bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design for Assembly Evaluation of Orientation Difficulty Features
Authors: Sturges Robert H. , Yang Jui-Te 
Published: March 2021

Abstract
In support of the effort to bring downstream issues to the attention of the designer as parts take shape, an analysis system is being built to extract certain features relevant to the assembly process, such as the dimension, shape, and symmetry of an object. These features can be applied to a model during the downstream process to evaluate handling and assemblability. In this paper, we will focus on the acquisition phase of the assembly process and employ a Design for Assembly (DFA) evaluation to quantify factors in this process. The capabilities of a non-homogeneous, non-manifold boundary representation geometric modeling system are used with an Index of Difficulty (ID) that represents the dexterity and time required to assemble a product. A series of algorithms based on the high-level abstractions of loop and link are developed to extract features that are difficult to orient, which is one of the DFA criteria. Examples for testing the robustness of the algorithms are given. Problems related to nearly symmetric outlines are also discussed.
Development of an Automatic Earring-Post Assembly System Using an Expert System Approach
Authors: Yang Biwu , Datseris Philip , Archer Todd 
Published: March 2021

Abstract
The problem of designing an automatic system to hand posts from bulk, to position them precisely and to weld them on findings, such as earrings, has been effectively solved by employing expert system methodologies and graph theory techniques. Design requirements are represented in terms of desired degrees of freedom, desired type of motion, and the complexity of the mechanism in terms of the number of independent loops. The expert system DOMES, Design of Mechanisms by an Expert System, developed at the University of Rhode Island, is employed to identify several kinematic structures of mechanisms which fulfill all requirements. Present semi-automatic systems require an operator to handle and position findings and posts into a welding machine at rates of approximately sixty findings per minute. The developed system handles four hundred findings per minute. Results show that mechanism design techniques based on graph theory and expert systems are powerful tools for creative mechanism design.
In this paper, emphasis is placed on the design of the mechanical system. However, the developed automatic earring-post assembly system includes several other features. A commercially available fusion welding machine is improved to attain rates of fourteen instead of three welds per second, a fifteen ton power press is integrated into the system and appropriate controls are designed and implemented together with light and acoustic sensors to synchronize the power press, the fusion welding equipment, and the post-handling equipment and to monitor system performance on a real-time basis.
Optimal Design of the Geometric Parameters of a Disk Cam Translating Follower Mechanism Using Chebychev Approximation
Authors: Peng Y. , Zhou J. , Dong Z. 
Published: March 2021

Abstract
A method for the structural design of a cam-translating roller follower mechanism with the minimum volume and least maximum pressure angle is presented. The design is formulated as a two-objective optimization problem subject to multiple constraints. The hierarchical approach for handling multi-objective optimization and application of the Chebychev approximation scheme for solving the nested maximization-minimization problem are discussed. The method presents a forthright approach to the complex optimal structural design of a cam-follower mechanism, and significantly improves present cam-follower mechanism design and optimization methods. A design example is used to illustrate the approach.
Intersection of Rays With Parametric Envelope Surfaces Representing Five-Axis NC Milling Tool Swept Volumes
Authors: Narvekar Ashish P. , Huang Yunching , Oliver James H. 
Published: March 2021

Abstract
A technique based on the theory of envelopes is presented to formulate a parametric representation of the surfaces swept by an axis-symmetric convex solid under general rigid body motion. The resulting swept surfaces are used to build a complete and precise swept volume model of the moving solid. Finally, an algorithm for finding the intersection of a ray with a swept volume is presented. The algorithm is sufficiently general to be useful in a variety of applications, including robotic path planning, design of mechanisms, and the simulation and verification of numerically controlled (NC) milling programs. Several examples of the algorithm are presented demonstrating ray intersections with swept volumes generated by a general seven-parameter NC milling tool model undergoing typical five-axis motion.
A New Damping Model for Non-Linear Stiffness Systems With Variable Preload Displacements and Constant Amplitude Decay Ratios
Authors: Xu T. , Lowen G. G. 
Published: March 2021

Abstract
This study of the behavior of non-linear stiffness systems with variable preload displacements and constant amplitude decay ratios showed that the energy loss per cycle is dependent on these preload displacements. By introducing a non-linear damping force, which is a function of both displacement and velocity, the associated work per cycle can be made approximately the same function of the preload displacement as is the case for the energy loss. In this manner, it becomes possible to make the resulting damping coefficient essentially independent of the preload displacement. This new damping model was incorporated into the mathematical description of an over-running sprag clutch. Confirming experimentation showed very good agreement with computed results.
A Constructive Variational Geometry Based Mechanism Design Software Package
Authors: Todd Philip H. 
Published: March 2021

Abstract
This paper describes the design and implementation of a variational geometry based mechanism design and analysis software package. A new, constructive approach to variational geometry allows positions and their derivatives to be computed using closed form expressions rather than an iterative procedure. This facilitates an interactive kinematics model. Statics and dynamics capabilities are added by means of the principle of least work and d’Alambert’s principle.
Examples are presented which highlight the flexibility and ease of use of the system.
Tolerance Synthesis Method for an Industrial Crank-Rocker Application
Authors: Benner Mark M. , Erdman Arthur G. 
Published: March 2021

Abstract
An emphasis on reducing product development lead-times in the automotive industry has received much attention recently. The synthesis and design of windshield wiper drive mechanisms is no exception. This paper examines and develops the new concept of performance synthesis for crank-rocker linkages with two prescribed positions as applied to windshield wiper systems. Various performance criteria are evaluated with respect to the effect on the desired motion of the crank-rocker linkage by manufacturing tolerances, elastic deflections and joint clearances. Three performance criteria are mapped in the crank-rocker synthesis solution space to aid in the selection of solutions when considering the performance demands of the windshield wiper system. A case study is presented to demonstrate the effectiveness of the new performance synthesis concept which simultaneously considers position tolerance sensitivity, transmission angles and angular acceleration magnitudes in the synthesis process.
A Symbolic-Numerical Approach for the Dynamic Modelling of Parallel Manipulators
Authors: Li Li , Chen Yong 
Published: March 2021

Abstract
A symbolic-numerical approach for the dynamic modelling of parallel manipulators is proposed in this paper. By extending the symbolic algebraic operation rules of the structural matrices and using an improved algorithm for the optimal operation of structural matrices, matrix elements in dynamic equations are generated automatically on the computer with minimization of number of floating-point multiplications/additions.
A Method for the Identification of Displacement Isomorphism of Planetary Gear Trains
Authors: Hsu Cheng-Ho , Lam Kin-Tak 
Published: March 2021

Abstract
The purpose of this paper is to present an efficient method for the identification of the displacement isomorphism of planetary gear trains. For every planetary gear train, the kinematic structure is characterized by its displacement graph and rotation graph. A mathematical representation, called the Structural Code, is introduced to represent the topological structure of the displacement graph and rotation graph of a planetary gear train. Based on the Structural Codes of displacement graphs and rotation graphs, the linear and rotational displacement isomorphism of planetary gear trains can be identified in an unambiguous way. Finally, an interactive computer program is developed for the automatic identification of the displacement isomorphism of planetary gear trains.
The Creation of a Multi-Link Load Balancing Mechanism for Planetary Gearing: Part 1 — Type Synthesis
Authors: Hong Zhang , Yang Ting Li , Chu Jin Kui , Cao Wei-qing 
Published: March 2021

Abstract
This series of papers design a multi-link load balancing mechanism for the Planetary Gearings with arbitrary number of planet gears. Based on the study of SGP load balancing mechanisms, this paper analyzed the relations between the function and kinematic structure of the multilink load balancing mechanism, and presented the topological characteristics and parameters of the kinematic chains suited for load balancing mechanism. Those topological parameters depend on the number of planet gears. In the type synthesis for the case of six planet gears, the kinematic chains with five degrees of freedom and eighteen links were enumerated according to the topological characteristics. The resulting mechanisms were 15 candidate multi-link load balancing mechanism.
A Sequential Implicit-Explicit Integration Method in Solving Nonlinear Differential Equations From Flexible System Modeling
Authors: Xu Jiechi , Baumgarten Joseph R. 
Published: March 2021

Abstract
The dynamic equations of motion obtained in the modeling of flexible structural systems with unknown rigid body gross motion are often highly nonlinear and possess time-varying coefficient matrices. The inherent characters of nonlinear large overall rigid body motion and linear small vibration are also involved in the system equations. Neither the implicit nor the explicit algorithm seems optimally suited and efficient by itself in dealing with these kinds of equations. This paper, therefore, presents a sequential implicit-explicit method in which it is attempted to achieve the attributes of both classes of algorithms. The equation system expressed in matrix form is first mapped to a subsystem in which the specified generalized coordinates are eliminated. The subsystem is then partitioned into two sets of coupled equations. One set of equations, describing the elastic motion, is linear with respect to the elastic generalized coordinates and is integrated implicitly. The other set of equations, governing the rigid body motion, contains the highly nonlinear coupling terms and is integrated explicitly with the back substitutions of the elastic kinematic properties already calculated in solving the first set of equations. A Newmark algorithm is employed to integrate the second order system of differential equations directly. A predictor-corrector scheme also coming from the Newmark algorithm is applied to the explicit integration. The procedures developed in the current paper are applied to simulating dynamic response of a complicated flexible system with mutually dependent rigid body unconstrained spherical motion and small elastic deformation.
Body Vibrations of a Legged Walking Machine
Authors: Gao Xiaochun , Song Shin-Min 
Published: March 2021

Abstract
Unlike in wheeled vehicles, compliance in walking machine systems changes due to the variation of leg geometry, as its body proceeds. This variation in compliance will cause vibration, even if external loads remain constant. A theory is thus developed to predict the body vibrations of a walking machine during walking. On the other hand, dynamic foot forces under body vibrations can be computed by application of the existing numerical methods. As an example, the body vibrations of a quadrupedal walking chair under different walking conditions are simulated in terms of the developed theory. The results show that the influence of body vibrations on the foot force distribution is essential and, in some cases, the walking chair may lose its stability due to its body vibrations, even though it is identified to be stable in a quasi-static analysis. The developed theory can also be extended to other similar multi-limbed robotic systems, such as multi-fingered robot hands.
Forming Dynamic Equations of Elastic Linkage and Investigation of Model Error
Authors: Zou Hui-jun , Zhang Mingli 
Published: March 2021

Abstract
In this paper, the approach in which KANE equation is combined with finite element method is used to derive the dynamic equation of elastic plane linkage. In these equations, arbitrary external forces acted on the linkages, distributive moment of inertia, lumped masses and concertrated moments of inertia set on arbitrary position of the linkage, higher order acceleration, shear, axial force, lengthwise and crosswise bend and rotating matrix are considered.
Inverse Kinematics of General 6R and 5R,P Serial Manipulators
Authors: Kohli Dilip , Osvatic Michael 
Published: March 2021

Abstract
In this paper we present a solution to the inverse kinematics problem for serial manipulators of general geometry. The method is presented in detail as it applies to a 6R manipulator of general geometry. The equations used are derived using a linearization method and dialytic elimination. In doing this, all variables except one, a tangent half angle of a joint variable, can be eliminated. The result is a 16 by 16 matrix in which all terms are linear in the suppressed variable. The unique design of this matrix allows the suppressed variable to be solved as an eigenvalue problem. Substituting these values of the suppressed variable back into the equations, all other joint variables can be found using linear equations. The result is the 16 solutions expected for the 6R case. The same technique is also applicable to manipulators with prismatic joints. We present the solution technique for all six possible 5R,P manipulators through numerical examples. The primary distinction between the technique presented in this paper and recently published Raghavan and Roth (90a,b.c) solution is that they removed two known spurious imaginary roots of multiplicity four to obtain a 16th order polynomial for 6R and 5R,P cases. In our formulation, the 16th degree polynomial can be derived directly without having to remove any spurious imaginary roots. Another distinction is that the solution procedure presented in this paper can be reduced to an eigenvalue problem. This results in significant gains in computation time.
Kinematic Singularities of Free-Floating Open-Chain Planar Manipulators
Authors: Agrawal Sunil Kumar , Rambhaskar J. 
Published: March 2021

Abstract
This paper deals with Jacobian singularities of free-floating open-chain planar manipulators. The problem, in essence, is to find the joint angles where the Jacobian mapping between the end-effector rates and the joint rates is singular. In the absence of external forces and couples, for free-floating manipulators, the linear and angular momentum are conserved. This makes the singular configurations of free-floating manipulators different from structurally similar fixed-base manipulators. In order to illustrate this idea, we present a systematic method to obtain the singular solutions of a free-floating series-chain planar manipulator with revolute joints. We show that the singular configurations are solutions of simultaneous polynomial equations in the half-tangent of the joint variables. From the structure of these polynomial equations, we estimate the upper bound on the number of singularities of free-floating planar manipulators and compare these with analogous results for structurally similar fixed-base manipulators.
Nonparametric Object Recognition With a New Tactile Sensor
Authors: Unsal S. , Shirkhodaie A. , Soni A. H. 
Published: March 2021

Abstract
Adding sensing capability to a robot provides the robot with intelligent perception capability and flexibility of decision making. To perform intelligent tasks, robots are highly required to perceive their operating environment, and react accordingly. With this regard, tactile sensors offer to extend the scope of intelligence of a robot for performing tasks which require object touching, recognition, and manipulation.
This paper presents the design of an inexpensive pneumatic binary-array tactile sensor for such robotic applications. The paper describes some of the techniques implemented for object recognition from binary sensory information. Furthermore, it details the development of software and hardware which facilitate the sensor to provide useful information to a robot so that the robot perceives its operating environment during manipulation of objects.
Generation of Surface Models of 3D Objects From Their Wire-Frame Models
Authors: Gupta S. , Shirkhodaie A. , Soni A. H. 
Published: March 2021

Abstract
This paper presents an algorithm to generate surface models of 3D objects from their wire-frame models. The algorithm firstly, obtains information about edges of the object from the wire-frame model of the object and uses this edge information to generate the pairs. A pair of an object is a combination of two non-collinear edges which have a common vertex. The algorithm then determines the unique plane passing through each pair and groups the coplanar pairs together. Then it sorts each of the groups of coplanar pairs to form one or more loops of edges. Finally for each group of coplanar pairs, all the loops are combined, using a few rules, to form faces of the object. Hence a surface model of the object is generated.
Breaching a Contract Versus Searching for a Job While Employed: Ethical Dilemmas Faced by Coaches and Administrators When Deciding About a Mid-Season Change in Leadership
Authors: Smith Allison , Gioseffi Yan , Graham Jeffrey 
Published: March 2021

The Pointers are a soccer team that play in Division A of the Demolition League. The president of the Pointers is Fernando Garcia, and the head coach is Guille Muller. The league has a poor culture of firing coaches throughout the season. With only a couple of games left in the season, the Pointers are going through a losing streak, and there are rumors Muller may be fired if the team does not win their next game. Simultaneously, Muller is receiving coaching offers from other teams within the league. The ethical dilemma surrounding this case refers to two scenarios (a) whether it is ethical for the president to negotiate with another coach while there is still one employed and (b) whether it is ethical for a coach to negotiate with another club while employed. Drawing from research in sport management, this case focuses on three ethical theories to create discussion surrounding the scenario: Utilitarianism, Deontology, and Virtue Ethics. Undergraduate and graduate students in sport management, human resources, and those who seek to be in a leadership position will have the opportunity to understand, analyze, and discuss these three theories and apply them to real-life scenarios, such as hiring and firing employees.
Physiological and Perceptual Recovery-Stress Responses to an Elite Netball Tournament
Authors: Russell Suzanna , Simpson Marni J. , Evans Angus G. , Coulter Tristan J. , Kelly Vincent G. 
Published: March 2021

Purpose: To investigate and explore the relationships between physiological and perceptual recovery and stress responses to elite netball tournament workloads. Methods: Nine elite female netballers were observed across a 3-day (T1–3), 4-match tournament. Participants provided salivary samples for cortisol and alpha-amylase analysis, completed the Short Recovery Stress Scale (SRSS), and reported session ratings of perceived exertion. Inertial measurement units and heart-rate monitors determined player load, changes of direction (COD), summated heart-rate zones, and jumps. Results: Analysis revealed 6 significant SRSS time effects: (1) decreased recovery markers of physical performance (P = .042), emotional balance (P = .034), and overall recovery (P = .001) and (2) increased perceptual stress markers of muscular stress (P = .001), negative emotional state (P = .026), and overall stress (P = .010). Salivary cortisol decreased over the tournament (T1–3) before progressively increasing posttournament with greater salivary samples for cortisol on T+2 compared with T3 (P = .014, ES = −1.29; −2.24 to −0.22]) and T+1 (P = .031, ES = −1.54; −2.51 to −0.42). SRSS overall recovery moderately negatively correlated with COD (r = −.41, P = .028) and session ratings of perceived exertion (r = −.40, P = .034). Cumulative workload did not relate to posttournament perceptual or salivary responses. Percentage change in salivary variables related (P < .05) to total player load, total COD, and overall recovery across specific cumulative time periods. Conclusions: During and after an elite netball tournament, athletes indicated increased perceptual stress and lack of recovery. The SRSS is a valuable tool for recovery–stress monitoring in elite tournament netball. It is recommended that practitioners monitor COD due to its negative influence on perceived overall recovery.
Load-matched acute and chronic exercise induce changes in mitochondrial biogenesis and metabolic markers
Authors: Rodrigues Natália Almeida , Gobatto Claudio Alexandre , Forte Lucas Dantas Maia , Sousa Filipe Antônio de Barros , Torsoni Adriana Souza , Fante Thais de , Manchado-Gobatto Fúlvia Barros 
Published: March 2021

We investigated the effects of acute and chronic exercise, prescribed in different intensity zones, but with total load-matched on mitochondrial markers (cytochrome C oxidase subunit IV (COX-IV), mitochondrial transcription factor A (Tfam), and citrate synthase (CS) activity in skeletal muscles, heart, and liver), glycogen stores, aerobic capacity, and anaerobic index in swimming rats. For this, 2 experimental designs were performed (acute and chronic efforts). Load-matched exercises were prescribed below, above, and on the anaerobic threshold (AnT), determined by the lactate minimum test. In chronic programs, 2 training prescription strategies were assessed (monotonous and linear periodized model). Results show changes in glycogen stores but no modification in the COX-IV and Tfam contents after acute exercises. In the chronic protocols, COX-IV and Tfam proteins and CS adaptations were intensity- and tissue-dependent. Monotonous training promoted better adaptations than the periodized model. Training at 80% of the AnT improved both performance variables, emphasizing the anaerobic index, concomitant to CS and COX-IV improvement (soleus muscle). The aerobic capacity and CS activity (gastrocnemius) were increased after 120% AnT training. In conclusion, acute exercise protocol did not promote responses in mitochondrial target proteins. An intensity and tissue dependence were reported in the chronic protocols, highlighting training at 80 and 120% of the AnT. Novelty: Load-matched acute exercise did not enhance COX-IV and Tfam contents in skeletal muscles, heart, and liver. In chronic exercise, COX-IV, Tfam, and CS activity adaptations were intensity- and tissue-dependent. Monotonous training was more efficient than the periodized linear model in adaptations of target proteins and enzymatic activity.