bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinematic Evaluation of Robots for Assembly Tasks
Authors: Zussman Eyal , Shoham Moshe , Lenz Ehud 
Published: March 2021

Abstract
An automatic assembly planning program should be able to analyze the assembly kinematic constraints, generate possible motions and select the appropriate assembly machines. This paper develops an approach for evaluating a robot for assembly tasks and planning its motions. The kinematical characteristics of both the robot and the assembly tasks are described by infinitesimal screws. The possible motions of the assembled parts are represented by convex cone of screws derived from the geometrical constraints. The robot’s possible motions are represented by the Jacobian cone, which is a modification of the Jacobian matrix that provides a common mathematical basis for convex cones operations. The selection procedure of the robot is based on the intersection of its cone with the assembly cones which results in feasible assembly directions for the robot. Choosing the optimal assembly direction and the robot posture is obtained by minimizing a cost function subjected to the constraints of both the robot and the assembly. Several given examples demonstrate the evaluation procedure and the planning approach.
On the Direct Kinematics of General Spherical Three-Degree-of-Freedom Parallel Manipulators
Authors: Gosselin Clément M. , Sefrioui Jaouad , Richard Marc J. 
Published: March 2021

Abstract
In this paper, the direct kinematics of general spherical parallel three-degree-of-freedom manipulators is investigated. A polynomial of degree 8 is obtained to describe this problem and it is shown that this polynomial is minimal since 8 real solutions corresponding to actual configurations have been found for a given set of actuator coordinates and a given architecture. This result completes the study on the direct kinematics of spherical three-degre-of-freedom parallel manipulators undertaken by the authors in a previous paper. An example of an architecture and a set of actuator coordinates which lead to 8 real solutions is presented to illustrate the results.
Direct Kinematics of General Stewart Platforms
Authors: Dhingra Anoop , Kohli Dilip , Xu Yong-Xian 
Published: March 2021

Abstract
A formulation for solving the direct kinematics of the general Stewart platform consisting of six moving and six grounded spheric joints is presented. The homotopy method is used for solving the direct kinematics of the platform, and it is shown that there exist a maximum of 40 possible solutions to the direct kinematics problem. These 40 solutions can be obtained by tracking only 64 homotopy paths. It is also shown that there are a maximum of 24 solutions for the Stewart platform with four spheric joints, and there exist a maximum of 16 solutions to the direct kinematics of the Stewart platform with three moving and three grounded spheric joints thus confirming the correctness of 24th and 16th degree direct kinematics polynomials obtained by other researchers.
A Coulomb Friction Model for Spherical Joints
Authors: Gutkowski L. J. , Kinzel G. L. 
Published: March 2021

Abstract
A method is presented to develop the “force-constraint” equations enforced by a spherical joint with Coulomb friction. The spherical joint is assumed to behave instantaneously as a revolute joint. This instantaneous revolute will have an axis along the instant screw axis between the two links connected by the joint. The effective radius of the instantaneous revolute will be a function of joint loading and the coefficient of friction.
Design and Fabrication of Microelectromechanical Systems
Authors: Ananthasuresh G. K. , Kota Sridhar , Crary Selden B. , Wise Kensall D. 
Published: March 2021

Abstract
An attempt has been made to summarize some of the important developments in the emerging technology of microelectromechanical systems (MEMS) from the mechanical engineering perspective. In the micro domain, design and fabrication issues are very much different from those of the macro world. The reason for this is twofold. First, the limitations of the micromachining techniques give way to new exigencies that are nonexistent in the macromachinery. One such difficulty is the virtual loss of the third dimension, since most of the microstructures are fabricated by integrated circuit based micromachining techniques that are predominantly planar. Second, the batch-produced micro structures that require no further assembly, offer significant economical advantage over their macro counterparts. Furthermore, electronic circuits and sensors can be integrated with micromechanical structures. In order to best utilize these features, it becomes necessary to establish new concepts for the design of MEMS. A set of key joints and mechanisms using which majority of the mechanical devices can be built, is identified. It is surmised that such an effort will be advantageous in designing micromechanisms as they form the basis for what we call fabrication building blocks (joints) and synthetic building blocks (mechanisms). The paper also reviews some of the fabrication techniques and the micromechanical devices that have already been made, and makes suggestions regarding the fabrication of a few generic mechanisms that can be made using these techniques. In particular, it discusses the fabrication of a motor-driven four-bar linkage using the “boron-doped bulk-silicon dissolved-wafer process” developed at The University of Michigan’s Center for Integrated Sensors and Circuits.
A Singularity Avoiding Kinematic Solution for a Four-Jointed Robot Wrist Using Heuristic Algorithm
Authors: Lee Wei-Ming 
Published: March 2021

Abstract
In this paper, a heuristic, singularity avoiding, trajectory generation algorithm is developed to solve the singularity problem of a four-jointed robot wrist. Starting from the inverse velocity solutions, a reduced Jacobian matrix is composed to map the system between the joint space and workspace. Six linear combinations of the joint rates are constructed to be used as a family of constraint functions. The forecasting function is very important in the whole algorithm. It is necessary to know in advance if the system is going into or near a singular configuration. The algorithm will determine through forecasting whether to switch from the current constraint function to another which possesses the smallest maximum joint velocity during the forecasting time interval. Trajectories which partially cover the wrist workspace are generated to prove singularity avoidance. The numerical result is shown in the maximum of the min-max joint velocity in different time intervals. It is indicated that the forecasting time interval will effect the singularity avoidance.
Workspace Evaluation of Stewart Platforms
Authors: Masory Oren , Wang Jian 
Published: March 2021

Abstract
The workspace and the dexterity of a Stewart Platform are effected by the choice of its major dimensions, actuators’ stroke and the kinematic constraints of its joints. An investigation of the effects of these parameters on workspace volume of the platform is presented. The obtained results were normalized so that these can be used as a design tool for the selection of dimensions, joints and actuators.
Structural Parameters Which Reduce the Number of Manipulator Configurations
Authors: Mavroidis Constantinos , Roth Bernard 
Published: March 2021

Abstract
The inverse kinematics of series-chain, six-degree-of-freedom manipulators has been developed to the point where it yields all possible configurations for a given end-effector position and orientation. In this paper we use the methods of inverse kinematics to uncover the conditions on the structural parameters which cause a manipulator to yield a lower maximum number of configurations than its general class. It is shown that the following conditions can cause a diminution In the maximum number of possible configurations: parallel joint axes, perpendicular joint axes, intersecting joint axes, and Bennett geometries. Using these geometries in 6R, 5R1P, 4R2P and 3R3P chains, this paper determines the reduction in degree of their characteristic polynomials.
Extrinsic Calibration of Portable Manipulators
Authors: Shooter Steven B. , Reinholtz Charles F. 
Published: March 2021

Abstract
Portable manipulators are installed for operation and then removed upon completion of their task. Typical applications of portable manipulators include the inspection of nuclear reactors, inspection and repair of nuclear steam generators and asbestos removal in buildings. In such operations, it is difficult to precisely position the manipulator at a fixed location within its workplace, yet this is critical for accurate tool positioning. It can be possible, however, to position the tool tip at several points in the environment using video feedback and manual operator control of the manipulator. This provides sufficient information to determine the position and orientation of the manipulator base frame with respect to the environment, hereafter referred to as extrinsic calibration. Following extrinsic calibration, subsequent moves of the manipulator can be automated. This paper describes a closed-form method for performing extrinsic calibration by contacting the tool to a total of six places on three orthogonal plane surfaces of reference.
Mechanical Design and Kinematic Analysis of a Three-Legged Six Degree-of-Freedom Parallel Manipulator
Authors: Zlatanov D. , Dai M. Q. , Fenton R. G. , Benhabib B. 
Published: March 2021

Abstract
In this paper a three-legged 6-dof platform-type parallel manipulator is described. Each of the legs is a serial subchain with three revolute joints connected to the output platform via a spherical joint. Due to the proposed asymmetrical 3-2-1 distribution of the controlled joints, a closed-form solution exists to the forward kinematics problem. The mechanical design of the manipulator has been developed. The forward and inverse kinematics as well as the instantaneous kinematics of the mechanism have been solved analytically.
Walking Machine Design Based on Certain Aspects of Insect Leg Design
Authors: Fichter E. F. , Kerr D. R. 
Published: March 2021

Abstract
A walking machine design originating from observations of insects is presented. The primary concept derived from insects is a leg used to apply force to the body without applying significant moments about the point of body attachment. This is accomplished with legs which have kinematic equivalents to ball-and-socket joints at body attachment and ground contact, with joints in the middle which only change distance between body and ground. Standing and walking with 6 legs of this design requires careful attention to static equilibrium equations but does not necessitate a control system which actively distributes forces to the legs. This paper considers necessary observational data, assumptions on which control is based, mathematical development for control and problems such as foot slip.
A Complex Number Approach for Absolute Precision Position Synthesis for Three Precision Positions
Authors: Mirth John A. 
Published: March 2021

Abstract
Dyads can be synthesized by prescribing the precision point coordinates and the absolute planar orientations of one dyad vector at each of three precision positions. This differs from traditional complex number methods wherein the vector orientations are described relative to one another. Absolute precision position synthesis can be performed for both motion generation, and path generation with prescribed timing. The method presented uses vector loop equations and complex number notation to produce a closed form solution for the three absolute precision position problem. Absolute precision position synthesis is applicable to cases that require specific coupler geometries. The synthesis of flat-folding mechanisms is an example of one such application.
A Dyad Search Algorithm for Solving Planar Linkages Using the Dyad Method
Authors: Romdhane Lofti 
Published: March 2021

Abstract
Based on graph representation of planar linkages, a new algorithm was developed to identify the different dyads of a mechanism. A dyad or class II group, is composed of two binary links connected by either a revolute (1) or a slider (0) pair with provision for attachment to other links by lower pair connectors located at the end of each link. There are five types of dyads: the D111, D101, D011, D001, and D010. The dyad analysis of a mechanism is predicated on the ability to construct the system from one or more of the five binary structure groups or class II groups. If the mechanism is complicated and several dyads are involved, the task of identifying these dyads by inspection could be difficult and time consuming for the user. This algorithm allows a complete automation of this task. This algorithm is based on the Dijkstra’s algorithm, for finding the shortest path in a graph, and it is used to develop a computer program, called KAMEL: Kinematic Analysis of MEchanical Linkages, and implemented on an IBM-PC PS/2 model 80. When compared to algorithmic methods, like the Newton-Raphson, the dyad method proved to be a very efficient one and requires as little as one tenth of the time needed by the method using Newton-Raphson algorithm. Moreover, the dyad method yields the exact solution of the position analysis and no initial estimates are needed to start the analysis. This method is also insensitive to the value of the step-size crank rotation, therefore, allowing a very accurate and fast solution of the mechanism at any position of the input link.
Joint Rotation Space of Five-Bar Linkages
Authors: Ting Kwun-Lon , Shyu J. H. 
Published: March 2021

Abstract
Unlike single degree of freedom linkages, the rotatability at a joint of a five-bar linkage is affected by the rotatability at another joint. Unless the linkage has full rotatability, the allowable inputs of a five-bar linkage are related. This article, by taking the interrelationship between the rotatability of two input angles into consideration, presents the most extensive study on the rotatability of five-bar linkages. The joint rotation space of a five-bar linkage is the region between the singular curves which represent the relationship between the input angular positions of the linkage at singular positions. By distinguishing five-bar linkages into C-C (crank-crank), C-R (crank-rocker), and R-R (rocker-rocker) types, there are totally nine C-C types, four C-R types and four R-R types of joint rotation space in classes I and II five-bar linkages. The results in this paper are essential for understanding the basic mobility and limitation of five-bar linkages. One may also find them useful in manipulators or multi-loop linkages which have a five-bar chain as the major or minor structure. The results are also applicable to spherical five-bar linkages.
Synthesis of Mechanisms Including Circuit Defects, Branch Defects and Input-Crank Rotatability
Authors: Cheng Jyun-Cheng , Kohli Dilip 
Published: March 2021

Abstract
In this paper, an analytical method is developed for synthesizing linkages (with a quadratic input-output equation) which are free from circuit and branch defects and, in addition, may be required to have fully rotatable cranks. A novel concept called the range defect of the input link is introduced. It is shown that the range defect results in a circuit defect. Further, all circuit defects except those introduced as a result of range defects can be eliminated by eliminating branch defects. The circuit defect introduced by the range defect is eliminated by first eliminating the range defect and then eliminating the branch defect. Inequalities are developed as a function of mechanism design variables which represent the existence of range defects and therefore a possible circuit defect. The circuit defect identifiers are then developed and used in the synthesis of function generating planar four-bar and spatial RSSR linkages. The method developed is general and is applicable to any mechanism with a quadratic input-output equation such as RSSP, spherical 4-bar and 4R3P linkages.
Identification of Flexible Link Dynamics Using Neural Networks
Authors: D’Arcangelis Lawrence , Nair Satish S. 
Published: March 2021

Abstract
Multilayered neural networks have found widespread use in the identification and control of dynamic systems. This study considers modeling issues for two time scale systems using neural networks for reliably estimating gradients for on-line control purposes. A structure for identification of a single link flexible arm is proposed and preliminary results are presented.
Mechanisms of the Ancient Greek Theater
Authors: Dimarogonas Andrew D. 
Published: March 2021

Abstract
The word Mechanism is a derivative of the Greek word mechane (which meant machine, more precisely, machine element) meaning an assemblage of machines. While it was used for the first time by Homer in the Iliad to describe the political manipulation, it was used with its modern meaning first in Aeschylos times to describe the stage machine used to bring the gods or the heroes of the tragedy on stage, known with the Latin term Deus ex machina. At the same time, the word mechanopoios, meaning the machine maker or engineer, was introduced for the man who designed, built and operated the mechane.
None of these machines, made of perishable materials, is extant. However, there are numerous references to such machines in extant tragedies or comedies and vase paintings from which they can be reconstructed: They were large mechanisms consisting of beams, wheels and ropes which could raise weights up-to one ton and, in some cases, move them back-and-forth violently to depict space travel, when the play demanded it. The vertical dimensions were over 4 m while the horizontal travel could be more than 8 m.
They were well-balanced and they could be operated, with some exaggeration perhaps, by the finger of the engineer. There is indirect information about the timing of these mechanisms. During the loading and the motion there were specific lines of the chorus, from which we can infer the duration of the respective operation.
The reconstructed mechane is a spatial three- or four-bar linkage designed for path generation.
The Synthesis of Cam-Oscillating Roller-Follower Mechanisms: A Unified Approach
Authors: González-Palacios Max Antonio , Angeles Jorge 
Published: March 2021

Abstract
A unified approach to the synthesis of the contact surface of cam-oscillating roller-follower mechanisms is presented. This is achieved using dual numbers. The surfaces of both cam and roller are obtained so that, at their contact line, a minimum-magnitude sliding velocity is produced. The differential geometry of the pitch surface and the pressure angle are both analyzed.
Multiloop Spatial Kinematic Analysis Based on the Joint Displacement Method
Authors: Yang Yu-Neng , Chieng Wei-Hua , Hoeltzel David A. 
Published: March 2021

Abstract
To accelerate the design automation process for the spatial mechanism design, this paper presents an efficient kinematic analysis method, called the joint displacement method. Based on this method, the kinematic analysis for a seven-link, two-loop spatial RSCC-SRR mechanism can be accomplished in 1.52 second on a PC/486-based computer for a complete 60-steps (6 degrees/step) crank-revolution. This method is applicable for both single-loop and multiloop spatial mechanisms with revolute, cylindrical, translational, spherical and universal joints, with the high computational efficiency which hasn’t been found in the literatures. The general purpose computer program coded in C language has been tested with a wide variety of mechanisms, which produces very satisfactory results.
A Dynamic Implementation of Keller’s Sketching Rules for Burmester Curves an Approach to Sensitivity Analysis
Authors: Nisbett J. Keith , Gupta Sanjay K. 
Published: March 2021

Abstract
Keller’s sketching rules for Burmester curves are implemented on the computer for automatic generation of valid and invalid regions for the existence of the curves. The rules are based on the poles of the coupler motion, which in turn are directly related to the precision positions. All six possible unique arrangements of poles are used in the sketching rules. The sketching rules provide a useful heuristic and geometric approach to relating the sensitivity of the curves to small changes in the pole locations. The regions and the curves are dynamically updated as the poles of the specified motion are moved by the user. The new curve obtained is checked to verify satisfaction of original tolerance specification on the precision positions. The procedure shows promise for artificially intelligent approaches to linkage design.
Kinematic Transformation Matrices for 3D Surface Contact Joints
Authors: Gutkowski L. J. , Kinzel Gary L. 
Published: March 2021

Abstract
A generalized procedure is presented for the development of a pair matrix that describes kinematic joints formed by contact between three-dimensional surfaces. The pair matrix is useful in the matrix-based kinematic analysis procedure put forth by Sheth and Uicker (1971) previously. Any two surfaces may make up the joint as long as the surfaces can be described parametrically, and contact takes place at one point. The corresponding pair matrix is a function of five pair variables.
The Optimal Design of Mechanisms Employing a Synthesis Based Merit Function
Authors: Gold Christian H. , Derby Stephen J. 
Published: March 2021

Abstract
A method of implementing three-precision point synthesis into the merit function of kinematic optimization problems was developed. The addition of synthesis reduced the order of the merit function from eight to four. The new merit function was tested on three optimization methods and compared to the standard non-synthesis optimization merit function. It was discovered that the performance of the new synthesis merit function depended heavily upon which of the three precision points were selected for use in the synthesis calculations. Subsequently, a method of pre-optimization selection of synthesis points was developed. It was found that when a favorable selection method was employed, the synthesis based merit function performed well, optimizing to a comparable merit function value in about 50 percent fewer function evaluations.
Errors in Constant-Velocity Shaft Couplings
Authors: Fischer Ian S. , Remington Philip M. 
Published: March 2021

Abstract
Shaft couplings with an odd number of joints are modeled with rotation matrices such that the transmission plane in which the axis of the central joint moves can be arbitrarily specified. It is shown that when the transmission plane coincides with the homokinetic plane, the mechanism functions as a constant velocity coupling, otherwise it does not. The cyclic variation in output speed, which occurs when the constant-velocity criteria is not met, is quantified and the results enable the design engineer to predict performance of constant-velocity couplings when deviation from ideal geometry occur because of manufacturing and installation tolerances or wear.