Detection of Human Contact by Thermal Exchange Observer of Robot Skin

Physical human-robot interaction (pHRI) enables to achieve various assistive tasks for people by robots such as collaborative robotics or motion assistance. It pertains both planning-control and hardware considerations. We propose a new soft robot skin that can detect human contact through thermal features. An electrically conductive pipe is interposed between graphite sheet that has high heat conductivity and soft material for cover compliance. Then the temperature of the water pipe is controlled by a heat source and a small water pump. Besides, an observer for estimating heat flow is implemented; it can detect human interaction by measuring the temperature change of the water pipe. Hence, there is no need to attach sensors to the robot skin's surface, which can be kept soft and eventually textured with a desired pattern. We assessed the validity of the prototype in experiments of contact detection by human fingers.