1,723,396 research outputs found
Evaluation of the effects of the communication cable on the dynamics of an underwater flight vehicle
No full textThis paper presents a numerical scheme to evaluate the effects of the communication cable attached to an underwater flight vehicle. Both simulation and model validation results show that the numerical scheme is effective and provides a means for developing a feed-forward controller to compensate for the cable effects when developing an autopilot for the tethered vehicle. Moreover, the numerical scheme can also be applied to predict the effects of the ROVs umbilical during its deployment. <br/
Robust control of autonomous underwater vehicles and verification on a tethered flight vehicle
No full textScope: Unmanned marine vehicles (UMVs) include autonomous underwater vehicles, remotely operated vehicles, semi-submersibles and unmanned surface craft. Considerable importance is being placed on the design and development of such vehicles as they provide cost effective solutions to a number of littoral, coastal and offshore problems. This new book highlights the advanced technology which is evolving to meet the challenges being posed in this exciting and growing area of research.Contents: Navigation, Guidance and Control of Unmanned Marine Vehicles. Nonlinear Modelling, Identification and Control of UUVs. Guidance Laws, Obstacle Avoidance and Artificial Potential Functions. Behaviour Control of UUVs. Thruster Control Allocation for Over-Actuated, Open Frame Underwater Vehicles. Switching-Based Supervisory Control of Underwater Vehicles. Navigation, Guidance and Control of the Hammerhead Autonomous Underwater Vehicle. Robust Control of Autonomous Underwater Vehicles and its Verification on a Tethered Flight Vehicle. Low-Cost High Precision Motion Control for ROV’s. Autonomous Manipulation for an Intervention AUV. AUV ‘r2D4’, its operation, and Road Map for AUV Development. Guidance & Control of a Biomimetic-Autonomous Underwater Vehicle. Seabed-Relative Navigation by Hybrid Structured Lighting. Advances in Real-Time Spatio-Temporal 3D Visualisation for Underwater Robotic Exploration. Unmanned Surface Vehicles - Game Changing Technology for Naval Operations. Modelling, Simulation and Control of an Autonomous Surface Marine Vehicle for Surveying Applications Measuring Dolphin MESSIN. Vehicle and Mission Control of Single and Multiple Autonomous Marine Robots. Wave-Piercing Autonomous Vehicles. Dynamics, Control and Coordination of Underwater Gliders.<br/
Reduced-order H? control of an autonomous underwater vehicle
No full textIt is well known that the reduced-order (least-order) H? control problem is a rank minimization problem subject to linear matrix inequality (LMI) constraints which is hard to solve due to the non-convexity of the objective and the trace heuristic is simple and efficient one among various heuristics that approximate the rank minimization problem. In this paper, a theoretical insight into the trade-off between the controller order and the performance of the closed-loop system is given. Autopilots (forward speed, heading and depth) for an autonomous underwater vehicle are synthesized based upon the trace heuristic. Simulation results as well as experimental results of heading control show that the reduced-order autopilots are desirable for practical implementation due to their simple structures and slight performance degradation
Understanding spectroscopic phonon-assisted defect features in CVD grown 3C-SiC/Si(1 0 0) by modeling and simulation
No full textFormation stabilization of underwater mobile sensing networks
No full textFormation control is essential for an underwater mobile sensing network (UMSN), an ad hoc network which wirelessly connects underwater vehicles of sensing and/or observing types via acoustic communications, to fulfill mobile sensing tasks. The problem of formation stabilization for an UMSN with varying communication topology is studied in this paper. Sufficient condition of formation stability is proposed in terms of stability analysis of linear time varying system and spectrum analysis of graph Laplacian of communication topology. Moreover, a design procedure for synthesis of formation controller is given
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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