If It Doesn't Fit: Reconfigure It!

In the EU-ICT project REPLICATOR, everything (r)evolves around adaptability in multi-modular robotic "organisms". The robotic modules ("cells") that form these organisms are similar to some of the SYMBRION project, with the extension of the "active wheel" robot which was specifically designed to support the reconfiguration process. The scientific research questions in this project are all concerning this reconfiguration process and how it can be efficient, effective, flexible, robust, resilient and adaptive. Evolutionary computation and bio-inspired morphogenetic algorithms play a key role in this project.

To allow this growth of such "robotic organisms" to happen, a set of robotic modules needed to be designed in a way that they have their specific unique capabilities but are inter-operable and compatible to each other. This means that they can physically dock to each other with a strong reversible docking mechanism that allows for challenging motion principles of the combined "organism", such as crawling or walking, which can cause enormous forces acting on these docking mechanisms. The reversibility of the docking is essential to allow reconfiguration of demand. All modules can share electric power and information along these docking ports, what is another essential feature, as the bio-inspired algorithms that run on these modules can exploit this nearest-neighbor interactions for producing stable and/or dynamic patterns of energy and information, what is a crucial aspect for body-formation and collective locomotion. There is no central control of these modules, each cell is autonomously acting within the collective. Besides these similarities and interoperability design aspects, each module has also unique features, which are described in the following.

My research in the EU-ICT project REPLICATOR is in cooperation with the following international and interdisciplinary partners: Universität Stuttgart, Germany; Universität Karlsruhe, Germany; Czech Technical University in Prague, Czech Republic; Scuola Superiore Di Studi Universitari E Di Perfezionamento Santa Anna, Pontedera, Italy; Fraunhofer Gesellschaft zur Förderung der angewandten Forschung, Germany; Allmende BV, Rotterdam, Netherlands; UBISENSE Ltd. Cambridge, UK, Sheffield University, UK; In my lab, Dr. Ronald Thenius, Prof. Heiko Hamann, Dr. Payam Zahadat, Dr. Jürgen Stradner, Mag. Michael Bodi and Mag. Markus Dauschan conduct significant work in this project.

The K-Bot

Each K-Bot robotic "cell" has 4 docking ports on all 4 sides in the X-Y plane but also a very strong central hinge that allows to deform the module in a way that one docking port can be rotated to point also into the Z axis direction.

It moves with 2 rotating screws on the bottom ("screw drive") allowing moving forward, backward, left, right, curved motion and rotating on the spot. Several LEDs and cameras allow directional signal exchange for communication with other robotic modules, e.g. to induce and facilitated the docking process.

The strong hinge in the center of this robot makes it the ideal module to produce crawling "organisms" that bend in rhythmical patterns, e.g. like caterpillars do, but it can also form walking "legs".

The fact that the docking ports are on all sides allows the creation of non-linear body shapes that are then connected through multiple docking elements, what makes them even more robust.

The K-bot is extremely robust and strong and can dock to other modules to form organisms

S-Bot moving alone and as a joint "organism"

The S-Bot (Scout bot)

This robot "cell" module shares many aspects with the K-Bot, however its locomotion and its hinge system is completely different. The fast rubberband tracks let it move similar to a tank, with moving forward, backward, curved motion and rotation on the spot. In contrast to the K-Bot it cannot move directly left or right, thus it has one degree of freedom less.

Also the hinge system is not as strong (mechanically) as the hinge of the K-Bot is, as it sits on a long lever that can move (rotate) the front plate up and down.

However, the S-Bot has also significant advantages over the K-Bot: It is much faster and agile than a K-Bot, thus it is also called to be the "scout bot" in the system, it can cope with significantly more difficult terrain and can push itself out of difficult situations when it got trapped by pushing down its from plate.

The Active Wheel

The active wheel robot module is specifically designed to construct and reconstruct robotic organisms. It has omni-directional wheels and a central hinge that allows it to maneuver in difficult terrain and to lift its two docking ports to certain heights in order to dock or undock the cubic modules safely. The active wheel has two cavities for large batteries in its "legs" allowing to store large amounts of energy. As the docking ports also allow the sharing of energy, the active wheel can be used to recharge robotic organisms or to carry energy from one organism to another, allowing energetic homeostasis over the whole population of robotic organisms.

The upper picture on the right shows an active wheel that carries two modules and lifts them up in order to dock them at a higher place to an organism.

The lower picture on the right shows an active wheel actively facilitating the assembly of a larger robot organism. At the end of the process the active wheel can stay docked to such an organism, to support its motion, to increase its stability, to give extra security in case it got stuck, to add an energy storage capacity or to be just available if any reconfiguration of the organism is needed later on.

Active wheels in action

The Robotic Zoo of REPLICATOR