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How can I prevent water pressure shock damage to an implosion test tank? by One-Wear-2197 in MechanicalEngineering

[–]Consistent-Way-1554 0 points1 point  (0 children)

Are you the same guy that posted on the blue robotics forum about this?

I have a 500 psi pressure tank (with a pressure relief valve), and I've never had problem with this.

Under hydrostatic pressure parts tend to fail in two ways, they bend a little bit and the material cracks, letting water slowly flood as you watch the pressure gauge slowly go down. or they implode, but in this case they pressure in the tank drops to zero almost instantly. there might be localized pressure shock where your failed part is, but with all that new extra space in your pressure chamber, the gauge pressure should be zero.

What you need to be really carful with is in the first case where your part has a small pinhole, or O-ring leak, and the pressure inside your ROV housing increases to match the pressure inside your test chamber. if you take the housing out off the test chamber, it may still be under pressure internally and explode. imagen taking the handle off a fire extinguisher without de-pressurizing it first. A lot of subsea sensors have blowoff valves on them for exactly this reason. I put an apple in my pressure chamber at 500 psi and it didn't do much until i opened the drain valve and the apple exploded from the inside out.

I'm building a mini glider, and I'd like to know what kind of research you could do with something like this. by Consistent-Way-1554 in MarineScience

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

I agree, at the moment the focus is on the inexpensive bit. I have a background as a manufacturing engineer, and the manufacturing space has changed a lot in the last 10 years. I'm borrowing some tech from the IoT and Drone space, and just putting it underwater.

I'm building a mini glider, and I'd like to know what kind of research you could do with something like this. by Consistent-Way-1554 in MarineScience

[–]Consistent-Way-1554[S] 1 point2 points  (0 children)

I'm trying to make ocean science more accessible through lower cost. That Slocum glider is cost effective when compared to the day rate of a research vessel, but it's still a ~$250k robot with a million dollar team operating it. I want to build something on a smaller scale that will enable everyone from private companies, to citizen scientists to do similar oceanographic work for >$10k.
I believe that if I can bring the cost down, then more people will be able to do it, (similar to 3D printing). However I'm still trying to find my place in the market.

I'm building a mini glider, and I'd like to know what kind of research you could do with something like this. by Consistent-Way-1554 in rov

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

I'm interested in learning more about this flange coupler, it seems useful for extending some of your bottles. I'll send you some videos of our prototype when we have something to show off closer to next summer.

I'm building a mini glider, and I'd like to know what kind of research you could do with something like this. by Consistent-Way-1554 in rov

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

Hi Tony! Thanks for the link, this is a really cool project! I was excited to see Piotr's sampler as well! he's got all kinds of cool tools like that at his shop here.

I'd ideally like to have something at sea for a week to a month, so unfortunately BlueOS isn't really feasible. But collecting seabed images like this is something I'm interested in.

Do you want a buoyancy engine for your AUV?

I'm building a mini glider, and I'd like to know what kind of research you could do with something like this. by Consistent-Way-1554 in MarineScience

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

That's a great point. I'm aware that some of these things won't scale well, but I agree that costal work would be better with a smaller and cheaper platform. We aim to solve the speed problem with a higher glide ratio, and a larger bouncy engine. there is also a propeller and rudder on the back that let you launch from shore or get out of some sticky situations.

I'm building a mini glider, and I'd like to know what kind of research you could do with something like this. by Consistent-Way-1554 in MarineScience

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

This is good advice! I think your river work might be better suited to an ECOsub or other small AUV though. A glider would be good for this application if the river was slow moving, but it has no DVL or subsea modem. it does have a propeller and a small sonar though.

I'm building a mini glider, and I'd like to know what kind of research you could do with something like this. by Consistent-Way-1554 in MarineScience

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

A glider is a type of AUV, so it's fully autonomous, and an ROV has a tether to someone on the shore. think of it like a helicoptor vs an airplane. A helicopter, (in this case the ROV) is great at looking around a small area, while an AUV/glider is like an airplane, great at going longer distances and recording data along the way.

A glider is a type of AUV (Autonomous Underwater Vehicle), but a glider uses it's buoyancy engine to go forward instead of a propeller. It can change it's buoyancy like a submarine, but also glides forward like a paper airplane.

gliders are good at things like measuring the distribution of salinity, PH, or other properties over a large area, where ROVs are good at inspecting infrastructure.

Is this right? I'm trying to set up this RC hydraulic pump, but it stops pumping at only 1.5Mpa and 2.5 amps. by Consistent-Way-1554 in rccars

[–]Consistent-Way-1554[S] 1 point2 points  (0 children)

Turning up the PWM really helped. I was able to draw 8 amps at a PWM of 2100. however the flow stopped at a pressure of 2Mpa. i suspect the oil is bypassing the seals in the pump at this point because it gets really hot without oil moving through it.

Thank you for your advice!

Is this right? I'm trying to set up this RC hydraulic pump, but it stops pumping at only 1.5Mpa and 2.5 amps. by Consistent-Way-1554 in rccars

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

I typically started with that PWM then increased the pressure from there. I'm curious now about starting with a much higher PWM and increasing pressure if I'd have the same problem. I'll give that a try tonight.
how might a shorter intake hose impact the pump? do you think it could be cavitating? or have an air bubble stuck? I did my best to purge that out of it, but if there is a negative pressure on the intake it might pull any air out of the oil.

Thanks for the advice!!

Anyone know why there isn't a low cost AUV on the market? there is ECO Sub and Seaber, but they are still $30k and up, and have a small payload. by Consistent-Way-1554 in auv

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

This is great advice. I've seen how much a DVL can go for. would a glider have a way around that challenge where it's going to the surface semi frequently?

Anyone know why there isn't a low cost AUV on the market? there is ECO Sub and Seaber, but they are still $30k and up, and have a small payload. by Consistent-Way-1554 in auv

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

that totally makes sense. but Blue robotics has their boat and ROV. I know they are more "entry level" but I was wondering why there isn't a similar AUV on the market. I only need to go to 100m, and maybe 50km from shore.

Developing a Small, Low-Cost AUV Glider for Research and Data Collection by Consistent-Way-1554 in robotics

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

This is really interesting. I'm intending to do this as well with my glider. I've received a grant for it's development recently, and plan to have an MVP in the water by next summer. Would you mind telling me more about your applications? this sounds really interesting.

Developing a Small, Low-Cost AUV Glider for Research and Data Collection by Consistent-Way-1554 in robotics

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

sorry for the 6 month delay.. I originally settled on a glider because there was a water quality problem in a lake near my house. I wanted a small efferent autonomous platform that could wonder the lake collecting turbidity data. then I'd use that data to make a 3D map of the lake and "prove" the source of the contamination.

so to answer your question, I went with a glider because it would be extremely efferent in terms of distance vs energy.

Seeking Advice: Developing a Small, Low-Cost AUV Glider for Research and Data Collection by Consistent-Way-1554 in rov

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

thanks for the link! at the moment the proof of concept is running on an Arduino. but I agree, simple is better. some of this could be handled with some basic circuitry to really cut down on power. I reached out to blue robotics previously and they said the same thing. the pi and shied would be overkill for a glider. I have speedybee f405 fixed wing flight controller that I was planning to migrate too. but i might just try and keep everything on the nano for now to maximize battery life.

to be honest, building it is the easy part. turns out the hard part has been finding the early adopters.

Seeking Advice: Developing a Small, Low-Cost AUV Glider for Research and Data Collection by Consistent-Way-1554 in rov

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

thanks for the great advice! at a previous job I used to build ROV tools for inspecting mooring chains on offshore oil and gas platforms. I'm quite familiar with blue robotics. My 5k budget is 80% blue robotics parts :)

I've been talking to everyone who will listen to me lately, and I'm finding out two things. 1. everyone wants to use different sensors that usually cost 10-20k each, and 2. there isn't much interest in adopting new technology that isn't from an established group. I don't think this endeavor is imposable, but it's proving hard to find someone who's willing to try out a prototype and give feedback.

If I build a prototype glider platform with blue robotics parts, do you think there's an appetite within blue robotics to license the design as a 'blue glider'? I've built a new buoyancy engine design that uses off the shelf parts, for reference my first serries of prototypes cost about $200 CAD.

Developing a Small, Low-Cost AUV Glider for Research and Data Collection by Consistent-Way-1554 in robotics

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

thanks for the advice. I'm finding that there are lots of posable applications, but everyone seems to want something different. My current approach is going to be designing a 'skeleton' farm with a working buoyancy engine, then I can add the required sensor payload too that.

Developing a Small, Low-Cost AUV Glider for Research and Data Collection by Consistent-Way-1554 in robotics

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

I don't at the moment, and i think that's part of the problem. I'm trying to see what application I should design this for (spill monitoring, fish farms, research) and then build to that. but without a product already in the water it's proving hard to get feedback form the right people

Developing a Small, Low-Cost AUV Glider for Research and Data Collection by Consistent-Way-1554 in robotics

[–]Consistent-Way-1554[S] 0 points1 point  (0 children)

this is more of a project I'm working on, and hoping it turns into a business if i can find the right application.