bluuebunny/crossref_metadata_2025_split huggingface dataset:
Task-Oriented Direct Synthesis of Serial Manipulators Using Moment Invariants
Authors: Dai Jian S. , Holland Neil , Kerr David R. 
Published: February 2021

Abstract
This paper applies the finite twist mapping to spatial manipulators and gives a new approach for the direct synthesis of serial manipulators by using moment invariants and task decomposition. The task is represented in an image space as a cluster of a large number of points and is related to the finite twist of the manipulator. For a given task, the new approach applies a series of analysis to the data, and produces a set of invariant criteria. The type and disposition of the proximal joint are identified, and the remaining regional structure may then be designed. The approach is based upon the numerical analysis of a task without recourse to graphical analysis and is computer programmable. This new design procedure is illustrated with a flowchart and a numerical example is given.
Kinematic Modeling of Underactuated Mechanical Grippers
Authors: Montambault Serge , Gosselin Clément M. 
Published: February 2021

Abstract
This paper presents the concept of underactuation applied to grippers and mechanical hands. The main objective of this work is the kinematic analysis and design of underactuated mechanisms. First, the kinematic and static modeling of these mechanisms is addressed and a general model is proposed. Then, a two-degree-of-freedom underactuated gripper based on a five-bar planar mechanism is studied in order to illustrate the usefulness of the model in a context of analysis and design.
Development of an Integrated System for Cam Design and Manufacture With Graphical User Interface
Authors: Aziz Rosman 
Published: February 2021

Abstract
The development of a Windows-based software package for the design and manufacture of cams is presented. There are four main modules in this software consisting of design, display, animation and NC program generation. From the data input the motion curves are constructed using building-block approach where proper blending at joint points are ensured. The interactive graphical user interface provide easy data entry for the user, and the output display give excellent graphics. B-spline curve fitting and techniques for offset free-form curves were employed to generate cutter path and cam profile. In order to evaluate the software, test samples were made, using the NC program generated. The test results were satisfactory.
A Geometric Model for Analysis and Design of Delta Parallel Robots
Authors: Gao Feng , Gruver William A. , Wang Hongrui , Zhang Yuru 
Published: February 2021

Abstract
A geometric model of the solution space for delta parallel robots is derived. We present an approach that classifies delta parallel robots in terms of 3-crank, 3-rocker, and change point mechanisms. By representing performance facors as character-istic curves within the model, the technique provides a foundation for investigating the relationships between robot performance and the link lengths of all possible mechanisms.
A Multi-Purpose Off-Line Path Planner Based on an A* Search Algorithm
Authors: Rankin Arturo L. , Crane Carl D. 
Published: February 2021

Abstract
Efficient navigation of an autonomous mobile robot through a well-defined environment requires the ability of the robot to plan paths. An efficient and reliable planar off-line path planner has been developed that is based on the A* search method. Using this method, two types of planning are accomplished. The first uses a map of all known obstacles to determine the shortest-distance path from a start to goal configuration. The second determines the shortest path along a network of predefined roads. For the most complicated environment of obstacles and roads, a near-optimal piecewise-linear path is found within a few seconds. The planner can generate paths for robots capable of rotation about a point as well as car-like robots that have a minimum turning radius. For car-like robots, the planner can generate forward and reverse paths. This software is currently implemented on a computer controlled Kawasaki Mule 500 all-terrain vehicle and a computer controlled John Deere 690 excavator.
Choice of Riemannian Metrics for Rigid Body Kinematics
Authors: Žefran Miloš , Kumar Vijay , Croke Christopher 
Published: February 2021

Abstract
The set of spatial rigid body motions forms a Lie group known as the special Euclidean group in three dimensions, SE(3). Chasles’s theorem states that there exists a screw motion between two arbitrary elements of SE(3). In this paper we investigate whether there exist a Riemannian metric whose geodesics are screw motions. We prove that no Riemannian metric with such geodesics exists and we show that the metrics whose geodesics are screw motions form a two-parameter family of semi-Riemannian metrics.
Singularity and Dexterity Analysis of the Carpal Wrist
Authors: Canfield Stephen L. , Ganino Anthony J. , Salerno Robert J. , Reinholtz Charles F. 
Published: February 2021

Abstract
This paper further explores the potential advantages of a symmetric, parallel-actuated pointing device known as the “Carpal wrist.” Much like its natural counterpart, the Carpal wrist has eight primary links, corresponding to the eight carpal bones of the human wrist, a parallel actuation scheme, similar to the flexor and extensor carpi muscles along the forearm, and an open interior passage, which forms a protected tunnel for routing hoses and electrical cables. The Carpal wrist also has the significant advantages of possessing closed form forward and inverse kinematic solutions and a large, dexterous workspace that is free of interior singularities (either considered separately or as part of a manipulator arm). As a result of its symmetric, parallel architecture, the wrist has a large payload capacity and can easily be adapted to a variety of actuation schemes. One embodiment of the Carpal wrist is shown in Fig. 1.
Control of Truss-Based Manipulators Using Virtual Serial Models
Authors: Williams Robert L. , Mayhew James B. 
Published: February 2021

Abstract
This paper introduces a novel method for Cartesian trajectory and performance optimization control of kinematically-redundant truss-based manipulators (TBMs), The Virtual Serial Manipulator Approach. The approach is to model complex in-parallel-actuated TBMs as simpler kinematically-equivalent virtual serial manipulators. Standard control methods for kinematically-redundant serial manipulators can then be adapted to the real-time control of TBMs. The forward kinematics transformation can be calculated more efficiently using the equivalent virtual parameters, compared to the computationally intensive in-parallel-actuated forward kinematics transformation. The method is applicable to any TBM whose modules can be modeled as a virtual serial chain. It also handles TBMs constructed of dissimilar modules, and compound manipulators with serial and in-parallel-actuated joints. The method is applicable for any level of kinematic redundancy.
Design Optimization of Variable Stroke Compressors to Minimize Vibration by Using Asymptotic Analysis
Authors: Ashrafiuon Hashem , Whitman Alan M. 
Published: February 2021

Abstract
A design optimization of a variable displacement compressor, in order to minimize its crankshaft vibration, is presented. A vibration mount installed between the flywheel and crankshaft is used as the optimizing element; the stiffness and damping values of the mount are selected so that the shaft vibration level is minimized over the cruise speed range while the maximum twist angle acceleration amplitude and transmitted torque are kept within acceptable limits for the entire operating speed range. An asymptotic analysis is used to obtain the nonlinear vibrational response. This analysis provides analytic expressions for the motion and forces in terms of the operating speed and other geometric, kinetic, and dynamic parameters. Consequently, the calculation of the objective and constraint functions is simple to do. A result of the analysis is that the optimal design is insensitive to changes in the magnitude and shape of the cylinder pressure excitation.
Analytical and Experimental Investigations of a Multi-Degree-of-Freedom Flexible Cam-Follower Mechanisma
Authors: Khanuja Sukhwant S. , Mahyuddin Andi I. , Midha Ashok 
Published: February 2021

Abstract
A multi-degree-of-freedom model is developed herein for prediction of response of an experimental cam-follower mechanism. Both transverse and axial flexibility of the follower rod and return spring, as well as transverse and torsional flexibility of the camshaft are included. The camshaft is assigned two rotational degrees of freedom, one at the cam and the other at the flywheel. The follower mass motion is also described by two degrees of freedom, one each in the axial and the transverse directions. The model takes into account the fluctuating camshaft angular speed and treats it as an input excitation. The governing second-order, nonlinear, nondimensionalized ordinary differential equations of motion, with time-periodic coefficients, are developed. In doing so, a comprehensive modeling of the kinematics of deformation of the flexible camshaft and follower system is considered, with the first inclusion of the transverse flexibility of the follower rod and return spring. With axial deflection, the transverse flexibility of the return spring gives rise to a phenomenon defined as moment stiffening. The transverse degree of freedom of the follower mass significantly influences the equivalent axial stiffness of the system. Its inclusion in the equation of motion yields a more accurate prediction of the experimental system behavior.
Design of a Two-Input Linkage-Based Motor
Authors: Shanshal Yassir , Farhang Kambiz 
Published: February 2021

Abstract
This paper proposes the use of a seven-bar linkage mechanism to obtain a multiply actuated motor. Design of two input mechanisms is presented involving two synthesis sub-tasks of input motion synthesis and dimensional synthesis. To this end a design methodology is presented based on the theory of small crank mechanisms. For the case of small motion, approximate equations are developed with the premise that as a result of small reciprocating motion of the input actuators, the motion of every link, with the exception of the output, is small. The motion, in turn, is expressed as a sum of an average and a small oscillatory angular motion about the average. A set of design equations are obtained from the approximate kinematic equations. The design methodology is exemplified using the synthesis of a seven-link mechanism with two translating inputs.
A Tooth Contact Analysis Model for Crossed Axis Helical Gears Under Load
Authors: Zhang Y. , Fang Z. 
Published: February 2021

Abstract
This paper presents an approach for the analysis of tooth contact and load distribution of helical gears with crossed axis. The approach is based on a tooth contact model that accommodates the influence of tooth profile modifications, gear manufacturing errors and tooth surface deformation on gear mesh quality. In the approach, the tooth contact load is assumed to be distributed along the tooth surface line that coincides with the relative principal direction of the contacting tooth surfaces. The model in this paper provides a quantitative analysis on gear transmission errors, contact patterns and the load distribution of helical gears with crossed axes when the tooth surfaces are deformed under load. As a numerical example, the contact of a pair of helical gears with a small crossing angle is analyzed by the computer program that implements the approach.
Closed-Form Displacement Analysis of 9-Link, 2-DOF and 10-Link, 3-DOF Mechanisms
Authors: Almadi Abdulaziz N. , Dhingra Anoop K. , Kohli Dilip 
Published: February 2021

Abstract
This paper addresses the closed-form displacement analysis problem of all mechanisms which can be derived from 9-link kinematic chains with 2-DOF, and 10-link kinematic chains with 3-DOF. The successive elimination procedure developed in the companion paper is used to solve the resulting displacement analysis problems. The input-output polynomial degrees as well as the number of assembly configurations for all mechanisms resulting from 40 9-link kinematic chains, and 74 10-link kinematic chains with non-fractionated degrees of freedom (DOF) are given. The computational procedure is illustrated through two numerical examples. The displacement analysis problem for all mechanisms resulting from these chains is completely solvable, in closed-form, devoid of any spurious roots.
Synthesis of Force-Generating Mechanisms
Authors: Tidwell Paul H. , Reinholtz Charles F. , Soper R. Randall 
Published: February 2021

Abstract
This work presents a unified method for the kinematic synthesis of mechanical-advantage function-generating mechanisms. These devices produce a specified nonlinear force or torque as a function of input position with resisting energy supplied to the mechanism from an external energy storage device such as a spring or load weight. This work differs from most past work in that the positions of the link carrying the external resisting load need not he specified.
A New Method and Automatic Generation for Kinematic Error Analysis of Complex Planar Mechanisms Based on the Ordered Single-Opened-Chains
Authors: Shan Song-Qing , Yang Ting-Li 
Published: February 2021

Abstract
This paper presents a new method for kinematic error analysis of planar complex mechanisms, i.e., the ordered single -opened -chains method. This approach is based on the ordered single-opened chains (namely, series binary links, in short, SOCs)and makes use of the properties of SOCs and the network constraint relationships between SOCs. Its mathematical model harmonizes with the structure, kinematics, and dynamics model of mechanisms. The kinematic error analysis equations with few unknown variables can be automatically generated and easily solved. Therefore, any planar complex mechanism can be automatically decomposed into a series of the ordered single-opened-chains and then its kinematic error analysis can be easily completed through this method. Perhaps, the most attractive features of this method are its high automation and convergence in computer implementations.
This work describes the principle of the ordered SOC method, introduces its computer automatic generation and compiles the corresponding computer program KEAPL. Two Examples are given at the end of the paper.
The proposed method can be easily extended to the kinematic error analysis of the spatial mechanisms.
Dynamic Analysis of Geared Robotic Mechanisms Using Graph Theory
Authors: Tsai Lung-Wen , Chen Dar-Zen , Lin Ta-Wei 
Published: February 2021

Abstract
A systematic methodology is developed for the dynamic analysis of a class of geared robotic mechanisms. The concepts of canonical graph representation, the equivalent open-loop chain, and the mechanical transmission lines of a mechanism are used to organize the analysis. The approach modifies the Newton-Euler recursive inverse dynamics algorithm for open-loop chains and tree structures to include gear joints. A recursive method for the evaluation of reaction forces is developed. It is shown that reaction forces can be efficiently computed from the highest level primary links followed by the secondary links, one or two levels at a time, working toward the base. This procedure is especially useful when the evaluation of dynamic loads of bearings and teeth teeth is desired for the design of such mechanisms. A two degree-of-freedom robot manipulator is used as an illustrative example.
Trajectory Control for Robotic Arc Welding Applications
Authors: Balkan Tuna 
Published: February 2021

Abstract
In this study, a PC based program is developed for robotic welding applications. This program includes synthetic generation of Cartesian trajectories based on prespecified points on the trajectory and predetermined velocity profile. Such points can be provided in the teach mode or by using a vision system assisted by a special algorithm. The control algorithm is based on the measurement of joint variable positions and rates resulting in a closed-loop system with a model-based part. These algorithms are applied to an industrial robot performing arc welding weaving applications and typical performance curves are obtained under simulated conditions.
Minimizing the Strain Energy for Flexible-Link Cooperating Manipulators
Authors: Sun Qiao , Sharf Inna , Nahon Meyer 
Published: February 2021

Abstract
In control of cooperating manipulator systems, force distribution is a central problem. For rigid manipulators, solutions are based on various criteria such as minimum potential damage to the grasped object, minimum energy consumption and optimal load distribution in actuators. However, when considering manipulators with structural flexibility, minimizing the deflections of the mechanical components becomes a highly desirable objective. In this paper, we propose a force distribution scheme based on a local minimum of the strain energy stored in the elastic links of the cooperating manipulators. Numerical example are given to demonstrate the effectiveness of the scheme.
The Cylindroid Associated With Finite Motions of the Bennett Mechanism
Authors: Huang Chintien 
Published: February 2021

Abstract
The finite kinematic geometry of the Bennett mechanism is explored, and a surprising finding is uncovered in this paper. The screw axes of all possible coupler displacements of the mechanism from any given configuration are shown to form a cylindroid. The screw system of the coupler displacement is obtained by using the intersection of finite screw systems associated with two corresponding revolute-revolute dyads. Inverse finite kinematic analysis is also performed to verify this new linear property of the Bennett mechanism.
Modeling and Identification of Non-Geometric Parameters in Semi-Flexible Serial Robotic Mechanisms
Authors: Cléroux Louise , Gosselin Clément M. 
Published: February 2021

Abstract
In order to ensure the rigid body assumption, serial manipulators have generally been overdesigned. This has resulted in large, heavy and bulky robots that can only manipulate loads which are small when compared to their own weight. Therefore, structural flexibilities are studied here in order to maintain static accuracy while reducing the weight of the robots. In this paper, the modeling and identification of serial manipulators with flexible joints and links is addressed. A general model is developed in order to take into account the flexibilities, and an algorithm is proposed for the identification of mechanisms from measured static poses.
On the Generation Synthesis of Movable Octahedral 6R Mechanisms
Authors: Lee Chung-Ching 
Published: February 2021

Abstract
The geometric characteristics of three well-known movable octahedral 6R mechanisms are described and then, by matrix algebra method, we derive their general displacement closed-form solutions for further investigation and analysis. Based on the fundamentals of three dimensional analytical coordinate geometry, a systematic approach is offered to generate the configuration of movable octahedral 6R mechanism with the help of computer graphics. In addition, a user-friendly computer aided program implementing the process of generation synthesis can be developed in Autolisp, a Lisp language interpreter within autoCAD. The numerical results for every generation and their constrained motion are confirmed by the derived analytical solutions. The physical models of these synthesized mechanisms are also built respectively.
Moving Toward Authentic, Learning-Oriented Assessment in Coach Education
Authors: McCarthy Liam , Allanson Ashley , Stoszkowski John 
Published: February 2021

As sports coaching continues to professionalize, the demand for and importance placed upon high-quality education and development programs for sports coaches is increasing. As a result, the landscape of provision is changing, and there is now a recognition of the key role that higher education institutes play in the education, development, and assessment of sports coaches. In this insights article, the authors argue that as there is a scarcity of research focused solely on assessment as a feature of coach education programs, there is something to be gained from examining how higher education institutes assess sports coaches. This represents an important contribution to the research literature, given that assessment is a feature of nearly all coach education programs and that the attainment of a specific award communicates to stakeholders (e.g., employers, athletes, parents) that a precise standard of practice has been met. As such, the authors identify how some higher education institutes are addressing the issue of assessment with sports coaches and highlight a series of assessment principles, alongside practical examples from the literature, which are intended to stimulate conversation in what the authors argue is an important area of study.
Medical costs and out-of-pocket expenditures associated with multimorbidity in China: quantile regression analysis
Authors: Zhao Yang , Atun Rifat , Anindya Kanya , McPake Barbara , Marthias Tiara , Pan Tianxin , Heusden Alexander van , Zhang Puhong , Duolikun Nadila , Lee John Tayu 
Published: February 2021

ObjectiveMultimorbidity is a growing challenge in low-income and middle-income countries. This study investigates the effects of multimorbidity on annual medical costs and the out-of-pocket expenditures (OOPEs) along the cost distribution.MethodsData from the nationally representative China Health and Retirement Longitudinal Study (CHARLS 2015), including 10 592 participants aged ≥45 years and 15 physical and mental chronic diseases, were used for this nationally representative cross-sectional study. Quantile multivariable regressions were employed to understand variations in the association of chronic disease multimorbidity with medical cost and OOPE.ResultsOverall, 69.5% of middle-aged and elderly Chinese had multimorbidity in 2015. Increased number of chronic diseases was significantly associated with greater health expenditures across every cost quantile groups. The effect of chronic diseases on total medical cost was found to be larger among the upper tail than those in the lower tail of the cost distributions (coefficients 12, 95% CI 6 to 17 for 10th percentile; coefficients 296, 95% CI 71 to 522 for 90th percentile). Annual OOPE also increased with chronic diseases from the 10th percentile to the 90th percentile. Multimorbidity had larger effects on OOPE and was more pronounced at the upper tail of the health expenditure distribution (regression coefficients of 8 and 84 at the 10th percentile and 75th percentile, respectively).ConclusionMultimorbidity is associated with escalating healthcare costs in China. Further research is required to understand the impact of multimorbidity across different population groups.