Browsing by Author "Chebili, Zakarya"

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    Comparative Analysis of Stiffness in Redundant Co-axial Spherical Parallel Manipulator Using Matrix Structural Analysis and VJM Method
    (Springer, 2023) Chebili, Zakarya; Alem, Said; Djefal, Selman
    Several studies have addressed stifness analysis through diferent available methods including fnite element analysis (FEA) and the virtual joint method (VJM) among others. However, matrix structural analysis (MSA) has not been used, although previous research has shown that it provides reliable results. Therefore, this paper focuses on the kineto-static analysis of a three-degree-of-freedom symmetrical parallel kinematic manipulator (PKM) with curved links, known as a spherical parallel manipulator (SPM). First, kinematic modeling is introduced through the inverse kinematic problem and the Jacobian matrix; then a detailed study of the stifness modeling is established. Secondly, the force–defection relationship is studied in the form of a numerical calculation and a graphical representation. Moreover, the kinematic redundancy is derived. Through MATLAB simulations, the defection of the joints in both parts, translation, and rotation, is graphically represented using a numerical calculation method. Comparatively, SPM is purposefully compared to VJM in order to determine the efciency of the proposed method. Interestingly, kinematic redundancy leads to better SPM performance, in which adding extra links (legs) to the robot strengthens the SPM structure and yields less joint defection. It is worth noting that the MSA technique successfully deals with complex structures such as closed-loop chains, which is clearly apparent in the simplicity of its mathematical model toward the considered robot.
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    Contribution to the design optimization of redundant parallel robots
    (Université M'Hamed Bougara Boumerdès : Faculté de Technologie, 2024) Chebili, Zakarya; Alem, Said(Directeur de thèse)
    This study investigates the design Enhancement of parallel kinematic manipulators (PKMs) with spherical linkages. The main goal is to enhance the robot's structural platform and to minimize joints deflection by utilizing kinematic redundancy. Firstly, a novel mathematical approach is proposed for modeling the desired SPM. This approach is based on Gosselin theory using the implementation of Euler's angles (orientation angles), which allows for modeling any type of Spherical Parallel Manipulator (SPM) by simply varying the desired robot's geometric parameters. The Advantage of this approach is to model any specific SPM platform by simply parameterizing the geometric parameters of the desired platform to the standard form model. Furthermore, a comprehensive stiffness analysis using Matrix Structural Analysis (MSA) validated through comparison with Virtual Joint Method (VJM) implemented in Matlab software. The study demonstrates and highlights the significant impact of redundancy on the kinematic and structural behavior of parallel structures. By leveraging kinematic redundancy (adding extra kinematic chains), leading to reduced robot joint deflection and enhanced stiffness. The incorporation additional kinematic chains, thus the manipulator manipulability and precision are improved, contributing to its overall performance. The findings underscore the significance of structural optimization and kinematic redundancy in advancing parallel manipulator design, with implications for a wide range of applications requiring precise and robust robotic manipulation