Dynamic Analysis of a Robotic Fish Propelled by Flexible Folding Pectoral Fins

Robotica ◽  
2019 ◽  
Vol 38 (4) ◽  
pp. 699-718 ◽  
Author(s):  
Van Anh Pham ◽  
Tan Tien Nguyen ◽  
Byung Ryong Lee ◽  
Tuong Quan Vo
Keyword(s):  
Power Stroke ◽  
Swimming Velocity ◽  
Force Model ◽  
Flexible Joints ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Recovery Stroke ◽  
Turning Radius ◽  
Relationship Of ◽  
The Relationship

SUMMARYBiological fish can create high forward swimming speed due to change of thrust/drag area of pectoral fins between power stroke and recovery stroke in rowing mode. In this paper, we proposed a novel type of folding pectoral fins for the fish robot, which provides a simple approach in generating effective thrust only through one degree of freedom of fin actuator. Its structure consists of two elemental fin panels for each pectoral fin that connects to a hinge base through the flexible joints. The Morison force model is adopted to discover the relationship of the dynamic interaction between fin panels and surrounding fluid. An experimental platform for the robot motion using the pectoral fin with different flexible joints was built to validate the proposed design. The results express that the performance of swimming velocity and turning radius of the robot are enhanced effectively. The forward swimming velocity can reach 0.231 m/s (0.58 BL/s) at the frequency near 0.75 Hz. By comparison, we found an accord between the proposed dynamic model and the experimental behavior of the robot. The attained results can be used to design controllers and optimize performances of the robot propelled by the folding pectoral fins.

Design and Dynamic Modeling of a Flexible Feathering Joint for Robotic Fish Pectoral Fins

2014 ◽  
Author(s):  
Sanaz Bazaz Behbahani ◽  
Xiaobo Tan
Keyword(s):  
Dynamic Model ◽  
Robotic Fish ◽  
Power Stroke ◽  
Hydrodynamic Drag ◽  
Pectoral Fin ◽  
Flexible Joint ◽  
Blade Element Theory ◽  
Pectoral Fins ◽  
Flexible Part ◽  
Recovery Stroke

In this paper, we propose a novel design for a pectoral fin joint of a robotic fish. This joint uses a flexible part to enable the rowing pectoral fin to feather passively and thus reduce the hydrodynamic drag in the recovery stroke. On the other hand, a mechanical stopper allows the fin to maintain its motion prescribed by the servomotor in the power stroke. The design results in net thrust even when the fin is actuated symmetrically for the power and recovery strokes. A dynamic model for this joint and for a pectoral fin-actuated robotic fish involving such joints is presented. The pectoral fin is modeled as a rigid plate connected to the servo arm through a pair of torsional spring and damper that describes the flexible joint. The hydrodynamic force on the fin is evaluated with blade element theory, where all three components of the force are considered due to the feathering degree of freedom of the fin. Experimental results on robotic fish prototype are provided to support the effectiveness of the design and the presented dynamic model. We utilize three different joints (with different sizes and different flexible materials), produced with a multi-material 3D printer, and measure the feathering angles of the joints and the forward swimming velocities of the robotic fish. Good match between the model predictions and experimental data is achieved, and the advantage of the proposed flexible joint over a rigid joint, where the power and recovery strokes have to be actuated at different speeds to produce thrust, is demonstrated.

scholarly journals Fluid Dynamics of Biomimetic Pectoral Fin Propulsion Using Immersed Boundary Method

2016 ◽  
Vol 2016 ◽  
pp. 1-22 ◽  
Author(s):  
Ningyu Li ◽  
Yumin Su
Keyword(s):  
Fluid Dynamics ◽  
Three Dimensional ◽  
Reconstruction Algorithm ◽  
Power Stroke ◽  
Hydrodynamic Characteristics ◽  
Ring Vortex ◽  
Immersed Boundary ◽  
Pectoral Fin ◽  
Local Flow ◽  
Recovery Stroke

Numerical simulations are carried out to study the fluid dynamics of a complex-shaped low-aspect-ratio pectoral fin that performs the labriform swimming. Simulations of flow around the fin are achieved by a developed immersed boundary (IB) method, in which we have proposed an efficient local flow reconstruction algorithm with enough robustness and a new numerical strategy with excellent adaptability to deal with complex moving boundaries involved in bionic flow simulations. The prescribed fin kinematics in each period consists of the power stroke and the recovery stroke, and the simulations indicate that the former is mainly used to provide the thrust while the latter is mainly used to provide the lift. The fin wake is dominated by a three-dimensional dual-ring vortex wake structure where the partial power-stroke vortex ring is linked to the recovery-stroke ring vertically. Moreover, the connection of force production with the fin kinematics and vortex dynamics is discussed in detail to explore the propulsion mechanism. We also conduct a parametric study to understand how the vortex topology and hydrodynamic characteristics change with key parameters. The results show that there is an optimal phase angle and Strouhal number for this complicated fin. Furthermore, the implications for the design of a bioinspired pectoral fin are discussed based on the quantitative hydrodynamic analysis.

The Mechanics of Labriform Locomotion I. Labriform Locomotion in the Angelfish (Pterophyllum Eimekei): An Analysis of the Power Stroke

1979 ◽  
Vol 82 (1) ◽  
pp. 255-271
Author(s):  
R. W. BLAKE
Keyword(s):  
Total Energy ◽  
Thrust Force ◽  
The Body ◽  
Power Stroke ◽  
Pectoral Fin ◽  
Propulsive Efficiency ◽  
Rate Of Increase ◽  
Element Approach ◽  
Total Thrust ◽  
Recovery Stroke

1. A blade-element approach is used to analyse the mechanics of the drag-based pectoral fin power stroke in an Angelfish in steady forward, rectilinear progression. 2. Flow reversal occurs at the base of the fin at the beginning and at the end of the power stroke. Values for the rate of increase and decrease in the relative velocity of the blade-elements increase distally, as do such values for hydrodynamical angle of attack. At the beginning and end of the power stroke, negative angles occur at the base of the fin. 3. The outermost 40% of the fin produces over 80% of the total thrust produced during the power stroke, and doe8 over 80% of the total work. Small amounts of reversed thrust are produced at the base of the fin during the early and late parts of the stroke. 4. The total amount of energy required during a cycle to drag the body and inactive fins through the water is calculated to be approximately 2.8 × 10−6 J and the total energy produced by the fins over the cycle (ignoring the recovery stroke) which is associated with producing the hydrodynamic thrust force, is about 1.0 × 10−5 J; which gives a propulsive efficiency of about 0.26. 5. The energy required to move the mass of a pectoral fin during the power stroke is calculated to be approximately 2.6 × 10−7 J. Taking this into account reduces the value of the propulsive efficiency by about 4% to about 0.25. The total energy needed to accelerate and decelerate the added mass associated with the fin is calculated and added to the energy required to produce the hydrodynamic thrust force and the energy required to move the mass of the fins; giving a final propulsive efficiency of 0.18.

The Agglomeration Mechanism of Network Emerging E-commerce Industry Based on Social Science

2022 ◽  
Vol 34 (3) ◽  
pp. 0-0
Keyword(s):  
Near Field ◽  
Industrial Agglomeration ◽  
Force Model ◽  
Data Sets ◽  
Industry Agglomeration ◽  
Production Factors ◽  
Wireless Broadband ◽  
Relationship Of ◽  
The Relationship ◽  
Coefficient Method

Network emerging e-commerce refers to the development of wireless broadband technology, smart terminal technology, near-field network, etc. as the driving force. It is the emerging e-commerce represented by the continuous development of modern e-commerce and the integration of commerce. This paper proposes to use Michael Porter’s cluster theory method, income increasing algorithm, and spatial Gini coefficient method to sort out and analyze the research results of industrial agglomeration problems, further study the relationship of e-commerce industry agglomeration mechanism, and build agglomeration simulation model , the construction of the centripetal force model of the industrial agglomeration area, through the analysis of the production factors of the e-commerce industry, and then study the influence of each factor on the development of the e-commerce industry. Finally, this paper selects and uses 16 standard mechanical data sets to investigate and analyze the agglomeration mechanism of the e-commerce industry, which verifies the accuracy and overall applicability of the method.

Functional morphology of undulatory pectoral fin locomotion in the stingray taeniura lymma (Chondrichthyes: dasyatidae)

1999 ◽  
Vol 202 (24) ◽  
pp. 3523-3539 ◽  
Author(s):  
L.J. Rosenberger ◽  
M.W. Westneat
Keyword(s):  
Beat Frequency ◽  
Motor Pattern ◽  
Power Stroke ◽  
Swimming Velocity ◽  
Pectoral Fin ◽  
Motor Patterns ◽  
Kinematic Data ◽  
Locomotor System ◽  
Anterior Dorsal ◽  
Undulatory Locomotion

Rajiform locomotion is a unique swimming style found in the batoid fishes (skates and rays) in which thrust is generated by undulatory waves passing down the enlarged pectoral fins. We examined the kinematic patterns of fin motion and the motor patterns of pectoral fin muscles driving the locomotor system in the blue-spot stingray Taeniura lymma. Our goals in this study were to determine overall patterns of fin motion and motor control during undulatory locomotion, to discover how these patterns change with swimming velocity and to correlate muscle function with kinematics and pectoral morphology. Kinematic data were recorded from five individuals over a range of swimming speeds from 22 to 55 cm s(−)(1) (0.9-3.0 DL s(−)(1), where DL is body disc length). Electromyographic (EMG) data were recorded from three individuals over a range of velocities (1.2-3.0 DL s(−)(1)) at seven locations (four dorsal, three ventral) along the pectoral fin. As swimming velocity increases, fin-beat frequency, wavespeed and stride length increase, number of waves and reduced frequency decrease and fin amplitude remains constant. There is variability among individuals in frequency and amplitude at a given speed. An inverse relationship was found in which a high fin-beat frequency is associated with a low fin amplitude and a low fin-beat frequency is associated with a high fin amplitude. The motor pattern of undulatory locomotion is alternate firing activity in the dorsal and ventral muscles as the wave moves along the fin from anterior to posterior. Fin muscles are active along the entire length of the fin except at the lowest speeds. As swimming velocity and fin-beat frequency increase, the time of activation of posterior muscles becomes earlier relative to the onset of activity in the anterior dorsal muscles. The duration of muscle activity is longer in the ventral muscles than in the dorsal muscles, indicating that they play a central role in the power stroke of the fin-beat cycle. The anterior muscles (dorsal and ventral) are active for a relatively longer part of the stride cycle than the posterior muscles. Both the anterior position and the large duty factor of the anterior muscles reflect the role of these muscles in initial wave generation. Synchronous recordings of kinematic data with EMG data reveal that the anterior dorsal and middle ventral muscles do mostly positive work, whereas the dorsal and ventral posterior muscles do negative work at most swimming speeds.

Pectoral fin locomotion in batoid fishes: undulation versus oscillation

2001 ◽  
Vol 204 (2) ◽  
pp. 379-394 ◽  
Author(s):  
L.J. Rosenberger
Keyword(s):  
Swimming Speed ◽  
Beat Frequency ◽  
Wave Number ◽  
Phylogenetic Position ◽  
Swimming Velocity ◽  
Pectoral Fin ◽  
Pectoral Fins ◽  
Rhinoptera Bonasus ◽  
Raja Eglanteria ◽  
Fin Length

This study explores the dichotomy between undulatory (passing multiple waves down the fin or body) and oscillatory (flapping) locomotion by comparing the kinematics of pectoral fin locomotion in eight species of batoids (Dasyatis americana, D. sabina, D. say, D. violacea, Gymnura micrura, Raja eglanteria, Rhinobatos lentiginosus and Rhinoptera bonasus) that differ in their swimming behavior, phylogenetic position and lifestyle. The goals of this study are to describe and compare the pectoral fin locomotor behavior of the eight batoid species, to clarify how fin movements change with swimming speed for each species and to analyze critically the undulation/oscillation continuum proposed by Breder using batoids as an example. Kinematic data were recorded for each species over a range of swimming velocities (1–3 disc lengths s(−1)). The eight species in this study vary greatly in their swimming modes. Rhinobatos lentiginosus uses a combination of axial-based and pectoral-fin-based undulation to move forward through the water, with primary thrust generated by the tail. The pectoral fins are activated in short undulatory bursts for increasing swimming speed and for maneuvering. Raja eglanteria uses a combination of pectoral and pelvic locomotion, although only pectoral locomotion is analyzed here. The other six species use pectoral locomotion exclusively to propel themselves through the water. Dasyatis sabina and D. say have the most undulatory fins with an average of 1.3 waves per fin length, whereas Rhinoptera bonasus has the most oscillatory fin behavior with 0.4 waves per fin length. The remaining species range between these two extremes in the degree of undulation present on their fins. There is an apparent trade-off between fin-beat frequency and amplitude. Rhinoptera bonasus has the lowest frequency and the highest fin amplitude, whereas Rhinobatos lentiginosus has the highest frequency and the lowest amplitude among the eight species examined. The kinematic variables that batoids modify to change swimming velocity vary among different species. Rhinobatos lentiginosus increases its tail-beat frequency to increase swimming speed. In contrast, the four Dasyatis species increase swimming speed by increasing frequency and wavespeed, although D. americana also changes wave number. Raja eglanteria modifies its swimming velocity by changing wavespeed and wave number. Rhinoptera bonasus increases wavespeed, Gymnura micrura decreases wave number, and both Rhinoptera bonasus and Gymnura micrura increase fin-tip velocity to increase swimming velocity. Batoid species fall onto a continuum between undulation and oscillation on the basis of the number of waves present on the fins.

The Swimming of Nymphon Gracile (Pycnogonida): The Vertical Lift Forces Generated while Swimming at Constant Depth

1977 ◽  
Vol 71 (1) ◽  
pp. 187-203
Author(s):  
ELFED MORGAN ◽  
STEPHEN V. HAYES
Keyword(s):  
Vertical Plane ◽  
Power Stroke ◽  
Constant Depth ◽  
Sedimentation Method ◽  
Recovery Stroke ◽  
Vertical Lift ◽  
Lift Forces ◽  
The Relationship

1. The vertical lift forces generated by the legs of Nymphon while swimming at constant depth have been estimated graphically using drag constants determined by a sedimentation method. Drag both normal and tangential to the different segments of the leg has been considered. 2. When holding station Nymphon characteristically employs a low elevation beat in which the upward force produced during the power stroke of each leg only just exceeds the predominantly downward force generated during the recovery. An upward lift component is also produced late during the recovery stroke. 3. The legs beat in a vertical plane and an investigation of the moments at the joints of the leg suggests that much of the power stroke is gravity assisted. 4. The upward lift produced by all eight legs agreed fairly well on average with the sinking force due to the animal's weight in water, and the vertical lift fluctuates rhythmically throughout the leg beat cycle. The relationship between the swimming gait and the amplitude of these fluctuations has been investigated. During the gait most frequently used by the animal fluctuations in vertical lift were found to be minimal.

scholarly journals A mechanical piston action may assist pelvic–pectoral fin antagonism in tree-climbing fish

2017 ◽  
Vol 98 (8) ◽  
pp. 2121-2131 ◽  
Author(s):  
Adhityo Wicaksono ◽  
Saifullah Hidayat ◽  
Bambang Retnoaji ◽  
Adolfo Rivero-Müller ◽  
Parvez Alam
Keyword(s):  
Finite Element ◽  
Energy Saving ◽  
Finite Element Simulations ◽  
Morphological Investigation ◽  
Pectoral Fin ◽  
Terrestrial Locomotion ◽  
Pectoral Fins ◽  
Biomimetic Robots ◽  
The Relationship ◽  
Pelvic Fin

In this research, we compared the anatomy and biomechanics of two species of mudskipper vs an aquatic sandgoby in view of terrestrial locomotion. Of particular interest was the relationship (if any) of pectoral fin movement with pelvic fin movement. We show that the pelvic fins of the terrestrial mudskippers studied herein, are retractable and move antagonistically with the pectoral fins. The pelvic fin of the sandgoby studied here is contrarily non-retractable and drags on any underlying substrate that the sandgoby tries to crawl across. We find that the pelvic and pectoral fin muscles of all fish are separated, but that the pectoral fins of the mudskipper species have bulkier radial muscles than the sandgoby. By coupling a detailed morphological investigation of pectoral-pelvic fins musculature with finite element simulations, we find that unlike sandgobies, the mudskipper species are able to mechanically push the pelvic fins downward as pectoral fins retract. This allows for an instant movement of pelvic fins during the pectoral fin backward stroke and as such the pelvic fins stabilize mudskippers through Stefan attachment of their pelvic fins. This mechanism seems to be efficient and energy saving and we hypothesize that the piston-like action might benefit pelvic–pectoral fin antagonism by facilitating a mechanical down-thrust. Our research on the biomechanics of tree-climbing fish provides ideas and greater potential for the development of energetically more efficient systems of ambulation in biomimetic robots.

Research on the Steering Character for Kiloton all Terrain Crane

2014 ◽  
Vol 1078 ◽  
pp. 187-190
Author(s):  
Zhong Ying Liu
Keyword(s):  
Deflection Angle ◽  
Steering System ◽  
Front Wheel ◽  
All Wheel Steering ◽  
Turning Radius ◽  
Minimum Turning Radius ◽  
Vehicle Capacity ◽  
Relationship Of ◽  
The Relationship ◽  
Two Degree Of Freedom

Based on the two degree of freedom model of kiloton all-terrain crane, he effects of relationship of deflection angle on turning radius were investigated in multi-axle steering system. MATLAB/Simulink was used to analyze the relationship of every axle in multi-axle steering and optimize the minimum turning radius. The studies show that the kiloton all-terrain crane adapted all-wheel steering driving at 5speed , and the front wheel angle was 32.3°, as compared to the rolling radius before optimization, the turning radius in all wheel turnaround reduced by 33%, which improved the vehicle capacity through the complex curve and increased the vehicle steering flexibility.

Mechatronic Design and Maneuverability Analysis of a Novel Robotic Shark for Coral Reef Detection

2021 ◽  
Author(s):  
Liyang Gao ◽  
Peng Li ◽  
Hongde Qin ◽  
Zhongchao Deng
Keyword(s):  
Coral Reef ◽  
Dynamic Model ◽  
Swimming Speed ◽  
Three Dimensional ◽  
Pectoral Fin ◽  
Spiral Motion ◽  
Pectoral Fins ◽  
Mechatronic Design ◽  
Grid Technique ◽  
Turning Radius

Abstract In this paper, mechatronic design of a novel robotic shark for coral reef detection is presented. To obtain good maneuverability, a barycenter regulating device is designed to assist the posture adjustment of the robotic shark at low speed. Based on STAR-CCM+ software, the lift coefficients and drag coefficients of pectoral fin are calculated using overlapping grid technique. Based on Newton-Euler approach, a dynamic model with particular consideration of pectoral fins for three-dimensional motion is established. A CPG controller is used to generate rhythmic motion of each joint. Furthermore, based on the dynamic model, three-dimensional trajectory of spiral motion and swimming speed in different oscillation parameters are simulated. The results show that swimming speed of the robotic shark can be improved by increasing the amplitude and frequency or decreasing the phase difference. Also, oscillation frequency plays a more significant role. Furthermore, under the action of single pectoral fin, the robotic shark can achieve spiral motion and the turning radius is about 35.8m under the parameters set in this article.

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