On handing down our tools to robots: Single-phase kinesthetic teaching for dynamic in-contact tasks

We present a (generalizable) method aimed to simultaneously transfer positional and force requirements encoded in a physical human skill (wood planing) from a human instructor to a robotic arm through kinesthetic teaching. We achieve our goal through a novel use of a common sensory configuration, constituted by a force/torque sensor mounted between the tool and the flange of a robotic arm. The robotic arm is endowed with integrated torque sensors at each joint. The mathematical model used to capture the general dynamic of the interaction between the human user and the wood surface is based on Dynamic Movement Primitives. During reenactment of the task, the system can imitate and generalize the demonstrated spatial requirements, as well as their associated force profiles. Therefore, the robotic arm acquires the capacity to reproduce the dynamic profile for in-contact tasks requiring an articulated coordination in the distribution of forces. For example, the capacity to effectively operate the plane on a wood plank over multiple strokes, according to the demonstration of the human instructor.