Auv

This paper presents the impact of introducing a two-controller on the linearized autonomous underwater vehicle (AUV) for vertical motion control. These controllers are presented to overcome the sensor noise of the AUV control model that effect on the tolerance and stability of the depth motion control. Linear quadratic Gaussian (LQG) controller is cascaded with AUV model to adapt the tolerance and the stability of the system and compared with FOPID established by the improved whale optimization algorithm (IWOA) to identify which controlling method can make the system more harmonize and tolerable. The developed algorithm is based on improving the original WOA by reshaping a specific detail on WOA to earn a warranty that the new IWOA will have values for the update position lower than the identified lower-bound (LB), and upper-bound (UB). Furthermore, the algorithm is examined by a set of test functions that include (unimodal, multimodal and fixed dimension multimodal functions). The ...

Background Biologging studies have revealed a wealth of information about the spatio-temporal movements of a wide range of vertebrates large enough to carry electronic tracking tags. Advances in autonomous underwater vehicles (AUVs or UAVs) and unmanned aerial vehicles (commonly known as drones), which can carry far larger payloads of sensor technologies, have revealed insights into the environment through which animals travel. Some AUVs have been used to film target animals, but are generally limited to periods as long as a drone operator can actively follow an animal. In the present study, we use an AUV, the REMUS-100 SharkCam, paired with a custom transponder tag attached to the shark, to autonomously follow three basking sharks for a cumulative total of 10.9 h to collect video and environmental data on their sub-surface behaviour. The basking shark is the second largest fish in the world and is endangered globally, but despite being subject to various biologging studies, little ...

The use of Lagrangian platforms and of Autonomous Underwater Vehicles (AUVs) in oceanography has increased rapidly over the last decade along with the development of improved biological and chemical sensors. These vehicles provide new spatial and temporal scales for observational studies of the ocean. They offer a broad range of deployment and recovery capabilities that reduce the need of large research vessels. This is especially true for ice-covered Arctic ocean where surface navigation is only possible during the summer period. Moreover, safe underwater navigation in icy waters requires the capability of detecting sea ice on the surface (ice sheets). AUVs navigating in such conditions risk collisions, RF communication shadowing, and being trapped by ice keels. In this paper, an underwater sea-ice detection apparatus is described. The source is a polarized continuous wave (CW) diode-pumped solid-state laser (DPSS) module operating at 532 nm. The detector is composed of a polarizin...

The summary: In the report questions of designing of autonomous underwater vehicles with usage simulation models are considered. The hydrodynamic model of dynamics of an autonomous underwater vehicle basing on theoretical and experimental definition of positional, rotational and inertial characteristics is designed. The program simulator of vertical maneuvering autonomous underwater under action of mid-flight propellers, bow and stern taxiing up devices and systems of change of a buoyancy and a trim is designed.

Background Biologging studies have revealed a wealth of information about the spatio-temporal movements of a wide range of vertebrates large enough to carry electronic tracking tags. Advances in autonomous underwater vehicles (AUVs or UAVs) and unmanned aerial vehicles (commonly known as drones), which can carry far larger payloads of sensor technologies, have revealed insights into the environment through which animals travel. Some AUVs have been used to film target animals, but are generally limited to periods as long as a drone operator can actively follow an animal. In the present study, we use an AUV, the REMUS-100 SharkCam, paired with a custom transponder tag attached to the shark, to autonomously follow three basking sharks for a cumulative total of 10.9 h to collect video and environmental data on their sub-surface behaviour. The basking shark is the second largest fish in the world and is endangered globally, but despite being subject to various biologging studies, little ...

Over the past decade, drones have become a popular tool for wildlife management and research. Drones have shown significant value for animals that were often difficult or dangerous to study using traditional survey methods. In the past five years drone technology has become commonplace for shark research with their use above, and more recently, below the water helping to minimise knowledge gaps about these cryptic species. Drones have enhanced our understanding of shark behaviour and are critically important tools, not only due to the importance and conservation of the animals in the ecosystem, but to also help minimise dangerous encounters with humans. To provide some guidance for their future use in relation to sharks, this review provides an overview of how drones are currently used with critical context for shark monitoring. We show how drones have been used to fill knowledge gaps around fundamental shark behaviours or movements, social interactions, and predation across multipl...

The benthic communities of the deep insular shelf at the Hind Bank marine conservation district (MCD), an important spawning aggregation site for groupers, were studied with the Seabed autonomous underwater vehicle (AUV) at depths between 32 and 54 m. Four digital phototransects provided data on benthic species composition and abundance of the insular shelf off St. Thomas, US Virgin Islands. Within the western side of the MCD, well-developed coral reefs with 43% mean living coral cover were found. The Montastrea annularis complex was dominant at all four sites between 33 and 47 m, the depth range where reefs were present. Maximum coral cover found was 70% at depths of 38--40 m. Quantitative determinations of sessile benthic populations, as well as the presence of motile megabenthic invertebrates and algae were obtained. The Seabed AUV provided new quantitative and descriptive information of a unique coral reef habitat found within this deeper insular shelf area.

In this work, a design of a gripper for the underwater OpenROV vehicle is presented. OpenROV is an open-source underwater vehicle design for remote underwater exploration. It can enable systems of underwater internet of things and real-time monitoring. Mechanical aspects of the presented gripper design are discussed including actuation, motion transmission, kinematics and general arrangement, which resembles a delta robot. The Denavit-Hartenberg (DH) notation will be employed to define reference frames on one of the fingers in order to build transformation matrices and the forward kinematics matrix. The results from the forward kinematics are used to define the workspace that can be covered by each finger. The maximum force from the fingertip is estimated using Newton-Euler equations. Finally, the transfer function and the mass moment of inertia of the second link in the finger, that is, the fingertip is calculated for control simulations. A control stability analysis is provided an...

The use of glassy polymers such as acrylics and polycarbonate for marine hulls, windows, and transparent housings has been in more demand due to increasing use of ROVs, AUVs, and smaller non-military submarines. New "Design By Analysis" (DBA) methods will provide for innovative applications while maintaining safety, reliability, and traceability.

The new approach will account for the type of application while enabling new materials and shapes through a combination of experimental and computational methods based on Verification, Validation, and Uncertainty Quantification (VVUQ). Previous standards for life-critical applications like diving systems and submarines were locked into 1970's empirical methods based on defined shapes without directly using material properties. Other uses of glassy polymers, like camera housings, have been more ad-hoc. The method under development will give equipment designers the option to use modern methods like Finite Element Analysis and Computational Fluid Dynamics to innovate within existing engineering code processes.

American Society of Mechanical Engineers (ASME) Pressure Vessels for Human Occupancy (PVHO) codes and standards was developed in the 1960's and 1970's based on US Navy-funded experiments. It has a proven safety record, so much so it was recently incorporated into the ASME Boiler and Pressure Vessel Code for industrial equipment. Limited by its empirical basis, it does not use material properties directly to allow you to reduce the thickness by increasing the strength, as one example. Another limitation is the tables in the code are limited to a specific range of shapes and geometric parameters, all of which were set over 50 years ago without any provision to add new shapes or parameters. These limitations have constrained later equipment development, particularly where there are requirements for engineering code compliance. The proposed DBA method under development through ASME uses PVHO applications as the benchmark for the most extreme risk, given the issue of having humans in a confined space under pressure. Once established, this method can be used for other applications ranging from spaceflight to autonomous vehicles to architectural use with the design margins adjusted based on risk analysis, all with traceability provisions for design, materials, manufacturing, and testing.

The techniques proposed for this DBA method are proven and can be used immediately by equipment designers regardless of being part of an ANSI-approved engineering standard.

Zusammenfassung Der Einsatz elektrischer Einzelradantriebe in Kraftfahrzeugen eröffnet auf Grund der Möglichkeit der schnellen und genauen radindividuellen Stellung positiver und negativer Drehmomente neue Potenziale für die Fahrdynamikregelung. Hierdurch wird eine Regelung des Reifenlängsschlupfes an jedem Rad mit hoher Dynamik und Genauigkeit sowie eine höhere Energieeffizienz ermöglicht, die mit konventionellen Eingriffen des Bremssystems nicht umsetzbar ist. Damit eine darauf aufbauende Regelung der Fahrzeugdynamik diese Vorteile konsequent ausnutzen kann, wird in diesem Beitrag ein hierarchisches Konzept zur Fahrdynamikregelung vorgestellt, das eine Unterteilung der Beobachtungs- und Regelungsstruktur auf Rad- und Fahrzeugebene vorsieht.

The Geomagnetic Polarity Time Scale (GPTS) provides a basis for the geological timescale, quantifies geomagnetic field behavior, and gives a time framework for geologic studies. We build a revised Middle to Late Jurassic GPTS by using a new multiscale magnetic profile, combining sea surface, midwater, and autonomous underwater vehicle near‐bottom magnetic anomaly data from the Hawaiian lineation set in the Pacific Jurassic Quiet Zone (JQZ). We correlate the new profile with a previously published contemporaneous magnetic sequence from the Japanese lineation set. We then establish geomagnetic polarity block models as a basis for our interpretation of the origin and nature of JQZ magnetic anomalies and a GPTS. A significant level of coherency between short‐wavelength anomalies for both the Japanese and Hawaiian lineation magnetic anomaly sequences suggests the existence of a regionally coherent field during this period of rapid geomagnetic reversals. Our study implies the rapid onset ...

This paper presents the impact of introducing a two-controller on the linearized autonomous underwater vehicle (AUV) for vertical motion control. These controllers are presented to overcome the sensor noise of the AUV control model that effect on the tolerance and stability of the depth motion control. Linear quadratic Gaussian (LQG) controller is cascaded with AUV model to adapt the tolerance and the stability of the system and compared with FOPID established by the improved whale optimization algorithm (IWOA) to identify which controlling method can make the system more harmonize and tolerable. The developed algorithm is based on improving the original WOA by reshaping a specific detail on WOA to earn a warranty that the new IWOA will have values for the update position lower than the identified lower-bound (LB), and upper-bound (UB). Furthermore, the algorithm is examined by a set of test functions that include (unimodal, multimodal and fixed dimension multimodal functions). The ...

This work explores both modeling and control of the experimental Ciscrea autonomous underwater vehicle. A 6-degree-of-freedom model is presented and validated for turn and emerge/sink maneuvers. Then, a constraint compensating algorithm is proposed based on quasi-sliding mode conditioning ideas and added to a pre-existing inaccessible proportional-derivative controller in order to improve the overall closed-loop response. By considering actuator constraints, the employed technique allows path following at greater speed than the original controller for a given error tolerance. Experimental results on the so-called Ciscrea underwater robot are presented.