Abstract-We present the methodology, algorithms, system design, and experiments addressing the self-assembly of large teams of autonomous robotic boats into floating platforms. Identical self-propelled robotic boats autonomously dock together and form connected structures with controllable variable stiffness. These structures can self-reconfigure into arbitrary shapes limited only by the number of rectangular elements assembled in brick-like patterns. An complexity algorithm automatically generates assembly plans which maximize opportunities for parallelism while constructing operator-specified target configurations with components. The system further features an complexity algorithm for the concurrent assignment and planning of trajectories from free robots to the growing structure. Such peer-to-peer assembly among modular robots compares favorably to a single active element assembling passive components in terms of both construction rate and potential robustness through redundancy. We describe hardware and software techniques to facilitate reliable docking of elements in the presence of estimation and actuation errors, and we consider how these local variable stiffness connections may be used to control the structural properties of the larger assembly. Assembly experiments validate these ideas in a fleet of 0.5 m long modular robotic boats with onboard thrusters, active connectors, and embedded computers. Note to Practitioners-This work addresses the deployment of large scale floating structures to accelerate humanitarian missions or disaster relief by assembling together many self-propelled ISO shipping containers equipped with actuators and sensors. Thousands of modules would be needed to form temporary bridges, harbors, or air strips in a full-scale deployment; we give efficient solutions to the ensuing large-scale assembly planning and multiboat routing problems. This work will be of interest to those considering assembly planning with many identical pieces. Our 1:12 scale experiments serve as a proof of concept system and a case study in the design of practical self-assembling components. The docking and maneuverability design elements will be of interest to those The authors are with the GRASP Laboratory and the Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104 USA (e-mail: jpaulos@seas.upenn.edu; neck@seas.upenn.edu; tarikt@seas.upenn.edu; juse@seas.upenn.edu; jaydavey@seas.upenn.edu; jongreco@seas.upenn.edu; kumar@seas.upenn.edu; yim@seas.upenn.edu). Color versions of one or more of the figures in this paper are available online at http://ieeexplore.ieee.org. This paper has supplementary downloadable multimedia material available at http://ieeexplore.ieee.org provided by the authors. The Supplementary Material includes a video summary of the experimental results described in the paper. In this short video, boats are shown navigating across an athletic pool and automatically self-assembling into prescribed structures (.mp4 video). This material is 30 MB in size. Digital Object Identifier 10.1109/TASE.2015.2416678 addressing self-reconfiguration in marine environments. We discuss tools and strategies which address the practical challenge of developing software for dozens of interacting robots, all floating out of physical reach. The approaches described here currently do not apply to arbitrary three-dimensional structures, or heterogeneously shaped elements.
Paulos et al. present a system in which self-reconfigurable modular boats self-assemble into prescribed floating structures, such as a bridge REF .
Automated Self-Assembly of Large Maritime Structures by a Team of Robotic Boats
IEEE Transactions on Automation Science and Engineering
IEEE Transactions on Automation Science and Engineering
Computer Science