Bio Inspired Underwater Robot with Undulating Fin Propulsion

A prototype of what underwater exploration might look like ? our bio-inspired RoV is the first step to using environment friendly locomotion to explore, map, and view the depths of the ocean. Using a streamlined body, we have attached fin-like structures to be able to move in fish-like manner. This

Project Title

Bio Inspired Underwater Robot with Undulating Fin Propulsion

Project Area of Specialization

Robotics

Project Summary

A prototype of what underwater exploration might look like – our bio-inspired RoV is the first step to using environment friendly locomotion to explore, map, and view the depths of the ocean. Using a streamlined body, we have attached fin-like structures to be able to move in fish-like manner. This undulating motion can be controlled via a microcontroller embedded within the RoV that can then be controlled by the user at the workstation.

This project features two distinct parts: the mechanical design and constraints, and the movement underwater through user control. The design of the body required computational fluid dynamic analysis, compliance with industry standards, and on-hand assembly. It also required procurement of different materials and integration of components. Finally, it required waterproof mechanisms for a modular structure, including O-rings and cable glands. The next part, locomotion, required electronic integration, the modeling and simulation of wave equations, and sensor calibration to correct errors. We had to place electronics within the RoV and connect the wirings to sensor and motors outside the body. Then the servo-motors needed to model undulating fin movement. This required further literature review and modelling of equations to create undulating movement that allowed for smooth, controlled, and regular movement. Each degree of freedom had to be tested individually and re-calibrated as needed. Finally, the sonar sensors and gyroscopes were used to log depth and orientation changes and correct any non-user movement i.e. automatically stabilize the orientation of the RoV. These corrections would allow for smoother user-movement and greater user satisfaction when exploring underwater.

Project Objectives

Nature is the best engineer and therefore an inspiration of our design. We plan to make a bio-inspired underwater robot with undulated fins propulsion. There are two main types of underwater robots: Remote Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs). We will be making a remote-controlled robot, the path and motion will be decided by a human operating.

Since wireless communication between underwater and land is very difficult, and highly expensive and sophisticated pieces of equipment are used, we will connect it to the ground station via an Ethernet cable.

In water, the pressure and forces acting on a body increase proportionally with an increase in depth. Since this is a prototype the intended depth it can sustain is 1 meter and the body is not intended to go to the depths of oceans. Therefore the material thickness and proportions were set keeping the depth limit into consideration.

Finally, the robot will have an auto-stabilization module. This module would allow user to easily operate SEAL V whilst navigating ocean currents. This module would simply detect disruptions in its orientation, and when the rate of these disruptions exceeds a threshold (set by the movement of the robot), it will stabilize itself before letting the user resume his or her movement.

The final part would be to detect objects such as fishes and underwater plants in realtime using some object detection algorithm (SSD or YOLO) using Deep Learning. This would allow the operator to track the desired object and aid marine research.

Project Implementation Method

SEAL V is an ROV. It has fins to cover distances underwater. These fin movements are unique to SEAL V's design as they use undulating or sinusoidal waves to create momentum. This allows for greater operations near the seabed where different kinds of debris might damage propellers.

Furthermore, using its auto-balancing system, SEAL V is uniquely situated to be remotely operated. Gyroscope sensors would allow for easy user operation even in the time of destabilizing currents.

This is a standalone product created for users who wish to explore the deep sea. The current quality of this project would not be of an industrial standard so as to allow for testing within some cost limit.

This robot is expected to be used by people who wish to capture moments underwater or by organizations that wish to explore different areas underwater that divers might have problem accessing. Using a Raspberry Pi, it is a wired product. However, wired communication allows for lag-less communication. Furthermore, the auto-balancing will allow users to focus on movement in the right direction and not on the orientation.

It is a simplistic in its functional attributes. Arising from its purpose, the main purpose of existence to explore underwater. This means it must be able to move in different directions: forward, backwards, diving, surfacing, and turning.

Furthermore, it must be able to send be able to record what it is seeing to send back to its user. Finally, to allow for a stable user experience, the body should be able to reorient itself automatically after some major turbulence. With this, a basic version of robot would be able to operate to a satisfactory degree.

Requirements:

Raspberry Pi will be used to calibrate the motors and sensors with, GPIOZero library will be used. Pi Camera (8MP) will be used for video feedback, and ethernet cable will connect the robot to the workstation.

Functional Requirements:

• Decreases drag and other resistant forces underwater
• Can move forward and backward
• Can rotate in the all direction to dive underwater and float back top and reorient itself
• Can dive up to 1.0m underwater
• Tracks sudden changes in orientation
• Reorients itself if there is a major disturbance in orientation.
• Send Live stream of the camera back to the user

Benefits of the Project

The project needs to be further developed and tested before commercial and industrial applications. These applications, though, can range from underwater exploration for mapping certain areas, to observing marine life in their natural habitat without disturbing their ecosphere. Further advancements may even allow automation of the drone completely and may be used to track marine life over extended periods of time. Another aspect of this project is, if equipped with the right sensors, the RoV can track oceanic properties and generate logs of these attributes over a certain time. It can also collect this data over a certain area to aid different marine scientists and meteorologists in their works and studies.

The applications are vast; however, the most demanding ones are in the areas of oil, gas, and mineral exploration, seabed mapping, search and rescue, monitoring sea life, monitoring underwater environmental changes, and military and defense.

Underwater robots can monitor the water quality, environmental changes, ecological changes, inspect pollution levels, and can be used for oceanographic research. We can observe, and even interact with marine life, this carries both research and entertainment applications.

Underwater robots can be used for collecting information about the sea such as 3-dimensional seabed and terrain mapping. It can also be used to investigate ship wreckages and find wreckage materials.

Deep-sea mining will turn oceans into the new industrial frontier. Oceans contain the largest and richest untapped mineral reserves in the world, and the race to send robots for finding potential sites as well as mining has accelerated at an unprecedented scale. Billions have already been invested in it with more to follow. This model is more suitable for finding potential sites, rather than to do hard mining.

Telecommunication cables in seabed often get damaged, for example, the famous incident of 2013 where optical fibers at the Indian Ocean got damaged, resulting in poor internet access across multiple countries in the region including Pakistan. It took them a few days only to identify where the damage occurred. With underwater robots such as ours, they can monitor these cables and quickly identify the fault area, at a very low cost.

One last but a very major application is in the Military and Defense industry where such robots can be used for surveillance. DARPA, a US Defense R&D organization, has announced to produce and invest in underwater robots with objectives of seabed mapping, and object detection to navigate. NATO has deployed underwater robots as coastline guards and Russia has stepped into the race as well. Undulating fins, allowing it to operate in stealth mode, would help in surveillance. 

These all are the industrial applications of our project, but since this is a prototype due to time and financial constraints, we cannot make it to that level. It would however serve as a proof of concept.

Technical Details of Final Deliverable

Delieverables in chronological order:

1. Material Testing for Flexible Fins:
   Different materials were tested for flexible fins, stress analysis and flexibility was computed at lab and TPU was shortlisted as the material with optimal flexibility with enough rigidity to avoid breakage.
    
2. Procurement:
   All electronic equipment were shortlisted. 6 Waterproof Servos were ordered from China, Underwater Sonar Sensors, Servo Metal Gears, Raspberry Pi, and Camera were procured and tested individually.
    
3. 3D Design:
   After few initial drafts a final 3D model on Solidworks software was designed catering to the streamlined body requirement and waterproofing. The final design was modular, and waterproofing was easiest in it, and it was the most streamlined design.
    
4. Manufacturing and Fluid Analysis:
   Different vendors were contacted for the 3D printing of body, eventually due to better quality and cheaper cost CNC Manufacturing was finalized. Order was given to a vendor at Gujranwala. Furthermore, Ansys software was used to get a fluid analysis of the streamlined body, the body's streamlined shape allowed it to have minimum pressure.
    
5. Assembling and Waterproofing:
   The body was manufactured, we visited the workshop to verify the dimensions, added waterproof enamel coating layer, and assembled the complete modular body. Complete waterproofing was done and tested. O rings were used to create pressure points at the point of contact of different modules preventing fluid flow, cable glands were used to pass the wirings through, complete industrial standards of waterproofing were applied.
    
6. Locomotion:
   Locomotion using undulated fins and synchronized sinusoidal waves to be generated. Wave equations for locomotion derived, physical implementation left. Obstacle Avoidance, and depth mapping planned.
    
7. Auto Stabilization and Artificial Intelligence:
   Gyroscope would be used to automatically stabilize the motion and orientation of robot. Use of PIDs to counter error and align both fins. Objects would be detected using Computer Vision using PiCamera using either an image recognition algorithm such as Haar Cascade or Object Detection Algorithm such as Yolo or SSD depending on the need for autonomous tracking of object.

Final Deliverable of the Project

HW/SW integrated system

Core Industry

Others

Other Industries

Core Technology

Robotics

Other Technologies

Artificial Intelligence(AI)

Sustainable Development Goals

Industry, Innovation and Infrastructure, Life Below Water

Required Resources

If you need this project, please contact me on contact@adikhanofficial.com