A new FES-assisted gait training system for hemiplegic stroke patients based on inertial sensors

An inertial sensor mounted on the foot of the affected body side represents an alternative to traditional foot switches in Functional Electrical Stimulation (FES)-assisted gait rehabilitation systems.The inertial sensor consisting of 3 gyroscopes and 3 accelerometers can be utilised to detect gait phases which can be applied to synchronise the electrical stimulation with the gait. Additionally, the sensor can be applied to estimate orientation and 3 dimensional movement of the foot. Based on the estimated orientation and linear position several movement parameters can be defined. The most important are the foot clearance, which is defined as maximal distance between foot and ground, and the sagittal angle of the foot in relation to the ground at the time as the heel hits the ground. In this paper we describe a practical system for FES-assisted gait training based on inertial sensors where the electrical stimulation is triggered by the gait phase detection and the stimulation intensity is automatically tuned by feedback of movement parameters