Underwater Stingray Mechanism Bot

Volume 8, Issue 5, May – 2023 International Journal of Innovative Science and Research Technology
ISSN No:-2456-2165
Underwater Stingray Mechanism Bot

Vedant Umbrajkar, Tanaya Deshpande, Parth Joshi, Prof. A. D. Zope
Pune Vidyarthi Griha’s College of Engineering and Technology, Pune
Abstract:- The paper deals with the design and reduced turbulence and drag result in a smoother and quieter
development of an underwater stingray mechanism bot. operation, which is less disruptive to aquatic life and allows
In this study, a unique underwater propulsion system for more accurate sonar readings.
based on stingray biomimicry is proposed. The device's
flexible and streamlined motion is modelled after a Silicone rubber sheet is used to enclose this bot. One of
Skotch-Yoke mechanism coated in a silicon rubber sheet. the primary advantages of silicone rubber sheets is their
The main goal of this project is to create an economical, flexibility. This property allows them to conform to complex
effective, and environmentally friendly underwater shapes and surfaces, making them ideal for use in
propulsion system that can be applied to a variety of tasks applications that require precise molding. In the case of the
such as underwater surveillance, marine research, and underwater stingray mechanism, the silicon rubber sheet is
ocean exploration. Traditional underwater propulsion used to mimic the flexible and streamlined movement of
systems may be expensive and detrimental to the marine stingrays, enabling smooth and efficient underwater
environment; the suggested mechanism offers a less propulsion.
expensive and more environmentally friendly substitute.
Flexible, long-lasting, and resistant to a variety of Acrylic material is used for the fins in the mechanism,
external variables are made possible by the employment as it is lightweight, which can be beneficial in applications
of silicone rubber sheet and acrylic sheet material in the where weight is a critical factor, such as in unmanned aerial
mechanism design. Experimental testing of the suggested or underwater vehicles. Additionally, acrylic sheet material is
underwater propulsion system based on stingray easy to machine, fabricate, and join, making it a versatile and
biomimicry has yielded excellent results, suggesting useful material for rapid prototyping and custom design.
potential for usage in a variety of underwater
applications. II. BIOMIMICRY
Keywords:-- Biomimicry, Stingray, Skotch Yoke Mechanism, Biomimicry is the practice of studying and imitating
Toroidal Propellers. natural systems, processes, and designs to solve human
problems and create innovative solutions. It involves using
I. INTRODUCTION nature as a model, a measure, and a mentor to design
sustainable and efficient systems. Biomimicry has already
An underwater stingray mechanism bot mimics the yielded numerous innovative solutions in a wide range of
undulations of a stingray fish. Due to the absence of fields.
conventional propellers, this robot moves through the water
with ease while producing far less noise than its natural In this project, the mechanism of a stingray fish that
counterpart. A stingray bot is a vital tool for marine uses undulating motion of the fins for propulsion and better
exploration and study since it can travel undetectably through maneuverability is proposed. There are various types of
the water because of its adaptive camouflage. Due to its mechanical systems that can be used to mimic this undulating
ability to blend in with its surroundings, it is also a prime motion, and this paper proposes the use of Skotch Yoke
contender for covert and stealthy activities like surveillance mechanism for the same. Toroidal propellers are also
and reconnaissance. included in the design for gliding and balancing the bot while
underwater.
The mechanism used in recreating the motion of this
fish is ‘Skotch Yoke Mechanism’. Skotch Yoke Mechanism III. METHODOLOGY
is a mechanism used to convert rotary motion into
reciprocating motion. The mechanism consists of a slotted A. Design
yoke that is connected to a rotating shaft, and a pin or slider The most important aspect of this bot is its design,
that moves back and forth in the slot. As the shaft rotates, the which is inspired by the stingray fish. The tapering fins and
pin or slider moves along the slot, causing the yoke to move the aerodynamic body are what make its locomotion
back and forth in a linear motion. efficient. The density of the bot (excluding the weight of the
electronic components) is the most important design
Toroidal propellers are used for the propulsion of the consideration as it affects locomotion and maneuvering
bot. These propellers are also used for balancing so that the control. Designing the bot with minimum weight and
bot movement is steady. A significant advantage of toroidal maximum volume is a challenge as both increase on adding
propellers is their ability to operate quietly, which is features, but a balance needs to be maintained. The aspect
particularly important in underwater applications. The ratio between the length and width of the fin bones is another
IJISRT23MAY1853 www.ijisrt.com 2681

ISSN No:-2456-2165
crucial consideration while designing the bot, as it a central hub. These blades rotate independently, allowing for
contributes the most to the weight and volume of the bot in omnidirectional thrust and enhanced maneuverability. Here
addition to varying the velocity of the bot. are some advantages of toroidal propellers:
 Omnidirectional thrust
B. Amplitude Enveloping  Enhanced manoeuvrability
The velocity of the bot is determined by the water  Increased efficiency
displaced by the fins, which depends on the amplitude of  Reduced noise and vibration
oscillation of the fin bones. This amplitude of oscillation is  Robust and compact design
defined by using an equation of fin displacement. [1] There
are 4 main ways/methods/equations of amplitude enveloping, D. Silicon Rubber Sheet
that are implemented to achieve the desired resulting The silicon rubber sheets are used to mimic the
propulsion: stingray’s fins and for insulating the bot’s body. The high
range of temperature resistance allows the bot to be used in
varying depths of water. The flexibility and elasticity of
silicone rubber is important to mimic the roughness of the
stingray’s surface. It also ensures a smooth wave formation
for efficient propulsion. It also makes an excellent electrical
insulant to help prevent electrical leakage.
E. Skotch Yoke Mechanism

The Scotch yoke mechanism consists of four main
components: a circular disk or crank, a connecting rod, a
slider or yoke, and a guide. The circular disk or crank is
connected to the source of rotary motion, usually a motor,
and rotates in a circular path. The connecting rod is
connected to the crankshaft and the slider or yoke, and
converts the rotary motion of the crankshaft into linear
motion of the slider or yoke. The guide provides support and
Fig 1 Types of amplitude envelopes guidance for the slider or yoke as it moves back and forth.
(a) The amplitude envelope is constant along the fins As the crankshaft rotates, the connecting rod moves the
(b)The amplitude envelope gradually increased from the slider or yoke back and forth along a straight line, with the
anterior part to the posterior speed and direction of motion determined by the rotation
(c)The amplitude envelope decreases from the anterior part to speed and direction of the crankshaft. The linear motion of
the mid part and increases toward the posterior the slider or yoke can be used to drive other mechanical
(d)The amplitude envelope increases from the anterior part to components, such as a piston, to generate work.
the mid part and decreases toward the posterior [2]
The Scotch yoke mechanism is commonly used in
Determination of the right equation of amplitude applications that require precise linear motion, such as in
enveloping is necessary as it will affect the maneuvering and engines, pumps, and compressors. It is also used in some
control of the bot along with the change in electronics that types of reciprocating saws and shapers. The main advantage
are used. The type of amplitude envelope is decided upon of the Scotch yoke mechanism is its simplicity and reliability,
their efficiency. [1] The most efficient method of amplitude as it has fewer moving parts than other types of mechanisms.
enveloping is method (b), and the same is applied to our bot. It consists of just a few components, such as the crank,
connecting rod, slider, and guide, which results in a simpler
The amplitude of every point along the fin is and more compact design. This simplicity contributes to the
determined by the equation: reliability of the mechanism, as there are fewer parts that can
fail or require maintenance.
𝐴(𝑥) = 2𝑥ℎ/𝐿
F. Electronics
Where, A(x) is a function of amplitude with respect to
the distance of the points from the start of the fin, h=  ESP32 development board
amplitude of the center of the fin and L is the length of the This microcontroller is used as a supervisory control
fin. [1] module for sending the motor control commands, connecting
with the control interface (explained in the next section), and
C. Toroidal propellers communicating with the BMS of the battery to ensure proper
Toroidal propellers, also known as cycloidal propellers functioning and overall safety of the system.
or omnidirectional propellers, are used in marine
applications. Unlike traditional propellers that rely on a  L298N Motor Driver
rotating shaft with fixed blades, toroidal propellers use a The L289N is a dual H-bridge motor driver that can
circular array of individually rotating blades arranged around provide speed and direction control for two motors

ISSN No:-2456-2165
simultaneously. The module can drive DC motors that have
voltages between 5 and 35V, with a peak current up to 2A.
 5V relay module
The relay module is used as a switch to open or close
the electrical circuit.
 12V 3600 mAh Li-ion rechargeable Battery

The rechargeable battery pack contains 6 Li-ion cells in
a 3s2p configuration with a nominal voltage of 12.6V and an
energy capacity of 3600 mAh. It also contains a built-in BMS
(battery management system) to protect the battery from
excessive current and short circuit.
 12V DC motors
There are a total of three DC motors, two of which are
used for balancing the bot, and one for the propulsion. Two Fig 3 Screenshot of this Interface
of these are 1000-rpm motors that are used for balancing,
while the propulsion motor is rated at 500 rpm. All three IV. CONCLUSION
come with an attached gearbox that can be used for adjusting
the torque and speed requirements. A hydrodynamic, silent and deep-diving capable
underwater vehicle inspired from the stingray fish was
The image below contains the electrical circuit as successfully designed, modelled using computer-aided
connected within the bot: designing software and mathematically modelled to verify
and analyses the final product.
ACKNOWLEDGEMENT
It gives an immense pleasure to submit the Seminar

report entitled “Underwater Stingray Mechanism Bot”. We
have tried our levels best to perform and present this topic to
the point framework. We take this opportunity to express a
word of gratitude towards all of them who have guided and
helped us in completing this project work We thank Prof.
A.D. Zope our project guide who has always encouraged us
and given freedom to bring out maximum and best possible
results from us. we also thank our Head of the Department,
Prof. Dr. M. M .Bhoomkar for extending helping hand
towards us. We would also like to thank all those who have
Fig 2 Electrical Circuit
directly or indirectly helped us in completion of this project.
Lastly, we would like to say that this project is our sincere
G. Bluetooth Powered Control Interface
effort to present our skills, ability and talent to the world.
The motors that are used for the propulsion and
balancing are controlled using the motor driver. The
REFERENCES
commands for this motor driver are sent using a Bluetooth
module from a control interface that is designed using
HTML-CSS code. The locomotion and balancing commands [1]. Y. hua Zhang, L. bing Jia, S. wu Zhang, J.
to control the motor are included in a C++ program using Yang, And K. H. Low, “Computational
Arduino libraries. Research on Modular Undulating Fin for
Biorobotic Underwater Propulsor,” J. Bionic
The control interface has a button for connecting the Eng., vol. 4, no. 1, pp. 25–32, 2007, doi:
motor driver via Bluetooth. It also contains buttons to switch
the system on and off, and one button each for the forward, 10.1016/S1672-6529(07)60009-2.
reverse, left, right, and stop commands. The image below [2]. J. He and Y. Zhang, “Development and Motion
shows a screenshot of this interface: Testing of a Robotic Ray,” J. Robot., vol.
2015,2015,doi: 10.1155/2015/791865

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Volume 8, Issue 5, May – 2023 International Journal of Innovative Science and Research Technology

Underwater Stingray Mechanism Bot

IJISRT23MAY1853 www.ijisrt.com 2681

E. Skotch Yoke Mechanism

IJISRT23MAY1853 www.ijisrt.com 2682

 12V 3600 mAh Li-ion rechargeable Battery

It gives an immense pleasure to submit the Seminar

IJISRT23MAY1853 www.ijisrt.com 2683

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