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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Teaching of a Welding Robot : An intuitive method using virtual reality tracking devices

Peters, Jannik January 2024 (has links)
In this research, the use of the SteamVR tracking system as a teaching method forindustrial robots was investigated, in particular, how it can make the setup of weldingapplications more intuitive. Therefore, an application was developed, that handles therecording of the teaching data and the control of the robot, which allow fast setup timesof a few minutes only. Tests were conducted and a static accuracy of 10 mm determinedat the TCP. This is not sufficient for welding. Further investigation of the tracking systemshowed directional dependencies, a slow dynamic response of the tracking, which can addanother 10 mm of error, and deviations at the pose determination between 3 and 20 mm,making this tracking setup only usable for applications, where no precision is needed.
2

Virtual Reality Locomotion : Four Evaluated Locomotion Methods / Rörelse inom Virtuell Verklighet : Utvärdering av Fyra Rörelsemetoder

Karlsson, Rasmus, Sveninge, Alvar January 2017 (has links)
Virtual Reality consumer hardware is now available for the masses through the HTC Vive, Oculus Rift and PlayStation VR. Locomotion or virtual travel inside immersive experiences is an area which is yet to be fully solved due to space constraints, problems with retaining immersion and potential sickness. This thesis had the goal of evaluating user preferences for four locomotion methods in Virtual Reality with a first generation HTC Vive through the gaming platform Steam.  The theoretical framework provides an elementary understanding of the field of Virtual Reality and how humans interact and get affected by locomotion in that context. To contextualize the experience of evaluating the locomotion systems the Hedonic-Motivation System Adoption Model is used as it covers intrinsic motivation which is common in video games, social networking and virtual worlds.  An extensive process for games selection has been performed which has resulted in four locomotion methods with four games per method. Sixteen participants got to test one locomotion method each where their gameplay got recorded for later observation. After each game session answers were provided by the participants based on surveys and after completion of all games a questionnaire gauged their sickness level.  The conclusion proved inconclusive. While the results without interpretation showed the locomotion method Artificial as the overall winner a range of potential problems were found with the study in general. Some problems included observations which did not provide the expected results, introducing doubt into either how the study was conducted or the reliability of certain users. A larger sampler size along with a better study procedure could possibly have provided a more conclusive answer.
3

Application and Evaluation of Lighthouse Technology for Precision Motion Capture

Sitole, Soumitra 25 October 2018 (has links) (PDF)
This thesis presents the development towards a system that can capture and quantify motion for applications in biomechanical and medical fields demanding precision motion tracking using the lighthouse technology. Commercially known as SteamVR tracking, the lighthouse technology is a motion tracking system developed for virtual reality applications that makes use of patterned infrared light sources to highlight trackers (objects embedded with photodiodes) to obtain their pose or spatial position and orientation. Current motion capture systems such as the camera-based motion capture are expensive and not readily available outside of research labs. This thesis provides a case for low-cost motion capture systems. The technology is applied to quantify motion to draw inferences about biomechanics capture and analysis, quantification of gait, and prosthetic alignment. Possible shortcomings for data acquisition using this system for the stated applications have been addressed. The repeatability of the system has been established by determining the standard deviation error for multiple trials based on a motion trajectory using a seven degree-of-freedom robot arm. The accuracy testing for the system is based on cross-validation between the lighthouse technology data and transformations derived using joint angles by developing a forward kinematics model for the robot’s end-effector pose. The underlying principle for motion capture using this system is that multiple trackers placed on limb segments allow to record the position and orientation of the segments in relation to a set global frame. Joint angles between the segments can then be calculated from the recorded positions and orientations of each tracker using inverse kinematics. In this work, inverse kinematics for rigid bodies was based on calculating homogeneous transforms to the individual trackers in the model’s reference frame to find the respective Euler angles as well as using the analytical approach to solve for joint variables in terms of known geometric parameters. This work was carried out on a phantom prosthetic limb. A custom application-specific motion tracker was also developed using a hardware development kit which would be further optimized for subsequent studies involving biomechanics motion capture.
4

Assessment of a Low Cost IR Laser Local Tracking Solution for Robotic Operations

Du, Minzhen 14 May 2021 (has links)
This thesis aimed to assess the feasibility of using an off-the-shelf virtual reality tracking system as a low cost precision pose estimation solution for robotic operations in both indoor and outdoor environments. Such a tracking solution has the potential of assisting critical operations related to planetary exploration missions, parcel handling/delivery, and wildfire detection/early warning systems. The boom of virtual reality experiences has accelerated the development of various low-cost, precision indoor tracking technologies. For the purpose of this thesis we choose to adapt the SteamVR Lighthouse system developed by Valve, which uses photo-diodes on the trackers to detect the rotating IR laser sheets emitted from the anchored base stations, also known as lighthouses. Some previous researches had been completed using the first generation of lighthouses, which has a few limitations on communication from lighthouses to the tracker. A NASA research has cited poor tracking performance under sunlight. We choose to use the second generation lighthouses which has improved the method of communication from lighthouses to the tracker, and we performed various experiments to assess their performance outdoors, including under sunlight. The studies of this thesis have two stages, the first stage focused on a controlled, indoor environment, having an Unmanned Aerial Vehicle (UAS) perform repeatable flight patterns and simultaneously tracked by the Lighthouse and a reference indoor tracking system, which showed that the tracking precision of the lighthouse is comparable to the industrial standard indoor tracking solution. The second stage of the study focused on outdoor experiments with the tracking system, comparing UAS flights between day and night conditions as well as positioning accuracy assessments with a CNC machine under indoor and outdoor conditions. The results showed matching performance between day and night while still comparable to industrial standard indoor tracking solution down to centimeter precision, and matching simulated CNC trajectory down to millimeter precision. There is also some room for improvement in regards to the experimental method and equipment used, as well as improvements on the tracking system itself needed prior to adaptation in real-world applications. / Master of Science / This thesis aimed to assess the feasibility of using an off-the-shelf virtual reality tracking system as a low cost precision pose estimation solution for robotic operations in both indoor and outdoor environments. Such a tracking solution has the potential of assisting critical operations related to planetary exploration missions, parcel handling/delivery, and wildfire detection/early warning systems. The boom of virtual reality experiences has accelerated the development of various low-cost, precision indoor tracking technologies. For the purpose of this thesis we choose to adapt the SteamVR Lighthouse system developed by Valve, which uses photo-diodes on the trackers to detect the rotating IR laser sheets emitted from the anchored base stations, also known as lighthouses. Some previous researches had been completed using the first generation of lighthouses, which has a few limitations on communication from lighthouses to the tracker. A NASA research has cited poor tracking performance under sunlight. We choose to use the second generation lighthouses which has improved the method of communication from lighthouses to the tracker, and we performed various experiments to assess their performance outdoors, including under sunlight. The studies of this thesis have two stages, the first stage focused on a controlled, indoor environment, having an Unmanned Aerial Vehicle (UAS) perform repeatable flight patterns and simultaneously tracked by the Lighthouse and a reference indoor tracking system, which showed that the tracking precision of the lighthouse is comparable to the industrial standard indoor tracking solution. The second stage of the study focused on outdoor experiments with the tracking system, comparing UAS flights between day and night conditions as well as positioning accuracy assessments with a CNC machine under indoor and outdoor conditions. The results showed matching performance between day and night while still comparable to industrial standard indoor tracking solution down to centimeter precision, and matching simulated CNC trajectory down to millimeter precision. There is also some room for improvement in regards to the experimental method and equipment used, as well as improvements on the tracking system itself needed prior to adaptation in real-world applications.

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