Master Degree / Yüksek Lisans Tezleri

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Augmented Reality-Based Model-Mediated Teleoperation: a Mobile Telerobot Case Study
(Izmir Institute of Technology, 2019) Kirişci, Nihat Çağhan; Dede, Mehmet İsmet Can
Teleoperation is defined as operating a robot in a remote environment. Teleoperation utilizes the strength and dexterity of robots and the interpretation and problem solving skills of humans. In a teleoperation system, the robot to be controlled is referred as the slave. The master is a device that the human operator interacts with to send commands to the slave or receive feedback from the slave environment such as haptic or audio. However, teleoperation of a robot in an unknown environment solely based on haptic and visual feedback is a demanding task. The effects of time delay in communication channels makes completing this task even more challenging. Model-Mediated Teleoperation (MMT) aims to solve this problem by creating a virtual model of the slave robot and the environment. This virtual model receives commands from the master and returns haptic feedback just as the real slave robot is interacting with the environment, effectively with no delay. However, without actually knowing where the position of the virtual robot corresponds in the real environment, it is still challenging to carry out the task. In this project, a novel augmented reality based method is proposed to render the virtual robot into the real life live video feed. Integration of the non-delayed robot into the real environment intends to solve this problem by enhancing the perception of the user.
Redundant Mobile Robort Control
(Izmir Institute of Technology, 2016) Çelik, Onur; Dede, Mehmet İsmet Can
Indoor mobile robots are one of the widely researched and developing technologies in robotic field since they can be used in the service robotics and industrial application domains. Moreover, a sub-category of mobile robots, omnidirectional mobile robots, allow performing tasks in narrow indoor spaces by providing better motion capabilities. Additionally, redundancy in mobile robots is started to be used for various advantages including fault tolerance and increased payloads. The objective of this thesis is to improve the design of the omnidirectional mobile robot that was previously constructed in IRL (IzTech Robotics Lab) and develop a redundancy resolution algorithm in order to control the redundant omnidirectional mobile robot to tolerate faults in the actuation system. Initially, the mechanical structure of the mobile robot is improved by the addition of a suspension system for each wheel assembly. A new onboard controller hardware is used and a new top-level controller is employed to be used along the redundancy resolution algorithm. Additionally, previously developed obstacle avoidance algorithm is improved by employing a new configuration of sensors and including a virtual damper to compensate for variable velocity level while approaching to an obstacle. The fault tolerance algorithm is developed in this thesis by integrating a pseudo inverse of the Jacobian matrix that is subjected to a virtual weighted matrix so that the motion of the mobile robot will sustain its motion even though there is an efficiency drop in one of the actuators. Top-level control algorithm along with the fault tolerance and the obstacle avoidance algorithms is experimentally tested and test results indicate that the mobile robot can achieve the primary task in the case of one of the actuator’s efficiency drops down to 70% or in the case of multiple obstacles on the path of the robot.
Unlimited-Wokspace Teleoperation
(Izmir Institute of Technology, 2012) Şahin, Osman Nuri; Dede, Mehmet İsmet Can
Teleoperation is, in its brief description, operating a vehicle or a manipulator from a distance. Teleoperation is used to reduce mission cost, protect humans from accidents that can be occurred during the mission, and perform complex missions for tasks that take place in areas which are difficult to reach or dangerous for humans. Teleoperation is divided into two main categories as unilateral and bilateral teleoperation according to information flow. This flow can be configured to be in either one direction (only from master to slave) or two directions (from master to slave and from slave to master). In unlimited-workspace teleoperation, one of the types of bilateral teleoperation, mobile robots are controlled by the operator and environmental information is transferred from the mobile robot to the operator. Teleoperated vehicles can be used in a variety of missions in air, on ground and in water. Therefore, different constructional types of robots can be designed for the different types of missions. This thesis aims to design and develop an unlimited-workspace teleoperation which includes an omnidirectional mobile robot as the slave system to be used in further researches. Initially, an omnidirectional mobile robot was manufactured and robot-operator interaction and efficient data transfer was provided with the established communication line. Wheel velocities were measured in real-time by Hall-effect sensors mounted on robot chassis to be integrated in controllers. A dynamic obstacle detection system, which is suitable for omnidirectional mobility, was developed and two obstacle avoidance algorithms (semi-autonomous and force reflecting) were created and tested. Distance information between the robot and the obstacles was collected by an array of sensors mounted on the robot. In the semi-autonomous teleoperation scenario, distance information is used to avoid obstacles autonomously and in the force-reflecting teleoperation scenario obstacles are informed to the user by sending back the artificially created forces acting on the slave robot. The test results indicate that obstacle avoidance performance of the developed vehicle with two algorithms is acceptable in all test scenarios. In addition, two control models were developed (kinematic and dynamic control) for the local controller of the slave robot. Also, kinematic controller was supported by gyroscope.

Master Degree / Yüksek Lisans Tezleri

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