Advancing ambulatory gait stability assessment with a small set of inertial sensors

Among older adults and individuals with gait impairments, gait stability problems are often early indicators of an increased risk of falls. Inertial measurement units (IMUs) are characterized by their real-time monitoring capability, convenience, and portability, making them suitable for assessing human gait stability in daily life. Early detection through IMUs allows for the identification of potential stability issues, enabling preventive interventions to reduce fall risk. The goal of this thesis is to propose a solution using a small set of IMUs to estimate the FPE, towards gait stability analysis in daily life. This goal is completed by addressing the following research questions:
1) How can we simplify a full-body model with a reduced set of segments for estimating WBAM?
2) What is the suitable local reference frame for expressing the WBAM and gait stability variables in 3-D cases in daily life conditions?
3) How can we estimate the WBAM and linear momentum, subsequently the FPE with a small set of IMUs? Addressing these three questions leads to the following main findings?
To conclude, this thesis proposes a portable solution of using only four IMUs to estimate gait stability related variables considering both the linear and angular momentum of the human body. The insights can be considered in the long-term tracking of gait stability in daily life conditions, understanding the contribution of linear and angular momentum to gait stability, and the development of feedback controller for balance assistance.