Title |
Excitation Frequency Characteristics of a Conductive Fabric Sensor Using the Bio-impedance for Estimating Knee Joint Movements |
Authors |
이병우(Lee, Byung-Woo) ; 이충근(Lee, Chung-Keun) ; 김진권(Kim, Jin-Kwon) ; 정완진(Jeong, Wan-Jin) ; 이명호(Lee, Myoung-Ho) |
DOI |
https://doi.org/10.5370/KIEE.2011.60.7.1427 |
Keywords |
Conductive fabric sensor ; Excitation frequency characteristics ; Bio-impedance ; Knee joint movement evaluation |
Abstract |
This study describes a conductive fabric sensor and determines an optimum excitation frequency of the sensor to evaluate knee joint movements. Subjects were composed of 15 males (age: 30.7pm5.3) with no known problems with their knee joints. The upper side of subjects' lower limbs was divided into two areas and the lower side of subjects' lower limbs was divided into three areas. The sensors were attached to 1 for 3 spot from a hip joint and to 3 for 4 spot from a knee joint which are the optimum conductive fabric sensor configuration to evaluate knee joint movements. As a result, the optimum excitation frequency for evaluating knee joint movements using conductive fabric sensors was 25 kHz. Average and standard deviation of bio-impedance changes from 15 subjects were 92.1pm137.2{Ω} at 25 kHz. The difference of bio-impedance changes between 25 kHz and 50 kHz was statistically significant (p<0.05) and the difference of bio-impedance changes between 25 kHz and 100 kHz was also statistically significant (p<0.001). These results showed that conductive fabric sensors are more sensitive to measure bio-impedance for evaluating knee joint movements as an excitation frequency decreases. |