Development of sole instrumentation system for estimating ground reaction force in biomechanics

Abstract

Ground reaction force (GRF) measurements have been widely used for various purposes such as gait phase analysis, abnormal gait detection, and control of exoskeletons. The GRF is usually measured by a force plate which is restricted to laboratory environment. Although many wearable GRF measurement systems for overcoming the limitation of the use of force plate, the restricted use in the laboratory environment, are developed, there are still problems such as bulkiness, low accuracy, low capacity and poor time response. In this thesis, a portable GRF sensing system for addressing the limitations of previous researches is proposed. The proposed system is separated into four parts (toe, left, right metatarsal, and heel parts) which are fitted to the curvature of the foot. One Z directional sensor is placed in each metatarsal part and a pair of sensors (one X directional sensor and one Z directional sensor) is located in toe and heel parts, respectively. The experiments consist of two tests; comparison of the data from the proposed system with that from force plate in static condition; analysis of dynamic condition. The static condition denotes standing test on the force plate and the dynamic condition denotes self-selected speed walking on the force plate. The proposed system is compact and measures the improved shear force, so it could be applied to measure the GRF in various environments such as treadmill walking, level ground walking, and stair walking.