PRE2019 3 Group17

Group

Team Members

Name	ID	Email	Major
Amit Gelbhart	1055213	a.gelbhart@student.tue.nl	Sustainable Innovation
Marleen Luijten	1326732	m.luijten2@student.tue.nl	Industrial Design
Myrthe Spronck	1330268	m.s.c.spronck@student.tue.nl	Computer Science
Ilvy Stoots	1329707	i.n.j.stoots@student.tue.nl	Industrial Design
Linda Tawafra	0941352	l.tawafra@student.tue.nl	Industrial Design

Time Sheets

Peer Review

Will be added later

Project Goal

The Problem

One of the great benefits of the coral reef is that in case of natural hazards, such as coastal storms, the reef on average can reduce the wave energies by 97% (Ferrario, 2014). Meaning that it can prevent storms and flooding and thus protect the coastal inhabitants. Since roughly 40% of the world’s population is located within a range of 100 km from the coast (Ferrario, 2014), protecting the coral reef will result in a reduction of a great amount of damage. This would not only be in regard to human lives but also to environmental destruction. In the case of these natural hazards, it is the government that will be imputable for the caused devastation. Sadly, the coral reefs have been degrading for a long time, and their recovery is lacking.

Due to the acidification and warming of oceans due to climate change, pollution and destructive fishing practices (Ateweberhan et al., 2013) the amount of coral reefs is declining. One of the factors that could prevent the downgrading of a reef, is the resistance of a reef, its ability to prevent permanent phase-shifts; and the resilience of a reef, its ability to bounce back from phase-shifts (Nyström et al., 2008). These phase-shifts are undesirable because the reef ends up in a state where it can no longer return to a coral-dominated state (Hughes et al., 2010). If the reef has better resilience, it will be able to bounce back quicker. One of the ways to improve the resilience of the reef is increasing the species richness and abundance through the use of acoustics (Gordon, et al., 2019), which improves the reef’s resilience by giving it protection from macroalgae (Burkepile and Hay, 2008). For a coral reef to flourish, a wide biodiversity of animals is needed. Fish that lay their larvae on corals are one of the essential components in a healthy reef ecosystem. However, once corals are dying, the fish do not use them for their larvae and the whole system ends up in a negative cycle. By playing sounds, with different frequencies, fish are tricked into believing that the corals are alive and come back with their larvae. This attracts other marine animals, which causes the entire system to flourish again (Gordon, et al., 2019).

A robot could be used to place these speakers, or a robot could function as a speaker itself. However, this is not the only way in which robots can help the reefs. Robots could be created to replace labor and time-intensive work, as well as support scientists, researches and rescue organizations. Acoustic enrichment is one application, but consider also researching the current state of the coral reef by monitoring sound instead (Lammers et al., 2007), or removing the dangerous crown-of-thorns starfish (Endean, 1982), or any other number of applications. The goal for this projects is to design a robot that can safely move through coral reefs. Because the coral reefs and ocean are sensitive, a robot that operates there needs to have some alterations in order to not risk damaging the reefs. The reefs are already endangered, any tool that is send down there to help them recover must be absolutely safe, and this will require some specialization.

In this project we will consider current robots that have been used in a number of environments, from land robots to robots used in the general deep sea, and even robots currently used in coral reefs. We will consider their benefits and drawbacks and discuss how their design could support a specialized coral reef robot.

The User

Our user will be researchers who could use our robot to research coral reefs, interact with them and support them. We have made contact with one researcher at a university, but we are still in discussion with him. He informed us his department recently ordered a drone for research, so we hope to get many useful insights from him. We will have a meeting, during which we intent to discuss the following questions:

• What are issues you are facing while studying/ managing/ maintaining coral reefs?
  • How do you deal with them now?
  • How could a robot help?
  • Is a underwater robot which is specialized for coral reefs relevant?
• Would this/ our robot be suitable?
  • Why?/ Why not?
  • What can be improved?
  • What is the most important aspect of the design which we need to consider?
• Do you like the robot you bought lately?
  • Why?/ Why not?
  • Which aspects should our robot also have and what can be optimized?
  • Is it easy to control the robot? Does it have a good user interface?
• If a specialized robot was available for a reasonable price, what applications would you like to use it for?
• What qualities would a drone need to be reef safe?
  • Certain chemicals to avoid specifically?
  • What do you find concerning about your current drone in this area?

Objectives

The main objective of the robot is to design a robot that can safely move through the coral reefs. Robot needs to be able to move and be stationary on the bottom of the ocean. The robot needs to navigate through the corals without bumping into it since this could damage the reefs. The robot also has to be capable to have a stationary position and therefore hold on the something on the bottom of the ocean without breaking of pieces of coral. The robot design should not pollute the ocean. There should not be any big risk for the ocean. So the risk of things like battery leakage or losing the robot should be minimalized. Also the materials should be chosen right. The robot needs to be unbreakable so no parts will get lost. System has to have a tele operating system that makes sense to the user. The user needs a way to let the robot do what they want. This can be by preprogramming or with a tele operating system that is adapted to the needs of the user. The robot needs to not disturb the live that is in the coral. Fish should not see the robot as food or as predator. Also the coating of the robot should be safe for whatever it might touch.

Deliverables

(Not up to date anymore)

• A model of the way the system works
• A detailed sketch of the robots itself
• The semi-functional prototype of the robot
• An additional report or Wiki for the explanation of the concept

Connection to the Larger Problem

This robot can be used to further research coral reefs more easily and it can be outfitted with various components to help improve the reefs. For instance, it could be outfitted with speakers for acoustic enrichment, so that people do not need to dive down to place them. (To be added: more detailed examination of use cases)

The Robot

Coral Reef Considerations

Risks by direct contact with coral:

• Coral breaking when bumping into coral. Especially branching corals are the most vulnerable since they are fragile because of their growth form (Hawking and roberts, 1997).
• Coral breaking when getting stuck in the propeller.
• Anchoring can break the coral.
• When not capable of handling strong currents, the robot could damage the coral by being pushed to the coral with great force.

Risks by indirect contact with coral:

• Sedimentation/turbidity caused by the propellor, which can lead to mortality of coral species as it reduces the light penetration. If sedimentation or turbidity persists for too long the coral reef’s diversity can change, where the tolerant species replace the sensitive coral species(PIANC, 2010).
• Plastic can seal light and oxygen from the corals and can release toxins, which can increase the chance of coral becoming ill (“Plastic Is Making Coral Reefs Sick”, 2018).
• Bacteria can travel on plastic. When pathogenic bacteria reach the coral, nothing can be done to fix it (“Plastic Is Making Coral Reefs Sick”, 2018).
• Anti-fouling paint can damage coral (PIANC, 2010)

Information on the different kinds of reefs and where they grow. Coral needs warm, well lit water as well as solid surfaces to settle on. There are 5 types of reef (mentioned in order of distance from the coast): fringing, patch, barrier, atoll and bank or platform reef, which are all explained in the paper. Per region/oceans over the world the area of reef in km2 is given. Also species diversity in coral reef over the world is given. Spalding, M. D., Green, E. P., & Ravilious, C. (2001). World Atlas of Coral Reefs (1st edition). Berkeley, Los Angeles, London: University of California Press.

Requirements, Preferences and Constraints

(In order to prevent further downgrading and instead increase the growth of the reef, large biodiversity of animals is required. It is therefore important that the robot can navigate through the water to guide the fish towards the reef. For this, the robot should firstly be able to detect where fish should be guided and then maneuver in the ocean without damaging any of the already existing reefs. Establishing which parts of the reef need to be tackled can be done by scanning the reef by means of taking pictures and comparing them to a database full of images of coral reef. A camera that operates well underwater is, therefore, a must. This camera will also be used in combination with a filter to navigate the robot in the water.

Since fish can be tricked in believing the coral is still alive through sounds of different frequencies, the robot will have to be capable of creating these sounds underwater. To achieve this, an underwater sound system is needing to be implemented inside the robot. Research done by Enger, Karlsen, Knudsen, and Sand (1993) shows that there is a wide range in frequency of what fish can hear. In this research, tests were done on different fish which resulted in hearing thresholds differing between the species. To know what frequency to send out at what moment, the robot will have to know what kind of fish are around and adjust its emitting sound. A database of the types of fish is needed to compare the with the camera detected fish.

Currently, the work that is needing to be done to make sure the coral reef is either still intact or regrowing, requires divers to go down in the ocean to explore and help out. Since the robot is going to replace these divers, they will have to be able to do exactly what the divers already can. This means that the robot should not solely be capable of helping the coral grow back, but also be able to communicate the current state of the ocean back to researchers. For this reason, underwater wireless communication should be possible. For to robot to be moving around in the water and going fairly deep, it should contain a battery that can last long enough for the robot to go down explore the area and lure fish long enough to an area that they will migrate there. However, implementing a system inside the robot that will generate energy, would increase the robot's functionality. This way the robot can be used more effectively over greater distances.)

State of the Art and Literature Study

Movement

• Options to move left and right:
  • Servo motors (or stepper) can be used to turn the tail → need to research the difference and see which one is easier and better to use
  • The rotor itself can turn → does this exist?
• Options to move up and down:
  • Regulate the density by sucking water in or out a water tank
  • Use a servo or stepper motor to tilt a tail up and down (which causes it to move up or down) → need to prototype to find out whether it works
• The robot can move down to the reef and be navigated to a spot where it can stay stationary. Two clips will grab a piece of rock to attach it to the ground
• Waterproof/ materials/ making process:
  • To 3D print it, is not the most viable option as it has to be printed in multiple parts and a 3D print needs a coating to make it waterproof. It is also a challenge to make a waterproof system which clicks into each other so that the prototype can be opened up for testing and maintenance
  • We could use a mold and make it from rubber or silicone. These parts can easily be screwed together as they are less rigid than 3D printed plastic. Through tests we need to find out whether this is waterproof
  • We could also put all the electronics in a bottle or waterproof bag so that they will not get damaged if the casing leaks

Sensors

• https://backend.orbit.dtu.dk/ws/portalfiles/portal/112200773/ChristensenPAAR2015.pdf
• https://www.sciencedaily.com/releases/2010/11/101123121105.htm

Fraunhofer-Gesellschaft. (2010, November 23). Underwater robots on course to the deep sea. ScienceDaily. Retrieved February 8, 2020 from www.sciencedaily.com/releases/2010/11/101123121105.htm

• “ The engineers from Fraunhofer Institute for Optronics, System Technologies and Image Exploitation in Karlsruhe, Germany are working on the "eyes" for underwater robots. Optical perception is based on a special exposure and analysis technology which even permits orientation in turbid water as well. First of all, it determines the distance to the object, and then the camera emits a laser impulse which is reflected by the object, such as a wall. Microseconds before the reflected light flash arrives, the camera opens the aperture and the sensors capture the incident light pulses.”
• “The powerful but lightweight lithium batteries”

User Interaction and Communication

Different underwater communication technologies are mentioned. Each technology has its own benefits and downsides. This paper explains how each works and what the speed, distance, power etc. it needed or can be reached.

Kaushal, H., & Kaddoum, G. (2016). Underwater Optical Wireless Communication. IEEE Access, 4, 1518–1547. https://doi.org/10.1109/access.2016.2552538

• Our implementation needs to be long-range
• Our implementation should not bother the fish or reefs
• We should consider/mention having some basic autonomous movement in case the wireless connection is disrupted. Also, in case of interference the robot should reject command it believes will damage the coral reefs (probably, the risk there is that it will misunderstand its environment and overrule the commands it receives and damage the coral reefs as a result)
• The kind of systems for telecommunication used to reach the depth of the ocean will be too expensive in our example case. We will probably use a way cheaper module in our example case and mention what could be used in the final product.
• Best currently available to normal people: http://www.top10drone.com/best-underwater-drones/
  • First, third and fourth ones uses wi-fi (fourth mentions having a wifi module inside the robot itself, but it is intended for close-to-civilization work)
  • Second one is connected to a cord but also has bluetooth functionality
  • Note: these all seem to go at most 100m deeps, whereas corals can be 400-6000m deep (https://ocean.si.edu/ocean-life/invertebrates/corals-and-coral-reefs). But there are also shallow water coral reefs that are as high as 15m below the surface, so we should be good. But we could look into what coral reefs we can reach with our modules. (Amit has a source that says up to 70m deep is fine)
• Options for real deep sea:
  • Bluetooth
  • Wifi (previously mentioned drones mention interference when using wifi, https://www.powervision.me/en/product/powerdolphin/specs mentions using wifi to connect to a mobile device on the shore, assume there is no interference)
  • Ultrasound (will it interfere with the fish? They are bothered more by low-frequency sounds than high-frequency sounds but is it completely safe? I can’t quickly find sources that say it’s no problem at all but a lot of researches have suggested using ultrasound to research coral reefs so it is likely fine) (we should also consider if it is a reliable way of doing things, since the soundwaves could bounce off of the corals, which would cause a lot of interference)
  • Worst case option is using a tether - but that could cause damage or be damaged
  • We don’t really have to worry about the water-air barrier, we can use buoy with signal receiver underwater to avoid interference. https://www.oceantechnologysystems.com/store/ffm-buddy-phone-packages/interspiro-aga-mkii-ffm-buddy-phone-package/ example of underwater communication between divers - ultrasonic
• Options for prototype: we can just use a cheap wifi module or ultrasound or something. It can be quite weak since we will be prototyping it in clear, shallow water.

Components

• “The most prolific reefs occupy depths of 18–27 m (60–90 ft), though many of these shallow reefs have been degraded.” - Biology of Corals | Coral Reef Systems
• Building an Arduino-powered underwater ROV - could be useful to see the software and component selection process
• Arduino-Based Submersible Robot Maps the Threatened Coral Reefs
• Underwater robot control system based on Arduino platform and robot vision module

• Motors
  • Waterproof Servos
• Camera
  • Arduino designed VS external camera
• Arduino based
• Wireless communication module (Wi-Fi?)
  • Arduino and HC-12 Long Range Wireless Communication Module
• Power source
• Weights?
  • We need to calculate the density it needs to navigate based on the motor
• Sensors
  • Location
  • Pressure
  • Gyro / accelerometer

Research into Current Underwater Drones

Scubo / Scubolino

https://tethys-robotics.ch/index.php/robots/ https://blog.arduino.cc/2016/06/13/scubo-is-an-omnidirectional-robot-for-underwater-exploration/

Robot Features:

• Omni-directional movement - this robot, as demonstrated in their trailer video, can move in any direction and can maneuver extremely well underwater. While physically large it is very agile. By images and videos it seems to have 8 propeller style motors
• Control and power via tether - this robot is tethered which also allows power throughput keeping the onboard batteries charged during operation. According to the video footage, it seems that the tether does not stop it from executing complex movements.
• SCUBO 2.0 (left) seems to be made of metal, however this does not seem to cause weight issues as it is designed to be buoyantly neutral, perhaps its downfall is its size.
• Scubolino (right) is the smaller successor to scubo 2.0 however there is not any information about it on their official site or other places online.

LarvalBot / RangerBot

• LarvalBot is an updated version of the RangerBot, both are specifically made for coral reefs
• LarvalBot specializes in delivering baby corals to coral reefs, RangerBot in killing crown-of-thorns starfish. But their general design is the same and specific for coral reefs. Most sources focus more on the video analysis capabilities of the robot, not things like hull design and material, we might need to contact the creators (https://research.qut.edu.au/qcr/people/matthew-dunbabin/).
• https://phys.org/news/2018-11-reef-rangerbot-larvalbot-coral-babies.html - the robots follow predetermined paths with manual input
• https://www.barrierreef.org/news/news/Robot%20makes%20world-first%20baby%20coral%20delivery%20to%20Great%20Barrier%20Reef - need to do further research, but this implies the modification from RangerBot to LarvalBot was made quite quickly, so the general design must be pretty adaptable. At time of this article, it was a tethered robot, but they were discussing doing it wirelessly.
• https://www.qut.edu.au/news?id=137688 - LarvalBot does preselected paths at constant altitude
• https://www.qut.edu.au/research/article?id=135108 - RangerBot has a camera and is controlled by an app. It took about 2 years to develop. This one has computer vision, real-time navigation and obstacle avoidance. “Multiple thrusters so it can move in every direction”. This article claims the RangerBot is innovative for using vision-based sensors instead of acoustics-based sensors.“Weighing just 15kg and measuring 75cm, it takes just 15 minutes to learn how to operate RangerBot using a smart tablet.”
• https://good-design.org/projects/rangerbot/ - high def pictures
• https://www.smithsonianmag.com/innovation/sea-star-murdering-robotsa-are-deployed-in-great-barrier-reef-180970177/ - “They also fleshed out RangerBot’s kit, giving it water-quality sensors, lights, removable batteries, and an extra thruster so that it could gather water samples, operate at night and for longer periods, and maneuver in all directions.”
• https://en.wikipedia.org/wiki/COTSBot - the version before RangerBot apparently used GPS for navigation
• https://asmedigitalcollection.asme.org/memagazineselect/article/140/10/36/369143/The-Starfish-TerminatorResearchers-Looking-to-Stop - finally some actual info on the COTSBot and RangerBot: “Equipped with six thrusters, two stereo camera systems used for navigation and detection, RangerBot will be smaller, more maneuverable, and hopefully affordable enough to build a fleet. The idea is that RangerBots would rid the reef of as many easy-to-reach COTS as possible, and then the divers would pull other starfish out of crevices with hooks and finish them off manually.”
• https://scholar.google.com/scholar?cites=10376427326136424177&as_sdt=2005&sciodt=0,5&hl=en - paper on using vision for navigation and collision detection, using the RangerBot as an example case. Explains that sonar doesn’t really work in coral reef environments, since they are too complicated. But camera’s work better than in other marine scenarios because the coral reefs are quite close to the surface, and the water is very clear. “The RangerBot AUV is built around two stereo camera pairs which provide all navigation, obstacle avoidance and science/management task information. The downward stereo pair has a camera baseline of 75 mm, with the forward stereo camera pair having a baseline of 120 mm. All image processing and mission execution software runs on-board the AUV using an NVIDIA Jetson TX2 module as the primary computation capability.” “Its unique thruster configuration allows full six Degree-of-Freedom control, including hover capabilities which is essential for low altitude manoeuvring in complex coral reef environments.”

References

Ateweberhan, M., Feary, D. A., Keshavmurthy, S., Chen, A., Schleyer, M. H., Sheppard, C. R. C. (2013). Climate change impacts on coral reefs: Synergies with local effects, possibilities for acclimation, and management implications. Marine Pollution Bulletin, Volume 74, Issue 2, pages 526-539. Retrieved from http://www.sciencedirect.com/science/article/pii/S0025326X13003020

Burkepile, D. E., Hay, M. E. (2008). Herbivore species richness and feeding complementarity affect community structure and function on a coral reef. Proceedings of the National Academy of Sciences, Volume 105, Issue 42, pages 16201-16206. Retrieved from https://www.pnas.org/content/105/42/16201

Endean, R. (1982). Crown-of-thorns starfish on the great barrier reef. Endeavour, Volume 6, Issue 1, pages 10-14. Retrieved from http://www.sciencedirect.com/science/article/pii/0160932782900047

Enger, P. S., Karlsen, H. E., Knudsen, F. R., & Sand, O. (1993). Detection and reaction of fish to infrasound. ICES mar. Sei. Symp., 196, 108–112. Retrieved from https://pdfs.semanticscholar.org/7491/2a618da033b24796f48e88e71eaa00a9b57d.pdf

Ferrario, F., Beck, M. W., Storlazzi, C. D., Micheli, F., Shepard, C. C., & Airoldi, L. (2014). The effectiveness of coral reefs for coastal hazard risk reduction and adaptation. Nature Communications, 5(1). https://doi.org/10.1038/ncomms4794

Gordon, T. A. C., Radford, A. N., Davidson, I. K., Barnes, K., Mccloskey, K., Nedelec, S. L., … Simpson, S. D. (2019). Acoustic enrichment can enhance fish community development on degraded coral reef habitat. Nature Communications, 10(1). doi: 10.1038/s41467-019-13186-2

Hawkins, J.P., Roberts, C.M., 1997. Estimating the carrying capacity of coral reefs for SCUBA diving. In: Proceedings of the 8th International Coral Reef Symposium, vol. 2, pp. 1923–1926.

Hughes, T. P, Graham, N. A. J, Jackson, J. B. C., Mumby, P. J., Steneck, R. S. (2010). Rising to the challenge of sustaining coral reef resilience. Trends in Ecology & Evolution, Volume 25, Issue 11, pages 633-642. Retrieved from http://www.sciencedirect.com/science/article/pii/S0169534710001825

Kaushal, H., & Kaddoum, G. (2016). Underwater Optical Wireless Communication. IEEE Access, 4, 1518–1547. From https://doi.org/10.1109/access.2016.2552538

Lammers, M. O., Brainard, R. E., Wong, K. B. (2008). An ecological acoustic recorder (EAR) for long-term monitoring of biological and anthropogenic sounds on coral reefs and other marine habitats. The Journal of the Acoustical Society of America, Volume 123, Issue 3. Retrieved from https://asa.scitation.org/doi/abs/10.1121/1.2836780

Nyström, M., Graham, N.A.J., Lokrantz, J., Norström, A. V.(2008). Capturing the cornerstones of coral reef resilience: linking theory to practice. Coral Reefs, Volume 27, Issue 4, pages 795–809. Retrieved from https://doi.org/10.1007/s00338-008-0426-z

PIANC. (2010). Dredging and Port Construction Around Coral Reefs (N°108). Brussels: PIANC Secretariat General.

Plastic Is Making Coral Reefs Sick. (2018, January 30). Retrieved 19 februari 2020, from https://www.plasticsoupfoundation.org/en/2018/01/plastic-is-making-coral-reefs-sick/