Pelvis motion analysis for gait phase estimation toward leg-dependent body weight support at different walking speed.

Gait phase based body weight support can be an effective method for patients who possess different ability in each leg and who require different unloading forces between the affected and unaffected sides. To realize this concept, we proposed a gait phase estimation method from pelvic motion focusing on the feature of its quasi-periodic movement at constant walking speeds. In this study, we analyzed the relationship between the turning point of pelvic motion and the heel contact point at different walking speeds. The values of time lag were not constant at different walking speeds; rather they declined as walking speed increased. In addition, the results indicate that the turning points of lateral movement and vertical movement always occurred in advance of heel contact under 6.0 (km/h). Under this condition, the gait phase estimation method can be adopted if the time lag values at different walking speeds are prerecorded.