Underwater Robotics

Barbara Davidde (ISCR), Roberto Petriaggi (ISCR), Gabriele Gomez de Ayala (Naumacos),The "GIS of Underwater Baiae" with 3D documentation: a useful tool to record the state of conservation of a Roman submerged town, International Scientific Colloquium on Factors impacting Underwater Cultural Heritage,13 December and 14 December 2011, Brussels (Belgium).

by Roberto Petriaggi

Poster presented at the International Colloquium held in Brussels in December 2011

In 2001 the Superior Institute for Conservation and Restoration (ISCR) launched Restoring Underwater.
Restoring... more In 2001 the Superior Institute for Conservation and Restoration (ISCR) launched Restoring Underwater.
Restoring Underwater is a project aimed to the study and experimentation of instruments, materials, methodologies and techniques for the restoration and conservation in situ of ancient submerged artefacts.
The tridimensional laser scanning survey plays a prominent role in the planning and finished stage of the restoration in order to show the restored piece in a museum.
This method of 3D documentation shows better the state of conservation of the monuments, and increase the value of scientific dissemination.

Nova Scotia's Ocean Technologies: A Global Value Chain Analysis of Inshore & Extreme Climate Vessels, Remotely Operated & Autonomous Underwater Vehicles, and Underwater Sensors & Instrumentation

by Lukas Brun

Co-authored with Gary Gerreffi, Joonkoo Lee, and Mary Turnipseed

Duke CGGC report on the local and global value chains for inshore & extreme climate vessels, remotely operated... more Duke CGGC report on the local and global value chains for inshore & extreme climate vessels, remotely operated (ROV) & autonomous underwater vehicles (AUV), and underwater sensors & instrumentation

Bio-inspired Compliant Robotic Fish: Design and Experiments

by Maarja Kruusmaa

H. El Daou, T. Salumäe, G. Toming, M. Kruusmaa, "Bio-inspired Compliant Robotic Fish: Design and Experiments", IEEE International Conference on Robotics and Automation, St. Paul, USA, May 14-18, 2012, to appear

This paper studies the modelling, design and fabrication of a bio-inspired fish-like robot propelled by a compliant... more This paper studies the modelling, design and fabrication of a bio-inspired fish-like robot propelled by a compliant body. The key to the design is the use of a single motor to actuate the compliant body and to generate thrust. The robot has the same geometrical properties of a subcarangiform swimmer with the same length. The design is based on rigid head and fin linked together with a compliant body. The flexible part is modelled as a non-uniform cantilever beam actuated by a concentrated moment. The dynamics of the compliant body are studied and a relationship between the applied moment and the resulting motion is derived. A prototype that implements the proposed approach is built. Experiments on the prototype are done to identify the model parameters and to validate the theoretical modelling

A Flexible Fin with Bio-Inspired Stiffness Profile and Geometry

by Maarja Kruusmaa

T. Salumäe, M. Kruusmaa, A flexible fin with bio-inspired stiffness profile and geometry", Journal of Bionic Engineering 8.4, Elsevier, 2011, pp. 418-428

Biological evidence suggests that fish use mostly anterior muscles for steady swimming while the caudal part of the... more Biological evidence suggests that fish use mostly anterior muscles for steady swimming while the caudal part of the body is passive and, acting as a carrier of energy, transfers the momentum to the surrounding water. Inspired by those findings we hypothesize that certain swimming patterns can be achieved without copying the distributed actuation mechanism of fish but rather using a single actuator at the anterior part to create the travelling wave. To test the hypothesis a pitching flexible fin made of silicone rubber and silicone foam was designed by copying the stiffness distribution profile and geometry of a rainbow trout. The kinematics of the fin was compared to that of a steadily swimming trout. Fin's propulsive wave length and tail-beat amplitude were determined while it was actuated by a single servo motor. Results showed that the propulsive wave length and tail-beat amplitude of a steadily swimming 50 cm rainbow trout was achieved with our biomimetic fin while stimulated using certain actuation parameters (frequency 2.31 Hz and amplitude 6.6 degrees). The study concluded that fish-like swimming can be achieved by mimicking the stiffness and geometry of a rainbow trout and disregarding the details of the actuation mechanism.

Against the flow: A Braitenberg controller for a fish robot

by Maarja Kruusmaa

T. Salumäe, I. Rano, O. Akanyeti, M. Kruusmaa, "Against the flow: A Braitenberg controller for a fish robot", IEEE International Conference on Robotics and Automation, St. Paul, USA, May 14-18, 2012, to appear

Underwater vehicles do not localise or navigate with respect to the flow, an ability needed for many underwater tasks.... more Underwater vehicles do not localise or navigate with respect to the flow, an ability needed for many underwater tasks. In this paper we implement rheotaxis behaviour in a fish robot, a behaviour common to many aquatic species. We use two pressure sensors on the head of the robot to identify the pressure differences on the left and right side and control the heading of the fish robot by turning a servo-motor actuated tail. The controller is inspired by the Braitenberg vehicle 2b, a simple biological model of tropotaxis, that has been used in many robotic applications. The experiments, conducted in a flow pipe with a uniform flow, show that the robot is able to orient itself, and keep the orientation, to the incoming current. Our results demonstrate that guidance of a fish robot relative to a flow can be implemented as a simple rheotaxis behaviour using two sensors and a Braitenberg 2b controller.

Variable stroke timing of rubber fins' duty cycle improves force.

by Keri Collins

ICAR2011 conference in Tallinn, Estonia

SubjuGator 2007

by Grzegorz Cieslewski

Distributed Coordination and Data Fusion for Underwater Search

by Srinivas Yerramalli

Modelling and adaptive control of a deepwater FSV

by Manuel Menezes de Sequeira

Co-authored with Carlos Silvestre, João Miranda Lemos, and João S. Sentieiro. Presented at the the 11th IFAC World Congress, Tallinn, Estonia, USSR, in August 1990.

This paper is concerned with the modelling and control of a Free Swimming Vehicle (FSV). A model which embodies a... more This paper is concerned with the modelling and control of a Free Swimming Vehicle (FSV). A model which embodies a detailed description of the FSV dynamics and captures hydrodynamic effects with realism is developed and used for Control System simulation and tests. The Control System relies on Long-Range Adaptive algorithms. These are shown to yield a good performance in the presence of the uncertainties and nonlinearities inherent to the FSV dynamics.