Mechanical Engineering / Makina Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4129

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Access Right: Open AccessAuthor: search.filters.author.Mobedi, Emir

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  • Conference Object
    Citation - Scopus: 3
    A Continuously Variable Transmission System Designed for Human–robot Interfaces
    (Springer, 2021) Mobedi, Emir; Dede, Mehmet İsmet Can
    Within a predefined limit, continuously variable transmission (CVT) systems can continuously vary the power transmission ratio. The transmission in CVTs is achieved via friction, belt or gear systems. If CVT designs can incorporate backdrivability, independent output position and impedance variation, shock absorbtion, and low mass and inertia, they can be employed in human–robot interfaces. Among various types of CVT designs, the two-cone drive CVT designs have a major drawback since the output torque and position cannot be changed independent of each other. The friction wheel used in this design does not have a holonomic motion capability and causes this inconvenience. In order to overcome this problem, a sphere is used in this work for the CVT design as the transmission element. In addition, it is stated in the literature that common CVT drive systems do not have the capability to be used in cyclic bidirectional motion. In the presented CVT design, a second sphere is added to the system with two springs from the lower part of the cones for pretension in order to solve the bidirectional transmission problem. In this paper, the working principle and conceptual design details of the novel two-cone CVT drive are presented. Experimental results showed that the novel CVT has the capacity to transmit bidirectional power with some accuracy. © 2021, Springer Nature Singapore Pte Ltd.
  • Book Part
    Citation - WoS: 1
    Citation - Scopus: 1
    Calibration Study of a Continuously Variable Transmission System Designed for Phri
    (Springer, 2020) Mobedi, Emir; Dede, Mehmet Ismet Can
    Variable stiffness actuators (VSAs) have been used in many applications of physical human-robot interfaces (pHRI). A commonly employed design is the spring-based VSA allowing the user to regulate the output force mechanically. The main design criteria of these actuation systems are the adjustment of output force independent from the output motion, and shock absorbing. In our recent work, we implemented certain modifications on the two-cone friction drive continuously variable transmission system (CVT) so that the CVT can be employed in pHRI systems. Subsequently, the optimized prototype is developed. In this study, we introduce the prototype of this new CVT systems, and its force calibration tests. The results indicate that the manufactured CVT is capable of displaying the desired output force throughout its transmission ratio range within a tolerance.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 12
    Geometrical Analysis of a Continuously Variable Transmission System Designed for Human-Robot Interfaces
    (Elsevier, 2019) Mobedi, Emir; Dede, Mehmet İsmet Can
    New robotic systems are placed out of their constrained workspaces in order to work alongside humans. Consequently, these applications call for robots monitoring and regulating physical human-robot interaction. These robots’ mechanical compliance should be varied when they are in physical contact with the human or their changing environments. This compliance variation can be achieved in a variety of ways. However, one common idea is the variation of joint stiffness mechanically, electromechanically or by control. The solution presented in this paper is an electromechanical way of varying the joint stiffness. Among the electromechanical methods for varying the joint stiffness, continuously variable transmission (CVT) systems can be used in human-robot interfaces if a set of design criteria are met. These criteria include backdrivability, independent output position and stiffness variation, shock absorbing and low mass/inertia. In this paper, a novel two-cone CVT design with a double spherical transmission element is introduced by taking into account the abovementioned criteria. Additionally, design parameters are identified via carrying out a geometrical analysis of this new CVT system.
  • Conference Object
    A Continuously Variable Transmission System Designed for Human-Robot Interfaces
    (IFToMM, 2018) Mobedi, Emir; Dede, Mehmet İsmet Can
    Continuously Variable Transmission (CVT) systems are being used for many applications such as automotive transmissions, robotics, aerospace. In an ideal condition, these systems have the potential to provide continuously varying power transmission within a predefined limit. This transmission is accomplished with the help of friction, belt or gear systems. CVT can find application in a human-robot interface if design criteria such as backdrivability, independent output position and impedance variation, shock absorbing and low mass and inertia can be satisfied. Even if there are various CVT designs in the literature for human-robot interfaces, the primary limitation of the two-cone drive CVT designs is that the output torque and the output position cannot be altered independently. The reason for this problem is that the friction wheel, which is designed to transmit the torque from the input cone to the output cone, gives rise to remarkable longitudinal friction force along the linear way. In order to overcome this problem, a sphere is used in this work for the CVT design as the transmission element. In addition, it is stated in the literature that common CVT drive systems do not have the capability to be used in cyclic bidirectional motion. In the presented CVT design, a second sphere is added to the system with two springs from the lower part of the cones for pre-tension in order to solve the bidirectional transmission problem. In this paper, the working principle and conceptual design details of the novel two-cone CVT drive are presented. Experimental results showed that the novel CVT has the capacity to transmit bidirectional power with some accuracy.
  • Book Part
    Citation - WoS: 1
    Citation - Scopus: 2
    Experimental Evaluation of Actuation and Sensing Capabilities of a Haptic Device
    (Springer, 2019) Mobedi, Emir; Görgülü, İbrahimcan; Dede, Mehmet İsmet Can
    Haptic devices are used to increase the telepresence level by providing the sense of touch to the human operator. Simultaneously, they capture the targeted motion of the human operator to generate a motion demand for the teleoperated slave system. Considering a scenario where the slave system’s end-effector is handled by the human operator at the master side, which is attached to the haptic device, an ideal haptic interaction involves the feeling of only the end-effector dynamics and the accurate sensation of the end-effector pose. The performance of a haptic device is based on these two functionalities. In this paper, the experimental evaluation of the actuation and sensing capabilities of a haptic device, HIPHAD v1.0 kinesthetic haptic device, is presented.