STARLIT

Smart automation and robotic tools as modular solutions in the industrial space sector TBC

On-orbit servicing (OOS) and in-orbit manufacturing and assembly (ISMA) operations are becoming increasingly important in todays and future space applications. Almost all potential applications require the ability to interact with robotic systems. Therefore, extensive R&D activities have been advanced in Germany, Europe and internationally in recent years to develop compact, lightweight and general-purpose manipulator arms for orbital use (e.g. ROKVISS, CAESAR, DEXARM, PIAP). As a result, the architectural concepts and underlying technologies for these systems are at an advanced stage of development. Tools that can be attached to the end effector of manipulators and operated to perform the actual contact operations such as gripping, screwing, riveting are usually less generic and designed for specific operations, which limits their use on individual missions. The subject of this project is the definition and development of an intelligent end effector for orbital robotic systems with manipulation capability. The basis for this development is the Multi-Purpose-Tool (MPT) tool architecture of AIRBUS Defence and Space GmbH (ADS). Core of this architecture is the separation of the tools into a generic propulsion and avionics module, as well as into the mission- and application-specific tool attachments. This separation enables the development of new tools for specific technological operations in a shorter time and with a lower budget. At DFKI, STARLIT will develop and evaluate robotic gripping tool attachments to enable robotic units to handle and manufacture large structures, such as antenna segments, in orbit.

Duration: 01.10.2021 till 31.03.2023
Donee: German Research Center for Artificial Intelligence GmbH
Sponsor: Federal Ministry for Economic Affairs and Climate Action
Grant number: 50RA2119
Partner:

Airbus Defence and Space

Application Field: Space Robotics
Related Projects: PULSAR (OG8)
Prototype of an Ultra Large Structure Assembly Robot (02.2019- 03.2021)
PERIOD (OG12)
PERASPERA In-Orbit Demonstration (Operational Grant 12) (01.2021- 12.2022)

Project details

On-orbit servicing (OOS) and in-orbit manufacturing and assembly (ISMA) operations are becoming increasingly important in todays and future space applications. Almost all potential applications require the ability to interact with robotic systems. Therefore, extensive R&D activities have been advanced in Germany, Europe and internationally in recent years to develop compact, lightweight and general-purpose manipulator arms for orbital use (e.g. ROKVISS, CAESAR, DEXARM, PIAP). As a result, the architectural concepts and underlying technologies for these systems are at an advanced stage of development. Tools that can be attached to the end effector of manipulators and operated to perform the actual contact operations such as gripping, screwing, riveting are usually less generic and designed for specific operations, which limits their use on individual missions. The subject of this project is the definition and development of an intelligent end effector for orbital robotic systems with manipulation capability. The basis for this development is the Multi-Purpose-Tool (MPT) tool architecture of AIRBUS Defence and Space GmbH (ADS). Core of this architecture is the separation of the tools into a generic propulsion and avionics module, as well as into the mission- and application-specific tool attachments. This separation enables the development of new tools for specific technological operations in a shorter time and with a lower budget.

At DFKI, STARLIT will develop and evaluate robotic gripping tool attachments to enable robotic units to handle and manufacture large structures, such as antenna segments, in orbit.

For this purpose, the development of a proof-of-concept mechanism and its partial qualification in the range of TRL 3-5 was aimed for 2022. The tool development is aligned with the PERIOD project, which is part of the Horizon 2020 space research cluster of the European Union for the promotion of technology in space robotics. Video 1 shows a study of the planned on-orbit assembly of an antenna, outside the ISS on the Bartholomeo platform.

To convert the rotary movement provided by the shaft of the MPT into a translatory movement for gripping the objects, kinematics were developed, calculated and compared. Requirements such as keep holding the objects in the event of a malfunction or compensating for the positioning inaccuracies of the manipulator were considered. Additionally, functional requirements, environmental requirements such as vibration- and thermal loads and the operation under vacuum, also had to be take into design decisions. The sum of available mechanically suitable components, which have already qualified for use in space or can be qualified in the near future, led by kinematics analysis to a division of the tools into a Gripper Drive Unit (GDU) and the actual end effectors. For geometric and technical reasons, the direct transmission of the rotary motion generated by the MPT was not possible to use for the operations.


The GDU (Fig. 1) converts the rotary motion from the MPTs input shaft into a translational motion provided to the tools. Limits for the drive shaft, realized due to hard end stops protects the following components from the input torque of the MPT. The GDU also contains parts of an interface that has already been tested in a previous project and enables the tools to be changed automatically in orbit.

Two tool attachments were developed as end effectors in the StarLit project. One is the Cleat Gripper (Fig. 2), which is used to grip connecting elements, and the Frame Gripper (Fig. 3), which can grip two-dimensional structures via a defined triangular geometry. In both tool attachments, the closing process is driven springs. Just the opening has been driven actively by the GDU. This enables the object to be held securely even in the event of a malfunction. For the frame gripper lever mechanisms are used in a smart way, to prevent back driving (opening du to applying force to the gripper jaws) and thus ensure safe handling of the objects. It is worth noting that the loss of objects in orbit must be avoided at all costs, as this would inevitably lead to dangerous space debris. Figures 4,5 and 6 show the basic structure of the Gripper Drive Unit and the tools.

Component tests have so far been carried out with the Cleat Gripper and the GDU. Figure 7 shows the Cleat Gripper during the vibration load tests, which were executed according to ECSS specifications on the shaker of the Zarm Technik AG. A final qualification can be made when the start configuration has been determined. The tools are also ready for and prepared for thermal-vacuum testing due to design and integration.

The validation of the tools will take place in operational tests at our partner Airbus Space and Defence in Bremen.

It stays exciting.

Publications

2023

Design and testing of mechanical gripping tools for On Orbit assembling
Niklas A. Mulsow, Adam Dabrowski, Martin Mallwitz, Leonard Maisch
Editors: 13th EASN International Conference Proceedings
In Journal of Physics: Conference Series, IOPscience, volume 2526, pages _-_, 2023.

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