Inherent Haptic Feedback From Supernumerary Robotic Limbs.

Supernumerary Robotics Limbs, or SuperLimbs for short, are wearable extra limbs for augmenting the wearer. SuperLimbs are attached directly to a human and, thereby, transmit a force from the environment to the human body. This inherent haptic feedback allows the human to perceive the interaction between the robot and the environment, monitor its actions, and effectively control the robot. This article addresses basic properties and the usefulness of the inherent haptic feedback from SuperLimbs in two exemplary cases. First, we show that the inherent haptic feedback allows the wearer to close the loop and manually regulate the force output of the SuperLimb. Second, we show that the inherent haptic feedback is sufficient for the wearer to supervise the autonomous actions of the SuperLimb. This ability is a critical requirement for safely and effectively performing multiple tasks simultaneously with the natural limbs and SuperLimbs. Together, these findings suggest the importance of designing SuperLimbs to take advantage of the inherent haptic feedback.