Using a Collaborative Robotic Arm as Human-Machine Interface: System Setup and Application to Pose Control Tasks.

While robotic arms have been used in a vast range of application areas, so far no extensive reports on the utilization as human-machine interface exist. Compared to HMI devices from literature, the robotic arm used in this work (KUKA LBR iiwa 14 R820) features a relatively large workspace and is able to generate force and torque feedback that surpasses the capabilities of literature devices. We describe the setup allowing to use the robotic arm as HMI and analytically determine the optimal initial pose of it based on the manipulability measure of Yoshikawa. To demonstrate that the robotic arm is able to serve as HMI, we report on a comparative study with a state of the art haptic HMI featuring 20 participants. Additionally, two applications from the context of planetary exploration are presented: The first considers the teleoperation of the pan-tilt unit of a lightweight rover unit and illustrates how the large workspace of the HMI benefits the precision of the teleoperation compared to a setup with a smaller workspace. The second experiment showcases the use of the force feedback of the HMI to enable a cooperation between the operator and a supporting path-following automation in a shared control of a simulated ground robot. Both the study and the applications highlight the performance, precision and reliability of our proposed system.