scholarly journals Design and Control of an Embedded Vision Guided Robotic Fish with Multiple Control Surfaces

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Junzhi Yu ◽  
Kai Wang ◽  
Min Tan ◽  
Jianwei Zhang
Keyword(s):  
Visual Processing ◽  
Vision System ◽  
The Body ◽  
Robotic Fish ◽  
Multiple Control ◽  
Caudal Fin ◽  
Embedded Vision ◽  
And Control ◽  
Control Surfaces ◽  
Pelvic Fin

This paper focuses on the development and control issues of a self-propelled robotic fish with multiple artificial control surfaces and an embedded vision system. By virtue of the hybrid propulsion capability in the body plus the caudal fin and the complementary maneuverability in accessory fins, a synthesized propulsion scheme including a caudal fin, a pair of pectoral fins, and a pelvic fin is proposed. To achieve flexible yet stable motions in aquatic environments, a central pattern generator- (CPG-) based control method is employed. Meanwhile, a monocular underwater vision serves as sensory feedback that modifies the control parameters. The integration of the CPG-based motion control and the visual processing in an embedded microcontroller allows the robotic fish to navigate online. Aquatic tests demonstrate the efficacy of the proposed mechatronic design and swimming control methods. Particularly, a pelvic fin actuated sideward swimming gait was first implemented. It is also found that the speeds and maneuverability of the robotic fish with coordinated control surfaces were largely superior to that of the swimming robot propelled by a single control surface.

Design and Analysis of a Wire-Driven Robot Tadpole

2012 ◽  
Author(s):  
Zheng Li ◽  
Wenqi Gao ◽  
Ruxu Du ◽  
Baofeng Liao
Keyword(s):  
Control System ◽  
Body Length ◽  
Power Supply ◽  
The Body ◽  
Pectoral Fin ◽  
Caudal Fin ◽  
Moving Direction ◽  
And Control ◽  
System Power ◽  
Pelvic Fin

Besides fish there are a lot of animals can swim effectively in the water, such as tadpole. Different from fishes using multiple fins to swim, tadpole has only one tail. It is well known that most fish employ the caudal fin to generate thrust, and use the pectoral fin, pelvic fin, etc. to balance the body and control its moving direction. However, the tadpole fulfilled all these tasks by the tail only. Hence, it is interesting to build a robot tadpole and study its motion. In this paper, a robot tadpole is designed. It has a blunt head and a tail. The control system, power supply and actuator are inside the head. The tail is a novel wire driven flapping propeller. The tail has a serpentine backbone with 7 joints, which are controlled by just one actuator. A prototype is built. The overall length of the robot tadpole is 328cm. Experiment results show that the robot tadpole can swim freely in the water. Its speed is affected by the flapping amplitude and frequency. In the experiments, the tadpole’s speed can reach 0.413 body length per second (BL/s), which matches the prediction from the propulsion model.

scholarly journals Body Flexibility Enhances Maneuverability in the World’s Largest Predator

2018 ◽  
Vol 59 (1) ◽  
pp. 48-60 ◽  
Author(s):  
P S Segre ◽  
D E Cade ◽  
J Calambokidis ◽  
F E Fish ◽  
A S Friedlaender ◽  
...  
Keyword(s):  
Open Ocean ◽  
The Body ◽  
Long Distance ◽  
Active Surfaces ◽  
Aquatic Locomotion ◽  
And Performance ◽  
And Control ◽  
Blue Whales ◽  
Control Surfaces ◽  
Complex Trajectories

Abstract Blue whales are often characterized as highly stable, open-ocean swimmers who sacrifice maneuverability for long-distance cruising performance. However, recent studies have revealed that blue whales actually exhibit surprisingly complex underwater behaviors, yet little is known about the performance and control of these maneuvers. Here, we use multi-sensor biologgers equipped with cameras to quantify the locomotor dynamics and the movement of the control surfaces used by foraging blue whales. Our results revealed that simple maneuvers (rolls, turns, and pitch changes) are performed using distinct combinations of control and power provided by the flippers, the flukes, and bending of the body, while complex trajectories are structured by combining sequences of simple maneuvers. Furthermore, blue whales improve their turning performance by using complex banked turns to take advantage of their substantial dorso-ventral flexibility. These results illustrate the important role body flexibility plays in enhancing control and performance of maneuvers, even in the largest of animals. The use of the body to supplement the performance of the hydrodynamically active surfaces may represent a new mechanism in the control of aquatic locomotion.

scholarly journals The genus Peckoltia with the description of two new species and a reanalysis of the phylogeny of the genera of the Hypostominae (Siluriformes: Loricariidae)

Zootaxa ◽  
2008 ◽  
Vol 1822 (1) ◽  
pp. 1 ◽  
Author(s):  
JONATHAN W. ARMBRUSTER
Keyword(s):  
New Species ◽  
Amazon Basin ◽  
Original Description ◽  
Color Pattern ◽  
The Body ◽  
The Other ◽  
Caudal Fin ◽  
Two New Species ◽  
Fin Spines ◽  
Pelvic Fin

Peckoltia contains 12 described species, eight of which are considered valid. Peckoltia arenaria, P. filicaudata, and P. ucayalensis are recognized as synonyms of P. bachi and P. kuhlmanni is recognized as a synonym of P. vittata. In addition, two new species are described. The type species of Peckoltichthys and Sophiancistrus are synonyms of P. bachi and both genera are recognized as junior synonyms of Peckoltia. The species of Peckoltia range throughout much of the Amazon basin, the upper Orinoco, the upper Essequibo, and perhaps the Maroni, and can be identified from most other ancistrins by having dentaries that form angle of 90° or less and from others with angled dentaries by lacking the synapomorphies of those genera. The species of Peckoltia vary from one another mostly in coloration. Peckoltia braueri, P. caenosa n. sp., P. cavatica and P. vittata lack spots on the head while the other species have them. Peckoltia braueri and P. cavatica have orange bands in the dorsal and caudal fins and have the bones and plates of the head and nape outlined in black (vs. no orange bands and head plates and bones not outlined in black in P. caenosa and P. vittata). Peckoltia caenosa has a color pattern consisting of dark vermiculations on the head and abdomen (vs. saddles or blotches on the head and faint dark spots on the abdomen in P. vittata). Among the species with spots on the head, P. lineola n. sp. and P. vermiculata have some of the spots combining to form vermiculations (vs. spots free in P. bachi, P. brevis, P. furcata, and P.oligospila) with the vermiculations larger than the pupil in P. lineola and narrower in P. vermiculata and the vermiculations radiating from a central point in P. vermiculata vs. no such pattern in P. lineola. Peckoltia bachi can be identified from the other species by having widened pelvic-fin spines that can be pulled ventrally such that they are completely ventral and parallel to the body (vs. pelvic-fin spines narrow and cannot be adducted ventral to body) and by having the eye low on the head (vs. high). Peckoltia brevis can be identified from P. furcata and P. oligospila by having well-developed dorsal saddles (vs. saddles faint), no spots on the body behind the nape (vs. spots generally present behind the nape); from P. oligospila by having bands in the caudal fin (vs. spots); and from P. furcata by having the lower caudal-fin spine longer than the upper (vs. upper spine longer). Peckoltia furcata can be identified from P. oligospila by having the upper caudal-fin spine longer than the lower (vs. lower spine longer) and by having bands in the caudal fin (vs. spots). Ancistrus yaravi had been recognized as a species of Peckoltia. The type of A. yaravi is lost, but the original description suggests that the species is the senior synonym of Neblinichthys roraima. A revised morphological phylogeny demonstrates the lack of support for Peckoltia and Hemiancistrus as monophyletic, and phenetic definitions are provided for the two genera. The phylogeny also demonstrates a lack of support of the genus Watawata.

Schistura madhavai, a new species of hill-stream loach from Sri Lanka, with redescription of S. notostigma (Teleostei: Nemacheilidae)

Zootaxa ◽  
2017 ◽  
Vol 4311 (1) ◽  
pp. 96 ◽  
Author(s):  
HIRANYA SUDASINGHE
Keyword(s):  
New Species ◽  
Sri Lanka ◽  
Lateral Line ◽  
The Body ◽  
Pairwise Distance ◽  
Caudal Fin ◽  
Dorsal Fin ◽  
Fin Ray ◽  
Line Ending ◽  
Pelvic Fin

Schistura madhavai, new species, is described from Suriyakanda, Sri Lanka. It is distinguished from all other species of Schistura in the peninsula of India and Sri Lanka by the combination of the following characters: 8–9 wide, brown postdorsal bars separated by narrow, white interspaces; width of interspaces ¼–⅓ times width of bars; black bar at caudal-fin base wider than interspaces on the body; incomplete lateral line, ending beneath dorsal-fin base; absence of an axillary pelvic lobe; adpressed pelvic fin just reaching anus; origin of the pelvic fin on a vertical through the last unbranched dorsal-fin ray. Schistura notostigma, the only other Sri Lankan species of Schistura, is redescribed. It can be distinguished from all other species of Schistura in the peninsula of India and Sri Lanka by the combination of the following characters: 6–7 wide, brown postdorsal bars; width of interspaces ½–1 times width of bars; complete, black bar at caudal-fin base narrower than width of interspaces between bars on body; emarginate caudal fin; incomplete lateral line ending beneath dorsal-fin base; adpressed pelvic fin surpassing anus; and origin of pelvic fin beneath first branched dorsal-fin ray. Schistura madhavai is separated from S. notostigma by an uncorrected pairwise distance of 3.0–3.8% for the 16S rRNA gene fragment. 

A new Schistura from an upper Mekong affluent in Yunnan (Teleostei: Nemacheilidae)

Zootaxa ◽  
2017 ◽  
Vol 4341 (4) ◽  
pp. 585
Author(s):  
MARCO ENDRUWEIT
Keyword(s):  
New Species ◽  
Yunnan Province ◽  
Anterior Part ◽  
The Body ◽  
Caudal Fin ◽  
Deep Body ◽  
Pelvic Fin

Schistura stala, new species, is described from the Mekong drainage in Dali, Yunnan Province, China. The new species is readily distinguished from congeners in the upper Mekong and adjacent drainages by having the caudal-fin bar reduced, stretching over the median ⅓ of the fin base. The species can be further diagnosed by a deep body; a short caudal fin, head and pelvic fin; 38 vertebrae modally; 9–12 faint irregular flank bars, that are often anastomotic or dissolved; and few scales scattered on the anterior part of the body. 

scholarly journals Pseudolaguvia moinensis, a new benthic miniature Asian catfish (Teleostei: Sisoridae) from Arunachal Pradesh, north-eastern India

2021 ◽  
Author(s):  
Lakpa Tamang
Keyword(s):  
New Species ◽  
The Body ◽  
Dorsal Spine ◽  
Caudal Fin ◽  
Spine Length ◽  
North Eastern ◽  
Brown Band ◽  
Peduncle Length ◽  
Asian Catfish ◽  
Pelvic Fin

A new species of miniature sisorid catfish is described, from the upper Brahmaputra river drainage in northeastern India. The new species is distinguished from all its congeners except P. ferruginea and P. focusa by having an elongate light brown to cream marks either side on ventro-lateral margin just above anus. Further, distinguished from its congeners by the following combination of characters: presence of a W-shaped dark brown band on caudal fin, thoracic adhesive apparatus extending closer to pelvic-fin base, smooth anterior margin of dorsal spine, a narrow V-shaped light brown to cream bands on side of the body, dorsal-spine length (10.7-14.7% SL), dorsal-fin base length (10.7-14.2% SL), pectoral-fin spine length (14.0-21.1% SL), pelvic-fin length (13.5-16.6% SL), caudal peduncle length (14.4-18.2% SL) and depth (7.8-9.9% SL), total vertebrae (30-31), caudal fin with a complete medial hyaline bands towards its anterior end, reaching outer margin of each lobe. Other combination of characters differentiating the new species from its congeners are provided in the respective diagnoses.

Dynamic Modeling of a Compliant Tail-Propelled Robotic Fish

2013 ◽  
Author(s):  
Vladislav Kopman ◽  
Jeffrey Laut ◽  
Maurizio Porfiri ◽  
Francesco Acquaviva ◽  
Alessandro Rizzo
Keyword(s):  
Equations Of Motion ◽  
Beam Theory ◽  
The Body ◽  
Robotic Fish ◽  
Body Dynamics ◽  
Flexible Fin ◽  
Optimization And Control ◽  
Rigid Component ◽  
And Control ◽  
Euler Bernoulli Beam

This paper presents a dynamic model for a class of robotic fish propelled by a tail with a flexible fin. The robot is comprised of a rigid frontal link acting as a body and a rear link serving as the tail. The tail includes a rigid component, hinged to the body through a servomotor, which is connected to a compliant caudal fin whose underwater vibration induces the propulsion. The robot’s body dynamics is modeled using Kirchhoff’s equations of motion of bodies in quiescent fluids, while its tail motion is described with Euler-Bernoulli beam theory, accounting for the effect of the encompassing fluid through the Morison equation. Simulation data of the model is compared with experimental data. Applications of the model include simulation, prediction, design optimization, and control.

scholarly journals Three new species of Hyphessobrycon (Characiformes: Characidae) from the upper rio Araguaia basin in Brazil

2003 ◽  
Vol 1 (1) ◽  
pp. 21-33 ◽  
Author(s):  
Flávio C. T. Lima ◽  
Cristiano R. Moreira
Keyword(s):  
New Species ◽  
Lateral Surface ◽  
Color Pattern ◽  
The Body ◽  
Ventral Region ◽  
Caudal Peduncle ◽  
Caudal Fin ◽  
Dark Color ◽  
Three New Species ◽  
Pelvic Fin

Three new species of Hyphessobrycon (Characiformes: Characidae) are described from the upper rio Araguaia basin. Hyphessobrycon langeanii n. sp. is distinguished from all congeners by the presence of a well-defined, round humeral spot, a reticulate color pattern, a broad, horizontally-elongate caudal-peduncle blotch, and a relatively wide, faint midlateral dark stripe. Hyphessobrycon eilyos n. sp. is distinguished from all congeners by the absence of humeral and caudal spots; by the presence of numerous dark chromatophores on the lateral surface of the body, intensely concentrated on the ventral region from the pelvic-fin origin to the end of the caudal-fin base, dorsal, adipose, and caudal fins with carmine red pigmentation in life; and the presence of 7-11 maxillary teeth. Hyphessobrycon weitzmanorum n. sp. is distinguished from all congeners by the combination of the possession of two humeral spots and a general dark color pattern. These three new species, along with Creagrutus molinus (Characidae), Apareiodon tigrinus (Parodontidae), Aspidoras velites (Callichthyidae), an undescribed member of the Hypoptopomatinae (Loricariidae), Cnesterodon septentrionalis (Poeciliidae), and Simpsonichthys cholopteryx (Rivulidae), all of which are apparently endemic of the upper rio Araguaia, indicate that this area is a previously unrecognized area of endemism.

Six-Legged Walking Robot for Inspection Tasks

2011 ◽  
Vol 180 ◽  
pp. 137-144 ◽  
Author(s):  
Stanisław Krenich ◽  
Marcin Urbanczyk
Keyword(s):  
Control System ◽  
Vision System ◽  
Control Unit ◽  
The Body ◽  
Walking Robots ◽  
Movement Trajectory ◽  
Level Control ◽  
Inspection Tasks ◽  
Dc Servomotor ◽  
And Control

In the paper an approach to design and control of reconfigurable walking robots is presented. Based on the biological inspiration the conception of the six-legged robot is proposed. In the first part a mechanical structure, basic kinematical and dynamical dependences in the robot legs are described. The structure, kinetics rules, gait patterns etc. are derived from typical stick insects. According to the above assumptions the body and the legs of the robot are designed and made. At all legs eighteen DC servomotors with resistant encoders are used. In addition at the robot head one DC servomotor for sensors or a vision system is introduced. In the second part a control system is discussed. The multi-level control unit is based on the AVR Atmega8/16 microcontrollers which are responsible for generating of a movement trajectory and at the same time for controlling of the all servomotors. For the proposed control system different gait algorithms and behaviour rules including a forward/back movement, avoiding of obstacles are worked out. They allow an autonomous work of the robot or remote control by an operator. In addition, during the walk the algorithms can match the type of attitudes and gaits to an environment. Next, some experiments of walking for different control algorithms are carried out and described. At the end some conclusions and directions of the further research are given.

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