Development of an instrumented lower limb orthosis for paraplegia : Trial manufacturing and evaluation of dorsal flexion controlled ankle joint applying MR brake (2nd Rep.)

Abstract

A dorsal flexion controlled lower limb orthosis for paraplegia is developed and evaluated. Dorsal flexion of ankle joint in swing phase is useful to get clearance between foot sole and floor, for easily carrying a lower limb from aft to fore. To realize this, MR brake is installed in the ankle joint of orthosis which is fan shaped and made of aluminum alloy to move 70 degrees from dorsal to plantar flexion. The MR brake filled with magneto-rheological fluid has an outer loop of MR fluid and flow viscosity is quickly changed by moving permanent magnet block. MR brake is active during the swing phase detected by the foot sole switches. The effect of the MR brake to hold the dorsal flexion in swing phase is proved experimentally by a polio patient of drop-foot on level walking.