WoS İndeksli Yayınlar Koleksiyonu / WoS Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7150
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Article Citation - WoS: 24Citation - Scopus: 26Synthesis of Function Generating Spherical Four Bar Mechanism for the Six Independent Parameters(Elsevier Ltd., 2011) Alizade, Rasim; Gezgin, ErkinThis study deals with the function generation synthesis of spherical four bar mechanism for six independent construction parameters φ0, ψ0, α1, α2, α3, and α4 by giving six or more design points with respect to the methods that are used in synthesis procedure. Quaternion algebra is used to derive the objective function of spherical four bar mechanism by following some rotational sequences. Three different methods as interpolation approximation, least squares approximation and Chebyshev approximation are used during synthesis procedure. During the consecutive trials in Chebyshev approximation, a new approach is taken to renew the design points φi by plotting the graph of the objective functions derivative and taking the roots of it as new design points with two boundary points. Separate examples are given for each section and the results are tabulated. Discussions about the study and comparisons between the used methods are given at the end of the study.Article Citation - WoS: 6Citation - Scopus: 7Classification of Manipulators of the Same Origin by Virtue of Compactness and Complexity(Elsevier Ltd., 2011) Gezgin, Erkin; Özdemir, SerhanThis work deals with a classification method that employs concepts such as complexity and compactness. The idea is to classify manipulators, or any other mechanism for that matter, of the same origin, based on the geometry of the joints, the tasks performed by the joints, the efficiency and the manufacturing cost to generate the specified efficiency. It is known that successive units on a single branch create individual uncertainties that affect the eventual quality of the performed operation [1]. An entropic expression quantifies this uncertainty in terms of the number of links and the unit effectiveness. The concepts of compactness and complexity have been formulated, and these concepts are explained through serial and parallel manipulators with varying parameters. Eventually, a cost function is created which is a function of complexity, uncertainty and the manufacturing cost. A worked example on M = 6 Stewart-Gough platform is given how this cost function could be taken advantage of when deciding an initial manipulator. A genetic algorithm is used for the optimization of the cost function, where the results are tabulated.Article Citation - WoS: 2Citation - Scopus: 2Trait-based heterogeneous populations plus (TbHP+) genetic algorithm(Elsevier Ltd., 2009) Tayfur, Gökmen; Sevil, Hakkı Erhan; Gezgin, Erkin; Özdemir, SerhanThis study developed a variant of genetic algorithm (GA) model called the trait-based heterogeneous populations plus (TbHP+). The developed TbHP+ model employs a memory concept in the form of immunity and instinct to provide the populations with a more efficient guidance. Also, it has an ability to vary the number of individuals during the search process, thus allowing an automatic determination of the size of the population based on the individual qualities such as character fitness and credit for immunity. The algorithm was tested against the classical GA model in convergence and minimum error performance. For this purpose, 5 different mathematical functions from the literature were employed. The selected functions have different topological characteristics, ranging from simple convex curves with 2 variables to complex trigonometric ones having several hilly shapes with more than 2 variables. The developed model and the classical GA model were applied to finding the global minima of the functions. The comparison of the results revealed that the developed TbHP+ model outperformed the classical GA in faster convergence and minimum errors, which may be explained by the adaptive nature of the new paradigm.Article Citation - WoS: 6Citation - Scopus: 8Structural Design of Parallel Manipulators With General Constraint One(Elsevier Ltd., 2010) Alizade, Rasim; Selvi, Özgün; Gezgin, ErkinIn this paper structural design of parallel manipulators with general constraint one regarding angular and linear-angular conditions are considered. Four known overconstrained mechanisms with angular and two new designs with linear-angular conditions are presented. 14 structural groups and end effector chains in subspace λ = 5 are examined. New formulations and definitions of constructing overconstrained manipulators are described. Using examined structural groups, all architectures of subspace λ = 5 parallel manipulators with revolute joints and single-loop are introduced via structural bonding.Article Citation - WoS: 39Citation - Scopus: 42Structural Synthesis of Serial Platform Manipulators(Elsevier Ltd., 2007) Alizade, Rasim; Bayram, Çağdaş; Gezgin, ErkinIn this paper, structural synthesis of serial platform manipulators is considered. Serial platform manipulators are created according to the development of the platforms and closed loops. Also a new structural formula of mobility of parallel Cartesian platform robot manipulators is presented. Structural synthesis of serial platform manipulators with lower and higher kinematic pairs with respect to their structures are also examined. Structural synthesis of parallel Cartesian platform robot manipulators is also introduced. History of structural formulas DOF are presented as a table with equations, authors, years and some commentaries. New and revised methods for structural synthesis of serial platform manipulators and parallel Cartesian platform robot manipulators are illustrated along with examples.Article Citation - WoS: 15Citation - Scopus: 20Structural Synthesis of Euclidean Platform Robot Manipulators With Variable General Constraints(Elsevier Ltd., 2008) Alizade, Rasim; Can, Fatih Cemal; Gezgin, ErkinIn this paper, new method for structural synthesis of Euclidean platform robot manipulators with variable general constraints (EPRM) is presented. Three dimensional motion of the base moving platform is generated by the motion of dyads on the Euclidean planes. Each dyad is connected to the moving base platform by universal, spherical or spherical in torus (St) kinematic pairs. This allows solving the structural synthesis of Euclidean robot manipulators with various DoF and different platform motions. New structural formulations with variable general constraints for the platform motion and the mobility of robot manipulators are presented. The new structural classification of simple structural groups with variable general constraints including platforms, hinges, legs and branch loops from different subspaces and space is also introduced. Moreover, new method for structural synthesis of serial, parallel and serial-parallel EPRM is illustrated along with examples. © 2007 Elsevier Ltd. All rights reserved.