LOTUSim: Multi-Domain Simulator for Marine Robotics
2026-07-03 • Multiagent Systems
Multiagent SystemsRobotics
AI summaryⓘ
The authors present LOTUSim, a free simulator designed for maritime robots that allows multiple users to interact with drones operating in air, on water, and underwater at the same time. It runs smoothly in real-time even when simulating large groups of different robots working together, which they confirmed through testing. They also developed a new underwater current model inspired by real ocean physics that is both faster to compute and more accurate than common existing models. This makes LOTUSim a good tool for training and research involving human operators controlling maritime robots. Overall, the authors focus on realism and interaction rather than just robot autonomy.
maritime roboticsreal-time simulationhuman-in-the-loopmulti-user interactionunderwater currentsEkman layerautonomy systemsGauss-Markov modelrobotic swarmsoperator training
Authors
Cédric Buche, Juliette Grosset, Hélène Lechêne, Marie Dubromel, Pierig Havez-Bodivit, Malcom Neo, Julien Prodhon
Abstract
Simulation is essential for maritime robotics, supporting operator training, mission rehearsal, and human-vehicle interaction in environments where real-world testing is costly or hazardous. Existing simulators focus primarily on autonomy systems and often lack human-in-the-loop interaction and realistic environmental physics. This paper introduces LOTUSim, an open-source, real-time maritime simulator supporting multi-user interaction across aerial, surface, and underwater robotic systems for coordinated naval-style operations. The first contribution of this work is enabling real-time interactive performance for users while ensuring scalability to large fleets operating within a shared interactive simulation environment. Validation demonstrates robust human-in-the-loop performance, maintaining strict real-time execution and high visual fidelity while scaling to large heterogeneous maritime drone swarms. The second contribution is a computationally efficient, Ekman-inspired layered, underwater current model that captures wind-driven, depth-dependent flow dynamics with sufficient physical fidelity for large-scale simulations. Validation against ocean reanalysis data demonstrates substantially improved accuracy compared to commonly used stochastic Gauss-Markov current models. These results confirm LOTUSim's suitability as a simulation platform for operatorin-the-loop maritime robotics research.