt Glenn , Farhang Kambiz , Abdo Jamil
Published: December 2020

Vibration of mechanical systems with friction depends on the physical characteristics of the frictional contact. The elastic characteristics are developed in a companion paper, wherein the results show the surface roughness manifested through nonlinear contact stiffnesses. This paper, the second of two companion papers, incorporates the elastic characteristics of contact between the pad surfaces and the rotor in a vibration model of an automotive caliper-disc brake system. The elastic representation of contact, in the form of polynomial functions of the relative pad/rotor displacements, are used to account for the effect of surface roughness on the vibration response of a caliper-disc brake system. The results indicate a range of frequencies due to the roughness induced stiffness nonlinearities.
Fatigue Testing Machines for Tensile and Bending Loaded Bolt Connections Using Sympathetic Vibration
Authors: Alt Attila , Tegel Oliver
Published: December 2020

In this paper previous tension and bending fatigue testing machines for bolt connections are presented. Their weak points are discussed, in order to show the difficulty of machine load and the demands of a load distribution in the bolt connection similar to the operating state, a measurement of stresses on the bolt and an economical actuation.

A new principle using the sympathetic vibration of a frame for applying the load is presented in comparison. It can be employed for tensile and bending load. The barrel of the bolt remains accessible for direct measurement of it’s strains. Formulas for the dimensioning of the frames considering their natural frequency and the tensile/bending load combination of the bolt connection are derived using the mechanics of elastic beams. The testing machines and their details are described.
A Systematic Method for Kinematics Synthesis of High-Speed Mechanisms With Optimally Integrated Smart Materials
Authors: Rastegar J. , Yuan L.
Published: December 2020

A systematic method is presented for kinematics synthesis of high-speed mechanisms with optimally integrated smart materials based actuators for the purpose of modifying the output link motion. As an example, the method is applied to a four-bar linkage mechanism that is synthesized for function generation to eliminate the high harmonic component of the output link motion. For mechanisms with rigid links, the high harmonic motions are generated due to the nonlinearity of the kinematics of their closed-loop chains. By eliminating the high harmonic component of the output motion, the potential vibrational excitation that the mechanism can impart on the overall system and its own structure is greatly reduced. The resulting system should therefore be capable of operating at higher speeds with increased precision. A numerical example is provided together with a discussion of the application of the method to other mechanism synthesis problems and some related topics of interest.
A Configurationally Adjustable Planar Stewart Platform Machining Center With Feasible and Optimum Placement of Workspace Relative to Toolpath
Authors: du Plessis L. J. , Snyman J. A. , Smit W. J.
Published: December 2020

This paper presents a new integrated configurational design system that allows for the feasible and optimum placement of the workspace of an adjustable planar parallel manipulator, relative to a specified machine toolpath. The basic design of the manipulator is such that the positioning and relative size of the workspace may be varied by means of the adjustable placement of the revolute joints. For a given specified toolpath an integrated geometry optimizer prescribes a manipulator configuration which, not only ensures feasibility, but also enhances performance through the minimization of an objective function related to the required actuator forces, subject to physical constraints.

The availability of the combination, of a physically adjustable platform coupled to a software geometry optimizer, is essential for the practical application of a planar parallel platform as a machining device for toolpaths of varied specifications. Here the proposed system is applied and tested through its application to a planar Stewart platform demonstrator with full adjustment capability. The platform serves to demonstrate the optimum machining motion obtained through the integrated design system. This system will later be incorporated in a more robustly constructed and fully equipped prototype platform for practical machining.
An Analytical Design for CaPaMan With Prescribed Position and Orientation
Authors: Ceccarelli Marco , Ottaviano Erika
Published: December 2020

A desired workspace can be described by a set of points, which prescribe desired positions and orientations of the movable plate of a parallel manipulator. In this paper we have proposed a formulation for designing CaPaMan (Cassino Parallel Manipulator) when position and orientation of the movable plate are prescribed. A numerical procedure has been deduced to solve design parameters by using analytical formulation of Direct and Inverse Kinematics for CaPaMan architecture.
Cartesian Control for the Inertial Measurement Unit Calibration Platform
Authors: Hall John J. , Williams Robert L. , van Graas Frank
Published: December 2020

The Department of Mechanical Engineering and the Avionics Engineering Center at Ohio University are developing an electromechanical system for the calibration of an inertial measurement unit (IMU) using global positioning system (GPS) antennas. The GPS antennas and IMU are mounted to a common platform to be oriented in the angular roll, pitch, and yaw motions. Vertical motion is also included to test the systems in a vibrational manner. A four-dof system based on the parallel Carpal Wrist is under development for this task. High-accuracy positioning is not required from the platform since the GPS technology provides absolute positioning for the IMU calibration process.
A New Drive With High-Load Capacity and High Transmission Efficiency
Authors: He Weidong , Li Xin , Li Lixing , Schmidt Linda
Published: December 2020

A patented double crank ring-plate-type cycloid drive is introduced in this paper. Its working principles, advantages and design issues are discussed. Some promising results of testing are also presented in this paper.
The Compound Union Theory and Method of Type Synthesis of Geared Linkage Kinematic Chains
Authors: Liu Chuan-He , Yang Ting-Li
Published: December 2020

The compound union theory and method of type synthesis of geared linkage kinematic chains is developed in this paper. The theory includes the new concepts, such as the basic geared kinematic chain, the compound union and the type code etc., the new constitution principle of geared linkage kinematic chains and four new theorems that are essential for type synthesis of geared linkage kinematic chains. One typical example and its results of the type synthesis are also given. It is proved that the compound union theory and method is systematic, strict, simple, practical and efficient.
Omni-Directional Mobility Using Active Split Offset Castors
Authors: Yu Haoyong , Dubowsky Steven , Skwersky Adam
Published: December 2020

A new concept for omni-directional platform and vehicle design using active split offset castors is presented. An active split offset castor (ASOC) unit consists of two coaxial conventional wheels driven independently and connected to the platform chassis by a link. The kinematics and characteristics of the ASOC are analyzed and compared with conventional active castors and steered wheels. The concept of building omni-directional platforms and vehicles using the ASOC is presented and their design and control are discussed. Experimental results from a prototype omni-directional platform are presented, which demonstrate the feasibility of the concept.
3-D Finite Element Analysis of Long Fiber Reinforced Composite Spur Gears
Authors: Alagöz Çağdaş , Arıkan M. A. Sahir , Bilir Ö. Gündüz , Parnas Levend
Published: December 2020

A method and a computer program are developed for 3-D finite element analysis of long fiber reinforced composite spur gears, in which long fibers are arranged along tooth profiles. For such a structure, the gear is composed of two regions; namely the long fiber reinforced and the chopped fiber reinforced regions.

Pre and post-processing modules of the program for the finite element analysis are written in Borland Delphi Pascal 3.0®. ABAQUS® is used for finite element analysis. Main inputs for the pre-processing module of the program are, information on basic gear geometry, gear drive data, material properties and long fiber reinforcement geometry. Finite element meshes are automatically generated and mesh information with other required data are written to a file in the input-file-format of ABAQUS®. Stresses are read from the output file of ABAQUS® by the post-processing module, and color-coded drawings for various stresses and failure index are displayed. For the long fiber reinforced region, failure indexes are calculated by using the tensor polynomial failure criterion.

Effects of reinforcing thickness and location of long fibers on gear strength are investigated. Stresses and failure index are calculated for different materials and fiber volume ratios.
Sensitivity of Wildhaber-Novikov Gears to Center Distance Variations
Authors: Esposito Antonio , Belfiore Nicola P.
Published: December 2020

In this paper, the sensitivity of the pressure angle to the variation of the center distance is determined analytically for a whole class of helical gears. The results are then applied to the case of Wildhaber-Novikov gears, showing that these gears are highly sensitive to center distance changes, which easily cause edge contact to occur between the teeth.
Effect of Internal Gear Flexibility on the Quasi-Static Behavior of a Planetary Gear Set
Authors: Kahraman Ahmet , Vijayakar Sandeep
Published: December 2020

Effect of flexibility of an internal gear on the quasi-static behavior of a planetary gear set is investigated. A state-of-the-art FEM/semi-analytical nonlinear contact mechanics formulation is employed to model a typical automotive automatic transmission planetary unit. The model considers each gear as deformable bodies, and meshes them to predict loads, stresses and deformations of the gears. Actual support and spline conditions are included in the model. The rim thickness of the internal gear is varied relative to the tooth height and gear deflections and bending stresses are quantified as a function of rim thickness. Influence of rim thickness on the load sharing amongst the planets is also investigated with and without floating sun gear condition. The results are discussed in detail and guidelines regarding the design of a planetary internal gear are presented.
Research of Gears With Progressive Path of Contact
Authors: Hlebanja Gorazd , Hlebanja Jože , Okorn Ivan
Published: December 2020

In recent years we have conducted research of new gears with a progressively curved path of contact as illustrated in Figure 1 below. We also tried to prove features anticipated for these gears. Thus our research focused on durability of this type of gears regarding to pitting and scuffing. We compared them to the involute gears of the same dimensions. We discovered a higher load capacity of tooth flanks of the new gears compared to the involute gears in case of scuffing. Both types of gears showed approximately the same load capacity against pitting if a transverse operating angle was the same in both cases. It has been proved that the new gears had better efficiency and considerable lower wear. We tested gear pairs made of through hardened steel and those nitrided after machining.

Our paper will discuss some results of the research work on the new type of gears for which we believe they will find their way to the practice.
Viscoelastic Tooth Root Stress Analysis on Fiber Reinforced Thermoplastic Poly-Imide (TPI) Gears
Authors: Donghui Gong , Moriwaki Ichiro , Saito Kenji
Published: December 2020

Although thermoplastic poly-imide (TPI) gears do not have sufficient strength for power transmission, carbon fiber reinforcement greatly improves the strength of TPI gears. Previous experimental research showed that although standard specimens made from carbon fiber reinforced (CFR) TPI has 2.4 times strength in static bending than specimens made from natural TPI, gears made from CFR-TPI yields bending fatigue strength about 10 times greater than gears made from natural TPI. The present paper explains this phenomenon using viscoelastic tooth root stress analysis. The experiments indicated that the natural TPI gears showed much larger viscoelasticity than the CFR-TPI gears. Thus, tooth root stresses were calculated for cases of large and small viscosity moduli. These calculations showed tooth root stress increased with the increase in the viscosity modulus. Also, viscoelasticity may induce heat due to hysteresis loss, and this heat should reduce gear durability. The increase in tooth root stress and the heat due to hysteresis loss must make the durability of the natural TPI gears very small. Therefore, the CFR-TPI can yield much more durable gears than the natural TPI.
Experimental Studies of Plastic Gears Without Lubrication
Authors: Rösler Jan , Tegel Oliver
Published: December 2020

Combinations of different plastic materials for use in gears have been studied experimentally. Both plastic/plastic and plastic/steel combinations of wheel and pinion have been analysed. Characteristic properties have been determined, and the material combinations have been evaluated and compared. This paper discusses the results of the experimental research and gives and outlook over further promising activities which could lead to new application areas for plastic gears.
Optimal Machine Tool Setting for Hypoid Gears Improving Load Distribution
Authors: Simon Vilmos V.
Published: December 2020

A method for the determination of optimal machine tool setting for manufacturing modified (mismatched) hypoid gears based on improved load distribution and reduced transmission errors is presented. The applied load distribution calculation is based on the conditions that the total angular position errors of the gear teeth being instantaneously in contact under load must be the same, and along the contact line of every tooth pair instantaneously in contact, the composite displacements of tooth surface points — as the sums of tooth deformations, geometrical surface separations, gear body bending and torsion, deflections of the supporting shafts, misalignments, and composite tooth errors — should correspond to the angular position of the gear. The tooth defonnations consists of the bending and shearing deflections of gear teeth and of the local contact deformations of the mating surfaces. The tooth deflections are calculated by the finite element method. As the equations governing the load sharing and load distribution are nonlinear, an approximate and iterative technique is used to solve this system of equations. The method is implemented by a computer program.

Using the program that was developed the influence of machine tool setting parameters for pinion manufacture on maximum tooth contact pressure, load distribution factor, and transmission errors is investigated. By successively choosing the optimal value for every machine tool setting parameter, and by applying the optimal set of these parameters, the maximum tooth contact pressure is reduced by 5.8%, the load distribution factor by 5.9%, and the angular position error of the driven gear by 65.4%, in regard to the hypoid gear pair manufactured by the machine tool setting determined by the commonly used method.
Feature Based Numerical Bearing Pattern Development and Optimization for Spiral-Bevel and Hypoid Gears
Authors: Gosselin Claude
Published: December 2020

A novel approach to the development of the bearing pattern for spiral-bevel and hypoid gears is presented. The numerical method uses the concept of “potential point of contact” to determine the shape of the separation between the meshing tooth surfaces in the vicinity of the Mean Point.

Machine settings are used as control parameters in the numerical solution to modify the shape and location of the bearing pattern.

The presented method, which has been used in the automobile industry for several years, allows substantial freedom in the development of spiral bevel and hypoid gear sets, even on conventional generators.
How to Obtain the Formal Tooth Bearing Pattern Between Hypoid Gear and the Conjugate Pinion
Authors: Ito Norio , Takahashi Koichi
Published: December 2020

In this paper, the relationships between the conjugate tooth surfaces of hypoid gears and the formal tooth bearing pattern are presented. First, we introduce the tooth surface elements necessary for the tooth bearing. Next, the tooth bearing pattern, which changes according to the generating condition of the pinion, is introduced. The hypoid gear pair is a formate gear and the pinion generated to run with such a gear. The conventional method for analyzing the tooth bearing pattern has been developed by the motion of generation between second-order tooth surfaces. In this paper, the tooth surface is expressed by the original third-order tooth surface, and the tooth bearing pattern is analyzed by the meshing motion of the tooth surface. The tooth bearing pattern obtained from such an analytical method becomes the formal tooth bearing. Therefore, the machine settings for accurate gear cutting become possible, and the desired tooth bearing pattern can be obtained beforehand without a trial cutting.
Simulation of Traction Drive Ratio Changes
Authors: Zou Z. , Zhang Y. , Zhang X. , Tobler W.
Published: December 2020

In the simulation model presented in this paper, the kinematic characteristics of traction drives are formulated using classical Hertzian contact theory and elasto-hydrodynamic theory. The roller swing motion is governed by an equation derived based on Newton’s Second Law and is coupled to the side slip, torque input and output, as well as ratio variations. A control strategy with feedbacks for both the roller swing and the piston displacement is applied for ratio control based on stability and responsiveness considerations. The model has been implemented systematically in Matlab/Simulink environment. The effectiveness of the ratio control system in terms of stability and accuracy is illustrated by the simulation results included in this paper.