Developing the sensor system for lower limb rehabilitation robot : for shifting of body-weight via insole flexi-force sensing

Abstract

This report reflects the methods for device-assisted body-weight shifting (BWS) during walking rehabilitation. The relevance of this report to device-assisted BWS is that it presents the specific kinematics of pelvis during walking, and suggests a way in which modification of the current robotic rehabilitation robot to assist patient with body-weight shifting can be implemented. The value of this report in relation to the study of lower-limb rehabilitation is the intensive literature study and the record of relevant experiments that involve some of the clinical rehabilitation equipment, in particular the electromyography system and the piezoelectric sensors.

This report includes, firstly, the design of a robotic mechanism for lateral pelvic control which is one of the key body-weight shifting during the stance phase of the walking gait cycle. In designing the robotic mechanism, intensive effort is made to simplify the pelvic movements and possible robotic assistance, thereby a detailed robotic mechanism for compensating one of the movements is designed. Secondly, it consists of the investigation of sensory information from the feet through thin-foil peizo-resistive sensor, known as the Flexi-force sensor, which is intended to provide sensor feedback to the mechanism. This Flexi-force sensor is one of most cost-effective clinical equipment to acquire temporal information of the walking gait. Lastly, the research is substantiated with the study of electromyography (EMG) pattern of lower-limb muscles during walking to understand the human biomechanics involved in normal unassisted walking and device-assisted walking.