Thesis
Design of an automated calibration device for electromagnetic tracking systems
Washington State University
Master of Science (MS), Washington State University
2007
Handle:
https://hdl.handle.net/2376/101586
Abstract
Electromagnetic tracking systems used in virtual reality applications are subject to tracking error due to magnetic field distortions caused by metallic objects in the environment which increases with increased distance from the transmitter. These problems can lead to a significant decrease in tracking performance of position and orientation during simulations in the virtual environment, creating a need for a calibration method of the tracking system. The calibration method involves collecting a set of data pairs for the receiver using the electromagnetic system and a secondary reference system of true physical locations. The goal of this research was to design a suitable device to automatically collect data points for this physical reference system without causing further distortion to the magnetic field. The calibration device was designed in order to accurately position the electromagnetic receiver at user-specified grid points throughout the tracking environment, thereby allowing the calculation of position and orientation error at each location. The calibration device we designed is a three axis Cartesian positioner interfaced via serial port with computer software for an automated methodology. The main components of the device are two perpendicular eight foot lead screw driven rails for x-y translation, with a descending nylon telescoping arm for z translation. The entire device is mounted to overhead framing and the main components are fixed to a smaller frame that can be translated; this allows for a calibration over a wide range of physical locations. The stepper motors that drive the axis’ are controlled via the Calibration of Virtual Environment (COVE) software, which allows the user to specify the calibration bounds as well as the resolution for each direction. Novel methods were created to avoid collision of the calibration device with objects in the environment. The device was installed and tested at a sponsor’s facility. Data was collected and analyzed for calibration of the facility. The tests showed that the density of calibration and the flexibility achieved with this device far exceed any previous methods used.
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Details
- Title
- Design of an automated calibration device for electromagnetic tracking systems
- Creators
- Gareth Douglas Cole
- Contributors
- Sankar Jayaram (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525185601842
- Language
- English
- Resource Type
- Thesis