Person: REİS, MURAT
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REİS
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MURAT
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Publication Elastic actuator design based on bending of cylindrical beam for robotic applications(Mdpi, 2020-09-01) Murat, Reis; Ebrahimi, Nafiseh; Jafari, Amir; REİS, MURAT; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü; 0000-0001-5853-488X; AAI-1786-2019The lack of suitable actuators has hampered the development of high-performance machines or robots that can compete with living organisms in terms of motion, safety, and energy efficiency. The adaptation properties of biological systems to environmental variables-for example, the control performance of biological muscle with variable stiffness properties-exceeds the performance of mechanical devices. The variable stiffness characteristics of elastic actuators are different from the operating principle of conventional solids. Although there has been a lot of work on the design of elastic actuators in recent years, a low-cost and compact elastic actuator that can be used in place of standard rigid servo actuators is not yet available. In this study, a standard servo motor has been transformed into an elastic actuator by an elastic coupling attached to the gear system. The elastic coupling consists of four small steel beams with a cylindrical cross section placed on the circular disk, and the stiffness of the actuator is adjusted by varying the clutch length of the cylindrical beams. In this study, this innovative design is explained, then the equations expressing the variation of the torsional stiffness of the cylindrical beams with the coupling length and solutions of these equations are given. The experimental results are presented to show the ability of the proposed actuator to control position and regulate the stiffness independently.Publication Vibration-based locomotion of an amphibious robot(MDPI, 2021-03-01) Cocuzza, Silvio; Doria, Alberto; Reis, Murat; REİS, MURAT; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi; 0000-0001-5853-488X; AAI-1786-2019In this research, an innovative robot is presented that can move both on land and water thanks to a vibration-based locomotion mechanism. The robot consists of a U-shaped beam made of spring steel, two low-density feet that allow it to stand on the water surface without sinking, and a micro-DC motor with eccentric mass, which excites vibrations. The robot exhibits stable terrestrial and aquatic locomotion based on the synchronization between body vibrations and the centrifugal force due to the eccentric mass. On the one hand, in aquatic locomotion, the robot advances thanks to floating oscillations and the asymmetric shape of the floating feet. On the other hand, the terrestrial locomotion, which has already been demonstrated for a similar robot, exploits the modes of vibration of the elastic beam. In this study, the effect of different excitation frequencies on the locomotion speed in water is examined by means of experimental tests and a numerical model. A good agreement between experimental and numerical results is found. The maximum locomotion speed takes place when the floating modes of vibration are excited.Publication A smart handheld welding torch device for manual spot laser welding(MDPI, 2022-11-01) Reis, Murat; Şerifagaoğlu, Emre; REİS, MURAT; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü; 0000-0001-5853-488X; AAI-1786-2019In producing custom-made systems, using a robotic welding line that can fine-tune welding parameters is not economical, and laser welding is usually done manually. The most common operator error in manual welding operations is the angular positioning error between the laser beam and the plate surface. This study introduces a smart handheld welding torch device that assists the welding operator with visual warnings. It measures the sheet surface angle to eliminate angular positioning errors, calculates the appropriate torch holding angles accordingly, and helps the laser welding process with the right angle. For this purpose, this study focused on micro-laser spot welding applications of stainless (inox) kitchen and hotel equipment, and the effect of angular positioning errors on the welding quality was investigated experimentally. Experiments show that when the angle between the surface normal and the welding torch is smaller than the critical welding angle, heat-induced traces or micro-deformations occur on the visible surface of the thin stainless material. In addition, there is a significant decrease in the weld quality, since a large enough weld area cannot be created at large values of this angle. The optimum torch angle range was determined using experimental results for the available laser welding parameters. With a standard welding torch and the smart torch, the welding operator was allowed to repeat the same task, and the payloads of the samples prepared in this way were measured. Test results show that using a smart welding torch with an angular positioning assist system significantly improves welding quality. Breaking force values vary in a wide range of welds made with a standard welding torch, and visual problems such as burning, puncture, and swelling are encountered on the visible surfaces of many samples with high strength values. When the developed smart torch was used, the breaking force remained within the desired reference range, and no visual defects were found in any sample.Publication A variable clutch mechanism for adjustable stiffness actuators based on bending and torsion of prismatic beams(MDPI, 2023-01-01) Reis, Murat; Tüfekçi, Kenan; REİS, MURAT; TÜFEKCİ, KENAN; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/Makine Mühendisliği Bölümü; 0000-0001-5853-488X; 0000-0001-5358-1396; AAI-1786-2019; AAG-7076-2021Today, a major obstacle to developing locomotion mechanisms that are as safe and energy efficient as living organisms has been overcome with the development of actuators with adjustable stiffness. This work presents an innovative clutch mechanism whose stiffness can be adjusted based on the combined bending and torsion of the prismatic beams. In this way, the stiffness of any rotary actuator can be adjusted with the help of this clutch mechanism. The adjustable clutch mechanism consists of elastic prismatic beams placed in any position in the power transmission unit. The stiffness of the clutch mechanism is controlled by varying the active clutch length of these prismatic elastic beams using an additional actuator. This work is a new version developed to solve the mechanical problems observed in our previous studies using elastic cylindrical beams. Cylindrical beams subjected to dynamic bending have a higher risk of cracking on the cylindrical surface over time. The cross-section of cylindrical beams subjected to bending is very narrow at the point furthest from the center, which bears the greatest load in bending. For this reason, it has been observed that the beams break due to micro-cracks on the surfaces of the cylindrical beams in long-term use. However, the rectangular beam proposed as a solution to this mechanical problem is subject to combined torsion and bending, complicating the analytical solution. In this study, the stiffness variation of an adjustable elastic coupling mechanism depending on the coupling length was obtained with a simplified discrete analytical approach. Torsional and bending stiffness of the prismatic beams were calculated separately, and their sum gave the angular stiffness of the actuator. The analytical results obtained using this simple approach are compared with the experimental and finite element analysis results. The results show that the current design can adjust the stiffness over a wide range and the simple analytical approach gives more accurate results as the clutch length increases.