Tom Nardi
Dan Maloney 3:00 PM
OK, hello all, let's kick it off. Welcome to the Hack Chat, I'm Dan and I'll be modding along with Dusan (I think) as we talk about underwater robotics with Tony White. Not sure I saw him log in yet, though -- are you out there Tony?
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Tony White 3:00 PM
Hi everyone! Happy to join you today and talk about some cool stuff! A bit about me -
Generally I consider myself a jack of all trades, with a speciality in rapid prototyping subsea and ocean surface applications. I’ve always enjoyed the water, followed that thread throughout my life, and have really grown into engineering in the medium with scuba diving and all manner of waterborne electromechanical systems testing. From recovering sensors to mapping surf breaks, so much is possible!
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Dan Maloney 3:00 PM
Hi Tony, welcome aboard!
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Tony White 3:00 PM
My career was launched with this project at Georgia Tech, over a decade ago! https://www.youtube.com/watch?v=hRv9uShOFTI
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hackerman49 3:01 PM
How was academia life at Georgia Tech?
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Tony White 3:02 PM
Tough! no grade inflation to be had there! Being on the water with the rowing team kept me sane
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Tony White 3:02 PM
After doing autonomous survey vessels in Louisiana / England with C&C Technologies / ASV Ltd., I went off to LA to develop swarm robotics and began working with Blue Robotics! This is a fun video too: https://www.youtube.com/watch?v=zNYzljKr_wY
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Dan Maloney 3:02 PM
Little bit of aside but still relevant, might kick off some discussion: We were talking in our editorial meeting yesterday about the submersible Alvin, which was built in 1964 and is still in operation? How do you think is that even possible?
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Dan Maloney 3:03 PM
https://en.wikipedia.org/wiki/DSV_Alvin
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Tony White 3:03 PM
Yes! I have some friends that have served as pilots to it
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Tony White 3:04 PM
It was built tough - titanium spheres, and lots of expensive materials. That said, I'm sure much has been renovated on it and refreshed over the years, particularly the controlling tech. It's capable of reaching some pretty incredible depths!
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Dan Maloney 3:05 PM
That's what we figured -- probably everything on the original vessel has bee replaced over the decades. Still, it's pretty amazing that it got this far
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hackerman49 3:05 PM
Very thorough engineering to be running since '64
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Tony White 3:06 PM
for sure! The ocean is pretty unforgiving, especially when it comes to corrosion. I'm more impressed by ships / boats - they exist at the most consistently violent place on earth - the sea/air boundary, which never stops moving! And many are in service today that are older still!
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tt2005 3:06 PM
There have been a series of major refits for DSV Alvin. I think the retired titanium spheres are on display on the WHOI campus in Woods Hole.
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Dan Maloney 3:06 PM
I mean, I'm a '64 model year myself and I'm still running. Just barely, but...
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Tony White 3:07 PM
😂
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Thomas Shaddack 3:07 PM
Wouldn't the titanium sphere undergo work hardening/embrittlement? Isn't that the major problem with titanium submarines?
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Tony White 3:08 PM
I'm not an expert in the materials science around the titanium used, but I do know that much of the titanium used in AUV spheres comes (came?) from Russia, which has been tough in recent years for the industry.
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Fred Fourie 3:08 PM
Hi Tony! Blue Robotics has been doing some amazing stuff with regards to lowering the barrier to entry for the underwater community. Which advances/improvements do you see coming into play in the next ~5 years. Alternatively, what should we be focusing on to improve/lower these barriers more?
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CLamb 3:08 PM
Have you worked on any underwater robots with umbilicals or were they all entirely self-contained?
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hackerman49 3:08 PM
Apart from the physical sub itself, I wonder how the digital aspects of it are holding up as far as cyber resiliency goes
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tt2005 3:09 PM
https://www.whoi.edu/what-we-do/explore/underwater-vehicles/hov-alvin/history-of-alvin/alvin-upgrade/ indicates the sphere was replaced in 2013
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Tony White 3:09 PM
Hi Fred! Great question. We've got a lot of exciting products in the pipeline, I think our wetlink connector series is the biggest game changer. Letting users terminate their own cables with connectors, with 0 potting involved, for <$100 will shake things up vs. current subconn connector practices < td>
</$100> |
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Thomas Shaddack 3:09 PM
Isn't there a lot of titanium (and other goodies) in the deep sea sediments, just itching to get mined?
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Tony White 3:10 PM
I've worked with ROVs, which use a tether, and autonomous surface vessels like the swarm I linked above, and of course the BlueRobotics BlueBoat. I've been developing a hovering AUV recently, hoping to get it in the water soon! All based on BlueOS / ArduSub
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Tony White 3:10 PM
As for "cyber resiliency " - it's uncommon to have an internet connection when in the field deploying an ROV! Nothing like an air-gap to keep a digital system safe....
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GitTyler805 3:10 PM
What about the communication protocol, Tony? You guys thinking about how all those ROV devices (thrusters, lights, grippers) will communicate in the future.
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Tony White 3:11 PM
Thomas I'm not sure if titanium is in the nodules that everyone is talking about harvesting from super deep in the pacific - mostly cobalt and other battery metals I think? Quite a tough environmental question
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CLamb 3:11 PM
How do you avoid getting the tether tangled or producing excessive drag?
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hackerman49 3:12 PM
Tony, it would be helpful for the community if the ArduSub docs were updated. They are a couple years behind
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Tony White 3:12 PM
GitTyler805 - we typically use TCP/IP over a twisted pair via homepluf adapter - like the powerline ethernet adapters used in many homes. We're working on some exciting stuff around 10baseT for similar communications between vehicle payloads (lights, grippers, etc.) and hope to upgrade our tether electronics to support 500m + at gigabit speeds. Currently our solutions top out at 300m / ~80mbps
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anfractuosity 3:12 PM
I saw an approach used by AUVs, where the battery pack is on a linear stage, which i believe helps it dive at certain angles, is that something you've used? (hope this message isn't repeated, got a failed to send error)
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Tony White 3:13 PM
Our ArduSub docs do indeed need an update - it's coming very soon! We have been updating the docs here quite a bit: https://blueos.cloud/docs/latest/usage/overview/
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darkmoon3d 3:13 PM
I thought the BlueRobotics wetlink connectors still required potting?
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Tony White 3:14 PM
@Clamb - tether management is often a huge consideration! If going super deep, a "clump weight" attached to the tether some distance from the ROV lets the ROV not have to fight tether drag. However, you can't go very far from the weight as a result! Our slim tether is a great way to reduce drag, as it only has a single twisted pair but is just as strong thanks to the equivalent amount of kevlar
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CPSfarmbot 3:15 PM
Hi Tony!
Thanks for the insights into the air-gap as a way of mitigating cyber threats. I'm interested in pulling a bit further on the cyber resilience thread. I assume that these underwater systems are equipped with a range of sensors and communication systems for navigation, data collection, and decision-making. Given that these systems are critical for their operations, I imagine they could also be potential attack vectors in certain scenarios.
Could you share more about how you address these vulnerabilities, particularly in terms of resilience against threats like GPS jamming or spoofing, and any interference with acoustic communications? How does the system handle situations where these communication or sensor systems are compromised? Are there redundancies or fallback mechanisms that ensure the robot can continue its mission reliably in such cases?
I’d love to hear more about the strategies you employ to ensure these systems are robust, even in the face of cyber-physical disruptions.
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Tony White 3:15 PM
@darkmoon3d no, we moved away from potting years ago! Our WetLink Penetrator is a mechanical gland that can seal the correct sizes of cable to 1000m! https://bluerobotics.com/store/cables-connectors/penetrators/wlp-vp/
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Thomas Shaddack 3:15 PM
Re barrier to entry... What about getting rid of pressure hull need? Fill the insides with gelled oil (candle gel is a fairly pure paraffin oil gelled with some styrene copolymer, a friend tested it for easily remeltable high voltage potting). Can be easily broken down for maintenance/repairs and then remelted again. Heard submarines use the potting-in-oil trick for stuff outside of the pressure hull, and the gelling trick may make it less likely to do accidental spills on the carpet. For the propulsion, what about motors with noncorroding ceramic bearings and fully potted coils, eliminating the need for moving seals?
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Tony White 3:16 PM
@anfractuosity I've seen moving batteries primarily on AUVs, buoyancy gliders in particular. Typically the Blue ROV2 doesn't angle down to descend, but just thrusts itself downwards like an upside-down quadcopter. I've not messes with a linear stage like that before directly!
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Tony White 3:19 PM
Hi @Thomas Shaddack - many deep deep vehicles do use oil-filled enclosures - the advantage is depth rating, but working with them is always a pain! Also, the oil in the enclosures will reach the external pressure thanks to a bladder that is compressed, keeping a 0 differential across the seal. This does mean that all your electronics have to be pressure proof - the small air spaces in mems devices like accelerometers are crushed at extreme pressure as a result! Therefore air-filled rigid enclosures are the best bet in most scenarios. We are starting a project with WHOI at Blue Robotics that may result in more affordable 6000m rated enclosures coming to the market someday!
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Tony White 3:21 PM
sending this again as I got a didn't send notification: Hi @CPSfarmbot - GPS isn't an issue for underwater systems - radio waves don't penetrate water! Typically acoustic localization systems are used, that may tie to a surface GPS. Generally, if the right acoustic frequencies were disrupted the vehicle would be helpless. It sounds like your question is more directed at AUVs, independent vehicles, that don't have a human a the controls?
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amok.mcconnell 3:22 PM
Are there any MEMS sensor devices that are designed for such depths?
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Tony White 3:22 PM
@amok.mcconnell they must be using something on those large workclass ROVs! I've not worked with their electronics directly, so I'm not sure....
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Tony White 3:23 PM
@Thomas Shaddack as for motors - that's actually how the Blue Robotics T200/T500/M200 work! We use oil-impregnated plastic bearings rather than ceramic, and the stator is potted, so no seal is required. When connectorized, we've had users use them at full ocean depth !
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Dan Maloney 3:25 PM
What kind of compounds are used for potting? Is it silicone? Or some other exotic polymers?
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CPSfarmbot 3:25 PM
@Tony White , my understanding was this chat was about " about the harsh engineering realities of underwater automation" and not just BlueRobotic tethered systems. From this perspective there are numerous vectors that should be consider for system resilience. I would even go as far as saying that even tethered systems are susceptible to cyber-physical compromises from the Repo to the Sensor. Some food for thought. Thank you for your time.
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Tony White 3:26 PM
there are many different types of potting compounds. Some are more flexible then other after cured, which can help with adhesion. Some can cure underwater, like loctite marine epoxy. Some are more thermally conductive! Generally, the environment they are cured in is critical to the performance, and if exposed to warm/cold conditions afterwards failures can result. O-rings on the other hand, always work!
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Thomas Shaddack 3:26 PM
Isn't it easier to put the MEMS things into tiny sealed pellets instead of having to maintain a whole big pressure hull with leaks? Small objects like this could be also easier made redundant to cope with seal failures.
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Thomas Shaddack 3:27 PM
Also, for garage lab tests, the pressure washers could be used for depth testing up to approx. 1 kilometer of simulated depth. They are used in DIY contexts for things including hydroforming.
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Tony White 3:28 PM
@CPSfarmbot for sure - not trying to keep the discussion centered on Blue Robotics tethered systems, they are just inherent to the ROV genre! Surface vehicles are definitely vulnerable to RF jamming, the nice thing about acoustic jamming is that the power required means that the radius of effectiveness is considerably more limited? I generally have avoided all military aspects of the field in my career, as I'd rather not contribute to anything that brings people harm
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Thomas Shaddack 3:29 PM
Are there ways to keep a mesh network between independent underwater vehicles? A way to monitor their relative positions? Eg. for autonomous seabed or shipwreck mapping.
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amok.mcconnell 3:30 PM
What about manipulator systems, what types of joints are used, what are the failure modes?
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Tony White 3:31 PM
@Thomas Shaddack Pressure washers are a great high-pressure source for test tanks! Definitely used stuff based on them before. It may be possible to pot MEMS to give them more strength, but liquids under pressure have a way of separating such bounds at a tribological level. The fastest route to prototypes is usually chucking the electronics you want in an enclosure and going from there!
As for mesh networking - acoustics have more limited channel bandwidth due to the low frequency (again compared to RF) but some of what you describe is definitely possible. Cerulean Sonar makes the ROVL, which supports multi vehicle use. https://docs.ceruleansonar.com/c/rov-locator/multi-unit-operation-swarms
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paul 3:32 PM
Hi all! I'm involved in a swarm entertainment water robotics project called "hydrones". I was wondering if there are any off the shelf, cheap. ultrasonic coms systems for underwater use?
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Thomas Shaddack 3:33 PM
Could we leverage the off the shelf piezo transducers for ultrasound washers/misters?
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Tony White 3:34 PM
@amok.mcconnell That's a broad question! Shaft seals are generally easier for rotary than linear applications. By joints, what sort of mechanisms are you thinking of? Avoiding galvanic corrosion is key, but generally water provides nice lubrication for most applications
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paul 3:34 PM
I was thinking maybe the parking assist ultrasonic transducers are weather-proofed, so maybe okay to a meter?
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Thomas Shaddack 3:34 PM
Could an array of such transducers, on the vehicle surface, act as a de facto 3d imaging sonar array (incl. passive modes)? The ability to focus a beam would be also helpful for communication. (More thought. Could the communication of one vehicle be used for simultaneous imaging by other vehicles, in a way akin to a bistatic/multistatic/passive radar?)
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Tony White 3:35 PM
Hi @paul it sounds like you're after an acoustic modem. Something like these may be affordable! https://succorfish.com/products/delphis/ This is also a good reference: https://udrc.eng.ed.ac.uk/sites/udrc.eng.ed.ac.uk/files/attachments/UDRC%2025-03-2021.pdf from this forum thread
https://discuss.bluerobotics.com/t/succorfish-nanomodems/14496
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darkmoon3d 3:35 PM
there's an excellent tutorial on instructables for building a cheap diy hydrophones https://www.instructables.com/Lets-Build-Some-World-Class-Hydrophones/ . perhaps this could be integrated into signal processing?
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Tony White 3:37 PM
@Thomas Shaddack typically the acoustics used for localization are much different than what would be needed to create a map from sonar returns. The Cerulean Surveyor multibeam (only $5k! ) is a good example of a small mapping device, where as the ROVL already linked is used for localization. Other localization systems use a longer (short) baseline like the WaterLinked UGPS. Remember, acoustic channels are typically Khz, rather than Ghz, so a lot less is possible from a bandwidth perspective !
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Tony White 3:37 PM
@darkmoon3d analog signal processing for communication with a hydrophone is a first step in developing things like an acoustic modem, for sure!
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amok.mcconnell 3:38 PM
I was wondering about joints / servos that give a manipulator grabber arm its movement, torque and position feedback. Are the motor bodies housed inside the ROV hull and linked through the hull mechanically or are the motors in the joint themselves?
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Tony White 3:39 PM
@amok.mcconnell typically subsea servos are housed in their own container, with penetrations for the mechanical rotation and the cable going to them. Blue Trails engineering makes a great option, and we're soon going to launch one from Blue Robotics! https://www.bluetrailengineering.com/product-page/underwater-servo-ser-20xx
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Tony White 3:40 PM
Reach Robotics makes many styles of manipulators, with sealed actuators - pricey but very cool! https://reachrobotics.com/products/manipulators/
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Tony White 3:40 PM
(for subsea applications)
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Thomas Shaddack 3:40 PM
That's why I wanted to combine multiple uses into the same signal environment. Sacrifice some efficiency in comm so the ping can be simultaneously used for ranging/imaging, and you don't have to share the medium with both kinds of signals. Encode data to the pings so the reflected sequences can be used for imaging and the received ones we didn't send ourselves can be used for comm (and if strength allows, also for imaging).
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Christopher 3:42 PM
Like a dolphin... theoretically possible
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darkmoon3d 3:42 PM
I've avoided using acoustic communication methods in favor of a tethered solution due to cost and simplicity on my own projects. hasnt it also been proven that acoustic methods are harmful to aquatic life?
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Tim McNerney 3:42 PM
I was impressed with the design of the swarm-ready "data diver." As much as I keep thinking about gliders and energy-saving, I really liked the way they "power down to depth" by reversing their thruster, and float to the surface when they stop thrusting.
Can you tell me what the teardrop-shaped capsule is all about? (sorry, I know we're trying to stay general and not about your company)
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Thomas Shaddack 3:42 PM
Aquatic life itself uses acoustic comm methods rather extensively.
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Tim McNerney 3:43 PM
Follow-up... if there are "only two moving parts" to a data-diver, how can it steer in 3D?
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Tony White 3:44 PM
acoustics are typically only harmful to marine life if at very high power levels, in close proximity. This occurs when sub-bottom trandsucers are probing the earth from large arrays, looking for oil deep in the earth. Can pop a whale eardrum easily! The amount of power in the water from a small sonar is typically not enough to cause issues, especially at the frequencies used. Range is also limited as water is 10x denser than air, so propagation losses are high!
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Christopher 3:44 PM
@Tim McNerney who's teardrop-shaped capsue?
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Tim McNerney 3:46 PM
@Christopher The data-diver has a clear payload/electronics tube, right next to it is a yellow "organic shaped" outrigger--that's what I'm calling "teardrop shaped"--and at the bottom is a caged thruster.
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Tony White 3:46 PM
Hi @Tim McNerney - The data divers were a blast to design! They were actually made with Apium, not Blue Robotics. They can only descend vertically, running one motor slightly faster than the other to "corkscrew" down. We did some cool synoptic measurements of internal waves with USCD researchers off San Diego with them!
The teardrop thing is overmolded buoyancy foam, positioned there for stability.
They were never commercialized, but this company is working on their successor! https://www.jaia.tech/
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Thomas Shaddack 3:46 PM
Thought I had re hydrophones. Poor man's SOSUS. Digitize the signals, add precision timestamps eg. from GPS, transfer on a non-realtime medium like internet (or record and pick up later if we don't need near-realtime processing).
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Tony White 3:47 PM
Yup, logging hydrophones and sharing the data later, or in realtime, is possible! I've been testing some hydrophone options for our Reef with the BlueBoat and doing just that - trying to record whale song! I got a bunch of reef sounds yesterday but no whales came by
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mikeb 3:48 PM
sorry I give up - first time here and last time - the text jumps too much - can't go back and read what I missed - tryed up arrow and just keep jumping to the bottom - no stinking way to read it - sorry my laptop screen only lets me see maybe three inches by the time the header and "you have" MESSAGE blocks the bottom - maybe this will be PDF and I cam read it next week - but over an hour and I an frustrated and fed up
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Tony White 3:49 PM
Using acoustics for both measurement and communication would be possible, but things like a multibeam imaging or echosounder are actually beam forming with multiple transducers, so doing a communications chirp at the same time may not be possible ? The folks at Cerulean Sonar are experts in the field, and always willing to consider new approaches!
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Fred Fourie 3:49 PM
That Jaia looks cool! any other companies like this you can recommend we keep an eye on for cool new stuff?
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Tim McNerney 3:49 PM
Thanks. Having mentored university students, I also think about ways to make untethered failures less heartbreaking. Testing long-range autonomy is hard.
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Tony White 3:50 PM
sorry @mikeb - you can scroll the chat window with your mouse, but it does seem to jump down with each new message. I'm not sure about a pdf, but the text will just exist here to read at your leisure!
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Tony White 3:50 PM
Autonomy in the ocean is indeed super difficult @Tim McNerney - out of sight out of mind! Quite a fun recipe for adrenaline imho
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Dan Maloney 3:50 PM
We'll be posting an transcript after the chat too, you can check back for a link
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Tim McNerney 3:51 PM
Since we keep coming back to acoustic modems... Have they gotten a) cheaper and b) less susceptible to near-shore noise?
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Tony White 3:51 PM
@Fred Fourie Remora robotics is set to revolutionize aquaculture with their resident ROV cleaning systems! https://remorarobotics.no/
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Thomas Shaddack 3:52 PM
The beamforming is generally done by transmitting the same message with different delays. (Steering of a microphone array into a direction uses the same trick - I think recording several microphones at once could then allow steering in postproduction, too.) The old Wullenweber antennas even used different lengths of coax as delay lines, I think. The F35 radar is said to be also able of acting as directional radio so it should work in principle.
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Tony White 3:52 PM
I'm not aware of any revolutions in acoustic modems - I've been researching some options for the Reef (linking since I keep mentioning https://bluerobotics.com/the-reef/ ) - but I've not heard of near-shore noise issues. Are you referring to reef-crackle, or engine noise from boats/ships?
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Tim McNerney 3:53 PM
I hadn't heard the term before, but yes, "reef-crackle"
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Dan Maloney 3:53 PM
Reef crackle?
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Tony White 3:54 PM
if you go to a healthy coral reef, and go for a swim, you'll hear quite a crackling! I can probably link a recording from yesterday shortly to illustrate
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Tony White 3:54 PM
I wasn't aware this could interfere with acoustic modems, but it doesn't surprise me! I'll have to checkout the FFT to see what frequencies it's affecting
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Thomas Shaddack 3:54 PM
WIFI uses multiple antennas tricks with using delayed/reflected signals as separate channels to use wider bandwidth. SDR radars use tricks with autocorrelation of modulated pulses to gain sensitivity. Could software radio have tricks for signal processing of acoustics?
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Tim McNerney 3:54 PM
In general I am interested in hearing in advancements in marine robotics that make the barrier to entry lower, especially for students.
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Tim McNerney 3:56 PM
Re: "reef crackle" or not... I guess I'm referring more to high white noise levels near the shore, e.g. from waves crashing, etc. In the open water, it is quieter.
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Tony White 3:56 PM
@Thomas Shaddack I'd imagine all those same tricks would apply! Multipath can be a bigger issue with acoustics then RF I believe
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Thomas Shaddack 3:56 PM
Yup, and multipath can be actually leveraged for more bandwidth.
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Thomas Shaddack 3:57 PM
https://en.wikipedia.org/wiki/MIMO
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Tony White 3:58 PM
I think the wetlink penetrator glands are a big advancement to help students @Tim McNerney - they are such an affordable way to bring a cable into an enclosure, and learn alot about sealing in the process! BlueOS in general is positioned as an open-source software pickup-truck to make development easy - with extensions like Node-Red students can be doing simple payload integrations quite quickly! https://bluerobotics.com/learn/blueos-and-node-red-guide/
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Tony White 3:58 PM
And Cockpit - an open source ground control station software makes customizing your drone control interface for any type quite easy too! https://github.com/bluerobotics/cockpit
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Tony White 4:01 PM
here is an example of that "reef crackle" recorded yesterday with an ACsense hydrophone! https://drive.google.com/file/d/14VRU9RANEXXzHPKZebg8GuOd_YLg2t7b/view?usp=sharing
https://acbotics.com/acsense-mini
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Thomas Shaddack 4:01 PM
Re the acoustic imaging, thought about a thing for divers for zero-visibility. megahertz transducers around the goggles, imaging within few feet, showing augmented reality image. The same could be, if it would work, used for robots to feel the space around them.
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Dan Maloney 4:02 PM
I think we've got the next "What's that Sound?" for the podcast...
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Tim McNerney 4:02 PM
@OceanLab Wow, these WetLink Penetrators are quite inexpensive. We were using waterproof connectors but never tried to solve the seal against the enclosure problem, as we were mostly staying near the surface.
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Tony White 4:03 PM
Very cool cooncepts @Thomas Shaddack ! A multibeam imaging sonar provides pictures for such situations, and I've seen some examples of products targeting divers with them. They typically cost many 10s of thousands of $, and so are limited to military / oil and gas applications typically? The Sonoptix Echo is $10k, and is the most affordable multibeam imaging sonar out there! This guide does a great job explaining the differences on sonar types: https://bluerobotics.com/learn/a-smooth-operators-guide-to-underwater-sonars-and-acoustic-devices/
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CLamb 4:03 PM
Do you ever use any dynamic buoyancy change to move in depth?
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Tony White 4:04 PM
Connectors are always going to be more expensive than a gland, as there is a lot more that goes into them. But for situations where you don't need to break the connection, they are great!
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Tim McNerney 4:05 PM
Do you have any advice on how to make reliable variable-buoyancy devices? (as a diver, I keep wanting to say "BC"). There are many ways to build these, but keeping it simple is super important underwater.
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Tony White 4:06 PM
That first project I did in college was the only time I've used a buoyancy engine in a project. On the small scale, they're typi
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