scholarly journals Design of a Labriform-Steering Underwater Robot Using a Multiphysics Simulation Environment

Robotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 11
Author(s):  
Daniele Costa ◽  
Cecilia Scoccia ◽  
Matteo Palpacelli ◽  
Massimo Callegari ◽  
David Scaradozzi
Keyword(s):  
Angular Velocity ◽  
Maximum Velocity ◽  
Constant Angular Velocity ◽  
Underwater Robot ◽  
Simulation Environment ◽  
Underwater Robots ◽  
Multiphysics Simulation ◽  
Pectoral Fins ◽  
Steering Torque ◽  
Carangiform Swimming

Bio-inspired solutions devised for Autonomous Underwater Robots are currently investigated by researchers as a source of propulsive improvement. To address this ambitious objective, the authors have designed a carangiform swimming robot, which represents a compromise in terms of efficiency and maximum velocity. The requirements of stabilizing a course and performing turns were not met in their previous works. Therefore, the aim of this paper is to improve the vehicle maneuvering capabilities by means of a novel transmission system capable of transforming the constant angular velocity of a single rotary actuator into the pitching–yawing rotation of fish pectoral fins. Here, the biomimetic thrusters exploit the drag-based momentum transfer mechanism of labriform swimmers to generate the necessary steering torque. Aside from inertia and encumbrance reduction, the main improvement of this solution is the inherent synchronization of the system granted by the mechanism’s kinematics. The system was sized by using the experimental results collected by biologists and then integrated in a multiphysics simulation environment to predict the resulting maneuvering performance.

Mathematical modeling of Couette flow in anomalous thermoviscous liquid

2011 ◽  
Vol 8 (1) ◽  
pp. 143-152
Author(s):  
S.F. Khizbullina
Keyword(s):  
Mathematical Modeling ◽  
Angular Velocity ◽  
Numerical Experiment ◽  
Temperature Dependence ◽  
Steady Flow ◽  
Couette Flow ◽  
Outer Cylinder ◽  
Flow Regimes ◽  
Constant Angular Velocity ◽  
Coaxial Cylinders

The steady flow of anomalous thermoviscous liquid between the coaxial cylinders is considered. The inner cylinder rotates at a constant angular velocity while the outer cylinder is at rest. On the basis of numerical experiment various flow regimes depending on the parameter of viscosity temperature dependence are found.

Comparison of the fast-start performances of closely related, morphologically distinct threespine sticklebacks (Gasterosteus spp.)

1996 ◽  
Vol 199 (12) ◽  
pp. 2595-2604 ◽  
Author(s):  
T Law ◽  
R Blake
Keyword(s):  
Angular Velocity ◽  
High Speed ◽  
High Performance ◽  
Gasterosteus Aculeatus ◽  
Morphological Characteristics ◽  
Maximum Velocity ◽  
Threespine Stickleback ◽  
Biomechanical Study ◽  
Maximum Acceleration ◽  
Fast Start

Fast-start escape performances for two species of threespine stickleback, Gasterosteus spp., were investigated using high-speed cinematography (400 Hz). The two fishes (not yet formally described, referred to here as benthic and limnetic) inhabit different niches within Paxton Lake, British Columbia, Canada, and are recent, morphologically distinct species. All escape responses observed for both species were double-bend C-type fast-starts. There were no significant differences between the species for any linear or angular parameter (pooled averages, both species: duration 0.048 s, distance 0.033 m, maximum velocity 1.10 m s-1, maximum acceleration 137 m s-2, maximum horizontal angular velocity 473.6 rad s-1 and maximum overall angular velocity 511.1 rad s-1). Benthics and limnetics have the greatest added mass (Ma) at 0.3 and 0.6 body lengths, respectively. The maximum Ma does not include the fins for benthics, but for limnetics the dorsal and anal fins contribute greatly to the maximum Ma. The deep, posteriorly placed fins of limnetics enable them to have a fast-start performance equivalent to that of the deeper-bodied benthics. Both the limnetic and benthic fishes have significantly higher escape fast-start velocities than their ancestral form, the anadromous threespine stickleback Gasterosteus aculeatus, suggesting that the high performance of the Paxton Lake sticklebacks is an evolutionarily derived trait. In this biomechanical study of functional morphology, we demonstrate that similar high fast-start performance can be achieved by different suites of morphological characteristics and suggest that predation might be the selective force for the high escape performance in these two fishes.

The Response of a Proprioceptor to the Undulatory Movements of Dogfish

1969 ◽  
Vol 51 (3) ◽  
pp. 775-785 ◽  
Author(s):  
B. L. ROBERTS
Keyword(s):  
Angular Velocity ◽  
Body Wall ◽  
Maximum Velocity ◽  
The Body ◽  
Nerve Fibres ◽  
Impulse Frequency ◽  
Segmental Nerve

1. Recordings were made from segmental nerve fibres in dogfish while body-wall strips were bent sinusoidally at frequencies and angles comparable with the movements of intact fish. 2. The sensory discharge recorded from a slowly adapting mechanoreceptor in the body wall was proportional to the angular velocity and to the amplitude of the movements. 3. The receptor discharged bursts of sensory impulses during every movement cycle near to the time of maximum velocity. 4. The impulse frequency and the number of potentials in each sensory burst was dependent on the frequency of the bending movement. The number of active units depended on the angle of displacement and on the position of the receptor. 5. These experiments show that this mechanoreceptor could provide information about the frequency and the angle of bending of the body of dogfish during swimming movements.

The Swimming of Nymphon Gracile (Pyconogonida)

1971 ◽  
Vol 55 (1) ◽  
pp. 273-287
Author(s):  
ELFED MORGAN
Keyword(s):  
Angular Velocity ◽  
Hydrodynamic Force ◽  
Beat Frequency ◽  
High Elevation ◽  
Dorsal Side ◽  
Constant Angular Velocity ◽  
Power Stroke ◽  
Lateral Thrust ◽  
Constant Depth ◽  
Recovery Stroke

1. The organization of the swimming legs of N. gracile has been described. The legs beat ventrally so the animal swims with the dorsal side foremost. The joints between the major segments of the leg are extended for most of the power stroke, but the distal segments articulate sequentially later in the beat, commencing with the flexion of the femoro-tibial joint at the end of the power stroke. Continued flexion reduces the leg radius considerably during the recovery stroke. 2. Animals swimming at constant depth were found to have a leg-beat frequency of about 1 beat/s. Above this the rate of ascent increased rapidly with increasing frequency of beat. Abduction or adduction of the leg usually occurred prior to the start of the power stroke with the femur in the elevated position. 3. Assuming a fixed limb profile at constant angular velocity, maximum lift was calculated to have occurred with the femur inclined at an angle of about 50° to the dorso-ventral body axis. The outward component of the lateral thrust decreased to zero at this point, and with further declination of the femur the lateral forces became inwardly directed. Of the different segments of the leg, tibia 2 and the tarsus and propodium contribute most of the hydrodynamic force. 4. The angular velocity of the leg varied during the power stroke, and the actual forces generated during two beats having the same amplitude and angular velocity but of high and low elevation were calculated. Greater lift occurred during the high-elevation beat when the leg continued to provide lift throughout the power stroke, whereas the low-elevation beat acquired negative lift values towards the end of the power stroke. The lateral thrust was now directed entirely inwards.

HISTORY OF DEVELOPMENT OF SQUID-LIKE BIOMIMETIC UNDERWATER ROBOTS WITH UNDULATING SIDE FINS

2015 ◽  
Vol 74 (9) ◽  
Author(s):  
Md. Mahbubar Rahman ◽  
W. B. Wan Nik ◽  
Yasuyuki Toda
Keyword(s):  
High Performance ◽  
Underwater Vehicle ◽  
The Body ◽  
Vehicle Design ◽  
Underwater Robot ◽  
Basic Tool ◽  
Underwater Robots ◽  
Fifth Generation ◽  
History Of Development ◽  
History Of

The underwater robot is a basic tool to explore the unknown territories in the underwater region of the coastal areas and oceans, both from the scientific and industrial perspectives. With the aim of developing an efficient and environmentally friendly underwater robot, a Squid-like robot with two undulating side fins has been developing for many years by the authors' group in Osaka University, Japan. The high ambitious project started in 2002; from then different models have been developed to reach the goal of achieving a high-performance underwater vehicle. The body and propulsion system of the robot have been developed by following the swimming mechanism of flat-fishes that use undulating side fins, e.g. Squid, Stingray Cuttlefish and Manta. The Squid-robot is now in its fifth generation of development. In the present paper, the review of the development of models of the Squid-robot is presented. The development of the mechanical system and the control system of each model is described in brief. Some CFD computations and motion simulations of Model-4 are also discussed. The background of developing a new model and the updated features are stated for each model respectively. The future target of development of the robot is also pointed out. The objective of this paper is to provide relevant and useful information to the engineers involved in underwater vehicle design, and for those with an interest in the fast-growing area of biomimetic swimming robots.

The Mathematic Model and Method for Solving the Dirichlet Heat-Exchange Problem for Empty Isotropic Rotary Body

2018 ◽  
Vol 277 ◽  
pp. 168-177
Author(s):  
Mykhailo Berdnyk
Keyword(s):  
Temperature Field ◽  
Dirichlet Problem ◽  
Heat Exchange ◽  
Angular Velocity ◽  
Integral Transformation ◽  
Mathematic Model ◽  
Constant Angular Velocity ◽  
Temperature Fields ◽  
Finite Velocity ◽  
Finite Space

It is the first generalized 3D mathematic model, which is created for calculating temperature fields in the empty isotropic rotary body, which is restricted by end surfaces and lateral surface of rotation and rotates with constant angular velocity around the axis OZ, with taking into account finite velocity of the heat conductivity in the form of the Dirichlet problem. In this work, an integral transformation was formulated for the 2D finite space, with the help of which a temperature field in the empty isotropic rotary body was determined in the form of convergence series by the Fourier functions.

Some Dynamical Characteristics of Propellers

1934 ◽  
Vol 38 (288) ◽  
pp. 987-997
Author(s):  
J. Morris
Keyword(s):  
Angular Velocity ◽  
Constant Angular Velocity ◽  
Dynamical Characteristics ◽  
Perpendicular Distance ◽  
Rigid Rod

Referring to Fig. 1, let xOy be the plane of rotation of a rigid rod AOA' consisting of a series of pairs of masses symmetrically disposed about O. Thus at a distance r on either side of O are masses mr. Let AOA' rotate with uniform angular velocity Ω, about the axis Oz and let the plane xOy simultaneously rotate about the axis Ox, supposed fixed in space, with constant angular velocity w. Let ρ be the perpendicular distance mrMr of mr to the axis Ox.

Inertial oscillations in a rigid axisymmetric container

1977 ◽  
Vol 358 (1692) ◽  
pp. 17-30 ◽  
Keyword(s):  
Angular Velocity ◽  
Constant Angular Velocity ◽  
Axial Plane ◽  
Axial Distance ◽  
Free Oscillations ◽  
Inertial Oscillations ◽  
Characteristic Cone ◽  
Characteristic Cones

Free oscillations of a fluid rotating with constant angular velocity Ω in a rigid axisymmetric container are considered. Approximations are sought for modes that vary rapidly in each axial plane, on the premise that the pressure at the axis varies with axial distance z as Re [A( z )e iino(z )], where n ≫ 1, o' is real, and A (z) and o (z) >do not vary rapidly with z The pattern made by the characteristic cones of Poincaré’s equation after repeated reflexions at the boundary proves pertinent. Modes are evaluated, with a proportional error o(n -1 ), for a class of containers that has special symmetries and for eigenfrequencies that produce reflexion patterns with topologies like those found in a sphere. The largest velocities in the modes considered occur near the circles where a characteristic cone touches a boundary.

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