System Architecture and Design Considerations for the Humanoid Robot Rollin’ Justin in Context of the Surface Avatar Mission

With continuous advancements in robotics, both in hardware and in software, the feasibility to deploy robotic assistants as co-workers for astronauts in real mission scenarios is coming in sight. In the context of the Surface Avatar International Space Station (ISS) telerobotic technology demonstration mission, we study the requirements in terms of user interface (UI), robotic capabilities, and communication to enable efficient usage of robots as astronaut's co-workers. During the experiments, astronauts onboard the ISS command a team of heterogeneous robots at the German Aerospace Center (DLR) in Oberpfaffenhofen, Germany, to perform experimental tasks in a Mars analog environment. In order to complete the tasks successfully, the astronauts have to select between different robot command modalities, namely teleoperation and supervised autonomy. While previous publications have mostly focused on the UI, the interfaces between robots and the UI, and the overall mission concept, this work sheds light on the robotic back-end and provides a description of our reference implementation. Utilizing the humanoid robot Rollin’ Justin as our prime use case, we describe the modules that enable the robotic capabilities that are offered to the astronauts as well as their implementations. As a core aspect of Surface Avatar is the ability to select from different command modes, i.e. supervised autonomy and direct teleoperation, we put special focus on the high-level modules that enable supervised autonomy, such as knowledge representation, belief state representation, and reasoning, as well as the teleoperation interfaces. The paper also describes the integration of the aforementioned modules into the overall system. In this work we share the decisions and iteration processes that lead up to our current design, the motivation behind the decisions, the limitations they imply on the system, and the lessons learned during the process. This work particular examines these modules in the context of the Surface Avatar experiment session and describes, in particular, the improvements that have been achieved in comparison to previous versions. While the system continues to evolve to support new features for upcoming experiment sessions, our description covers the state of the robot during the first ISS experiment sessions and the two following prime sessions of Surface Avatar.