Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Article Citation - WoS: 7Citation - Scopus: 7Gravity Compensation of a 2r1t Mechanism With Remote Center of Motion for Minimally Invasive Transnasal Surgery Applications [article](Cambridge University Press, 2023) Aldanmaz, Ataol Behram; Ayit, Orhan; Kiper, Gökhan; Dede, Mehmet İsmet CanThis work addresses the gravity balancing of a 2R1T (2 rotations – 1 translation) mechanism with remote center of motion. A previously developed balancing solution is modified and applied to a prototype and test results are presented. The mechanism is an endoscope holder for minimally invasive transnasal pituitary gland surgery. In this surgery, the endoscope is inserted through a nostril of the patient through a natural path to the pituitary gland. During the surgery, it is vital for the manipulator to be statically balanced so that in case of a motor failure, the patient is protected against any harmful motion of the endoscope. Additionally, static balancing takes the gravitational load from the actuators and hence facilitates the control of the mechanism. The mechanism is a 2URRR-URR type parallel manipulator with three legs. The payload mass is distributed to the legs on the sides. By using counter-masses for two links of each leg, the center of mass of each leg is lumped on the proximal link which simplifies the problem to balancing of a two degree-of-freedom inverted pendulum. The two proximal links with the lumped mass are statically balanced via springs. Dynamic simulations indicate that when the mechanism is statically balanced, generated actuator torques are reduced by 93.5%. Finally, the balancing solution is implemented on the prototype of the manipulator. The tests indicate that the manipulator is statically balanced within its task space when the actuators are disconnected. When the actuators are connected, the torque requirements decrease by about 37.8% with balancing.Article Citation - WoS: 1Citation - Scopus: 1Enumeration and Instantaneous Mobility Analysis of a Class of 3-Upu Parallel Manipulators With Equilateral Triangular Platforms(Cambridge University Press, 2022) Boztaş, Sercan; Kiper, GökhanIn this study, several joint axis orientations on equilateral platforms and the limbs of 3-UPU parallel manipulators (PMs) are examined. The generated joint layouts for the platforms were matched with each other to generate and enumerate manipulator architectures based on certain assumptions. The structures of thus obtained manipulators are examined and limb types were determined. These limb types were analyzed using screw theory. The instantaneous mobility of the manipulators and the motion characteristics of the moving platforms are tabulated. The finite mobility analysis of one of the manipulators is performed using a software package as an example. Among several different 3-UPU PM architectures, 118 novel 3-UPU PMs with non-parasitic 3-degrees-of-freedom are significantly important. The classified 3-UPU PMs with determined motion characteristics can be used by researchers as a design alternative for their specific design task. © The Author(s) 2021. Published by Cambridge University Press.Conference Object Citation - Scopus: 4Static Force Balancing of a 2r1t Parallel Manipulator With Remote Center of Motion(Springer Verlag, 2019) Yaşır, Abdullah; Kiper, Gökhan; Dede, Mehmet İsmet Can; Van der Wijk, VolkertAssistive robots in surgical applications should be gravity balanced due to safety considerations. This study presents a gravity balancing solution for a 3-degree-of-freedom parallel manipulator to be used as an endoscope navigation robot for transnasal minimal invasive surgery applications. The manipulator has a rather simple structure that allows individual balancing of the three legs in their respec-tive planes of motion. First, sole counter-mass balancing is investigated, but it is seen that the extra mass amount is too much. Sole spring balancing is not consid-ered as an option due to constructional complexity. A hybrid solution as a combi-nation of counter-mass and spring balancing is devised. In the proposed solution, the masses on the distal links of a leg are balanced with counter-masses so that all masses are lumped to the link connected to the base of the manipulator. Hence the problem is simplified into the balancing of a pendulum. The necessary formula-tions are derived and numerical calculations demonstrate that the hybrid balancing yields a feasible solution.Conference Object Manipulator Design for a Haptic System With Improved Performance(Springer, 2021) Sekendiz, Veysel; Görgülü, İbrahimcan; Karabulut, Mehmet Görkem; Kiper, Gökhan; Dede, Mehmet İsmet CanThis paper presents the work carried out to improve the design of an existing kinesthetic haptic device. The proposed improvement is designated for enhancing this device’s impedance width which is a common metric in performance evaluation of haptic devices. In this study, kinematic design optimization, static balancing, constructional design enhancement and actuation system design studies are presented.Conference Object Citation - WoS: 6Citation - Scopus: 3A Geometrical Approach for the Singularity Analysis of a 3-Rrs Parallel Manipulator(Springer Verlag, 2018) Tetik, Halil; Kiper, GökhanIdentifying singularity manifolds of parallel manipulators analytically is a hard task due to their complex kinematics and passive joints. This study proposes to use the geometrical conditions of singularities in order to identify the singularity manifolds for a 3-RRS parallel manipulator. The singularity surfaces for both inverse and forward kinematics singularities are obtained and plotted.