Abstract
Hand-finger motion tracking during daily life is often used in rehabilitation for diagnostic and human-computer interaction etc. Traditionally, optical tracking systems (OTSs) are used. However, these systems are restricted to lab environments with expensive cameras and data acquisition systems. Ambulatory tracking out of a lab, using inertial sensors and magnetometers, is becoming increasingly popular to obtain insight in daily life.
There are two main disadvantages of the inertial and magnetometer-based tracking system. Firstly, the most existing methods are limited by high number of sensors, thus not satisfying the requirement of minimum obtrusiveness. Secondly, most existing methods require an accurate kinematic hand and finger model. From these two disadvantages, the goal of this thesis was derived: developing a minimally obtrusive inertial and magnetic sensing system that can be used in an ambulatory setting without kinematic information. The thesis was a joint work between Northwestern Polytechnical University (NPU) and University of Twente (UT), which has two parts. The first part was mainly about calibration of magnetometers, which provides basis for the follow-up work related to the localization with a magnetometer. This part was finished at NPU. The second part was to estimate the fingertip pose with few inertial sensors, magnetometers and a magnet, which was finished at UT.
The first part is addressed in Chapter 2 and 3. Chapter 2 and Chapter 3 present calibration methods of magnetometers. The second part is addressed in Chapter 4, 5, 6 and 7. Chapter 4 presents a method that improves the OTS-based orientation estimation performance by fusing gyroscope information. Chapter 5 presents a method to estimate fingertip orientation relative to the hand only with inertial sensors. Chapter 6 presented the position estimation of fingertips relative to the hand, with one magnetometer on the fingertip and one magnet on the dorsal side of the hand. Chapter 7 presents the results that fused method in chapter 5 and 6.
There are two main disadvantages of the inertial and magnetometer-based tracking system. Firstly, the most existing methods are limited by high number of sensors, thus not satisfying the requirement of minimum obtrusiveness. Secondly, most existing methods require an accurate kinematic hand and finger model. From these two disadvantages, the goal of this thesis was derived: developing a minimally obtrusive inertial and magnetic sensing system that can be used in an ambulatory setting without kinematic information. The thesis was a joint work between Northwestern Polytechnical University (NPU) and University of Twente (UT), which has two parts. The first part was mainly about calibration of magnetometers, which provides basis for the follow-up work related to the localization with a magnetometer. This part was finished at NPU. The second part was to estimate the fingertip pose with few inertial sensors, magnetometers and a magnet, which was finished at UT.
The first part is addressed in Chapter 2 and 3. Chapter 2 and Chapter 3 present calibration methods of magnetometers. The second part is addressed in Chapter 4, 5, 6 and 7. Chapter 4 presents a method that improves the OTS-based orientation estimation performance by fusing gyroscope information. Chapter 5 presents a method to estimate fingertip orientation relative to the hand only with inertial sensors. Chapter 6 presented the position estimation of fingertips relative to the hand, with one magnetometer on the fingertip and one magnet on the dorsal side of the hand. Chapter 7 presents the results that fused method in chapter 5 and 6.
| Original language | English |
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| Qualification | Doctor of Philosophy |
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| Award date | 24 Feb 2022 |
| Place of Publication | Enschede |
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| Print ISBNs | 978-90-365-5333-9 |
| DOIs | |
| Publication status | Published - 24 Feb 2022 |