Sürdürülebilir Yeşil Kampüs Koleksiyonu / Sustainable Green Campus Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7755

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Access Right: Open AccessAuthor: search.filters.author.Kiper, Gökhan

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  • Master Thesis
    Design of Hybrid Cable-Constrained Parallel Mechanisms for Walking Machines
    (Izmir Institute of Technology, 2018) Kiper, Gökhan; Kiper, Gökhan; Demirel, Murat; Kiper, Gökhan; Carbone, Giuseppe; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The objective of this thesis study is to propose novel cable-constrained parallel mechanisms for walking machines. According to the literature, hybrid structured parallel mechanisms can overcome mechanical design, control system and workspace limitations compared to other structures. This thesis study introduces two novel hybrid structured leg mechanisms comprising rigid links and passive cables. Kinematic structure of the proposed mechanisms are (UPU-2Pa)-(UPU-2Pa)and (UU-2Pa)-P. Both designs have a hip, a knee and a foot platform. Two rotational constraints about horizontal axes are added to the moving platforms by using parallelograms with passive cables. The rotational constraint about the vertical axis is provided by rigid links and joints. Thus, the proposed designs have pure translational motion. The detailed analysis of the mechanism design with anchored cables is conducted. A CAD model is constructed and a dynamic simulation for human-like gait trajectory is performed in SolidWorks® environment. Once the computed actuator torques and forces are found suitable, a first prototype is built to check the proposed solution. Considering the problems encountered in this first prototype, a second prototype of the (UU-2Pa)-P mechanism is built. The prototype is operated using a real-time PCI controller and experimental results are presented. The mechanisms presented in this thesis is one of the few cable-constrained parallel manipulator designs in the literature. Such a manipulator design is used for a walking machine for the first time. The prototype and test results are quite satisfactory, so hopefully more detailed research can be conducted on this topic in the future.
  • Conference Object
    Citation - Scopus: 3
    Design and Simulation of a Novel Hybrid Leg Mechanism for Walking Machines
    (Springer Verlag, 2018) Demirel, Murat; Carbone, Giuseppe; Kiper, Gökhan; Demirel, Murat; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    This paper introduces a novel hybrid structure design that is composed of rigid links and cables for a robotic leg with static walking. The proposed mechanism is characterized by actuated hip joints, passive knee joints and an actuated prismatic foot joint. The foot is the moving platform of the proposed mechanism which possesses pure translational motion due to the passive parallelograms with cables. Kinematic analysis has been worked out for evaluating a typical human-like gait trajectory. A 3-D model has been developed and simulation are made in SolidWorks® environment. Simulation results show that the proposed mechanism is able to perform an ovoid walking cycle of a foot point and the computed actuator torques and forces are in a feasible range for a low-cost and easy-operation design. The simulation results will be used for a prototype construction in a future work.
  • Master Thesis
    Design Modification of a Front Window Mechanism for the Cabin of an Earth Moving Machine
    (Izmir Institute of Technology, 2017) Jovichikj, Radomir; Kiper, Gökhan; Kiper, Gökhan; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    This thesis study investigates the front window mechanism used in an earth moving machinery. Since the mechanism is actuated by the operator, the required actuation force for the mechanism needs to be as minimum as possible. The problem of this thesis is defined by Turkey branch of Mecalac Company and the final test of this study are performed in their facility. First, the problem definition and aim of the study is presented. Furthermore, the literature review is also presented. Then, the current mechanism attached on the earth moving machinery is investigated. Firstly, kinematic analysis is performed in order to be able to perform the force analysis. Following that, using three different approaches (Newton-Euler approach, virtual work method and graphical approach), the static force analysis is done. The aim of this analysis to obtain the required actuation force, both for opening and closing the mechanism. By using three different approaches, the result obtained after each method are compared and confirmed. Furthermore, a simulation of the mechanism is prepared in MATLAB/Simulink® environment. This step provided a numerical simulation verification for the resulting actuation forces. Then the work carried out for the minimization of the actuation force is presented. By changing the parameters of the springs attached on the current mechanism, changing the link lengths of the mechanism and changing the application point of the actuation force, the change in the magnitude of the required actuation force is observed and minimized. Among all trials, only changing the spring position led to useful results. Finally, the test setup to measure the performance and experimentally verify the proposed solution is explained and the results are given. The results show that with the modified location of the spring, both of the maximum force requirements and the work requirements are lowered.
  • Master Thesis
    Modelling and Control of a 3-Rrs Parallel Manipulator
    (Izmir Institute of Technology, 2016) Tetik, Halil; Kiper, Gökhan; Tetik, Halil; Kiper, Gökhan; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology
    The focus of this thesis study is to model and control a parallel robot manipulator located in Rasim Alizade Mechatronics Laboratory (Izmir Institute of Technology Mechanical Engineering Department). The purpose of this robot is to manipulate heavy payloads. It is considered as the base part of a hybrid manipulator. This thesis study deals with a 3-RRS parallel manipulator with 3 identical limbs. Each limb comprises two parallel revolute joint axes. The manipulator has a base and a moving platform which are in the shape of equilateral triangles. The mobile platform of this manipulator has 3-degrees-of-freedom: it can rotate around x- and y-axes and translate along the z-axis. To obtain the mathematical model of the parallel manipulator, firstly the mobility analysis is performed. Then, a constraint analysis is performed to obtain the dependent pose parameters of the moving platform in terms of the independent parameters. Following that kinematic, singularity, workspace and inverse dynamic analyses are performed. To validate the mathematical model of the PM, several simulations are run in MATLAB/Simulink R environment. Once the mathematical model is validated, the control studies are carried out. The motion of the 3-RRS PM is controlled by activating stepper motors with two different controllers (a CNC controller and a PCI card). To obtain a desired motion of the moving platform, firstly the desired task space coordinates of the moving platform are transformed into joint space coordinates using inverse kinematics. With the CNC controller a trapezoidal velocity, with the PCI card a trapezoidal jerk profile is generated. To test the control over the PM, 3 magnetic encoders are attached to the shafts of input links at each limb. Furthermore, a 3-axis gyroscope is attached to the center of the moving platform to track its rotational trajectory.
  • Master Thesis
    Design of a Reconfigurable Deployable Structure for Post Disaster Housing
    (Izmir Institute of Technology, 2014) Ataer, Fulya; Korkmaz, Koray; Kiper, Gökhan; Korkmaz, Koray; Kiper, Gökhan; 02.02. Department of Architecture; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of Technology; 02. Faculty of Architecture
    In this thesis, the possibility of constructing reconfigurable deployable structure composed of planar linkage units has been explored. The first part of the thesis is devoted to literature survey on housing recovery. When the current researches on post disaster housing are investigated, it is observed that most of post disaster housing or temporary buildings in the literature are predefined portable, demountable or relocatable buildings. Deployable buildings serve for a single function. A study into the existence of alternative forms of a reconfigurable deployable structure has been done. The conditions for the alternative forms to be a multi-functional building have been derived. Reconfigurable deployable structure presented here is a single degrees-of-freedom (DoF) multi-loop linkage which has more than two configurations. The alternative forms that a linkage is constructed with the same links and connections are called configurations or assembly modes of the linkage. During its motion, the linkage may pass from one assembly mode to another, which is called reconfiguration or assembly mode change. Design and position analysis of the linkage mechanism have been implemented in Microsoft Excel® environment. The link lengths can be varied in this environment and the motion of the structure can be simulated by changing input joint parameters. Four different case studies have been designed in Microsoft Excel®. A reconfigurable deployable structure can be used as a multi-functional shelter or canopy which can take many forms in a few minutes for urgent needs after disasters, military purpose or public needs. Its deployed and retracted (or compact) geometries are explored. As a case study the dimensions of links are presented. Installation process for different functions is explained. The full concept for the structure, from outer covering material to foundation is then detailed. Finally, a sample material cost analysis is performed to determine if the product is financially feasible.