Joint flexion/extension angle estimation using ultra-wideband (UWB) radios

• Main Author: Liu, Hao
• Other Authors: Soh Cheong Boon
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Electrical and electronic engineering::Control and instrumentation::Medical electronics
• Online Access: http://hdl.handle.net/10356/61347
• Institution: Nanyang Technological University

Joint flexion/extension angle parameter is essential for investigating complex gait disorders, and monitoring of process in rehabilitation. This is very important for medical applications. There are many methods to measure the joint flexion/extension angle. Comparing with other measuring methods, wearable Ultra Wideband (UWB) radio is good candidate for human motion tracking due to its high ranging and positioning accuracy, low cost, less power consumption and robust performance in various environments. The purpose of this report is to present a wearable system for estimating human elbow joint flexion/extension angle based on Ultra Wideband radios. A UWB transmitting antenna and a receiving antenna were placed on human elbow adjacent segments. Goniometer was attached on human elbow with UWB transceivers together to ensure the measurement could be conducted under same reference frame for comparison. The distances were calculated between transmitter and receiver through the estimation of propagation delay. Time of arrival (TOA) of the first arrival path is the most common method to estimate the distance. Lastly, the estimated distance was used to estimate the joint flexion/extension angle by applying anti-cosine rule. The performance of this wearable UWB based system was compared with the goniometer by simultaneously measuring elbow joint angle at three different moving speeds. The experimental results demonstrate that the system has reasonable performance with a slightly increase in error. It is shown that the system has sufficient accuracy for clinical applications.