With the development of modern computer based systems, gait analysis has been an active research topic in recent years and gait tracking system is widely applied into physical therapy and rehabilitation such as stroke rehabilitation and elderly clinical trials. The demand for gait digitization stimulates the improvement of gait tracking system. However, for this specific system, accuracy remains a problem although the IMU based tracking system precedes the optical gait tracking system for its simple use and relatively independence of the environmental influence. Moreover, large hospitals and rehabilitation centers suffer high expenses on the tracking system.

In this thesis, we focus on the proposed “9-Axis gait tracking system”, which is made up of two modules, a popular commercial 9-...[ Read more ]

With the development of modern computer based systems, gait analysis has been an active research topic in recent years and gait tracking system is widely applied into physical therapy and rehabilitation such as stroke rehabilitation and elderly clinical trials. The demand for gait digitization stimulates the improvement of gait tracking system. However, for this specific system, accuracy remains a problem although the IMU based tracking system precedes the optical gait tracking system for its simple use and relatively independence of the environmental influence. Moreover, large hospitals and rehabilitation centers suffer high expenses on the tracking system.

In this thesis, we focus on the proposed “9-Axis gait tracking system”, which is made up of two modules, a popular commercial 9-Axis sensor and a Wi-Fi enabled MCU, with total cost around 100 HKD. It records the gait data with finely calibrated IMU, and draws the support from the state-of-the-art orientation filtering algorithm with experimental optimal control settings plus merged gravity and geomagnetic information, as well as the linear cancellation procedure for velocity drift to reconstruct accurate and stable gait trajectory for analysis.

We evaluate performance of 9-Axis gait tracking system by comparing it with 6- Axis gait tracking system implemented in both outdoor and indoor environment with single step test, straight-line walking test in short and long distance, square path test, triangle path test, zigzag path test, slight and strong magnetic interference environment, in most of which show overwhelming advantage of 9-Axis data’s trajectory.

As for commercial use, the proposed IMU based “9-Axis gait tracking system” keeps small in size and simple in operation. The single node system is ready for daily use in sports and fitness while the full tracking system is able to bring professional rehabilitation analysis report to people in special need with lower cost.

Key words: gait tracking, 9-Axis sensor, calibration, orientation, trajectory