Browsing by Author "Brink, Lambert"

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    Research and development to produce a first generation running power measurement device
    (Stellenbosch : Stellenbosch University, 2024-03) Brink, Lambert; Smit, Willem; Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering.
    ENGLISH ABSTRACT: This research contributes to the engineering and the understanding of power kinetic power measurements while walking or running based on each stride. This research explores ways of applying power measurements through a low-power embedded apparatus placed on the foot. In doing so, the study identifies current marketplace models (not necessarily footbased), refines the measurement of external factors such as spatio-temporal parameters, and identifies the overall accuracy of these models. The methodology, through comprehensive research, proposes an algorithm for implementing a net mass/energy balance equation. This algorithm, applied in its simplest form necessitated the need for a speed (velocity) measurement and subsequently also identified the need for gait measurements, velocity estimation, position estimation and free space orientation measurements. This thesis outlines the measurement and analyses of several spatio-temporal parameters using an embedded foot device. Once applied the parameters are analysed and used to calculate the simplistic kinetic output. The hardware design primarily focuses on the measurement of acceleration, angular acceleration, and magnetic flux, which are essential components of an Inertial Measurement Unit (IMU) device. This is achieved with a simple Microcontroller unit (MCU) accompanied by the integration of data storage with flash memory or a ”Google Sheet” platform. Furthermore, data transmission is processed with a Bluetooth Low Energy (BLE) device. The parameters are then analysed on the device itself, where the orientation is calculated using a quaternion-based implementation. Additionally, filtered acceleration is measured and calculated in gravity free space, ensuring accurate velocity calculations that are free of drift due to the Zero Velocity Update (ZVU) algorithm implementation. Following velocity calculation, position estimation is calculated in conjunction with the gait measurement, enabling the measurement of speed and distance travelled, thus allowing the analysis of a kinetic power measurement using basic motion. Applying the quaternion-based orientation calculation yielded high accuracy, enabling the correct measurement of subsequent parameters, such as the filtered acceleration and velocity. In contrast, gait measurement encountered challenges. Despite its accuracy, it had difficulty capturing data within the data storage segment, leading to various issues. With data and storage segmentation, the gait calculation has improved accuracy with the ability to measure each step. Furthermore, velocity and position estimation were drift free and within 10% accurate compared to the testing methods. Finally, utilising the combined measurements, a speed calculation (distance travelled over stride time) was used, showing promise for achieving a reliable kinetic power result. This analysis indicates that the foot device is capable of generating a relative power measurement on an embedded foot device, provided that it is not obstructed by storage segmentation. The research also revealed that the accuracy of the Stryd pod was not accurate when implemented for walking, which would be similar for other market marketplace models. The foot device highlights the inconsistency with the theoretical kinetic power method across different devices. Nevertheless, the spatio-temporal measurements are more consistent, and with further research, development and testing within the individual sections an open source standardised method can be produced.