The importance of haptics in generating exoskeleton gait trajectory using alternate motor inputs

Human gait requires both haptic and visual feedback to generate and control rhythmic movements, and navigate environmental obstacles. Current lower extremity wearable exoskeletons that restore gait to individuals with paraplegia due to spinal cord injury rely completely on visual feedback to generate limited pre-programmed gait variations, and generally provide little control by the user over the gait cycle. As an alternative to this limitation, we propose user control of gait in real time using healthy upper extremities. This paper evaluates the feedback conditions required for the hands to generate complex rhythmic trajectories that resemble gait trajectories. This paper involved 18 subjects who performed a virtual locomotor task, where contralateral hand movements were mapped to control virtual feet in three feedback conditions: haptic only, visual only, and haptic and visual. The results indicate that haptic feedback in addition to visual feedback is required to produce rhythmic hand trajectories similar to gait trajectories.