Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Conference Object Kinematic and Dynamic Analysis of a New Type of Spatial 6-Dof Parallel Structure Manipulator(China Machine Press, 2004) Alizade, Rasim; Bayram, ÇağdaşThis paper addresses the dynamics and kinematics of a 6xUPS type parallel structure manipulator that consists of six branches and a platform. The problem of forward and inverse displacement analysis is considered on the base of solution of the forward displacement problem for each UPS branch as a serial manipulator. Basic dynamics equations have also been considered. The values of reduced moments and forces have been determined that provides the required input forces and moments. Thus, we deal with inverse dynamics problems. Dynamic model of this type of spatial manipulator is described by a system of six non-linear differential equations of second order with applying Lagrange-Euler methods.Article Citation - WoS: 17Citation - Scopus: 18Least Square Approximate Motion Generation Synthesis of Spherical Linkages by Using Chebyshev and Equal Spacing(Elsevier Ltd., 2013) Alizade, Rasim; Can, Fatih Cemal; Kilit, ÖzgürIn this paper, approximate motion synthesis of spherical linkages is presented. Rigid body guidance of a spherical four-bar mechanism is performed by a spherical RR open chain. In the first step, position of a point on rigid body and orientation of a rigid body on a unit sphere are described. Synthesizing function of spherical dyad is derived by means of using unit vectors that describe location of two revolute joints and tip point. Being based on the theory of function approximation and besides the linearization of nonlinear synthesis equations by using superposition method, the design procedure for real solutions of fourth order polynomial equation is developed. In the second step, approximate motion generation synthesis of spherical dyad is presented by using least-square approximation. Chebyshev spacing and equal spacing are used in the determination of poses. In the final step, two numerical examples are given to show how error graph is varied in terms of selected poses. The spherical motion generation synthesis of spherical four-bar mechanism is obtained by the combination of the two real solutions of the synthesis of two spherical dyads. © 2012 Elsevier Ltd.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: 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.Article Citation - WoS: 45Citation - Scopus: 57Analytical Synthesis of Function Generating Spherical Four-Bar Mechanism for the Five Precision Points(Elsevier Ltd., 2005) Alizade, Rasim I.; Alizade, Rasim; Kilit, ÖzgürThis paper presents an analytical method for synthesis of function generating spherical 4R mechanisms for the five precision points. For the design requirements an additional parameter, reference value of output angle, ψ0, was added to angular link length parameters, α i(i = 1, ..., 4). In the dimensional synthesis procedure, a novel approach of polynomial approximation method was proposed to determine these five design parameters. Using this method, a set of five non-linear equations was easily transformed into a set of fifteen linear equations. Hence, the problem was reduced to the solution of a cubic polynomial equation. Moreover, a graphical method in a CAD environment is proposed to verify the solutions. © 2005 Elsevier Ltd. All rights reserved.Article Citation - WoS: 52Citation - Scopus: 61Structural Synthesis of Parallel Manipulators(Elsevier Ltd., 2004) Alizade, Rasim; Bayram, ÇağdaşIn this paper, structural synthesis and classification of parallel manipulators are considered. Parallel manipulators are classified according to their platform type(s) and connections between them. New and revised methods and formulations for designing variety of parallel manipulators with single and multiple platforms are presented along with examples.Book Part Citation - Scopus: 4Derivation of Input/Output Relationships for the Bennett 6r Linkages Based on the Method of Decomposition(Springer, 2014) Alizade, Rasim; Kiper, Gökhan; Dede, Mehmet İsmet Can; Uzunoğlu, EmreThe Bennett overconstrained 6R linkages are the double-planar, the double-spherical and the plano-spherical 6R linkages. These mechanisms are obtained by combining simple planar and/or spher-ical mechanisms and then removing one of the common links. This paper presents the derivation of the input/output relationships for these mechanisms using the decomposition method. This method is based on writing the input/output equations for the two imaginary loops comprising the 6R mechanism and then eliminating the imaginary joint variable. It is found that the resulting input/output equations con-tain up to 4th power of trigonometric terms, such as cos4 θ.