1,721,000 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 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
Design and Control of a Cooperative System of an Autonomous Surface Vehicle and a Remotely Operated Vehicle (ASV-ROV)
No full textMarine robotics plays a fundamental role in executing various underwater complex missions. In this scenario tethered Remotely Operated Vehicles (ROVs) offer benefits such as efficient data transmission and strong physical connection for emergency cases, but their motion is confined by the length of the tether. This study addresses the issue of extending the range of the ROV by implementing a new control strategy cooperating with an Autonoumous Surface Vehicle (ASV). The proposed system ASV-ROV confronts two main challenges: the constrained movement of the ROV and the risk of cable entanglement. Therefore, a new control system is built to provide the ROV a smooth motion and avoid situations that are likely to generate cable entanglements. The new control system enables the ASV to align and to keep a certain distance from the ROV, regulating at the same time the released cable length in the water. The paper addresses the design of ASV-ROV cooperative system, the modelling of each vehicle, the control strategy, and simulation results. Future work research is also outlined at the end
Simulative validations of RT^2: A Real-Time Ray-Tracing technique for acoustic-based range evaluation
No full textDexROV project: Control Framework for Underwater Interaction Tasks
No full textAbstract:
In this work, the control framework of the DexROV Horizon 2020 project is presented. The framework is based on the task priority concept, extended by the authors to allow the activation and deactivation of tasks. The general concepts of control objectives, task and actions are given. The execution of a pipeline's weld inspection is used as study case to test the proposed framework in a simulation setting
- …
