91 research outputs found
Control oriented modeling of a twin thruster autonomous surface vehicle
No full textThis work investigates and identifies a first principles maneuvering model for a small size robotic twin thruster autonomous surface vessel (ASV) that includes and explains the sources of nonlinearity and asymmetry of this class of robots. With respect to state of the art ASV models, the proposed one accounts for the effects generating a transverse thrust, explaining the asymmetric turning radii. The model also accounts for the need to adapt the hydrodynamic derivatives when the ASV performs large or tight turns. An experimental dataset has been acquired using the ULISSE ASV and it is used to support the proposed model in comparison to the “baseline” one often used in the literature. The improved precision of the proposed model in fitting experimental data is a necessary prerequisite to design model-based motion controller and navigation systems with enhanced performance
A task-priority based control approach to distributed data-driven ocean sampling
No full textThe paper illustrates the basic ideas and relevant algorithmic developments underlying the proposal for a task-priority based control approach to distributed data-driven ocean sampling applications. This approach is deemed allowing a better formalization of the overall motion problem of the involved team of agents; that apart the ultimate mission objective, also result characterized by other different control objectives directly related with both operability and safety aspects of the entire sampling system. Also, the proposed approach, other than leading to a unifying algorithmic structure, also seems allowing to foresee good possibilities for different types of downgrading toward efficient decentralized implementations
A PID-backstepping Hybrid Position and Attitude Control of a Bi-copter AUV with a Moving Mass
No full textHybrid Cable Thruster Actuated Remotely Operated Underwater Vehicle
No full textThis paper introduces a novel Hybrid Cable Thruster Actuated Remotely Operated Underwater Vehicle (HCT-ROV), merging the strengths of ROVs and Cable-Driven Parallel Robots for enhanced underwater capabilities. It presents the world's first HCT-ROV prototype, together with a control law using Quadratic Programming (QP) for efficient operation. Extensive MATLAB simulations and prototype tests demonstrate superior performance in tasks like object transportation. This research work paves the way for advanced underwater exploration and operations, emphasizing the need for further optimization in real-world applications
Visual Servoed Autonomous Landing of an UAV on a Catamaran in a Marine Environment
No full textThis paper introduces a procedure for autonomous landing of a quadrotor on an unmanned surface vehicle in a marine environment. The relative pose and velocity of the vehicle with respect to the quadrotor are estimated using a combination of data coming from a vision system, which recognizes a set of AprilTags located on the vehicle itself, and an ultrasonic sensor, to achieve further robustness during the final landing phase. The considered software and hardware architecture is provided, and the details about the landing procedure are presented. Software-in-the-loop tests were performed as a validation step for the proposed algorithms; to recreate realistic conditions, the movements of the landing platform have been replicated from data of a test in a real marine environment. In order to provide further proof of the reliability of the vision system, a video sequence from a manual landing of a quadrotor on the surface vehicle in a real marine environment has been processed, and the results are presented
WiMUST: A cooperative marine robotic system for autonomous geotechnical surveys
No full textThis paper presents the main results of the European H2020 WiMUST project, whose aim was the development of a system of cooperative autonomous underwater vehicles and autonomous surface vehicles for geotechnical surveying. In particular, insights on the overall robotic technologies and methodologies employed, ranging from the communications and navigation framework to the cooperative and coordinated control solutions are given. The software architecture and the lessons learnt from the preliminary field test are also discussed. Finally, field results of the final survey campaign carried out in the Atlantic Ocean are presented, demonstrating how a team of seven robots could autonomously conduct a geotechnical survey, producing seismic images without artifacts
A Unifying Task Priority Approach for Autonomous Underwater Vehicles Integrating Homing and Docking Maneuvers
No full textThis research proposes a unified guidance and control framework for Autonomous Underwater Vehicles (AUVs) based on the task priority control approach, incorporating various behaviors such as path following, terrain following, obstacle avoidance, as well as homing and docking to stationary and moving stations. The integration of homing and docking maneuvers into the task priority framework is thus a novel contribution of this paper. This integration allows, for example, to execute homing maneuvers close to uneven seafloor or obstacles, ensuring the safety of the AUV, as safety tasks can be given the highest priority. Furthermore, another contribution shown in the paper is that the proposed approach tackles a wide range of scenarios without ad hoc solutions. Indeed, the proposed approach is well suited for both the emerging trend of resident AUVs, which stay underwater for a long period inside garage stations, exiting to perform inspection and maintenance missions and homing back to them, and for AUVs that are required to dock to moving stations such as surface vehicles, or towed docking stations. The proposed techniques are studied in a simulation setting, taking into account the rich number of aforementioned scenarios
Task priority control of underwater intervention systems: Theory and applications
No full textThis paper presents a unifying task priority control architecture for underwater vehicle manipulator systems. The proposed control framework can be applied to different operative scenarios such as waypoint navigation, assisted teleoperation, interaction, landing and grasping. This work extends the results of the TRIDENT and MARIS projects, which were limited to the execution of grasping actions, to other applications taken from the DexROV and ROBUST projects. In particular, simulation results show how the control framework can be used, for example, for pipeline inspection scenarios and deep sea mining exploration
Towards the Use of a Team of USVs for Civilian Harbour Protection: USV Interception of Detected Menaces
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