Fleet of autonomous boats could service cities to reduce road traffic

The future of transportation in waterway-rich cities such as Amsterdam, Bangkok, and Venice -- where canals run alongside and under bustling streets and bridges -- may include autonomous boats that ferry goods and people, helping clear up road congestion. Researchers from MIT's Computer Science and Artificial Intelligence Laboratory (CSAIL) and the Senseable City Lab in the Department of Urban Studies and Planning (DUSP), have taken a step toward that future by designing a fleet of autonomous boats that offer high maneuverability and precise control. The boats can also be rapidly 3-D printed using a low-cost printer, making mass manufacturing more feasible. The boats could be used to taxi people around and to deliver goods, easing street traffic. In the future, the researchers also envision the driverless boats being adapted to perform city services overnight, instead of during busy daylight hours, further reducing congestion on both roads and canals. "Imagine shifting some of infrastructure services that usually take place during the day on the road -- deliveries, garbage management, waste management -- to the middle of the night, on the water, using a fleet of autonomous boats," says CSAIL Director Daniela Rus, co-author on a paper describing the technology that's being presented at this week's IEEE International Conference on Robotics and Automation. Moreover, the boats -- rectangular 4-by-2-meter hulls equipped with sensors, microcontrollers, GPS modules, and other hardware -- could be programmed to self-assemble into floating bridges, concert stages, platforms for food markets, and other structures in a matter of hours. "Again, some of the activities that are usually taking place on land, and that cause disturbance in how the city moves, can be done on a temporary basis on the water," says Rus, who is the Andrew and Erna Viterbi Professor of Electrical Engineering and Computer Science. The boats could also be equipped with environmental sensors to monitor a city's waters and gain insight into urban and human health. Co-authors on the paper are: first author Wei Wang, a joint postdoc in CSAIL and the Senseable City Lab; Luis A. Mateos and Shinkyu Park, both DUSP postdocs; Pietro Leoni, a research fellow, and Fábio Duarte, a research scientist, both in DUSP and the Senseable City Lab; Banti Gheneti, a graduate student in the Department of Electrical Engineering and Computer Science; and Carlo Ratti, a principal investigator and professor of the practice in the DUSP and director of the MIT Senseable City Lab. Better design and control The work was conducted as part of the "Roboat" project, a collaboration between the MIT Senseable City Lab and the Amsterdam Institute for Advanced Metropolitan Solutions (AMS). In 2016, as part of the project, the researchers tested a prototype that cruised around the city's canals, moving forward, backward, and laterally along a preprogrammed path. The ICRA paper details several important new innovations: a rapid fabrication technique, a more efficient and agile design, and advanced trajectory-tracking algorithms that improve control, precision docking and latching, and other tasks. To make the boats, the researchers 3-D-printed a rectangular hull with a commercial printer, producing 16 separate sections that were spliced together. Printing took around 60 hours. The completed hull was then sealed by adhering several layers of fiberglass. Integrated onto the hull are a power supply, Wi-Fi antenna, GPS, and a minicomputer and microcontroller. For precise positioning, the researchers incorporated an indoor ultrasound beacon system and outdoor real-time kinematic GPS modules, which allow for centimeter-level localization, as well as an inertial measurement unit (IMU) module that monitors the boat's yaw and angular velocity, among other metrics. The boat is a rectangular shape, instead of the traditional kayak or catamaran shapes, to allow the vessel to move sideways and to attach itself to other boats when assembling other structures. Another simple yet effective design element was thruster placement. Four thrusters are positioned in the center of each side, instead of at the four corners, generating forward and backward forces. This makes the boat more agile and efficient, the researchers say.