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  • Küçük Resim
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    A Comparative Study for Computational Cost of Fundamental Robot Manipulators
    (Ieee, 2011) Toz, Metin; Küçük, Serdar
    The computational cost of the dynamic equations is very important in real time control applications of industrial robot manipulators. Basically, the computational cost depends on the joint properties, the method used for deriving the dynamic equations and the algorithm efficiency. In this study, the dynamic equations for the sixteen three and six degrees of freedom fundamental robot configurations were derived using Newton-Euler (N-E), Lagrange-Euler (L-E) and Hamiltonian (H) methods in symbolic form. The computational costs of these dynamic equations for both three and six degrees of freedom manipulators are obtained. Some comparisons considering the joint properties, the method and the workspace geometries of the manipulators are performed and some important conclusions are summarized.
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    Development of derivation of inverse Jacobian matrices for 195 6-DOF GSP mechanisms
    (2016) Toz, Metin; Küçük, Serdar
    One of the key issues in robotics is finding high-performance manipulator structures. To evaluate the performance of a parallel manipulator, researchers mostly use kinematic performance indices (such as condition number, minimum singular value, dexterity, and manipulability), which are based on inverse Jacobian matrices. Driving the inverse Jacobian matrix of even one parallel manipulator is a very cumbersome process. However, in this paper, general equations for the inverse Jacobian matrices of 195 GSP mechanisms are symbolically derived by considering 4 basic leg types having 1 angular and 4 distance constraints. With the help of these general equations, the development of the inverse Jacobian matrix for a GSP mechanism can be achieved by defining only the leg connection points on the base and moving platforms with minimum cost. Having derived the inverse Jacobian matrices, one can directly compute kinematic performance indices to measure and compare the manipulator performance of the 195 GSP mechanism. These analyses may yield new high-performance GSP mechanisms for use in engineering, medical device design, and other applied branches. Two different mechanisms (symmetrical and asymmetrical) are given as examples to describe the methodology for deriving the inverse Jacobian matrices. Finally, 2 numerical examples are given for illustrating the practical applications of the procedure.
  • Küçük Resim
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    Development of derivation of inverse Jacobian matrices for 195 6-DOF GSP mechanisms
    (Tubitak Scientific & Technical Research Council Turkey, 2016) Toz, Metin; Küçük, Serdar
    One of the key issues in robotics is finding high-performance manipulator structures. To evaluate the performance of a parallel manipulator, researchers mostly use kinematic performance indices (such as condition number, minimum singular value, dexterity, and manipulability), which are based on inverse Jacobian matrices. Driving the inverse Jacobian matrix of even one parallel manipulator is a very cumbersome process. However, in this paper, general equations for the inverse Jacobian matrices of 195 GSP mechanisms are symbolically derived by considering 4 basic leg types having 1 angular and 4 distance constraints. With the help of these general equations, the development of the inverse Jacobian matrix for a GSP mechanism can be achieved by defining only the leg connection points on the base and moving platforms with minimum cost. Having derived the inverse Jacobian matrices, one can directly compute kinematic performance indices to measure and compare the manipulator performance of the 195 GSP mechanism. These analyses may yield new high-performance GSP mechanisms for use in engineering, medical device design, and other applied branches. Two different mechanisms (symmetrical and asymmetrical) are given as examples to describe the methodology for deriving the inverse Jacobian matrices. Finally, 2 numerical examples are given for illustrating the practical applications of the procedure.
  • Küçük Resim
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    Dexterous workspace optimization of an asymmetric six-degree of freedom Stewart-Gough platform type manipulator
    (Elsevier, 2013) Toz, Metin; Küçük, Serdar
    In this paper, an asymmetric Generalized Stewart-Gough Platform (GSP) type parallel manipulator is designed by considering the type synthesis approach. The asymmetric six-Degree Of Freedom (DOE) manipulator optimized in this paper is selected among the GSPs classified under the name of 6D. The dexterous workspace optimization of Asymmetric parallel Manipulator with tEn Different Linear Actuator Lengths (AMEDIAL) subject to kinematics and geometric constraints is performed by using the Particle Swarm Optimization (PSO). The condition number and Minimum Singular Value (MSV) of homogenized Jacobian matrix are employed to obtain the dexterous workspace of AMEDLAL. Finally, the six-DOF AMEDLAL is also compared with the optimized Traditional Stewart-Gough Platform Manipulator (TSPM) considering the volume of the dexterous workspace in order to demonstrate its kinematic performance. Comparisons show that the manipulator proposed in this study illustrates better kinematic performance than TSPM. (C) 2013 Elsevier B.V. All rights reserved.
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    Dimensional optimization of 6-DOF 3-CCC type asymmetric parallel manipulator
    (Taylor & Francis Ltd, 2014) Toz, Metin; Küçük, Serdar
    In this paper, dimensional optimization of a six-degrees-of-freedom (DOF) 3-CCC (C: cylindrical joint) type asymmetric parallel manipulator (APM) is performed by using particle swarm optimization (PSO). The 3-CCC APM constructed by defining three angle and three distance constraints between base and moving platforms is a member of 3D3A generalized Stewart-Gough platform (GSP) type parallel manipulators. The dimensional optimization purposes to find the optimum limb lengths, lengths of line segments on the base and moving platforms, attachment points of the line segments on the base platform, the orientation angles of the moving platform, and position of the end-effector in the reachable workspace in order to maximize the translational and orientational dexterous workspaces of the 3-CCC APM, separately. The dexterous workspaces are obtained by applying condition number and minimum singular values of the Jacobian matrix. The optimization results are compared with the traditional GSP manipulator for illustrating the kinematic performance of 3-CCC APM. Optimizations show that 3-CCC APM have superior dexterous workspace characteristics than the traditional GSP manipulator.
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    Dual fluoroscopic evaluation of human tibiofemoral joint kinematics during a prolonged standing: A pilot study
    (Elsevier - Division Reed Elsevier India Pvt Ltd, 2019) Uzuner, Sabri; Rodriguez, Marcel L.; Li, Leping; Küçük, Serdar
    A complete knowledge of tibiofemoral joint kinematics is essential for understanding the function of the healthy and pathological joint. The objective of the present study was to establish a dual fluoroscopic measurement protocol and a data processing approach for the creep response of the knee joint in order to further evaluate the mechanical properties of articular cartilage and meniscus in vivo. A computational approach was developed for the determination of 3D translations and rotations of the joints of young participants with no history of injury using dual fluoroscopic images of loaded joints and joint geometry reconstructed from magnetic resonance imaging of the unloaded joints. High-resolution X-ray images were obtained for the distal femur and proximal tibia during 10-min standing when approximately 3/4 body weight was slowly applied to the right leg and then kept constant for the rest duration of the test. Anatomic coordinate systems were established for the 3D models of distal femur and proximal tibia. Translations and rotations of the joint as functions of time were then evaluated using the X-ray images and these coordinate systems with the JointTrack software. The displacements in the proximal-distal direction obtained from two participants were consistent, showing a substantial increase in the initial phase when joint loading increased from nil to 3/4 body weight and a continued small increase over time while the joint loading remained constant. The maximum anterior-posterior translations during 10-min standing were approximately 4 mm for both participants, although one showed better stability than the other. In conclusion, a creep loading protocol of the knee joint can be reasonably established for in vivo conditions and evaluated with the image-based computational approach. (C) 2019 Karabuk University. Publishing services by Elsevier B.V.
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    Parallel manipulator software tool for design, analysis, and simulation of 195 GSP mechanisms
    (Wiley, 2015) Toz, Metin; Küçük, Serdar
    In this paper, a new parallel manipulator software tool based on the MATLAB Graphical User Interface (GUI) is developed for design, analysis and simulation of 195 6-DOF General Stewart Platform mechanisms (GSP). The new proposed tool called as GSPDAP uses four basic leg types to design GSP mechanisms. Point or line coordinates required for leg connections are sufficient for GSPDAP to design a GSP mechanism. Once the design of a GSP mechanism is completed, GSPDAP provides the user with several analyses such as inverse kinematics, Jacobian matrix, workspace, and dexterity. It is not necessary for the user to have preliminary knowledge to obtain the inverse kinematics or Jacobian matrix etc. Additionally, GSPDAP generates symbolic equations for the inverse kinematics and the inverse Jacobian matrices of 195 GSP mechanisms. Including 195 parallel manipulator in its library, GSPDAP provides the educational users to profoundly improve the understanding of parallel manipulator fundamentals through interactive simulation. Parallel manipulators are more complex structures than their serial counterparts. Therefore, designing even one parallel manipulator is very cumbersome and expensive issue. In this condition GSPDAP may provide educators and students to design their manipulators in a computer environment with minimum cost. (c) 2015 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:931-946, 2015; View this article online at ; DOI