Reconfigurable robots can physically merge and form new types of composite systems. This ability leads to additional degrees of freedom for robot operations especially when dynamically composed robotic systems offer capabilities that none of the individual systems have. Research in the area of reconfigurable multi-robot systems has mainly been focused on swarm-based robots and thereby to systems with a high degree of modularity but a heavily restricted set of capabilities. In contrast, this thesis deals with heterogeneous robot teams comprising individu- ally capable robots which are also modular and reconfigurable. In particular, the autonomous application of such reconfigurable multi-robot systems to enhance robotic space exploration missions is investigated.
Exploiting the flexibility of a reconfigurable multi-robot system requires an appropriate sys- tem model and reasoner. Hence, this thesis introduces a special organization model. This model accounts for the key characteristics of reconfigurable robots which are constrained by the availability and compatibility of hardware interfaces. A newly introduced mapping func- tion between resource structures and functional properties permits to characterise dynamically created agent compositions. Since a combinatorial challenge lies in the identification of feasi- ble and functionally suitable agents, this thesis further suggests bounding strategies to reason efficiently with composite robotic systems.
This thesis proposes a mission planning algorithm which permits to exploit the flexibility of reconfigurable multi-robot systems. The implemented planner builds upon the developed organization model so that multi-robot missions can be specified by high-level functionality constraints which are resolved to suitable combinations of robots. Furthermore, the planner synchronises robot activities over time and characterises plans according to three objectives: efficacy, efficiency and safety. The planner’s evaluation demonstrates an optimization of an exemplary space mission.
This research is based on the parallel development of theoretical concepts and practical solu- tions while working with three reconfigurable multi-robot teams. The operation of a reconfig- urable robotic team comes with practical constraints. Therefore, this thesis composes and eval- uates an operational infrastructure which can serve as reference implementation. The identi- fication and combination of applicable state-of-the-art technologies result in a distributed and dynamically extensible communication infrastructure which can maintain the properties of re- configurable multi-robot systems.
Field tests covering semi-autonomous and autonomous operation have been performed to char- acterise multi-robot missions and validate the autonomous control approach for reconfigurable multi-robot systems. The practical evaluation identified critical constraints and design ele- ments for a successful application of reconfigurable multi-robot systems. Furthermore, the experiments point to improvements for the organization model.
This thesis is a wholistic approach to automate reconfigurable multi-robot systems. It identi- fies theoretical as well as practical challenges and it suggests effective solutions which permit an exploitation of an increased level of flexibility in future robotics missions.