Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 6 of 6
Full-Text Articles in Ocean Engineering
Control System Performance And Efficiency For A Mid-Depth Lagrangian Profiling Float, B. Mcgilvray, C. Roman
Control System Performance And Efficiency For A Mid-Depth Lagrangian Profiling Float, B. Mcgilvray, C. Roman
Christopher N. Roman
This paper presents the development of a new mid-depth Lagrangian profiling float with a primary emphasis on the control system performance and efficiency. While deep water floats have demonstrated much success in open ocean environments, many are not suited for the additional challenges associated with coastal regions. To study these regions, which are often subject to varying bathymetry within the operating range and higher variations in water density, a more advanced system is required. This new design utilizes pressure and altitude feedback to drive a high volume auto-ballasting system (ABS). The main operating modes of this float include step inputs …
Preliminary Model Tests For The Design Of A Gliding Deep Water Elevator, Christopher Roman, T. Gregory, E. Martin, A. Sanguinetti, J. Drummond
Preliminary Model Tests For The Design Of A Gliding Deep Water Elevator, Christopher Roman, T. Gregory, E. Martin, A. Sanguinetti, J. Drummond
Christopher N. Roman
This paper presents progress on the design of a "smart elevator" to be used in conjunction with deep sea ROV operations. Deep sea elevators are gravity driven untethered platforms used to deliver and or return items from the sea floor. Elevators are used when items are too large or heavy to be handled by the ROV, or when the turn around time to recover and redeploy the ROV system for sample removal is prohibitive. Unfortunately, efficiency is complicated by the precision with which elevators can be landed at a specific location on the bottom and recovered on the surface because …
Consistency Based Error Evaluation For Deep Sea Bathymetric Mapping With Robotic Vehicles, Christopher Roman, Hanumant Singh
Consistency Based Error Evaluation For Deep Sea Bathymetric Mapping With Robotic Vehicles, Christopher Roman, Hanumant Singh
Christopher N. Roman
This paper presents a method to evaluate the mapping error present in point cloud terrain maps created using robotic vehicles and range sensors. This work focuses on mapping environments where no a priori ground truth is available and self consistency is the only available check against false artifacts and errors. The proposed error measure is based on a disparity measurement between common sections of the environment that have been imaged multiple times. This disparity measure highlights inconsistency in the terrain map by showing regions where multiple overlapping point clouds do not fit together well. This error measure provides the map …
Optical And Acoustic Habitat Characterization With The Seabed Auv, Hanumant Singh, Ryan Eustice, Oscar Pizarro, Christopher Roman
Optical And Acoustic Habitat Characterization With The Seabed Auv, Hanumant Singh, Ryan Eustice, Oscar Pizarro, Christopher Roman
Christopher N. Roman
The Seabed AUV is an Autonomous Underwater Vehicle (AUV) built to serve as a readily available and operationally simple tool for high resolution imaging. It is a hover-capable vehicle that performs optical sensing with a 12 bit 1280/spl times/1024 CCD camera and acoustic high resolution mapping using an MST 300 kHz sidescan and a 675 kHz pencil beam bathymetric sonar. The AUV has been designed for operations from small vessels with minimal support equipment. It has an operational depth of 2000 meters and at 1 m/s can run for up to 10 hours. In this paper we report on the …
Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh
Estimation Of Error In Large Area Underwater Photomosaics Using Vehicle Navigation Data, C. Roman, H. Singh
Christopher N. Roman
Creating geometrically accurate photomosaics of underwater sites using images collected from an AUV or ROV is a difficult task due to dimensional errors which grow as a function of 3D image distortion and the mosaicking process. Although photomosiacs are accurate locally their utility for accurately representing a large survey area is jeopardized by this error growth. Evaluating the error in a mosaic is the first step in creating globally accurate photomosaics of an unstructured environment with bounded error. Using vehicle navigation data and sensor offsets it is possible to estimate the error present in large area photomosaics independent of the …
Advances In Fusion Of High Resolution Underwater Optical And Acoustic Data, H. Singh, C. Roman, L. Whitcomb, D. Yoerger
Advances In Fusion Of High Resolution Underwater Optical And Acoustic Data, H. Singh, C. Roman, L. Whitcomb, D. Yoerger
Christopher N. Roman
We report efforts to merge data from the complementary modalities of optical and acoustic sensing for obtaining more accurate representations of the seafloor. We show that the principal obstacles to merging the acoustic and optical imaging modalities are the distortions inherent to each modality. The construction of geometrically accurate photomosaics is dominated by incremental errors arising as individual images are scaled and warped to form the photomosaic. For microbathymetric mapping, principal errors arise from sensor position and orientation calibration parameters that affect our ability to construct maps from sonar data that are commensurate with sensor and navigation resolution. We show …