Dynamics of sprung leg and control of swinging leg in paraplegic walking

摘要

Exploiting natural dynamics of sprung orthosis leads to ease of control of natural-like swing phase in paraplegic gait. A new technique for generating the swing phase in paraplegic gait is proposed in this paper. The new hybrid orthosis is referred to as Spring Brake Orthosis (SBO). In this method the knee and hip are simultaneously flexed to initiate the swing phase. In the SBO, three elements namely spring, brake, and muscle are involved in synthesising the leg swing function. It is shown that hip flexion can be produced without the need for the withdrawal reflex, hip flexor stimulus or any mechanical actuator at the hip. This mechanism simplifies the control task and results in motion, which is smooth, and more-natural like trajectory than that produced by the flexion reflex for gait in spinal cord injured subjects. The artificially stimulated muscle is used as the power source. A scheduling controller is adopted to control such hierarchical structure movement and regulate the electrically stimulated muscle torque. The results of several trials show the repeatability of this mechanism and normal-like swing phase.