bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Isomorphism Index and its Applications to Kinematic Chains and Mechanisms
Authors: Vijayananda K. , Mruthyunjaya T. S. 
Published: December 2020

Abstract
In this paper a novel method for the identification of the structure of a kinematic chain has been proposed. By expressing in discrete steps the process that usually goes with the visual comparison of two kinematic chains, a reliable and fast computational test for the detection of isomorphism is developed and successfully implemented on a digital computer. No counterexamples for the test have been encountered among kinematic chains and graphs. Also the new isomorphism index directly detects distinct mechanisms that can be derived from the chain. With slight modifications to the method multiple jointed kinematic chains and the driving mechanisms are also identified.
Kinematics of 3-DOF Pyramid Manipulator by Principal Screws
Authors: Huang Zhen , Wang Jing 
Published: December 2020

Abstract
This paper discusses kinematics of a 3-RPS parallel pyramid manipulator using the principal screws. Firstly, the principal screws are identified by quadric degeneration. The planar conies representing the relations between the pitches and the three linear inputs are described, and the three-dimensional distribution of the axes of all the twists is illustrated. Finally, a numerical example is given successfully.
Synthesis of Reconfigurable Machine Tools With Screw Theory
Authors: Moon Yong-Mo , Kota Sridhar 
Published: December 2020

Abstract
In this paper, we present a systematic methodology for designing Reconfigurable Machine Tools (RMTs). The synthesis methodology takes as input a set of functional requirements — a set of process plans and outputs a set of kinematically-viable reconfigurable machine tools that meet the given design specifications. We present a mathematical framework for synthesis of machine tools using a library of building blocks. The framework is rooted in (a) graph theoretic methods of enumeration of alternate structural configurations and (b) screw theory that enables us to manipulate matrix representations of motions to identify appropriate kinematic building blocks. The methodology described in this paper provides a mathematical framework to address dynamic stiffness, and accuracy prediction of the kinematically-viable designs that are generated by the synthesis procedure. This methodology has been implemented in a program, called PREMADE (PRogram for REconfigurable MAchine tool DEsign), and the results are validated against commercial machine tool designs.
Dimensional Synthesis of Bennett Linkages
Authors: Perez Alba , McCarthy J. M. 
Published: December 2020

Abstract
This paper presents a synthesis procedure for a spatial 4R linkage, known as Bennett’s linkage. It is known that the two solutions of the RR chain synthesis equations form a Bennett linkage. While analytical solutions to these equations have been developed previously, this paper uses the cylindroid that is known to exist for a Bennett linkage to simplify the solution process. It is interesting that geometric constraint associated with the spatial 4R chain simplifies the solution of the RR chain design equations. An example design is presented.
A New Approach for the Reduction of Vibrational Excitation in Kinematics Synthesis of High Speed Linkages
Authors: Yuan L. , Rastegar J. 
Published: December 2020

Abstract
A new method is presented for the modification of the output motion of linkage mechanisms with closed-loop chains using cams positioned at one or more of its joints. In particular, the method is applied to a four-bar linkage mechanism that is synthesized for function generation for the purpose of eliminating the high harmonic component of the output link motion. By eliminating the high harmonic component of the output motion of a mechanism, the potential vibrational excitation that the mechanism can impart on the overall system, including its own structure, is greatly reduced. The resulting system should therefore be capable of operating at higher speeds with increased precision. For mechanisms with rigid links, the primary source of high harmonic motions is the nonlinearity of the kinematics of closed-loop chains. With the present method, the higher harmonic motions generated due to such nonlinearities are eliminated by the integration of appropriately designed cams that are used to vary the effective link lengths. A numerical example is provided together with a discussion of the related topics of interest.
The Ray Optimization Method for the Determination of Workspaces of Planar Parallel Manipulators of General Design
Authors: Hay A. M. , Snyman J. A. 
Published: December 2020

Abstract
An extension to a novel optimization approach for the determination of workspaces of planar manipulators is presented. This approach provides a general method for the determination of manipulator workspaces and has the advantage that it may easily be automated. The method consists of finding a suitable initial radiating point interior to the accessible output set of the manipulator, and then determining the points of intersection of a representative pencil of rays, emanating from this point, with the boundary of the accessible set. The points of intersection are determined by means of an optimization approach in which a dynamic constrained optimization algorithm is used. If any section of the workspace boundary cannot be determined due to non-convexity, then the missing section is mapped using a suitably chosen new radiating point. The method is illustrated by its application to a generally constrained planar parallel manipulator. The method has been implemented in a practical, interactive computer code that has been used to determine convex and non-convex workspaces of different parallel manipulators of arbitrary geometry.
Joint Rotation Space, Workspace, and Singularity-Free Workspace of Parallel Five-Bar Manipulators
Authors: Ting Kwun-Lon , Zhang Yi 
Published: December 2020

Abstract
Closed-loop manipulators, while offering some advantages over the open-loop manipulators, also introduce new topics of study such as their joint rotation space (JRS) and workspace. In the previous studies, the concept of JRS was very effective in the study of the allowable inputs of five-bar linkages[11], and the concepts of sheet and side[7] were later introduced for the purpose of clearly describing all of the joint rotation spaces associated to a parallel manipulator with two degrees of freedom. However, of the two types of singularity of parallel manipulators, only the uncertainty singularity was considered in the aforementioned studies. The stationarity singularity was not indicated in the JRS of the manipulators, which would not be sufficient in the design and trajectory planning of parallel manipulators where the one-to-one correspondence between the JRS and the wrist point workspace would be required. This paper reports an extensive study on the JRS and singularity-free workspace of the parallel five-bar manipulators. The objective of the study is to establish a one-to-one corresponding relationship between the JRS and singularity-free workspace. A concise and sufficient way is proposed to thoroughly recognize the JRS and workspace of the parallel five-bar manipulators. The result can be applied in the design and trajectory planning of parallel five-bar manipulators, and the concepts can be extended to other parallel manipulators.
Modeling Gait Transitions of Quadruped and Their Generalization With CMAC Neural Networks
Authors: Lin Jian-Nan , Song Shin-Min 
Published: December 2020

Abstract
The gait transition models of a quadruped are studied based on gait kinematics and CMAC neural networks are applied to learn and generalize these gait transition models. Three gait transition cases are studied: from wave gait to continuous follow-the-leader gait, from walk to trot, and from trot to gallop. Four solution methods are proposed for solving the gait transition models. Computer simulations are conducted to evaluate and display the gait transition models. The good transition gaits are then selected to train CMAC neural network gait transition models. The performance of the CMAC gait transition models are evaluated and found to be satisfactory.
A Mechanical Design of One D.O.F. Anthropomorphic Finger Based on a Human Finger Motion
Authors: Figliolini Giorgio , Ceccarelli Marco 
Published: December 2020

Abstract
In this paper we propose an analytical formulation for simulation and design of one d.o.f. articulated finger mechanism with three phalanges. The formulation is based on a study of design and operation of index human finger. In particular, we propose a suitable mechanical design for an anthropomorphic finger as both an approximation of human architecture and an easy practical design. Kinematic characteristics are illustrated with numerical examples.
On the Structural Synthesis of Multi-Fingered Hands
Authors: Lee Jyh-Jone , Chen Chun-Po 
Published: December 2020

Abstract
Compared to the serial type of six-freedom robot arm attached with an end-effector, the multi-fingered hand system can provide more dexterity and versatility in the field of autonomous manipulation tasks. Designs of multi-fingered hands can be found in the literature, to name a few, Mechanical Hand by Skinner [13], Multi-jointed Finger System by Okada [6], Stanford/JPL Hand (or Salisbury Hand) [11], Utah-MIT Hand [3], and NTU-1 Hand [5]. Generally, these mechanical hand systems have been designed to simulate a subset function of human hands. The structures of these systems basically resemble the skeleton of human hand and are constructed by designers’ intuition. Not much literature addressed about the structural synthesis of multi-fingered hands.
This paper presents a new approach for the structural synthesis of multi-fingered hands. It takes into account both the total mobility and the force closure criterion of the system. Based upon the Grübler’s mobility equation, relations regarding the numbers of fingers, contact geometry, and object freedoms are established. Subsequently, by applying the force closure criterion, the total number of possible multi-fingered hands with given mobility are synthesized.
Simulating Cervical Vertebrae Motion Using Elementary Contact Pairs
Authors: Kecskeméthy Andrés , Lange Christian , Grabner Gerald 
Published: December 2020

Abstract
Described in the paper is the mathematical modeling of a vertebrae pair using multibody methods and impact analysis techniques with elementary contact geometry for the facet joints. The results are compared with existing approaches and with experimental data, showing a good agreement with the latter and an efficiency boost compared to existing approaches by a factor of 350. The investigations are focused on the vertebrae pair C5-C6 but can be easily extended to other vertebrae.
Modeling of Planar Flexible Link Manipulators: Parameter Identification Using Genetic Algorithm
Authors: Megahed S. M. , Hamza K. T. 
Published: December 2020

Abstract
In this paper, a model for simulation of planar flexible link manipulators is presented. Identification of the model parameters is done based on experimental results obtained from separate experiments performed on every link in the manipulator. A simple experimental procedure is used to determine the first three natural frequencies and damping ratios corresponding to them. The experimental data provides guidance in selecting an appropriate number of elements per link for modeling, mass and stiffness parameters and an initial value of damping parameters. Further enhancement of the model is performed through Genetic Algorithm optimization of the damping parameters with the objective function to be minimized defined as the sum of squares of errors between the experimental response and the simulated one. After optimization, the simulated response and the experimental one are closely matching.
The Kinematics of Redundant Tetrahedron Based Variable Geometry Truss Manipulators Based on Neural Network
Authors: Xu Li-Ju , Wu Jiang 
Published: December 2020

Abstract
The forward displacement analysis of redundant tetrahedron based variable geometry truss manipulators is obtained based on BP neural network, and then a solution to inverse displacement analysis problem is obtained. According to the above network model, the first- and second-order influence coefficients are derived, and the pseudo-inverse of Jacobian matrix is obtained by using a neural network. Finally the simulation calculation of kinematics for a seven celled tetrahedron-tetrahedron variable geometry truss manipulator is given for illustration.
Effect of Sintering Process and Rolling on Surface Durability of Sintered Metal Gears
Authors: Koide Takao , Oda Satoshi , Nakamura Hitoshi , Onishi Michinari 
Published: December 2020

Abstract
This paper presents a study on the surface durability of sintered metal gears. Gear blanks made of partially prealloyed steel powders were compacted and sintered under various processes, then they were hobbed and case-hardened. Some gears were surface-rolled under various amount of rolling before case-hardening. The contact fatigue tests were carried out for these gears using the power-circulating-type gear test machine. The effects of sintering processes and rolling on the surface durability and wear of sintered metal gears were determined. Furthermore, the surface durability of the above-mentioned sintered metal gears was compared with that of the wrought steel gears. The density of sintered metal gears increases by adopting a double-press-double-sinter (2P2S) process as the sintering process. The surface density of the sintered metal gears tends to increase with rolling for the case of gears with relatively lower density. The surface durability of sintered metal gears tends to increase with an increasing surface density. The surface durability of sintered metal gears may approach that of the wrought steel gears by adopting the appropriate sintering and rolling processes.
An Experimental Investigation of Bending Fatigue Initiation and Propagation Lives
Authors: Singh Avinash 
Published: December 2020

Abstract
It has long been recognized that the fatigue life of a component can be divided into a crack initiation phase and a crack propagation phase, but researchers have typically ignored one phase or the other in their analytical models. Even in the stress-life method of life prediction, which implicitly includes both phases, no distinction is made between the initiation and propagation phases. In this paper a methodology for generating initiation and propagation S-N curves will be outlined. It will be shown that for components like gears, both phases represent significant portions of total life. It will also be shown that gear bending fatigue lives for variable amplitude load tests are better predicted by a two-stage linear damage theory compared to the commonly used Miner’s total life linear damage theory.
Optimization for the Dynamic Behavior of High Speed Spiral Bevel Gears
Authors: Fang Zongde , Yang Hongbin , Zhou Yanwei , Deng Xiaozhong 
Published: December 2020

Abstract
A new approach for optimizing the dynamic behavior of spiral bevel gear drives has been developed. The local synthesis, tooth contact analysis (TCA) and loaded tooth contact analysis (LTCA) techniques were used to constitute the design process with feedback, by which a contact ratio being near 2.0 or 3.0 would be achieved. An improved dynamic behavior of the spiral bevel gear drives under certain operating load or a wide range of load could be obtained.
Effects of Tooth Profiles and Addendum Modification on Efficiency of Cylindrical Worm Gears
Authors: Yoshino Hidehiro , Ohshima Fumihiro 
Published: December 2020

Abstract
Power transmission efficiencies of five cylindrical worm gear pairs with different profiles and different addendum modifications were measured. The convex, concave or trapezoid profile and also the positive, negative or zero addendum modification was given to each gear pair. The efficiency of worm gears does not change if only the tooth profile is changed. However, it changes (increases) when the change in the profile and the addendum modification were combined. For example, the efficiency of worm gears with the convex tooth and the negative addendum modification increased by 3% to 91% and that of with the concave tooth and the positive modification increased by 4% to 91.5%. The reason why the efficiency increases is investigated and discussed by analyzing the meshing and lubricating conditions between the meshing teeth. As a result, it will be shown that the efficiency of worm gears is strongly influenced by the condition of oil film formation between the teeth.
Tooth Contact Analysis of Double Enveloping Hourglass Worm Gearing on the Condition That Errors Mixed With Deformation
Authors: Qin Datong , Qin Dongxing , Yang Yalian , Hu Jianjun 
Published: December 2020

Abstract
An accurate geometry and contact finite element model of double enveloping hourglass worm gearing with manufacturing errors are constructed. The hybrid method of finite element method and penalty function method is employed to investigate the contact pattern and contact pressure on tooth surface as well as the load share among contacting tooth pairs with the coexistence of manufacturing error and load. The influences of different values of load and different types of errors on contact pattern and contact pressure as well as load share are studied. The mutual influences of the load and the error on tooth contact and load share are also analyzed. Some results useful for production and application of the worm gearing are presented.
A Study on Noise in Synchronous Belt Drives: Experimental and Theoretical Analysis of Impact Sound
Authors: Zhang Weiming , Koyama Tomio 
Published: December 2020

Abstract
There are two kinds of noise in synchronous belt drives. One is steady sound caused by transverse vibration of belt, and another is impact sound radiating from meshing point of belt and pulley. Recently, it has been reported that the impact sound is due to the sound occurring in an air pipe built up between pulley groove and belt because the frequency of impact sound coincides with the fundamental natural frequency of an open ended pipe whose length equals width of the belt. However, this conclusion is obtained experimentally, there has no theoretical analysis provided. In this study, an analysis of the impact sound is provided to prove its generation mechanism and discuss factors that influence the level of sound theoretically. Sound field in an open ended pipe subjected to an impulsive sound source is analyzed. Comparison between experimental and analytical results is carried out. It is concluded that the level of impact sound is in proportion to the width of belt, and the acoustic energy of impact sound is in proportion to the cube of the width of belt.
Prediction of Automotive Gearboxes Dynamic Behavior: Part A — Experimental Validation of a Global Numerical Model
Authors: Yakhou Karim , Bourdon Adeline , Play Daniel 
Published: December 2020

Abstract
Numerical models have been developed to simulate the overall dynamic behavior of automotive gearboxes. They are based upon Finite Element Methods and their main originality is to integrate all the couplings between the various mechanical components of the gearboxes. The purpose of this study is to qualify these numerical models, and then, use them in order to determine gearboxes new design trends. In this first part of two companion papers, an experimental validation procedure has been implemented in two main stages. The first one is devoted to the study of mechanical systems under load but not-rotating. It is organized according to a “step by step” procedure. Starting with the shafts, the other components are gradually mounted and integrated into the mechanical system being considered. Thus, the modeling of the various parts has been validated and the existence of significant couplings has been confirmed. In the second stage of the procedure, the whole gearbox is studied under operating conditions. Preliminary tests at low rotational speeds allow the determination of the quasi-static transmission error under load. The results are used as input data for numerical simulations. Then tests are conducted at higher speeds with various resistant torques. Dynamic transmission error and dynamic loads transmitted by bearings are recorded. A good correlation between experiments and computations ensures the validity of the main a-priori modeling assumptions.
Experimental and Numerical Investigations on the Influence of Tooth Friction in Spur and Helical Gear Dynamics
Authors: Velex Philippe , Cahouet Violaine 
Published: December 2020

Abstract
An original model based upon a finite element procedure is introduced for analyzing the influence of tooth friction on spur and helical gear dynamics. The equations of motion are solved by combining a time-step integration method with several iterative algorithms aimed at satisfying normal and tangential contact conditions. Comparisons between simulated and measured quasi-static bearing forces are satisfactory and largely validate the theoretical developments. Results also reveal the potentially significant contribution of tooth friction to gear vibration and noise. Simulations are then extended to high speeds and the interest of considering both transmission error and tooth friction excitations to achieve silent gears is discussed.
Modeling and Analysis of Sliding Friction in Gear Dynamics
Authors: Vaishya Manish , Houser Donald R. 
Published: December 2020

Abstract
Sliding resistance on gear teeth can have a dominant effect on housing vibration and noise, due to fluctuating excitation and high force transmissibility in the off-line of action direction. Hence reliable modeling of friction from tribological considerations, supported by experimental data, is of utmost importance. This paper examines some lubrication theories and validates them with 2-disk tests and quasi-static loaded gear tests. From the knowledge of friction characteristics, a lumped parameter system is synthesized for a pair of spur gears. This model includes sliding friction, mounting compliances and lateral-torsional vibration coupling. A different formulation has been applied, which unlike most current models, accounts for energy dissipation in the system due to friction. The influence of various excitations like transmission error, friction and parametric variations, on dynamic response of gears is investigated. Finally, the model is evaluated with dynamic tests carried out on a spur gear set, under varying conditions of torque, speed and lubricant.