Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
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Master Thesis Design of a Physical Human-Robot Interface for Lifting Operations(Izmir Institute of Technology, 2022) Nalbant, Uğur; Dede, Mehmet İsmet Can; Dede, Mehmet İsmet CanIn this thesis, the design of a physical human-robot interface for lifting operations which controls the vertical movement of the payload is studied. The new design uses a low stiffness type of admittance control method that is aimed at reducing the surface impact force of the payload and providing better control for the operator while having the option of high stiffness admittance control. To reduce impact forces by using low stiffness admittance control, a sliding handle mechanism is introduced into the system. This type of design includes springs and bearings to create a low stiffness admittance-type user interface. Mathematical models are developed to calculate spring forces and mechanical strength. According to design requirements and mathematical calculations, the prototype is designed and manufactured. In the tests, it is seen that the spring forces are low, and the sliding motion of the handle is not consistent over different displacements. According to the test results, revisions are done, and the final design of the system is developed. In the final tests, it is seen that the new design of the physical human-robot interface performance is improved and the problem of the sliding motion of the handle is solved. Also, the surface impact forces are reduced with low stiffness admittance control. Another improvement of the new design is the ability to control the payload with high stiffness admittance control if the user chooses it. With this option, users can control the payload by touching the payload. Having both types of control methods, the user can choose which type of control method to use to handle payload in the factory.Master Thesis Design and Development of a Continuously Variable Transmission System To Be Used in Human-Robot Interfaces(Izmir Institute of Technology, 2018) Mobedi, Emir; Dede, Mehmet İsmet CanContinuously Variable Transmission (CVT) systems are being used for many applications such as automotive transmissions, robotics, and 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 a set of design criteria including backdrivability, independent output position and stiffness 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. Considering the friction drive CVT designs, 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 the work presented in this thesis 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. Additionally, an adjustment of the normal force applied on the cones is designed in order to regulate the shock absorption limitations.