bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Placement of Serial Manipulators
Authors: Abdel-Malek Karim , Yu Wei 
Published: December 2020

Abstract
Criteria and implementation for the placement robot manipulators with the objective to reach specified target points are herein addressed. Placement of a serial manipulator in a working environment is characterized by defining the position and orientation of the manipulator’s base with respect to a fixed reference frame. The problem has become of importance in both the medical and manufacturing fields, where a robot arm must be appropriately placed with respect to targets that cannot be moved. A broadly applicable numerical formulation is presented. While other methods have used inverse kinematics solutions in their formulation for defining a locality for the manipulator base, this type of solution is difficult to implement because of the inherent complexities in determining al inverse kinematic solutions. The approach taken in this work is based on characterizing the placement forcing a cost function to impel the workspace envelope in terms of surface patches towards the target points and subject to functionality constraints, but that does not require the computation of inverse kinematics. The formulation and experimental code are demonstrated using a number of examples.
Design and Analysis of a Four-Degree-of-Freedom Hybrid Spherical Scanning Apparatus
Authors: Chen Chuanqi , Li Perry Y. , Erdman Arthur G. 
Published: December 2020

Abstract
The design of a novel scanning apparatus used for digitizing dental impression molds is presented. The apparatus consists of a four-degree-of-freedom hybrid spherical linkage capable of moving the dental mold relative to a laser scanner along a curved path in the specified orientations. Since closed form inverse kinematics solutions are not available for the multiple degree-of-freedom spatial mechanism in question, symbolic and numerical computation techniques are used extensively for kinematics analysis, dimension design, and optimization. In addition, mechanical design and simulation software (Pro/Engineer & Pro/Mechanica), as well as the rapid prototyping machines are used to reduce the development cost and cycle time.
Design of the Stackbot™ Cam Track Palletizer/Material Handling Device
Authors: Derby Stephen , Kirchner Ned 
Published: December 2020

Abstract
A novel palletizing/material handling device has been created. This novel design (US patent applied for) was developed by assessing the needs of many industrial companies. This device trades the unlimited flexibility and position addressability of standard servo driven robots and material handling machines for a limited set of palletizing locations, by use of a multi track cam plate. The resulting combinations of reduced complexity degrees of freedom result in a less expensive and more marketable product.
PennSyn: A Topology Synthesis Software for Compliant Mechanisms
Authors: Saxena A. , Wang X. , Ananthasuresh G. K. 
Published: December 2020

Abstract
In this paper, we present PennSyn, a software with graphical user interface that provides an automated design route from function specifications to fabrication of fully compliant mechanisms. PennSyn uses the notion of maximizing the flexibility and stiffness of a continuum simultaneously through multi-criteria objectives for the topology synthesis of compliant mechanisms. Both the optimality criteria and quasi Newton mathematical programming methods are employed as optimization algorithms in PennSyn. Reliability in the optimality criteria method is ensured using a one variable search while the volume constraint is addressed by global resizing of variables without altering the function value locally. The design continuum is represented using ground structures of linear truss and frame finite elements. These element types are easy and robust in implementation and help provide effortless extraction and transfer of optimal topologies into commercial CAD packages. An edge detection algorithm is used with PennSyn for boundary extraction of optimal compliant geometries. The resulting data is stored in IGES format for easy portability into commercial modeling and analysis software packages.
Multiple-Segment-Pseudo-Rigid-Body Model Concept in Compliant Mechanism Design and Analysis
Authors: Mettlach Gregory A. , Midha Ashok 
Published: December 2020

Abstract
The concept of a pseudo-rigid-body model for a flexible member proven very instrumental in the design and analysis of compliant mechanisms. It provides a means by which a compliant mechanism may be modeled as an equivalent pseudo-rigid-body mechanism. This makes it possible for compliant mechanisms to be analyzed and designed using a wealth of existing methods for rigid-body mechanisms. Oftentimes, however, it is not possible to model a compliant member with a typical pseudo-rigid-body model. This may be due to a force or displacement boundary condition applied to a compliant member at a point other than the beam end. For situations such as these, a planar, multiple-segment pseudo-rigid-body model concept is introduced which allows arbitrary beam type compliant members, regardless of geometry, loading, or boundary conditions, to be modeled as an assemblage of rigid members with torsional springs at characteristic pivots. This methodology enables existing analysis and synthesis methods to be applied in the design of complex compliant mechanisms.
Gait Planning for Quadruped Turning
Authors: Ye Tina Y. , Song Shin-Min 
Published: December 2020

Abstract
Gait planning for turning is important to the control of legged locomotion. For practical reason, it is necessary for a quadruped to change its walking direction without slowing down or making a stop. In this paper, we formulate a gait planning which enables a quadruped walking in a straight line to change its gait to increase stability first, make a turn and finally recover to its original gait for straight-line walking. All of this is performed under a constant speed condition. The result shows that with some simple foot adjustments, the turning can be initiated at any foot lifting or placing event during a cycle.
Identifying the Pose Between a Head Mounted Display and a Head Pose Sensor
Authors: Reynolds Craig , Everett Louis J. , Volz Richard A. 
Published: December 2020

Abstract
Head mounted displays (HMDs) are common hardware in a virtual reality environment. Sensors are commonly installed on the helmet to provide information about where the operator is looking. If the operator rotates the helmet, the virtual scene should rotate correspondingly. If the point of rotation (POR) of the operator’s head differs from the POR used to transform the image, the display may behave in bizarre ways. In “enhanced reality” and similar applications the virtual scene must also accurately correspond to the real world. When the virtual scene must accurately correspond to a real scene, it becomes necessary to accurately match the virtual display to the real world. A method for automatically collecting data to align these scenes is described and demonstrated in this paper. A theoretical basis for the method and experimental data are presented. Results indicate that the underlying assumptions of the theory are reasonable and that the errors in the method are reasonable.
Dynamic Modeling and Analysis of a Two D.O.F. Mobile Manipulator
Authors: Naderi D. , Meghdari A. , Durali M. 
Published: December 2020

Abstract
This paper presents the kinematic and dynamic modeling of a two degrees of freedom manipulator attached to a vehicle with a two degrees of freedom suspension system. The vehicle is considered to move with a constant linear speed over an irregular ground-surface while the end-effector tracks a desired trajectory in a fixed reference frame. In addition, the effects of highly coupled dynamic interaction between the manipulator and vehicle (including the suspension system’s effects) have been studied. Finally, simulation results for the end-effector’s straight-line trajectory are presented to illustrate these effects.
Unstable Configurations and Redundant Actuation in Planar Mechanisms
Authors: Kohli D. , Pan C. A. , Dhingra A. K. 
Published: December 2020

Abstract
In an unstable configuration, a mechanism loses controllability and gains at least one unwanted degree of freedom (DOF) instantaneously. Based on the concept of direct kinematics singularity, we develop an analytical formulation to express unstable configurations of planar N-link mechanisms with single or multiple loops. The dependence of unstable configurations, on the choice of input links, is illustrated through a 7-link 2-DOF mechanism. The unstable configurations are derived for fifteen input link combinations, which are chosen from two different active inputs in six movable links. To gain mechanism controllability at unstable configurations, actuators at passive joints can be introduced. By changing inputs at the unstable configuration and actively actuating one of the passive joints, we gain controllability. It is shown that for a mechanism with F degrees of freedom and L independent closed-loops, the minimum number of actuators needed to fully control the mechanism is F + L.
FEM Model for the Tooth Root Bending Stress Analysis of Mating Helical Gears
Authors: Ambruosi Giancarlo , Bianco Giuseppe , Corte Orazio Della , Lang Claus-Hermann , Paradiso Domenico , Pierro Gennaro 
Published: December 2020

Abstract
The role of simulation in the engineering phase of the product is becoming increasingly important, due to the variety of analysis which can be performed in a shorter time and at reduced costs also identifying weak spots of a component or system, before volume parts have been produced.
An FEM model of mating cylindrical helical gears has been developed with the aim of evaluating tooth root bending stress during the engagement.
The accurate description of the tooth geometry was provided by an in-house developed software having a direct interface with the FEM pre-processor. This software simulates the manufacturing process, taking into account the geometry of manufacturing tools and the machining parameters. Tooth micro-geometry corrections have been included to better match the real geometry.
In the FEM model, the tooth mesh has been optimized in order to reduce the errors due to the domain discretization, in the numerical solution of the contact problem. A non-congruent mesh with special connectivity has been used to minimize the model size and therefore the computation time.
The model has been validated by experimental data. Static tests have been performed on innovative test apparatus. The test rig allows the measurement of tooth root bending strains of two mating helical gears engaged in a specified fixed mesh position.
Performance Rating and Optimization of Spur Gear Drives With Small Number of Teeth
Authors: Arikan M. A. Sahir 
Published: December 2020

Abstract
Performance rating of spur gear drives with small number of teeth is made and variations of contact ratio, circular tooth thicknesses at pinion and gear tooth tips, lengths of the pinion addendum and dedendum portions of the line of action, AGMA geometry factor J for the pinion and the gear and their ratio, and AGMA geometry factor I with addendum modification coefficient are determined. Thus, it is made possible to design gear drives with properties such as, maximum possible contact ratio, maximum length of the pinion addendum portion of the line of action, maximum length of the pinion dedendum portion of the line of action, equal AGMA geometry factors J for the pinion and the gear (i.e. equal pinion and gear tooth root stresses), and maximum AGMA geometry factor I (i.e. minimum tooth contact stress). Rack cutter tip fillet radius and rack cutter geometry are considered in the analysis, which are the basic factors that determine the gear tooth fillet profile.
A New Approach to Design Multi-Stage Gear Drives Using Simulated Annealing Algorithm
Authors: Chong Tae Hyong , Bae Inho 
Published: December 2020

Abstract
The research on the design of gear drives is mainly focused on dimensional design of single-stage gear drives. Recently, however, the need for designing multi-stage gear drives has been increased with more applications of the gear drives in high speed and small space. The design of multi-stage gear drives is a time-consuming process, because it includes some more complicated problems that are not needed to consider in the design of single-stage gear drives. The design problems include not only dimensional design but also configuration design; we have to determine number of reduction stages, to set gear ratios and to configure gear drive elements. There is no definite rule or principle for these types of design problems. Thus the design practices largely depend on the ‘sense’ and the experiences of the designer (mostly done by trial and error).
We propose a new and generalized design algorithm to support designer at the preliminary design phase of multi-stage gear drives, which integrates dimensional design and configuration design process. The proposed design algorithm consists of four steps. In the first step, the user determines number of reduction stages. In the second step, gear ratios of every stage are determined using random search method, and the ratios are used as the basic input for dimensional design of gears in the next step. The dimensions of gears are determined in the third step using generate and test method. The strength and durability of each gear is guaranteed by the bending strength and pitting resistance rating practices using AGMA rating formulas. In the final step, configuration design is carried out using simulated annealing algorithm; the positions of gears and shafts are determined to minimize the geometrical volume (size) of a gearbox while avoiding interferences between them. These steps are carried out iteratively until a desirable solution is acquired.
In order to validate the availability, the proposed design algorithm is applied to the preliminary design of 4-stage gear drives. The design solution shows considerably good results in both aspects of dimensional and configuration design.
Dynamic Behavior of Atmosphere in a Tooth Space of a Spur Gear During Mesh Process From the Viewpoint of Efficient Lubrication
Authors: Houjoh Haruo , Ohshima Shun-ichi , Miyata Shinji , Takimoto Takayuki , Maenami Kentaro 
Published: December 2020

Abstract
Lubrication of gear tooth is necessary for cooling as well as reducing friction losses. It is, however, difficult for rather high speed gear because both rotation of the gear itself and associated aero motion interferes the lubrication. In Addition lubrication consumes excess energy due to such kind of churning.
To realize efficient lubrication it is worthy to feed lubricant from both ends of tooth in axial direction by the aid of sucking action of tooth spaces just after meshing. This probably make possible that the oil can reach the tooth surface as earlier as possible.
Authors investigated the action of air due to pumping action of a spur gear pair by means of both pressure measurement and the hot wire anemometry at the bottom of tooth space to get fundamental data to asses the feasibility of the proposed way. It has been revealed that the behavior is mostly governed by geometric characteristics around the mesh area rather than operational speed, i.e., temporal response of the pressure and flow velocity is proportional to the speed of gear. It has been also found that pressure variation precedes the flow velocity. Sucking phenomena begins when the backlash space passes through the pitch point whereas the pressure is readily negative due to the mass inertia effect of air getting out of the tooth space.
Evaluation of Pitting Life of Carburized Gears Lubricated by ATF and Traction Oil
Authors: Yamanaka Masashi , Kishi Kazuhiko , Inoue Katsumi , Kato Masana , Masuyama Tomoya , Morikawa Kunihiko , Nagahara Mikio 
Published: December 2020

Abstract
This paper presents the result of fatigue tests carried out with an ATF and two types of traction oil. Since the performance of these oils as working fluid is preferred, the performance as a lubricant is inferior. The pitting life is evaluated by the value of D computed by the surface roughness and EHL film thickness. The high traction coefficient causes the tooth surface temperature rise by frictional heat, and then the oil film thickness and pitting life are decreased. To evaluate the performance of these oils as lubricants, the tooth surface temperature at the pitting tests is measured and the EHL film thickness is calculated with it for computing the value of D precisely. All results of fatigue test with three types of oils are examined together and it is found out that they are evaluated by the value of D only. The experimental formula to estimate the pitting life is obtained. This procedure is useful to design the surface gear strength of the automotive ATs and CVTs.
Fatigue Failure and Strength Evaluation of Traction Drive Rollers
Authors: Kato Masana , Deng Gang , Yamanaka Masashi , Yamamoto Ryoji , Ono Noboru , Inoue Katsumi 
Published: December 2020

Abstract
The surface fatigue failures of the traction drive rollers are different to that of gears and bearings because of the high traction force, skew and small slip ratio. In this research, fatigue tests of traction rollers were performed in different slip ratios and skew angles. The effects of running conditions on the fatigue lives of traction drive rollers are clarified and explained based on the surface crack growth and wear situations. Although a higher slip ratio will make a lower fatigue life, the fatigue strength will increase inversley under the skew conditions, because of the differences in mechanical and tribological condition for surface crack growth and the severe surface wear, which diminishes the surface crack length. For evaluation of the effects of such as slip ratio and skew on the fatigue strength of traction rollers, a new method is put forward in which the relationship between the surface temperature index and fatigue life is used instead of S-N curve.
Estimating the Endurance Limit of 9310, 4340M, and 4360 Steel Gears
Authors: Wern Chien , Zareh Hormoz , Carter Matt , Jones Kelly , Renzelmann Mike 
Published: December 2020

Abstract
Single tooth bending fatigue behavior of three gear alloys, namely carburized 9310, induction hardened 4340M and 4360 alloys were examined. The alloys were fabricated into gears having a module of 2.12 (12 diametral pitch) with 12.7 mm (1/2 inch) face width. As the gear geometry was different from that recommended in SAE Single Tooth Gear Bending Fatigue Test standard (SAE-J1619), a test fixture was designed to accommodate these gears. The fixture has the added feature of conjugate action, not found in the SAE test standard. The gears were slowly bent in the fixture to determine the yield load. Then fatigue loads of 85%, 75%, and 65% of yield load were used to determine the number of cycles to failure. The expected endurance limit for single tooth bending fatigue was determined statistically from the finite portion of the load-cycles to failure curve.
Impact Bending Fatigue Strength of Gear Teeth Case-Hardened by Nitriding and Carburizing
Authors: Maenosono Koji , Ishibashi Akira , Sonoda Keiji 
Published: December 2020

Abstract
Almost all gears used for power transmission of automobiles have been case-hardened by carburizing. Recently, strict demand for reducing running noise and vibration from the power transmission gears requires, in most cases, an additional finishing operation such as grinding and/or honing after carburizing. Nitriding is conducted at a temperature of about 820 K which is lower than the transformation temperature, and thus quenching is not required, resulting in smaller heat treatment deterioration. However, nitrided gears hardly used in practice as for power transmission gears.
In the present investigation, experiments were conducted, using test gears case-hardened by two different methods, carburizing and plasma-nitriding. Test results showed that the fatigue strength of carburized gears was higher than that of nitrided gears in most cases when the test gears were made from the same steel. However, the impact fatigue strengths of nitrided gears made from a high tension steel with additional alloy elements Mo and V were higher than those of carburized gears made from the carbon and alloy steels which have been, used as for gear material. The other high tension steel containing neither Mo nor V could not bring about a sufficiently high fatigue strength in comparison with the conventional carburized gears. It should be noted that the impact fatigue strength of carburized gears made from the high tension steel was higher than the ones made of conventional carburizing steel.
Evaluation of Bending Strength of Carburized Gears Based on a Quantification of Defect Size in the Surface Layer
Authors: Masuyama Tomoya , Kato Masana , Inoue Katsumi , Yamashita Toshihiko 
Published: December 2020

Abstract
The fatigue strength of steel is generally proportional to the hardness up to a certain point. However, the relationship of hardness to fatigue strength is more complicated for the case of high strength material, mainly because the defects in the material sensitively reduce the strength. This paper presents a determination of the defect size in carburized gear teeth and a method of strength evaluation based on this size.
A micro notch is artificially processed at the fillet of carburized gear tooth by means of Focused Ion Beam, and the bending fatigue test is performed. The threshold notch depth αn th, which is the limit not to reduce the fatigue strength, is obtained by the test. The threshold notch depth is used as a measure to determine the size of latent defects in the surface layer. The αn th of the gears of which non-martensitic layer is removed by electro-polishing is shorter than the above one.
The surface layer is observed by using scanning electron microscope and electron probe micro analyzer to clarify the characteristics of latent defects. Many micro cracks besides a long crack in the nonmartensitic layer, Cr oxides and Mn oxides near the surface, and Si segregated in grain boundary are observed. This shows they trigger the initiation of fatigue crack, and therefore, the defect size limits the strength. Consequently, the strength is expressed by an experimental formula of vickers hardness and square root of the projected area of the defect obtained above.
Effect of Setting Errors on Manufactured Surfaces of Spiral Bevel Gear and Pinion
Authors: Shunmugam M. S. , Rao B. Subba 
Published: December 2020

Abstract
Settings for generation of spiral bevel gear and pinion are determined in such a manner that the conjugate action in the gear pair is improved during their meshing. Any error in these settings would result in a deviation from the desired surface. Therefore, it is important to identify the critical settings and exercise greater care in their settings. In the present work, simulation of the generation process is carried out and the surfaces obtained are represented with reference to an idealized surface namely the involute spiraloid, established from first principle. The deviations of the surface resulting from the changes in the setting are also presented conveniently as normal deviations. From these results, the critical setting values are identified and are reported in this paper.