Tactile Physical Human-Robot Interaction: A Continuous Coupling Paradigm for Walking Assistance

Abstract

Physical human-robot interaction requires robots to respond to intent and support balance without explicit commands. In walking assistance, most systems rely on discrete interfaces or distal sensing, limiting their ability to engage continuous physical interaction and regulate whole-body dynamics. Here, we show that large-area tactile coupling at the human torso provides a physically grounded channel through which intention alignment and stability support are intrinsically unified. By enabling safe interaction at mechanically meaningful regions-waist and underarms-the robot directly participates in regulating coupled human-robot dynamics rather than reacting to detected events. Using a tactile-centered control framework on a walking support robot, we demonstrate that locomotion stability, reduced muscular effort, and balance loss mitigation emerge naturally from continuous tactile interaction, without explicit commands or independent safety mechanisms. These results suggest torso-level tactile coupling offers a principled pathway toward safer, more cooperative physical human-robot interaction.