1 Hydrobionics

Master thesis of Per-Johan Sandlund & Hans Jakob Føsker The Oslo School of Architecture and Design, Spring 2014

Students:

Hans Jakob Føsker Per-Johan Sandlund

Supervisors:

Steinar Killi

Etienne Gernez

2 3 Students

Hans Jakob Føsker, 29 Per-Johan Sandlund, 29 From Oslo, Norway From Nordmaling, Sweden Mail: [email protected] Mail: [email protected] Phone: +47 40648591 Phone: +46 70 2227953 Web: www.Hydrobionics.no Web: www.Hydrobionics.no

4 5 Table of contents

Intro 6

Broad research 16

Influential projects 22

Scope definition 36

Concept ideation 40

Focused research 68

Concept development 80

Result 102

User secenario 106

Reflection 116

Image: wallpaperswide.com 6 7 Intro

We propose an open Structure of the report We start with a brief introduction.

source bionic AUV to allow After the introduction we will outline the research that has influenced this project. Then we will define the scope of our concept before taking you hobbyists to conduct deep through our development phase. After the concept development phase, we will sum up our result and ocean exploration and in the offer our own reflection on the project. process help further ocean science as a whole.

8 9 Land 29% Explored 5%

Ocean 71% Not explored 95%

The Pacific ocean seen from space. Image from google earth. The oceans Their importance The worlds oceans cover 71% of The oceans contain a complex our planet, yet scientists estimate interdependent biosphere about that only 5% of the water has been which we understand very little. We do explored1. Of those 5%, most of know, however that we are completely reliant on it as the algae supplies our what we know is really only about the atmosphere with 70% of its oxygen. It’s surface, or waters shallow enough the ocean, not the rainforest that keeps for human divers. The world record us breathing 1. Yet, through ignorance for deep diving is currently at 534 or disinterest our species is destroying it m2. Consider for a moment what at an alarming rate through overfishing, that means when the ocean has an carbon emissions and other stress average depth of 4.3 Km. factors. 2

1 http://mashable. com/2013/09/25/ocean-vs-space/ 1 http://education. nationalgeographic.com/education/ 2 http://en.wikipedia.org/wiki/ activity/save-the-plankton-breathe- Deep_diving freely/?ar_a=1 2 http://edition.cnn. com/2013/03/22/world/oceans- overfishing-climate-change/ 10 11 Edith Widder was able to capture a live giant squid on camera, by simply being Image: http://www.noaanews.noaa.gov/ quiet. stories2005/s2370.htm Image: deepseanews.com

Todays equipment Infiltrate Ocean research equipment today Todays deep ocean equipment is is extremely expensive, excluding typically very loud. In an environment all but the best funded teams from that is normally dead quiet, noisy doing work on deep sea exploration. equipment scares off wildlife before researchers get the chance to observe it.

Edith Widder applied a change of tactics to be the first ever to capture a live giant squid on video; simply by being quiet.

12 13 Like amateur astronomers We envision a future where amateur contributions1. ocean explorers will contribute with Hopefully a similar organization and data for the scientific community in culture could help us uncover the the same way amateur astronomers mysteries of our oceans in the near do today. future.

Amateur astronomers help out with data collection by providing many smaller telescopes in addition to the relatively few but large telescopes available to professional astronomers.

Organizations such as the American 1 http://en.wikipedia.org/wiki/ Association of Variable Star Amateur_astronomy#Scientific_ Observers, help coordinate these research

Targeting the hobbyist market By creating an AUV that is low cost and open source, this project aims to provide the opportunity for hobbyists to perform ocean exploration, democratizing access to the worlds ocean floors.

Image: http://www.iau.org/news/ pressreleases/detail/iau0904/

14 15 Our project We propose a bionic, autonomous underwater vehicle or AUV to infiltrate subsea habitats. Our AUVs morphology is largely based on a tuna, and has been given the name AUTuna. Based on our research we have come to believe that if we make a quiet fish looking robot, aquatic life might ignore it giving it access to undisturbed sea creatures in their natural habitat.

16 17 Broad Research

How can we as industrial designers contribute to ocean research?

We started this explorative project with a very broad approach. We posed the question, how can we as industrial designers could contribute to ocean research, thinking that it would probably amount to designing a sailing robot.

What follows is the research and findings we made that have influenced the direction of this project.

Knowing nothing about the industry we tracked down some individuals who we thought might give us the necessary insights.

18 19 Roberto De Almeida Until recently Roberto worked “Any data is better than no data!” is often in a format that is very for marineexplore.org, an ocean hard to process. Either as a lengthy research database with aggregated He also mentioned that existing scholarly journal paper, or as a data focussing on normalizing and knowledge is largely unavailable to spreadsheet with raw data values visualizing all openly available ocean the public, residing on local hard without any visual representation. data. His position there gives him a drives in researchers offices. These things make it very hard for unique birds eye view of the field. anyone without intimate knowledge He said there are a lot of black holes “A lot of research exists only on the of the work to make any sense of it. in his maps. A lot of areas remain computer of the researcher who completely unknown, and that gathered it”. rather than obsessing about data quality, it’s more important to get He went on to point out that what something out there, and refine it data is made available to the public, later. “Any data is better than no data!”

– Roberto De Almeida Roberto De Almeida Ocean Data Engineer at Marinexplore

Image: marinexplore.com

Marineexplore.org aggregates and visualizes all openly available ocean data.

20 21 Peter Keen Peter is an operational oceanographer, meaning he makes a living out of launching and retrieving, as well as designing custom ocean research equipment.

His opinion on existing technology, is that because most of it has been developed for the offshore oil & gas industry with completely different needs in mind, it is generally bad for ocean research.

Overall, todays equipment lacks a more holistic approach in the design phase, which today is done by engineers solving specific tasks.

Peter Keen on what should be our main focus: “Whatever you do will be great”

Peter Keen Operational oceanographer. Here seen in Antarctica. Image: keen-marine.com 22 Image: keen-marine.com 23 Influential projects

Influential projects The following is a summary of the projects we found in our research that have influenced our diploma.

Image: wallpaperswide.com/ 24 25 “To truly appreciate and understand the oceans and it’s inhabitants, we have to Graham Hawkes holding a scale model of the Super Falcon submersible. be able to move like them: Image: Balint Porneczi/Bloomberg Gracefully and gently.” –Graham Hawkes

Graham Hawkes’ Super Falcon Graham Hawkes is a marine engineer we’ve been diving with noisy motors and undersea explorer who has a and blinding lights into the waters different approach to how we as expecting to see things. humans should explore the ocean and its inhabitants. “To truly appreciate and understand the oceans and its inhabitants, we We saw a National Geographic have to be able to move like them. documentary1 featuring among Gracefully and gently.” others mr Graham Hawkes who had lots of comments on how we until just His philosophy made us believe recently have treated the oceans as more strongly in the value of animal a 2D object. It also baffled him how movements, and want to incorporate them into our project.

1 https://www.youtube.com/ watch?v=ZElzys4AhNs from 37:25

The Super Falcon in action. Image: Tony Wu Photography 26 27 Edith Widder on how to explore the oceans with the help of quiet platforms: “Attracting animals rather than scaring them away”

Edith Widder, Image: teamorca.org

Edith Widder & the Giant Squid In 2012, Dr. Edith Widder was part of In a TED Talk, Widder also comments a team of researchers who employed at length on how we are scaring off new tactics to capture video of a wildlife with our noisy equipment. 1 living giant squid. Although mankind has known about this creature for hundreds of years, no one has ever seen one alive until Widder’s team 1 http://www.ted.com/talks/ caught one on video. edith_widder_how_we_found_the_ giant_squid Their approach was to mimic the bioluminescent light show of a common jellyfish that it displays when attacked. This is a last ditch resort intended to attract something bigger than what’s attacking it. The giant squid knows that when the light show is visible, there is food near by.

First giant squid ever captured on video. Image: Deepseanews.com 28 29 Image: http://www.digitallife.gr/wp- Image: https://plus.google. content/uploads/2012/03/lions04.jpg com/112302113750019621047/photos/ photo/5819182310430285106

Infiltrate the Habitat An example of a land based project that uses unobtrusive infiltration to capture unique footage, is the Beetlecam Project. The Beetlecam is an RC buggy with an armored shell mimicking a turtle. Lions mostly ignore turtles, so the Beetlecam is able to capture images that would be impossible to capture by other means.

30 31 Open rov ready for shipping An Open rov checking out a shipwreck. Image: Openrov.com Image: Openrov.com

The Open ROV project ”There are only a few teams on Eric Stackpole’s open source This lead us to believe that an open Remotely Operated Vehicle is a low source & low cost platform would budget Do It Yourself counterpart to be a far more valuable contribution this planet that can undertake the commercial Remotely Operated than something geared towards well Vehicles used among other things for funded research teams. multimillion-dollar projects to maintenance work in the oil industry. In a New York Times article the Open ROV is heralded as the future of build full ocean depth research ocean exploration. technology” - Victor Zykov, director of research -”There are only a few teams on at the Marine Science & Technology this planet that can undertake Foundation. multimillion-dollar projects to build full ocean depth research technology” - Victor Zykov, director of research at the Marine Science & Technology Foundation.1

1 http://bits.blogs.nytimes. com/2012/05/28/a-mini-sub- made-from-cheap-parts-could- change-underwater-exploration/?_ php=true&_type=blogs&_r=0) 32 33 Research findings NASA’s mars rover curiosity taking a There are a lot of problems that selfie on the surface of mars. we could have made a project Image: http://en.wikipedia.org/wiki/ Curiosity_(rover) about. Peter Keen and Roberto De Almeida’s remarks confirm that. But in our opinion the biggest problem, and the one we think we are best I’m gonna explore the suited to address, is the industry’s surface on mars. But first, lacking ability to generate public Let me take a selfie... interest for their work.

Public interest Scientific journal papers are not an engaging format, and lose the battle for attention to things like the Mars Rover, Space X or Mars One. We think this is a major problem because lack of public interest means that policy makers looking for voters will not be as concerned with matters concerning the oceans. However, there are a few projects The submarine Deepsea Challenger at that have demonstrated the ability the deepest known point on Earth, the Mariana Trench. Piloted by the Canadian to catch the public eye. On one movie director James Cameron end of the financial scale is James Image: npr.org Yes! Cameron’s Deepsea Challenge 1, and on the other is the OpenROV project 2.

The Deepsea Challenge was a Cool! manned dive to the deepest known point in the ocean, 10,908 meters down into the Mariana Trench off the coast of Guam. This project generated lots of interest with several Youtube videos each with up to half a million views.

The OpenRov Project is an open Booring... source system developed to let amateurs and hobbyists explore shallow waters from a small boat or pier. Their Youtube channel has a few tens of thousands of views, and they were featured in the New York Years of measurements in Alaska Presented in a data sheet. Times tech blog. Survey made by the Institute of Marine Science at UAF’s School of Fisheries and Edith Widder’s discovery of the giant Ocean Science squid was a Youtube blockbuster, Image: http://www.ims.uaf.edu/gak1/ being reposted countless times generating millions of views, as well as being featured on CNN, the Discovery Channel, TED.com and a number of other channels.

1 http://deepseachallenge. com/ 2 http://www.openrov.com/

34 35 Hello!?!

Remotely operated vehicles (ROV’s) are noisy and scare off the wildlife they are trying to observe.

Video What they have in common is Blend in engaging video of locations, From Graham Hawkes and Edith environments and/or animals Widder’s work we surmise that the otherwise completely inaccessible use of quiet infiltration will produce to most people. We also think that video of natural animal behaviors, OpenROV in particular attracts rather than video of a fish escaping attention because now all of a the ROV that filmed it, or simply no sudden, the average Joe can go fish at all. out and explore on his own without any funding. Given the fact that new Biomimetics3 species are discovered on every deep When aiming to unobtrusively 1 sea dive we believe that the more infiltrate an environment it really cameras in the water, the better. only makes sense to try to move like something that might belong there. Further there are many performance benefits to be gained from tapping into 3.8 billion years of trial and error.

3 What is Biomimetics? From Wikipedia: Biomimetics or biomimicry is the imitation of the models, systems, and elements of nature for the purpose of solving complex human problems. The terms biomimetics and biomimicry come from the Greek words bios, meaning life, and mimesis, meaning to imitate. A closely related field is bionics, 1 http://mashable. in short the study of biomimetic com/2013/09/25/ocean-vs-space/ robotics. 36 37 Scope definition

Scope definition We are going to create the first stepping stones for an open source, low cost bionic AUV platform. We will focus primarily on the biomimetics of form factor and kinematics, and leave advanced programming and electromechanical engineering to someone more capable.

Although there are many measurements that can be taken that would be useful to scientists, we have decided to focus on video as our primary data format because video of strange marine creatures is what seems to most effectively hook the publics attention.

Image: wallpaperswide.com 38 39 What else is out there? RoboTuna A robotic tuna made by the Googling far and wide we found Massachusetts Institute of only a few projects that have created Technology. bionic submersibles. “Built to simulate the action of a fish, the RoboTuna was designed by American engineers Narotuna at the Massachusetts Institute of Robotic tuna made in 2009. Technology, (MIT), to see if a robot A project by the mechanical sub could mimic the way tuna swim. engineering school of ETH The metallic tuna proved to use less Zurich. (Swiss Federal Institute of energy and to be more maneuverable Technology). than other robot subs.”

It was designed to explore the use of Text above from London science bio inspired locomotion principles. museum http://www.naro.ethz.ch/p2/ http://www.sciencemuseum.org.uk/ Image: https://www.facebook.com/ narooriginal.html images/manualsspl/10328063.aspx pages/Naro-nautical-robot Image: http://www.sciencemuseum.org.uk/

Naro Taratuga MIT Soft robotic fish A robotic sea turtle, also made by the mechanical engineering school Also made by researchers from MIT of ETH Zurich. This prototype was made primarily to http://www.naro.ethz.ch/p2/ showcase the capabilities of narooriginal.htmll soft robotics. The robot uses compressed carbon dioxide as the energy source for its inflating actuator. While extremely agile, it’s limited to a maximum of 20 to 30 strokes and would not work at all below a few meters in the ocean as the compressed gas would not expand.

http://newsoffice.mit.edu/2014/soft- robotic-fish-moves-like-the-real- thing-0313

Image: https://www.facebook.com/ pages/Naro-nautical-robot Image: http://newsoffice.mit.edu/

Our contribution Although these projects are most impressive, none of them are of much help if you are wanting to create one for yourself. They make it seem like such projects require a team of engineers working for a year and have not made their work available for public use. None of them can dive deeper than the bottom of a swimming pool either.

Our contribution will be to make and share a robot that is designed to go deep and intended to be recreated by individuals on a limited budget.

40 41 Concept Ideation

Concept Ideation The following section covers our exploration of biomimetics and targeted research into various marine propulsion systems and biorobotics.

Image: wallpaperswide.com 42 43 Building a test tank

A 700 liter test tank.

The tank was built out of plywood, tarp Hans Jakob assembling the test tank. and duct tape.

Testing In order to test ideas and iterate quickly, we built a 700L test tank. It formed the basis of our test routine where we built lots of low definition physical sketches of marine animals. This proved a very efficient method of validating a concept. What follows are the test notes from this phase.

44 45 Actuators

The wire displayed on this image is Flexinol wire shrinks about 5% when Flexinol-brand nitinol, a nickel-titanium heated to 100°C. Here its heated with shape memory alloy. an electric current

Muscle wire Nitinol Our robots needed muscles. In our case we got some 300mm Preferably, our robots would have x 0.1mm strands that contracted silent muscles. Nitinol, also known fully in 0.1 second, drawing 0.7 A at by brand names such as Flexinol 12V. It relaxed in 2 seconds after the or Muscle-wire, is a nickel-titanium current was removed. The required shape memory alloy that returns to temperature for it to contract is a “remembered state” when heated. ~100C which for our wires required Flexinol specifically increases its cross a minimum of 200mA in air at room sectional area, thereby shortening in temperature. The force generated by length. The contraction is remarkably one strand was 222g which is quite strong, and the contraction speed impressive for something that weighs is limited only by how fast it can be less than 1g. Because it contracts, heated. Conversely, the relaxation it is possible to measure through its rate is directly linked to how fast electrical resistance how much it has the wire cools after the current is shortened. A long wire will have more removed. And best of all, they’re resistance than a shorter wire. Using dead silent. that information, one could regulate the current accordingly so that a large burst is supplied to contract the wire quickly, and then just pulse current intermittently to maintain the desired position.

46 47 Nitinol in cold water Prototyping with servos Because the nitinol works on Although nitinol is awesome, wire to determine whether or not temperature changes, the wires we settled on using servos for the resistance difference is linear or showed absolutely no reaction when our prototypes because of both not. If it’s non-linear we would have submerged in 4°C water and supplied programming and hardware to create lookup tables for every step with 12V. But, when we coated the simplicity. With a servo, one can of a given contraction resolution. wire with a thin layer of silicone, precisely specify an angle to a Servos also come complete with it reacted just as if in air at room hundredth of a degree, and the mounting geometries making for temperature. Too much silicone, and servo will send its output shaft to very easy assembly, where nitinol the relaxation took a lot longer. that angle. With nitinol on the other would require constructing a custom hand, we would have to measure skeleton for every actuator. the resistance of several lengths of

48 49 Jellyfish

Jellyfish Conclusion We were eager to test a concept The jellyfish was indeed simple, but around a jellyfish, because of it’s very its incredible inefficiency disqualified simple kinematics. The kinematic it from further testing. It was both the complexity is so much lower than most power hungry and the slowest the others, that the jelly was the only of our tests. water test we did using flexinol. The jellyfish ran a very simple contract- relax cycle, of 0.5 seconds of contraction phase, followed by a 3 second relaxation phase.

The pulling force of the flexinol was mostly absorbed in the length axis of the silicone surrounding the wire without generating much flexion, as there was no rigid material to resist the wire. Therefore, although the wire contracted very strongly the jellyfish mantle had very little force. Even when we used the 0.3 mm wires, the jellyfish was quite weak, even though it pulled a staggering 9 A during each contraction phase.

50 51 Twister 1 Twister 2

Twister 1 Twister 2 An early concept inspired by To give the twister a second chance penguins winged propulsion. The we attempted to streamline the body twister is a mechanically simplified by removing two fins, and giving it a version of a penguin or a sea turtle tapered rear end. where a single servo oscillates large wings to create thrust. Conclusion It seemed better but to compensate Conclusion for the missing fins the wingspan had In the water it fought itself more than to be so large that it wouldn’t fit in it generated thrust. Also, we had no the tank. Requiring such large control way of steering it. surfaces in relation to it’s own size is a weakness. Also, we still had no obvious way to steer it.

52 53 Squid

Squid The balloon squid. We had hunch that a squid would be very efficient. This was the only electronics free sketch model consisting of one balloon filled with water, with a 1 mm jet nozzle. The squid managed to swim 4-5 lengths in our tank which equates to 12-15 meters on one filling of the balloon. It was very slow, but also very graceful. We tried adding two more 1 mm holes to the nozzle. That increased the speed somewhat, but cut the range in half.

Conclusion The squid didn’t seem very efficient, as it had to move extremely slowly to cover much of any distance. We left the concept as we couldn’t figure out a way for the balloon squid to refill itself without using a pump of some sort.

54 55 Eel

Sketching with servos. Not that impressive.

Eel We were keen to test a fish like creature, to compare it to the other forms of locomotion.

The eel sketch was a creature made from cardboard, duct tape, automotive clay and condoms that used 9g submicro servos for motion.

Conclusion Besides from being a visual atrocity, the robot was poorly balanced and veered off to the side. Testing various fin geometries, the results were that a fin covering the posterior 2/3 of the robots body proved the most efficient. This is in line with research we did later which showed that what this robot did was replicate how eels swim. Another conclusion is that the 9g submicro servos aren’t strong enough to deform the skin needed to waterproof them.

56 57 Whale

Resisting reaction forces Without pectoral fins, the whale just moved its midsection up and down while the fin remained stationary.

Whale Eager to test with stronger servos, the whale bot was the first sketch model we did using high power servos. We bolted the servos together, forming the tail of the robot, and ziptied that to the bottom of a 1.5 L soda bottle forming the body. To save energy, we opted for waterproofing the servos themselves, rather than encasing them in a waterproof shell.

We added flat boards to serve as pectoral fins. At first we placed them where we thought pectoral fins Pectoral fins should be, near the front of the robot, but this just changed the pivot point of the wobble. We moved the fins to the apex of the curve created when the robot was at max deflection to any one side. This drastically reduced the wobble, and more of the force directed backwards

=Force

58 59 Whale Fin One 1mm PET sheet. Too stiff and did not flex to provide an appropriate pitch angle

Speed and deflection We experimented with different settings for individual servo deflections, starting with 45 degrees. That proved too much as the whale bopped up and down more than it swam forward even though it had fins made to counteract that.

Lowering the angular deflection to Whale Fin Two 30 degrees removed most of the PET sheet, Zipties and tape fin. This wobble, and the robot swam nicely design proved to be more efficient forwards. as the tape flaps and PET sheet spine flexed enough to pitch the fin in the water

Conclusion The results were very promising, but the whale would require additional fins to steer laterally in the water.

60 61 Fish

Fish Buoyancy Spurred on by our success with the To take the complexity of neutral whale, we simply flipped the whale buoyancy out of the equation we bot to one side, changed the tail fin added a large bottle as a flotation and made it into a fish. device. Once in the water, the bottle fish far PET Foil test outperformed everything we had By simply folding a 0.5mm PET tried so far. sheet into a foil and dragging it through the water we could feel a dramatic difference in lift generated in comparison to a flat board. We added the foil fin to the bottle fish.

Foil shaped tail fin

62 63 The fish steers by shifting its tails center A flatter body resists more lateral force. point.

Body shape Steering Although the bottle fish had dorsal generating much lateral resistance. We added steering capabilities by In theory, a whale robot could fins to counteract the lateral force of Studying pictures of fish, we observed shifting the center point of the servo be made just as effective, but we the tail, the body moved significantly that their bodies are most often quite oscillations left or right. prefer the lateral agility gained from back and forth. We attribute this flat, providing a lot of surface area to steering by shifting the servo centers, to the cross section of the body resist the lateral force of the tail fin. rather than using additional fins. being cylindrical, and as such not

64 65 Oil filling of servos... Emptying servos of oil...

A note on water and Therefore, all air pockets should Another less obvious factor is the pressure proofing ideally be oil-filled. For our purposes, impact of thermal expansion rates of different materials. If the components Dealing with DIY underwater oil can be considered incompressible forming a seal are assembled at electronics was not surprisingly, very and will not decrease appreciably in room temperature with significantly difficult. We realized early on that volume at any pressure found in any different thermal expansion if our final prototype was to last for part of the ocean. We oil filled the coefficients, one will shrink more more than one test dive, there could interior of our servos intending for than the other when submerged in be no half measures. Everything them to be pressure proofed, but cold water. That could lead to the needs to be properly sealed with the oil added so much friction in the seal being broken. greased o-rings, and any structure internal motor, that one servo fried with an air cavity needs to be strong itself. We had to drain all of them and enough to resist the water pressure forget about our intended deep dive without deforming enough to break for this prototype. the seals.

66 67 Various tests of active buoyancy control. Non of them matched our demands of energy efficiency or being pressure neutral.

A note on buoyancy Ballast tanks Cooled oil Controlling buoyancy is a very energy the submersible has to overcome The concept is simple. Pump water When in water of the same efficient way to dive or ascend, at a force of 1100 kilograms for every into the tank until its no longer temperature, oil is buoyant. When least near the surface. To do this, square centimeter of surface area buoyant. cooled significantly oil in water will the submersible must increase or of the volume it needs to displace. sink as it contracts and its volume decrease it’s total water displacement Sharks provide a simple solution to The ballast tank system worked decreases while its weight remains without changing its weight. This this. -Flight. beautifully in our test tank, but can unchanged. is trivial near the surface, but great Sharks have no swim bladders, and not be used at any great depths with depths it becomes extremely use hydrodynamic lift over their out great difficulty. This is because Our second concept on active challenging as the pressure can be pelvic fins to maintain desired level the pressure outside the ballast buoyancy was to control the as high as 1100 Bars. That means in the water. This is the exact same tank would require the pump to be temperature of an oil volume to that to increase it’s displacement, mechanism that keeps man made incredibly powerful, and the tank change its buoyancy. aircraft flying. would have to be made extremely Regular cooking oil is almost pressure strong so as to not implode. neutral, and the concept worked, but required way too much energy to cool down the oil volume. We tried to lower the temperature with a battery and a thermoelectric cooler. This failed even though we had an excessively powerful battery.

68 69 Focused Research

Focused Research The following section sums up the research that has been in some way useful for the end result. How it has been implemented in the shaping of the AUTuna is shown in the concept development section.

70 Positioning Communication Underwater GPS is not possible. That Wireless underwater communication means, that any positioning has to is acoustic only, which means be done by acoustic pinging, or by introducing noise and running inertial measurement. Because one counter to our intent. Also, acoustic of our goals is to be as unobtrusive communication only allows for very as possible, we have ruled out low bandwidth stuff like a string of acoustics. An Inertial Measurement numbers or a text. Video streaming Unit or IMU can calculate position is quite impossible. Therefore all the remarkably accurately. It works by ROVs are tethered to provide a real calculating speed through measuring time video feed to the surface. accelerations. Any acceleration will mean that the speed has changed. As long as one keeps track of speed and heading over time, one can work out positioning. This example from Youtube1 shows an experiment where someone tracks the position of a foot The tether of an ROV spooled with impressive accuracy. up on deck. Image: http:// teacheratsea.wordpress.com/ tag/cable/

1 https://www.youtube.com/ watch?v=6ijArKE8vKU

Tracked data from a foot walking a spiral staircase Images: https://www. youtube.com/watch?v=6i- jArKE8vKU

72 73 You can always add lead Another insight, was that one should always strive to make the submersible as buoyant as possible. A bit counterintuitive, but the idea is that different missions may call for different payloads. More battery, a large sonar, a heavy camera system, etc. To make it neutral and balanced in the water once the instrumentation has been fitted, “You can always add lead”.

London In order to gain insight, we went longer the cable, the stronger the to London for the Oceanology ROV’s thrusters needs to be to pull International Exhibition. An annual them. The stronger the thrusters, the subsea industry trade show, where more power they need. The more all the manufacturers of ROVs, AUVs power the cables need to conduct, and other underwater products come the larger their cross section has to to show off their goods. The key take be. The larger the cables, the more away from the exhibition, was that drag they create…. This spirals out cables are a serious problem. Not of control at about 4 km. Because only do they seriously hamper the of this we decided that our robot maneuverability of the ROV, but they needed to be autonomous. An AUV have a practical maximum length of with no cable can be made much 4km, which if you think about it is smaller and more manageable than an absurd amount of cable to deal a deep diving ROV, and as long as with. The spools required are often it can withstand the pressure, it can much larger than the ROV itself. But dive all the way down to the bottom the real problem is that the cables of the Mariana Trench. create a lot of drag in the water, and provide currents with a lot of surface to pull off of. That means that the

74 75 Fish anatomy

Body deflection Fish Swimming forms Biologists have classified the swimming kinematics of fish who swim by oscillating their tails into Anguilliform five categories. From the Wikipedia article on fish locomotion1:

Anguilliform: Carangiform: Seen in eels and lampreys, this Body undulations are restricted to Subcarangiform locomotion mode is marked by the posterior third of body length whole body deformations in large with thrust produced by a stiff caudal amplitude waves. Both forward and fin backward swimming is possible by this type of swimming. Thunniform: The most efficient aquatic locomotion Carangiform Subcarangiform: mode with thrust being generated Similar to anguilliform swimming, but by lift during the lateral movements with limited amplitude anteriorly that occurring in the caudal fin only. increases as the wave propagates This locomotion mode has evolved posteriorly, this locomotion mode is under independent circumstances in Thunniform Speed teleost (ray-finned) fish, sharks, and often seen in trout. 0 km/h 130 km/h marine mammals.

1 http://en.wikipedia.org/wiki/ Fish_locomotion

76 77 Fish fins We did extensive research on fin shape in relation to the animal’s top speed through the water. From that research it follows that what all the fastest creatures have in common is that their fin, or rather hydrofoil is shaped with a high aspect ratio, low relative tip area, and a lunate planform. The best example of an animal that follows these rules this is the black marlin, which has been measured by a BBC camera team to speeds of up to 128 kph.1

1 https://www.youtube.com/ watch?v=mD7t057XIi8 78 79 Focused research Summary. A Froude Efficiency of 1 would mean The various locomotion systems rank Aquatic locomotion that 100% of the energy put into as follows: It was pretty obvious once we made a the locomotion system would be fish robot, that the oscillating foil of a converted into forward motion with Jellyfish: fish is far superior to any of the other zero loss. Also known as impossible. 0.09 forms of marine animal propulsion. A Froude Efficiency of 0 would mean Very bad. We later found some research on that 0% is converted into forward the matter that confirms this. The motion and most likely that the Squid: Image: http://www.canadianman- energy efficiency of marine animal actuator has malfunctioned. 0.29 ufacturing.com/wp-content/up- propulsion is measured in what is About three times better than a loads/2010/11/10-oct-whalepower-tu- jellyfish, but still rather inefficient. Image: http://whalesightings.blogspot. becle-hydrofoil-360.jpg referred to as Froude Efficiency. It is According to wikipedia’s article on 1 no/2011_09_01_archive.html a dimensionless number, or rather a aquatic locomotion and the journal ratio. It is the ratio between power article “Oscillating foils of high Thunniform Swimmer: input over power output. propulsive efficiency”2 0.87. Very efficient and outperforms most man made propulsion systems which typically land at 0.7. We will of course Humpback whale flippers base the kinematics of our final -8% more lift 1 http://en.wikipedia.org/wiki/ prototype on this swimming style. Further we came across some -32% less drag research on the bumpy flippers on Aquatic_locomotion, -40% higher angle of attack before 2 http://dspace.mit.edu/ humpback whales that concluded stall. that the so called tubercles, i.e. bitstream/handle/1721.1/25614/ Triantafyllou-1998-Oscillating.pdf the bumps on the leading edge of An article from design-engineering. the humpback whale flipper makes com2 on the study cites a wind- 1 them perform better . They list turbine that improved it’s annual up some remarkable numbers for energy output by 20% just from performance improvement over a switching to tubercled blades. smooth edged hydrofoil of the same size and planform:

1 http://scitation.aip. 2 http://www.design- org/content/aip/journal/ engineering.com/features/whale-of- pof2/16/5/10.1063/1.1688341 an-idea

Yellow fin tuna Image: http://www.ausasiagroup.com/ PX_AATUNA/WTBF_Fish_Species.html 80 81 Concept development

Concept development We wanted to create an initial first step towards an open source bionic AUV. To prototype it we focused mainly on the development of biomimetic kinematics and biomimetic physical form. We chose to work with servos for actuators. These make it easier to prototype the swimming motions than muscle wire would, but are noisy and would not be used in a final product. Because this particular prototype is not intended to dive to any great depths the camera and other electronics on board exist solely to create an engaging proof of concept that is able to swim autonomously in a controlled environment. For a fully seaworthy AUV we would need more work on programming so the AUTuna could navigate and perform a real dive.

82 83 Tubercled hydrofoils(Bright colored) Caudal keel

Tuna body shape

Flat Window

Pectoral fins for vertical steering

Starting point Visability The shape of the fish is almost The black color was chosen mostly completely dictated by the research because we like it, although it could from the previous phase. It’s body have been any color as below a few has an elliptical cross section to hundred meters there is no light in resist the lateral forces of the tail which to see anyway. We made some fin and an overall shape inspired by of the fins yellow to improve visibility the tuna rather than one of the very during launch and retrieval as a black fastest swimmers such as the black object below the surface is nearly marlin. This is because the marlin and impossible to see. The yellow fins are its family of so called billfish have a also a nice reference to the yellowfin much longer shape, which would tuna. make for a very cumbersome robot.

84 85 Tail fin movement

Water flow

Caudal keel

Tuna seen swimming from above.

Tubercled hydrofoils Caudal Keel The fins are tubercled hydrofoils to The posterior tail joint has been maximize the angle of attack and given a caudal keel like that of a real Caudal keel thereby thrust. tuna which helps stabilize flow and streamline the tail for stable lateral movement of the tail through the water.

86 87 Camera

LED package

Light sensors

Range finders

Head The shape of the head is defined by the components it needs to carry. It is a hydrodynamic casing for a pressure resistant cylindrical housing for a camera, 4 rangefinders for obstacle avoidance each needing a flat transparent window and an LED array with light sensors to control lighting for the camera.

88 89 Dorsal and Abdominal fin resists lateral force.

Pectoral and pelvic fins resist vertical force of the AUTuna’s slight buoyancy.

Positioning of fins Fin size Electronics The positioning of the fins is The size of the fins is a compromise. The electronics are housed in a driven by our experience from the Ideally we want larger caudal and flexible oil bladder made from a earlier testing. The vertical fins pectoral fins, and smaller dorsal common household item, a silicone are positioned centrally where the and pelvic fins. But, we opted for sugar bread form from IKEA. The majority of the lateral deflection the benefit of having them all be bladder is mounted against a flat from the tail motion would occur instances of the same fin in order membrane with standard cable without them. The Autuna is made to rationalize production by only glands for each cable required for to be slightly buoyant and use requiring a single mold. the servos and the sensor module hydrodynamic downforce to keep it in the head. This setup is inherently submerged. That way, if it runs out pressure proof, as the flexible silicone of battery or something else fails, it will deform to allow any air bubbles will simply float to the surface. The inside to compress without straining Autuna has two sets of horizontal the watertight seal. Another benefit, fins. One articulated set near the is that the need to waterproof the front that vary their pitch to steer it depth sensor module is removed as up or down, and one stationary set it can be contained within the oil that to the rear for the front set to work will always hold the same pressure as against. the outside water.

90 91 The tailored fish skin folded up around the tail in spite of compensative cuts

A simple nylon stocking outperformed the sewn skin

Skin The AUTuna is designed to be might discourage any future would- draped in a drag-reducing outer skin. be AUTuna builders. We therefore This doesn’t need to be waterproof, opted for a simple nylon stocking. it needs only to follow the form of The stocking proved to outperform the body underneath as closely as the tailored suit in terms of figure possible. At first we thought sewing hugging and ability to flex with the a tailored suit was the best option. movement of the robot. However, We made a prototype from a vinyl a suit with a zipper would make backed nylon textile, but it didn’t flex changing the battery and performing well enough, and was a very involved other service easier to do. effort. So much so, that we thought it

92 93 Analyzing the swim pattern of a tuna we found on Youtube (https://www.youtube.com/ Interface for sketching swimming Porting the swim pattern watch?v=mSYLXQcFWZM) patterns made in Processing. to the servos.

Modelling the thunniform swimming style Because thunniform swimmers were the tail motion and one to control shown to greatly outperform the rest, the pitch of the tail fin, we were we decided to build a thunniform able to fairly accurately recreate robot. Recreating the swimming style the thunniform swimming style. of a tuna was done by watching video The length of the servo joints are of a tuna swimming, and writing a based on findings done with visual piece of software in Processing that comparison of a video of a tuna, to allowed us to graphically experiment the graphical representation in the with changing body proportions, swimming style software. angular deflection of the joints and their phase offsets. We found that with four articulated joints, three for

94 95 Linear servo sweep cycle

Sine wave servo sweep cycle

Improving the kinematics Programming the fish This saves a lot of microcontroller At first we ran the code with linear required resolution for the prototype’s Once the angular deflections and processing power, when it can simply back-and-forth motion, which looked swim cycle and extracting the angular phase offset for each servo was find the next servo value in a table very robotic. When we drove the values from the swim style software. determined, it was a simple matter to rather than computing it for every deflections of each joint from a sine To calibrate things, we were able to program what we refer to as the swim step. The one we used can be found wave, we discovered that what makes get the software to send the values to cycle of the Autuna. Each servo runs at http://www.meraman.com/htmls/ movement look biological is smooth the microcontroller in real time. through a cycle of 360 steps, with en/sinTableOld.html. The values from accelerations. The sinusoidal swim values from a sine wave with its lower the sine wave are mapped to the cycle brought the fish to life, with The code for our fish swimming style extreme at 0, and higher extreme angular deflections determined for its movement looking graceful and tool can be found on our Github at 360. The wave exists as a lookup each servo by the Processing tool. effortless. Once the swimming style repository for those who want to give table of values generated with an matched the tuna from the video, it it a try. Hydrobionics -> Autuna online digital sinewave generator. was just a matter of deciding on the

96 97 Code structure The main loop of the Autuna program level needed for the camera. If below runs a check of all the sensors, it fades the LED array up. If above, before it determines where to angle it fades the LED array down. Finally, Main loop the servos. First it checks the depth the program iterates the position in Check sensors↘ module and angles the pectoral fins the swim cycle sine wave table, and Check depth, adjust heading↘ to maintain the target depth. Second, adds any sensor driven offsets to the Check obstacle sensors, adjust heading ↘ it checks for obstacles with the optical new servo positions. After writing Check Light, adjust light↘ range finders. If one or more of them the new positions to the servos, it Check sensors↘ report a reading within the threshold repeats the process. The arduino Check depth, adjust heading↘ of 300 mm, the program offsets the code for the AUTuna can be found Check obstacle sensors, adjust heading ↘ servo positions to steer the robot on Github along with the swimming Check Light, adjust light↘ away from whatever triggered the form software. sensor. Third, it checks the ambient light levels to determine whether they are above or below the target

98 99 First tank swimming test Buoyancy and balance We were honestly quite surprised When first submerging the AUTuna, when the Autuna just worked on the it was not surprisingly very buoyant first try in the water. It took its very first as we had taken “you can always add swim strokes with ease, although the lead” to heart. We added 530 grams tank walls were triggering its lateral of ballast, which we positioned rangefinders constantly causing it to carefully in order to balance the twitch back and forth a little to avoid robot. This also means that the making contact. AUTuna has a payload capacity of 530 grams.

100 101 Cold. Success!

Open water swimming test Confident that our fish worked, Although it was just video from a we went to a local beach for the mostly featureless sandy bottom, first open water test. With enough there was something very intriguing space to maneuver, the AUTuna about how the camera moved. It astonished us with how well it moved oscillated slightly from side to as it in the water. It looked completely glided through the water, looking like effortless, something that can’t be something out of a jaws movie. rendered with a still picture and really As the AUTuna currently has no must be seen in a video. Once back positioning systems, Hans Jakob had on land, we extracted the footage to get into the water with it to keep it from the onboard camera which we from swimming away. found to be absolutely hypnotic.

Well.. The camera was placed slightly tilted. But, none the less, the footage was captivating

102 103 Result

The result The AUTuna swims like a cross between a shark and a tuna. With relaxed strokes to the tail beat frequency of a shark in the swimming style of a tuna, it glides gracefully through the water with a cruise speed of about 1 meter/second.

104 105 AUTUNA Open source Bionic AUV

Something to build on The AUTuna is an excellent starting point for the DIY community to develop further. We have done the hard work of defining fish kinematics and writing software to recreate them. And perhaps more importantly, shaped a machine with a form factor so unusual that it catches the attention of individuals otherwise not interested in subsea technology. The following pages outline how we envision a likely user scenario.

106 107 Assemble Following detailed video instructions online, the assembly of the AUTuna would be an enjoyable learning experience, not just a means to an end.

Order a kit The AUTuna would be sold in much the same way as the OpenROV or any RC model, as a kit where the user does most of the assembly. Only the parts requiring precise or advanced machinery would come premade. Such as printed circuit boards, machined parts and other electronics. It is not a simple product, and as such requires the user to get well acquainted with it’s components and inner workings.

108 109 AUTUNA Open source Bionic AUV

A highly portable AUV Program its route Once the body is assembled, the fins At the launch site the user would need are field detachable, allowing the only to attach the fins, and plan a AUTuna to fit nicely in a bag for ease mission on a smartphone app before of transportation to launch sites. launching the AUTuna into the water. The AUTuna will then autonomously carry out the mission defined by the user, before returning home.

110 111 Motion triggered video recording We propose that the AUTuna employ simple computer vision to determine whether or not the image has changed since the previous frame, and so detecting if there has been any movement, or if there is anything in frame at all. That way one will not have to sift through recordings with hours of black nothing, and the AUTuna can undertake longer dives with less required video storage space. An example of this technology is the open source Motion for linux, a software motion detector intended for security cameras1.

1 http://www.lavrsen.dk/ foswiki/bin/view/Motion/WebHome

112 113 Share Once the AUTuna has been retrieved the user extracts the footage and shares it online if anything of note was captured.

114 115 AUTUNA Open source Bionic AUV

Available at: Github.com/ Hydrobionics/Autuna Download the code and 3D models.

116 117 Reflection

Looking back on the project Having done such a project is also hopes to crowdsource innovation The project started with a very valuable in and of itself, as we doubt for deep waters, the world would of future military drone technology. wide scope. Our starting point was we’ll ever have the opportunity to learn about the depths a lot faster. (http://diydrones.com/profiles/ that we wanted to “explore what work so exploratively again. Therefore we firmly believe that blogs/darpa-creating-its-own-diy). kind of contribution we as industrial the more cameras in the water, the designers could make to ocean better. Looking at what has happened science”, and we believed we would through open source technology in settle on a more user friendly sailing Thoughts on our result other industries such as 3D printing drone of some sort. In hindsight As outlined in our introduction, very Shaping the AUV as a fish, that moves through the Reprap Project or we find it a little baffling how it has little is known about the worlds like a real fish, will according to all our airborne drones through DIY Drones, morphed from there into a bionic oceans. It’s absurd to note how research provide numerous benefits we believe that if the same were autonomous underwater vehicle, or much we know about Mars and other both in terms of performance, and to happen for the ocean science AUV for short. This is the first time planets, and how little we know getting attention. It has certainly community, the world might be a either of us have ever taken on a about the oceans. The oceans are attracted the attention of our peers better place for it. We hope that project with a brief this vague, and paramount to our existence, yet our across classes at AHO. our project could contribute to the running a project with such a wide species seems more fascinated by much needed push that gets the ball scope has been very difficult. Not other planets than our earthly waters. Although the AUTuna performed rolling. knowing what the result would be nor However, when a video of an unusual beautifully on it’s first open water trial, who the intended user was, made animal from the ocean appears on it would have been very interesting the research phase very unfocused youtube, it can go viral as seen earlier to have more time with it to explore as there was no clear way to assess in our report with Edith Widder and other fin placements, different whether something was relevant for her video capture of the giant squid. planforms and cross sections of the project or just very interesting. Netflix has no reason to care about the hydrofoils and variations of the This caused the research phase to anything else than what attracts kinematics. We did observe a slight take very long, leaving little time for viewers. The fact that they have lateral oscillation of the head which concept development. several documentaries about oceans effectively means it’s dumping makes us believe that there is an energy to the sides that should have With that said, we can’t imagine interest there, but that it needs more been directed backwards. Another having thought of the concept we material to flourish into something set of dorsal and abdominal fins landed on, were it not for the broad more than casual entertainment. We would probably fix this. research we did. We didn’t know until think that the more people who see late March that we were going to do video of new or beautiful or bizarre Open source technology has a bionic AUV, and we find it baffling or otherwise exciting species, the democratized other industries by that we between then and May more people will be able to relate to bringing the costs down to a level that have designed and built a working our oceans. As outlined early on in a hobbyist can afford. Prime examples underwater biomimetic robot. Our this report, amateur astronomers are are the Reprap Project & DIY Drones. impression over the years has been providing a valuable service to the The reprap project is an initiative to that students at AHO usually settle world’s professional astronomers. make a machine that is capable of for a few renderings and a physical Although the amateurs have lower completely replicating itself. (http:// model no more than a visual mockup. quality equipment, they are providing reprap.org/wiki/RepRap) They are higher bandwidth with more eyes on far from achieving it still, but along Although the project has been the skies. Amateur astronomers are the way they have started a billion challenging, it has also been a typically the first to discover new dollar industry, the consumer 3D valuable experience. Because the celestial bodies, and the professional printer market. Makerbot, Ultimaker project targets the Do-It-Yourself community use their findings as a and all the rest owe their existence community, the work would suffer reference for where to point their to the Reprap project. More closely a lack of credibility if we had not telescopes. Democratizing access to related to our project, the DIY actually “done it ourselves”. We equipment that can lower cameras Drones forum, is a forum where have gained extensive experience deep into the water, would likely hobbyists share experiences from in the challenges facing an provide a lot of cameras in the water building and operating homemade underwater electronics build such and could stand to provide the same aerial drones. (http://diydrones. as waterproofing cable connections, for the deep ocean. Open ROV is com/) The US military’s Defense or balancing buoyancy and center of providing this for shallow water and Advanced Research Projects Agency, gravity. We wouldn’t have had any is creating quite a stir as seen in the DARPA was impressed enough by of these insights if we didn’t actually New York Times (reference) article the collective knowledge of the DIY make the robot. about them. If we could help provide Drones community to launch their a platform that can provide the same own derivative, the “UAV Forge” in 118 119 Hydrobionics

Master thesis of Per-Johan Sandlund & Hans Jakob Føsker The Oslo School of Architecture and Design, Spring 2014

Students:

Hans Jakob Føsker Per-Johan Sandlund

Supervisors:

Steinar Killi

Etienne Gernez

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