Impedance-controlled robots are widely used on Earth to perform interaction-rich tasks and will be a key enabler for In-Space Servicing, Assembly and Manufacturing (ISAM) activities. This paper introduces the software architecture used on the On-Board Computer (OBC) for the planned SpaceDREAM mission aiming to validate such robotic arm in Lower Earth Orbit (LEO) conducted by the German Aerospace Center (DLR) in cooperation with KINETIK Space GmbH and the Technical University of Munich (TUM). During the mission several free motion as well as contact tasks are to be performed in order to verify proper functionality of the robot in position and impedance control on joint level as well as in cartesian control. The tasks are selected to be representative for subsequent servicing missions e.g. requiring interface docking or precise manipulation. The software on the OBC commands the robot's joints via SpaceWire to perform those mission tasks, reads camera images and data from additional sensors and sends telemetry data through an Ethernet link via the spacecraft down to Earth. It is set up to execute a predefined mission after receiving a start signal from the spacecraft while it should be extendable to receive commands from Earth for later missions. Core design principle was to reuse as much existing software and to stay as close as possible to existing robot software stacks at DLR. This allowed for a quick full operational start of the robot arm compared to a custom development of all robot software, a lower entry barrier for software developers as well as a reuse of existing libraries. While not every line of code can be tested with this design, most of the software has already proven its functionality through daily execution on multiple robot systems.

翻译：阻抗控制机器人在地球上广泛用于执行交互密集型任务，并将成为在轨服务、组装与制造（ISAM）活动的关键使能技术。本文介绍了德国航空航天中心（DLR）与KINETIK Space GmbH及慕尼黑工业大学（TUM）合作开展的SpaceDREAM任务中，为验证此类机械臂在近地轨道（LEO）性能而设计的星载计算机（OBC）软件架构。该任务计划执行多项自由运动及接触任务，以验证机器人在关节级位置与阻抗控制以及笛卡尔空间控制中的功能完备性。任务设计具有后续服务任务的代表性，例如需完成接口对接或精密操作等场景。OBC软件通过SpaceWire总线控制机器人关节执行任务指令，同步读取相机图像与多传感器数据，并通过以太网链路经航天器将遥测数据传回地面。该软件架构在接收航天器启动信号后即可执行预定义任务，同时具备可扩展性以支持未来任务接收地面指令。核心设计原则是最大限度复用现有软件，并保持与DLR现有机器人软件栈的高度兼容。相较于全定制开发，该方案使机械臂能快速投入全功能运行，降低了软件开发者的入门门槛，并实现了现有代码库的复用。虽然此设计无法对每行代码进行测试，但大部分软件已通过在多套机器人系统中的日常运行验证了其可靠性。