Ambulatory sensing of gait kinematics using inertial measurement units (IMUs) usually uses sensor fusion filters. These algorithms require measurement updates to reduce drift between segments. A full body IMU suit can use biomechanical relations between body segments to solve this. However, when minimising the sensor set, we lose a lot of this information. In this study, we explore the assumptions of zero moment point (ZMP) as a possible source of measurement updates for the sensor fusion filters. ZMP is otherwise utilised for humanoid gait in robots. In this study, first, the relation between the ZMP and centre of pressure (CoP) is studied using a GRAIL system, consisting of opto-kinetic measurements. We find that the mean distance over the gait cycle between ZMP and CoP is 10.5±1.2% of the foot length. Following this, we show how these results could be used to improve measurements in a minimal IMU based sensing setup.

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Persistent URL dx.doi.org/10.1109/EMBC.2019.8857314, hdl.handle.net/1765/123913
Conference 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2019
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Citation
Refai, M.I.M. (Mohamed Irfan Mohamed), Van Beijnum, B.-J.F. (Bert-Jan F.), Buurke, J.H, Saes, M. (Mique), Bussmann, J.B.J. (Johannes B.J.), Meskers, C.G. (Carel G.), … Veltink, P.H. (Peter H.). (2019). Portable Gait Lab: Zero Moment Point for Minimal Sensing of Gait. In Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS (pp. 2077–2081). doi:10.1109/EMBC.2019.8857314