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by J. Burger (~192 kB)
Determining the Feasibility of Measuring Outdoor Road Cycling Kinematics using Inertial Motion Capture Technology
The Electro-Thermal Properties of Integrated Circuit Microbolometers
Investigation into a Multilateration Laser Tracking System for the National Metrology Institute of South Africa
Determining the Feasibility of Measuring Outdoor Road Cycling Kinematics using Inertial Motion Capture Technology by J. Cockcroft and C. Scheffer
Abstract: Unlike traditional optical systems, inertial motion capture systems (IMSs) can measure human kinematics outdoors as well as in a laboratory. However, these systems are sensitive to magnetic interference. This study evaluated an IMS for use in sports performance analysis, using road cycling as a case study. The objective was to establish the feasibility of obtaining accurate outdoor kinematic data on competition-level road bicycles. Ten male cyclists were recorded on their own bicycle on a stretch of road wearing the IMS. Results revealed unacceptable magnetic interference to the IMS near the pedal and handlebar interfaces. Therefore, accurate full-body cycling kinematics is not currently feasible on most competition-level road bicycles. However, lower limb flexion measurements are possible using the IMS’s kinematic coupling algorithm which obtained RMS errors of less than 3.5° for all joints in a benchmark test with an optical system regarded as gold-standard.
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The Electro-Thermal Properties of Integrated Circuit Microbolometers by M. du Plessis, J. Schoeman, W. Maclean and C. Schutte
Abstract: The use of uncooled infrared sensors in thermal imaging is a fast growing market in the fields of security and health. The integration of uncooled or room temperature infrared sensors onto a silicon CMOS chip will facilitate the manufacture of large imaging arrays. At the University of Pretoria we are researching the integration of microbolometer infrared sensors onto CMOS readout electronic circuits using post processing techniques. The microbolometer utilises the change in resistance of a temperature sensitive resistive material, e.g. vanadium oxide or a thin metal film, to measure the amount of infrared radiation falling onto the device and heating the device. The microbolometer structure should be thermally isolated from the bulk silicon to achieve the required sensitivity. In this paper we will describe the device structures, as well as the techniques we used to determine experimentally the electrical, thermal and electro-thermal properties of the devices. Of interest to us are the following parameters: 1) temperature coefficient of the bolometer resistive layer, 2) thermal conductivity of the device, 3) thermal capacitance of the total sensor structure and 4) the thermal time constant. The microbolometer thermal characteristics can also be modelled and simulated using CoventorWare software.
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Investigation into a Multilateration Laser Tracking System for the National Metrology Institute of South Africa by G.P. Greeff and O.A. Kruger
Abstract: A baseline study for the implementation of multilateration with a laser tracker for the Dimensional Laboratory of the NMISA (National Metrology Institute of South Africa) was completed. Software which requires one laser tracker to perform sequential multilateration was developed for the lab. Simulation studies are also done with this program for verification and configuration motivation purposes. Other aspects of the study involved developing a prototype laser tracker station and performing kinematic simulation analysis on gimbal type trackers. With practical experience gained, recommendations are made for future multilateration development in the Dimensional Laboratory.
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