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Department: search.filters.department.Department of Mechanical EngineeringSubject: search.filters.subject.Automatic control

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Now showing 1 - 4 of 4
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    Design and adaptive sliding-mode control of hybrid magnetic bearings
    (Institute of Electrical and Electronics Engineers (IEEE), 2018) N/A; N/A; Department of Mechanical Engineering; Zad, Haris Sheh; Khan, Talha Irfan; Lazoğlu, İsmail; PhD Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179391
    In this paper, a hybrid magnetic bearing (HMB) prototype system is designed and analyzed. Two compact bearings are used to suspend the rotor in five degrees of freedom. Electromagnets are used for axial suspension of the rotor, while permanent magnets are used for the passive radial stability. A brushless DC motor is designed in order to rotate the shaft around its axis. The 3-D finite-element model of the HMB system is established and distribution of magnetic fields in the air gaps and magnetic forces on the rotor under various control currents and displacements is calculated. A nonlinear adaptive sliding-mode controller is designed for the position control of the rotor in axial direction. Since the control characteristics of the active magnetic bearing system are highly nonlinear and time varying with external interference, a radial basis function compensator is designed first, and then, a sliding-mode control law is used to generate the control input. The stability analysis for the designed controller is given based on the Lyapunov theorem. Experimental setup is built to guide the design process. The performance of the HMB system based on the designed control algorithm is evaluated under different operating conditions.
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    Experimental analysis of boring process on automotive engine cylinders
    (Springer, 2010) Özkeser, Salih O.; N/A; Department of Mechanical Engineering; Şenbabaoğlu, Fatih; Lazoğlu, İsmail; Master Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; 179391
    In this article, mechanics of boring process on cast iron automotive engine cylinders is explored experimentally. In order to shorten the boring cycle time and to improve quality of the cylinder holes, effects of various cutting conditions as spindle speed, feedrate, inserts, and coatings are investigated. Real-time cutting forces are measured with dynamometer during the process. Surface roughness on the engine cylinders, flank, and crater tool wears are measured and compared in various cutting conditions. It is concluded that by selecting proper cutting conditions, cutting forces can be controlled below a threshold value, cycle time can be shortened, tool life and part quality can be increased; therefore, the cost of automotive engine boring process can be reduced significantly.
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    Generating robot/agent backchannels during a storytelling experiment
    (Institute of Electrical and Electronics Engineers (IEEE), 2009) Al Moubayed, S.; Baklouti, M.; Chetouani, M.; Dutoit, T.; Mahdhaoui, A.; Martin, J. -C.; Ondas, S.; Pelachaud, C.; Urbain, J.; Department of Mechanical Engineering; Yılmaz, Mustafa Akın; Tekalp, Ahmet Murat; PhD Student; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; N/A
    This work presents the development of a real-time framework for the research of Multimodal Feedback of Robots/Talking Agents in the context of Human Robot Interaction (HRI) and Human Computer Interaction (HCI). For evaluating the framework, a Multimodal corpus is built (ENTERFACE_STEAD), and a study on the important multimodal features was done for building an active Robot/Agent listener of a storytelling experience with Humans. The experiments show that even when building the same reactive behavior models for Robot and Talking Agents, the interpretation and the realization of the behavior communicated is different due to the different communicative channels Robots/Agents offer be it physical but less-human-like in Robots, and virtual but more expressive and human-like in Talking agents.
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    Robotic additive turning with a novel cylindrical slicing method
    (Springer London Ltd, 2022) N/A; N/A; Department of Mechanical Engineering; Yiğit, İsmail Enes; Khan, Shaheryar Atta; Lazoğlu, İsmail; Phd Student; PhD Student; Faculty Member; Department of Mechanical Engineering; Graduate School of Sciences and Engineering; Graduate School of Sciences and Engineering; College of Engineering; N/A; N/A; 179391
    The turning process used from ancient times to today's modern turning centers is based on material removal. This article presents a new work to integrate additive manufacturing into the turning process and generate complex free-form additive turning part geometries. The conventional slicing method used in AM is the planar slicing method. In the planar slicing method, the computer-aided design (CAD) model is sliced using planes, and as a result, two-dimensional toolpaths are formed. A new slicing method is required to achieve additive turning parts. This work proposes a generalized, cylindrical slicing method that generates nonplanar toolpaths wrapped around a cylinder. The model is sliced by cylindrical layers, with increasing radii at each layer. As a result, three-dimensional toolpaths that are suitable for additive turning are generated. In conventional AM, lower tensile strength is observed in the build orientation of the part where the layers bind. Additive turning increases the low tensile strength observed in conventional AM. Additionally, it reduces and, at times, even eliminates the support structures required for certain CAD models. The cylindrical slicing results are verified by additively turning different CAD models using a six-axis robotic serial manipulator fitted with a fused filament fabrication end effector and an external turning axis. Tensile tests are conducted on conventional AM and additive turning models to verify the improvement in tensile strength.