Human guidance: suggesting walking pace under manual and cognitive load

This paper presents a comparison between two different approaches to control human walking cadence, with the further aim to assess if the users can synchronize to the suggested rhythm with low efforts while performing other tasks. Elastic haptic bands are used to suggest walking-pace during an exercise aimed at reproducing real industrial or human-robot cooperation task. The proposed system consists of two wearable interfaces for providing timing information to the users, and a pressure sensor to estimate the real gait pattern, thus resulting in a combination of walking-state monitoring and vibro-tactile stimuli to regulate the walking pace. Vibrational stimuli with a constant presentation interval are alternately and repeatedly given to the right and left side of the human body, in accordance with the desired walking cadence. We tested two different interface placements: wrists and ankles. The guidance system has been evaluated under mental and manual workload using an additional task: balancing a small sphere in the center of a flat surface. Experimental results revealed that subjects prefer the ankle position for what concerns wearability, comfort and easiness in task execution. Examples of the proposed approach in daily use are training and coaching in sports, rehabilitation, and human-robot cooperation and interaction.