bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanics of Roller Chain-Sprocket Contact: A General Modelling Stragegy
Authors: Kim Mahn Shik , Johnson Glen E. 
Published: March 2021

Abstract
An extensive analysis of the contact phenomenon occuring between a roller chain and sprocket was given by Binder in 1956. Naji and Marshek complemented Binder’s work by presenting a theoretical and experimental investigation of the contact phenomenon under quasi-static conditions during the early 1980’s. The problem is very complex, and significantly complicated due to the non-trivial geometry of the sprocket tooth, manufacturing tolerances, and changes in clearances between components due to wear. Accordingly, several simplifying assumptions were necessary in the previous investigations.
In this paper, a more detailed model of the quasi-static contact phenomenon is developed from first principles. The new model includes the external loading conditions, the curvature difference between the roller and the seating curve, the net error in the chain pitch (defined as the error in the chain pitch minus the error in the sprocket pitch), and Coulomb friction between the tooth and roller, the roller and bushing, and the bushing and pin. No assumption regarding the pressure angle at each contact point is made — rather the pressure angle at each contact point is calculated during the solution. (This is a very significant difference between the present and previous analyses). An efficient strategy for the computation is outlined.
In a companion paper (“Mechanics of Roller Chain - Sprocket Contact: Observations About the Contact Phenomenon and Load Distribution” submitted for presentation at this conference), results generated by the new model are presented and discussed. A comparison with experimental data taken from the literature (Naji and Marshek, 1983) indicates that excellent quantitative prediction of load distribution is possible. Finally, practical observations about chain performance (including effects of manufacturing tolerance and wear, and guidelines for incorporation of idler sprockets) are presented.
Optimization in a Design System for Complex Products
Authors: Malmqvist Johan 
Published: March 2021

Abstract
This paper describes a system for parametric design and optimization of complex products. In the system, the use of knowledge-based and mathematical programming methods is combined. The motivation is that while knowledge-based methods are well suited for modeling products, they are insufficient when dealing with design problems that can be given an optimization formulation. This weakness was approached by including the information necessary for stating an optimization problem in the product models. A system optimization method can then be applied. The system also performs sensitivity analysis and has an interactive optimization module.
The use of the system is illustrated by an example; the design and optimization of a two-speed gearbox.
A Computational Investigation Into the Structure of Form and Size Errors Based on Machining Mechanics
Authors: Srinivasan R. S. , Wood Kristin L. 
Published: March 2021

Abstract
The central theme of this paper is the representation of tolerances in engineering design and manufacturing. A sub-problem of this central theme is the structure of form and size errors created by typical machining processes. This subproblem is addressed using a fractal-based procedure. In particular, workpiece profiles are generated for the shaping manufacturing process, using a simulation model and incorporating the basic shearing mechanism of machining with typical error sources. The resultant profiles are analyzed using a fractal-based, box counting algorithm. The results, which reveal the presence of variational structure, are discussed, emphasizing the relationship between total variability and function. Finally, modifications and future directions to the research are presented.
An Investigation Into Model Aggregation in Optimal Design
Authors: Hebert R. , Rao J. R. Jagannatha 
Published: March 2021

Abstract
In this article we examine the behavior of optimal design models when the parameters are progressively unfixed in a process referred to as model aggregation. While this is a common modeling practice, its consequences on solution properties are not always predictable. Using no special assumptions on problem data, we develop an upper bound result for the aggregation process and highlight the difficulties which arise when even a single parameter is unfixed. We also present a generalization of the commonly studied “portal frame” problem as a design case study. While aggregation has only benign effects on the solution of this model, interesting new results are obtained when model perturbations more severe than simple aggregation are imposed on this problem.
Optimal Design of an Overhead Crane Runway Girder
Authors: Rajagopalan Rajkumar , Trabia Mohamed B. 
Published: March 2021

Abstract
The objective of this paper is to minimize the manufacturing cost of an overhead crane runway girder. The work involves the minimization of the material cost of the girder, the welding cost, and the bolting cost. An I section was selected for the problem. The main constraint imposed on the problem is that stiffeners of any kind are not to be used. AISC design specifications are used to formulate the problem. Condition for separation of the optimization problem into two subproblems is presented.
Two-Level Nonlinear Mixed Discrete-Continuous Optimization-Based Design: An Application to Printed Circuit Board Assemblies
Authors: Praharaj S. , Azarm Shapour 
Published: March 2021

Abstract
In this paper, a new approach for optimization-based design of non-linearly mixed discrete-continuous problems has been developed. The approach is based on a two-level decomposition strategy in which the entire domain of variables is partitioned into two levels, one involving the continuous variables and the other involving the discrete variables. Variables in one level are optimized for fixed values of the variable from the other level. A modified penalty function is formed, based on monotonicity analysis, to solve for the discrete variables, and a conventional optimization method was used to solve for the continuous variables. To improve the computational effectiveness of the approach, a constrained derivative relationship was also adopted. The performance of the entire algorithm is then demonstrated through an example involving printed circuit board assemblies. The objective in the example is to maximize assembly reliability by: (1) adding redundant components to the boards and (2) optimally distributing allocated mass flow to the individual channels of the circuit boards. Number of variables in the example is then varied to investigate the effectiveness and potential of the approach for large-scale problems.
Second Order Design Sensitivity Analysis of Kinematically-Driven Mechanical Systems
Authors: Cao Qiushu , Krishnaswami Prakash 
Published: March 2021

Abstract
Second order design sensitivity information is required for several design applications, including second order optimization, minimum sensitivity design and reliability design. The problem of computing this information in a generalized manner becomes difficult when the dependence of system response on design is not explicitly known, as in the case of kinematic systems. This paper presents a general method for second order design sensitivity analysis of constrained mechanical systems. This method uses the constrained multi-element technique for kinematic analysis combined with a direct differentiation approach for obtaining first and second order design sensitivities of the system response. The method was implemented in a computer program on which several examples were solved. Three of the examples are presented in this papers. For each example, the second order sensitivities are checked against values obtained by finite differencing. In all cases, the agreement is seen to be very close, indicating that the proposed method is accurate and reliable.
Computation of Spatial Displacements From Redundant Geometric Features
Authors: Ge Q. J. , Ravani B. 
Published: March 2021

Abstract
This paper follows a previous one on the computation of spatial displacements (Ravani and Ge, 1992). The first paper dealt with the problem of computing spatial displacements from a minimum number of simple features of points, lines, planes, and their combinations. The present paper deals with the same problem using a redundant set of the simple geometric features. The problem for redundant information is formulated as a least squares problem which includes all simple features. A Clifford algebra is used to unify the handling of various feature information. An algorithm for determining the best orientation is developed which involves finding the eigenvector associated with the least eigenvalue of a 4 × 4 symmetric matrix. The best translation is found to be a rational cubic function of the best orientation. Special cases are discussed which yield the best orientation in closed form. In addition, simple algorithms are provided for automatic generation of body-fixed coordinate frames from various feature information. The results have applications in robot and world model calibration for off-line programming and computer vision.
A Solid Boundary Based Tolerance Representation Model
Authors: Liu S. , Dong Z. 
Published: March 2021

Abstract
An ambiguous representation of design geometry and its allowed variation is essential to design and manufacturing analysis tools using geometric modeling. In this paper, a new approach for modeling and representing mechanical tolerances, using information embedded in the solid model, is introduced. The work focuses on mathematical mapping between the nominal and variant configurations of design geometry, using boundary face-based model variables. The method identifies the relation between the errors of part geometry, represented by a solid model and measured using a coordinate measuring machine, and the tolerances, specified by dimensioning and tolerancing standards. The work is of benefit in understanding of the fundamental nature of geometric errors and tolerances; it guides the specification of dimensional and geometric tolerances; and, contributes to automated mechanical tolerancing in a solid modeling based system.
A 3-D Vision System Model for Automatic Object Surface Sensing
Authors: Theodoracatos Vassilios E. , Calkins Dale E. 
Published: March 2021

Abstract
The development of a “light striping” (structured light) based three-dimensional vision system for automatic surface sensing is presented. The three-dimensional world-point reconstruction process and system modeling methodology involves homogeneous coordinate transformations applied in two independent stages; the video imaging stage using three-dimensional perspective transformations, and the mechanical scanning stage, using three-dimensional affine transformations. Concatenation of the two independent matrix models leads to a robust four-by-four matrix system model. The independent treatment of the two-dimensional imaging process from the three-dimensional modeling process, has reduced the number of unknown internal and external geometrical parameters. The reconstructed sectional contours (light stripes) are automatically and in real-time registered with respect to a common world coordinate system in a format compatible with B-spline surface approximation. The reconstruction process is demonstrated by measuring the surface of a 19.5-ft long by 2 feet beam rowing shell. A detailed statistical accuracy and precision analysis shows an average error, 0.2 percent (0.002), of an object’s largest dimension within the the camera’s field-of-view. System sensitivity analysis reveals a nonlinear increase for angles between the normals of the image and laser planes higher than 45 degrees.
Boundary Surface Recovery From Skeleton Elements: Part II — Skeleton Surfaces
Authors: Gelston Sean M. , Dutta Debasish 
Published: March 2021

Abstract
Skeleton curves and surfaces have many applications in computer aided design and analysis and the construction of skeletons has been an active area of research. We consider the inverse problem that of recovering boundary surfaces from given skeleton elements. The skeleton of any 3D object will, in general, consist of curves and surfaces. Therefore, any boundary reconstruction algorithm must systematically process the surfaces generated by the skeletal curves and the skeletal surfaces. In a companion paper (Part I) we considered the reconstruction of boundaries corresponding to skeletal curves. In this paper (Part II) we consider the reconstruction of boundaries corresponding to skeletal elements that are surfaces. Implemented examples are also included.
Three Dimensional Robot Path Planning With Workspace Considerations
Authors: Liu C. Y. , Mayne R. W. 
Published: March 2021

Abstract
This paper considers the problem of robot path planning by optimization methods. It focuses on the use of recursive quadratic programming (RQP) for the optimization process and presents a formulation of the three dimensional path planning problem developed for compatibility with the RQP selling. An approach 10 distance-to-contact and interference calculations appropriate for RQP is described as well as a strategy for gradient computations which are critical to applying any efficient nonlinear programming method. Symbolic computation has been used for general six degree-of-freedom transformations of the robot links and to provide analytical derivative expressions. Example problems in path planning are presented for a simple 3-D robot. One example includes adjustments in geometry and introduces the concept of integrating 3-D path planning with geometric design.
A Computational Environment for Dextrous Workspace Analysis
Authors: Wang J. Y. , Wu J. K. 
Published: March 2021

Abstract
This paper presents an interactive engineering environment for dextrous workspace analysis of manipulators. The environment contains a mechanical system modeling tool, an automatic differentiation package, and numerical solvers that map one-dimensional and two-dimensional solution sets of nonlinear parametrized kinematic constraint equations. Row-rank deficiency of constraint sub-Jacobian matrices is used as a necessary condition for characterizing the boundaries of the workspaces and dextrous workspaces of manipulators. A cursor driven animation capability, developed in an interactive graphics environment allows the user to retrieve system configurations by dragging the cursor along solution branches. An animation of the assembled configuration along that solution branch is then displayed. Thus, a better understanding of the kinematic behavior of mechanical systems that limits their dexterity can be obtained. A construction backhoe mechanical system is used to demonstrate the capability of the method developed.
Minimization of the Vibration Energy of Thin-Plate Structures
Authors: Inoue Katsumi , Townsend Dennis P. , Coy John J. 
Published: March 2021

Abstract
An optimization method is proposed to reduce the vibration of thin-plate structures. The method is based on a finite-element shell analysis, a modal analysis, and a structural optimization method. In the finite-element analysis, a triangular shell element with 18 degrees of freedom is used. In the optimization, the overall vibration energy of the structure is adopted as the objective function, and it is minimized at the given exciting frequency by varying the thickness of the elements. The technique of modal analysis is used to derive the sensitivity of the vibration energy with respect to the design variables. The sensitivity is represented by the sensitivities of both eigenvalues and eigenvectors. The optimum value is computed by the gradient projection method and a unidimensional search procedure under the constraint condition of constant weight.
A computer code, based on the proposed method, is developed and is applied to design problems using a beam and a plate as test cases. It is confirmed that the vibration energy is reduced at the given exciting frequency. For the beam excited by a frequency slightly less than the fundamental natural frequency, the optimized shape is close to the beam of uniform strength. For the plate, the optimum shape is obtained such that the changes in thickness have the effect of adding a stiffener or a mass.
Position Kinematics of a Mixed Mechanism
Authors: Husain Muqtada , Waldron Kenneth J. 
Published: March 2021

Abstract
Although robotics has traditionally focused on the serial chain structures typical of industrial robots, fully parallel structures such as the Stewart Platform have also found considerable industrial use. Actively coordinated mechanisms which have combinations of serial and parallel characteristics have been practically employed, and can be expected to become more important in the future. There has been very little study of the kinematic and static characteristics of these mechanisms which have combinations of the characteristics of fully serial and fully parallel structures. This work addresses the direct and inverse position kinematics of such a hybrid mechanism with combination of serial and parallel structure which has multiple, actively controlled actuators. While not the most general possible configuration, this particular case does include many important features of the general mechanism, and the solution obtained gives useful insight for developing a general theory of forward and inverse kinematics which will be equally applicable to serial, parallel and combination structures. Such a theory is necessary for rational design of hardware and software for such systems.
Forward Position Analysis of Nearly General Stewart Platforms
Authors: Zhang Change-de , Song Shin-Min 
Published: March 2021

Abstract
This paper presents the closed-form solution of forward position analysis of the nearly general stewart platform, which consists of a base and a moving planar platforms connected by six extensible limbs through spherical joints in the two planar platforms. It becomes a general stewart platform if the centers are not constrained to those two planes. In this study, transformation matrix is used to represent the position of the moving platform. Based on the six dependency equations of the rotation matrix and the six constraint equations related to the six link lengths, a set of six 4-th degree equations in three unknowns are derived. Further derivations produce twenty-one dependent constraint equations. By simultaneous elimination of two unknowns a 20-th order polynomial equation in one unknown is obtained. Due to dual solutions of other unknowns, this indicates a maximum of forty possible solutions. The roots of this polynomial are solved numerically and the realistic solutions are constructed using computer graphics.
Forward Displacement Analysis of a Class of the 6-6 Stewart Platforms
Authors: Guozhen Wang 
Published: March 2021

Abstract
In this paper, a special form of the Stewart platform, namely, that in which the top platform and base platform are similar and corresponding vertices are connected by six prismatic joints, is presented. We have developed the closed-form solution for the forward displacement analysis of this mechanism. When the six vertices of top platform are in a quadratic curve, this mechanism becomes singular. This new theoretical result has been confirmed by numerical example.
Geometrical Properties of Modelled Robot Elasticity: Part I — Decomposition
Authors: Lipkin Harvey , Patterson Timothy 
Published: March 2021

Abstract
A new geometric decomposition is introduced that diagonalizes the 6 × 6 stiffness and compliance matrices which model robot elasticity. Using screw theory, a congruence transformation is developed from the three orthogonal wrench-compliant axes and the three orthogonal twist-compliant axes. The diagonal elements are the stationary values of linear and rotational compliance and stiffness. This generalizes and is analogous to principal axes and principal values for stress, strain, and rotational inertia. It is proved that the decomposition always exists for both the nonsingular and singular cases.
The Characteristic Point and the Characteristic Length of Robotic Manipulators
Authors: Tandirci Murat , Angeles Jorge , Ranjbaran Farzam 
Published: March 2021

Abstract
The characteristic point of a serial manipulator is defined here as a point on the end-effector, at which the condition number of the Jacobian matrix is minimized. However, when evaluating the condition number of the Jacobian matrix, dimensional inhomogeneities arise, that render the condition number physically meaningless. As a means to cope with this problem, the entries of the Jacobian that have units of length are divided by a characteristic length L that is chosen so as to minimize the condition number of the dimensionless Jacobian matrix thus resulting. Finally, the values of the joint variables minimizing the condition number of the dimensionless Jacobian lead to a naturally defined home configuration of the manipulator. The concepts introduced here are illustrated with a few examples involving industrial manipulators.
Geometry-Based Optimal Rate Coordination for Robot Manipulators With Redundancy
Authors: Varma K. R. Hareendra , Huang Ming Z. 
Published: March 2021

Abstract
The redundancy resolution problem for kinematically redundant serial chain manipulators is addressed. In this paper, we present a generalization of the geometry based rate allocation algorithm, developed initially in [12] for only minimum norm solution, to obtain the optimal joint rate solution for any specified objective function, with or without weightage. This generalization is made possible through a geometrical interpretation of the common pseudoinverse-based gradient solution scheme, and by developing a modified formulation for the objective function as a minimum criterion not with respect to the origin of the joint rate space, but with respect to another point in the joint rate space represented by the gradient of the specified objective. Application examples of the algorithm including procedures of solution are demonstrated using 7R manipulators with two generic types of geometry. A closed form optimal solution for the 7R anthropomorphic arm considered is also presented.
Die Producibility Evaluation Method
Authors: Shivaram Arun , Naganathan Nagi G. 
Published: March 2021

Abstract
Given the design of a sheet metal component that is to be produced by pressworking, there can be more than one design for the die to produce that component. It will be desirable if a mechanism exists to identify the better of the design alternatives. A method referred to as Die Producibility Evaluation Method (DPEM) is presented in this paper to evaluate the design of a given pressworking die. The method involves identification and classification of the parameters involved in the design and operation of the pressworking die. These parameters are categorized as design cost factors and process cost factors. For a given die design, the design and process cost factors are identified and the results are tabulated in the DPEM table. In order to illustrate the method, a particular sheet metal component is chosen. A set of dies required to produce this component is then designed by a novice designer. This design is referred to as the initial design. The Die Producibility Evaluation Method is applied to the initial design, the DPEM table is updated, and an improved design is identified based on the evaluations recorded in the DPEM table. In order to provide a measure of quality, a second design is carried out under the guidance of an expert designer and is referred to as the reference design. It is shown that the improved design closely matches the reference design, thus illustrating the level of performance and applicability of the Die Producibility Evaluation Method.