Introduction and past research: Inertial sensors are great for orientation estimation, but they cannot measure relative positions of human body segments directly. In previous work we used ultrasound to estimate distances between body segments . In  we presented an easy to use system for gait analysis in clinical practice but also in-home situations. Ultrasound range estimates were fused with data from foot-mounted inertial sensors, using an extended Kalman filter, for 3D (relative) position and orientation estimation of the feet. Validation: From estimated 3D positions we calculated step lengths and stride widths and compared this to an optical reference system for validation. Mean (±standard deviation) of absolute differences was 1.7 cm (±1.8 cm) for step lengths and 1.2 cm (±1.2 cm) for stride widths when comparing 54 walking trials of three healthy subjects. Clinical application: Next, the system presented in  was used in the INTERACTION project, for measuring eight stroke subjects during a 10 m walk test . Step lengths, stride widths and stance and swing times were compared with the Berg balance scale score. The first results showed a correlation between step lengths and Berg balance scale scores. To draw real conclusions, more patients and also different activities will be investigated next. Future work: In future work we will extend the system with inertial sensors on the upperand lower legs and the pelvis, to be able to calculate a closed loop and improve the estimation of joint angles compared with systems containing only inertial sensors.
|Title of host publication||5th Dutch Conference on Bio-Medical Engineering, BME 2015|
|Place of Publication||Egmond aan Zee, The Netherlands|
|Number of pages||1|
|ISBN (Print)||not assigned|
|Publication status||Published - 22 Jan 2015|
|Event||5th Dutch Bio-Medical Engineering Conference, BME 2015 - Hotel Zuiderduin, Egmond aan Zee, Netherlands|
Duration: 22 Jan 2015 → 23 Jan 2015
Conference number: 5
|Conference||5th Dutch Bio-Medical Engineering Conference, BME 2015|
|Abbreviated title||BME 2015|
|City||Egmond aan Zee|
|Period||22/01/15 → 23/01/15|
- BSS-Biomechatronics and rehabilitation technology
Weenk, D., van Meulen, F., van Beijnum, B. J. F., Droog, A., Roetenberg, D., Hermens, H. J., & Veltink, P. H. (2015). Gait analysis using ultrasound and inertial sensors. In 5th Dutch Conference on Bio-Medical Engineering, BME 2015 (pp. -). Egmond aan Zee, The Netherlands: BME.