Several physico-mechanical designs evolved in fish are currently inspiring robotic devices for propulsion and maneuvering purposes in underwater vehicles. Considering the potential benefits involved, this paper presents an overview of the swimming mechanisms employed by fish. The motivation is to provide a relevant and useful introduction to the existing literature for engineers with an interest in the emerging area of aquatic biomechanisms. The fish swimming types are presented, following the well-established classification scheme and nomenclature originally proposed by Breder. Fish swim either by body and/or caudal fin (BCF) movements or using median and/or paired fin (MPF) propulsion. The latter is generally employed at slow speeds, offering greater maneuverability and better propulsive efficiency, while BCF movements can achieve greater thrust and accelerations. For both BCF and MPF locomotion, specific swimming modes are identified, based on the propulsor and the type of movements (oscillatory or undulatory) employed for thrust generation. Along with general descriptions and kinematic data, the analytical approaches developed to study each swimming mode are also introduced. Particular reference is made to lunate tail propulsion, undulating fins, and labriform (oscillatory pectoral fin) swimming mechanisms, identified as having the greatest potential for exploitation in artificial systems.

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Review of fish swimming modes for aquatic locomotion

Application of robotics in offshore oil and gas industry- A review Part II

Advancements in the field of autonomous underwater vehicle

We present a new variable curvature continuum kinematics for multisection continuum robots with arbitrarily shaped backbone curves assembled from sections with three degrees of freedom (DoFs) (spatial bending and extension, no torsion). For these robots, the forward kinematics and the differential forward kinematics are derived. The proposed model approach is capable of reproducing both the constant and variable backbone curvature in a closed form. It describes the deformation of a single section with a finite number of serially connected circular arcs. This yields a section model with piecewise constant and, thus, a variable section curvature. Model accuracy and its suitability for kinematic real-time control applications are demonstrated with simulations and experimental data. To solve the redundant inverse kinematics problem, a local resolution of redundancy at the velocity level through the use of the robot's Jacobian matrix is presented. The Jacobian is derived analytically, including a concept for regularization in singular configurations. Experimental data are recorded with Festo's Bionic Handling Assistant. This continuum robot is chosen for experimental validation, as it consists of a variable backbone curvature because of its conically tapering shape.

A Variable Curvature Continuum Kinematics for Kinematic Control of the Bionic Handling Assistant

This paper presents a novel and unified analytic formulation for kinematics, statics, and shape restoration of multiple-backbone continuum robots. These robots achieve actuation redundancy by independently pulling and pushing three backbones to carry out a bending motion of two-degrees-of-freedom (DoF). A solution framework based on constraints of geometric compatibility and static equilibrium is derived using elliptic integrals. This framework allows the investigation of the effects of different external loads and actuation redundancy resolutions on the shape variations in these continuum robots. The simulation and experimental validation results show that these continuum robots bend into an exact circular shape for one particular actuation resolution. This provides a proof to the ubiquitously accepted circular-shape assumption in deriving kinematics for continuum robots. The shape variations due to various actuation redundancy resolutions are also investigated. The simulation results show that these continuum robots have the ability to redistribute loads among their backbones without introducing significant shape variations. A strategy for partially restoring the shape of the externally loaded continuum robots is proposed. The simulation results show that either the tip orientation or the tip position can be successfully restored.

/pdf/analytic-formulation-for-kinematics-statics-and-shape-awo8twmmnh.pdf

Analytic Formulation for Kinematics, Statics, and Shape Restoration of Multibackbone Continuum Robots Via Elliptic Integrals

AMADEUS is a dexterous subsea robot hand incorporating force and slip contact sensing, using fluid filled tentacles for fingers. Hydraulic pressure variations in each of three flexible tubes (bellows) in each finger create a bending moment, and consequent motion or increase in contact force during grasping. Such fingers have inherent passive compliance, no moving parts, and are naturally depth pressure-compensated, making them ideal for reliable use in the deep ocean. In addition to the mechanical design, development of the hand has also considered closed loop finger position and force control, coordinated finger motion for grasping, force and slip sensor development/signal processing, and reactive world modeling/planning for supervisory 'blind grasping'. Initially, the application focus is for marine science tasks, but broader roles in offshore oil and gas, salvage, and military use are foreseen.

/pdf/amadeus-advanced-manipulation-for-deep-underwater-sampling-2zvrwbck8m.pdf

AMADEUS: advanced manipulation for deep underwater sampling

AMADEUS is a dexterous subsea robot hand incorporating force and slip contact sensing, using fluid-filled tentacles for fingers. Hydraulic pressure variations in each of three flexible tubes (bellows) in each finger create a bending moment, and consequent motion or increase in contact force during grasping. Such fingers have inherent passive compliance, no moving parts, and are naturally depth pressure-compensated, making them ideal for reliable use in the deep ocean. In addition to the mechanical design, development of the hand has also been considered for closed loop finger position and force control, coordinated finger motion for grasping, force and slip sensor development/signal processing, and reactive world modelling/planning for supervisory "blind grasping". Initially, the application focus is for marine science tasks, but broader roles in offshore oil and gas, salvage, and military use are foreseen. Phase I of the project has been completed, with the construction of a first prototype. This paper summarizes the developments in Phase I. Further details for each area of investigation are referenced.

/pdf/amadeus-advanced-manipulator-for-deep-underwater-sampling-2wzql57u9z.pdf

AMADEUS: advanced manipulator for deep underwater sampling

AMADEUS is a dextrous subsea robot hand incorporating force and slip contact sensing, using fluid filled tentacles for Jingers. Hydraulic pressure variations in each of three flexible tubes (bellows) in each Jinger create a bending moment, and consequent motion or increase in contact force during grasping. Such Jingers have inherent passive compliance, no moving parts, and are naturally depth pressure-compensated, making them ideal for reliable use in the deep ocean. In addition to the mechanical design, development of the hand has also considered closed loop finger position and force control, co-ordinated Jinger motion for grasping, force and slip sensor developmenthignal processing, and reactive world modelling/planning for supervisory 'blind grasping'. Initial&, the application focus is for marine science tasks, but broader roles in offshore oil and gas, salvage, and military use are foreseen. Phase I of the project is complete, with the construction of a first prototype. Phase 11 is now underwq, to deploy the hand fom an underwater robot arm, and carry out wet trials with users. This paper summarizes the developments in phase I. Further details for each area of investigation are referenced.

Advanced MAnipulator for DEep Underwater Sampling

The general characteristics of a dynamic simulator for advanced robotics are discussed. The features of a dynamic simulator, ARS, for advanced robotic applications, currently under development at the University of Genova, are outlined. The flexibility of ARS makes it suitable for the simulation of underwater vehicles and robots. With this objective, simple models of the hydrodynamic effects are presented. >

R. Bono

Papers

AMADEUS: advanced manipulation for deep underwater sampling

AMADEUS: advanced manipulator for deep underwater sampling

Advanced MAnipulator for DEep Underwater Sampling

Dynamic simulation tools for the analysis and design of AUVs

1997 Index IEEE Robotics and Automation Magazine Vol. 4