Modeling and Control of a Floating Marine Litter Collection Device

Marine litter poses a significant environmental threat, with detrimental effects on marine ecosystems through toxic chemical release, entanglement, ingestion by marine life, and microplastic formation. Floating waste collection devices, such as the Waste Out of Water (WoW) system developed by the University of Florence, offer a solution by intercepting debris before it disperses into open waters. The WoW device employs a buoyant sliding-cylinder mechanism to regulate water inflow, driven by water level variations, while a pump-controlled outflow directs polluted water to a filtration system. This study proposes a fluid-dynamic model of the WoW system, incorporating factors such as inflow dynamics, outflow regulation, buoyancy, friction, and motion constraints. The model is treated as a grey-box, the parameters are estimated through the solution to an optimization problem in the frequency domain, and the model is validated against experimental data collected during the device operation. Moreover, a simple PID control strategy is implemented in the simulation to show the potential ability to control the device to an operational point of interest. These findings provide useful insights into improving floating waste collection devices and their deployment for effective marine pollution mitigation.