Knee joint angle monitoring system based on inertial measurement units for human gait analysis

Abstract

Gait Analysis involves analyzing human walking, particularly its temporal parameters. Gait parameters (cadence, step length, trajectory of center of mass, etc) require measurements of lower-limb joint angles. The most commonly used techniques for gait analysis are optical systems. However, these systems have several drawbacks which include: markers need to be attached to the human body; it is required a considerable amount of time for setting up the experimental session; High cost; Bulk and space requirements; finally, they are restricted to a limited place or laboratory. Inertial measurement units (IMU) can be used in body-worn biomechanical monitoring devices for movement data collection in daily life. This paper presents a system based on 2 IMUs for knee joint angle monitoring to be used for long-time periods in out-of-lab daily life. For validation, the system was compared to a visionbased motion capture system, in a set of experiments involving walking on a treadmill under three different velocities (slowspeed, normal-speed, high-speed). Obtained results showed high correlation (>0.94) between measurements from the developed device and the vision-based motion capture system, according to the obtained concordance correlation coefficients.