BlueRobotics Marine ROV Thrusters
Phil Pilgrim (PhiPi)
Posts: 23,514
I'd like to bring this company, which got its start via Kickstarter, to the forum's attention. BlueRobotics makes thrusters for marine ROVs. I'm using their T100 thrusters (image below) in the class I'm teaching. They are very sound performers, are reasonably priced, and do not corrode in salt water. They also sell reversible ESCs for the 3-phase brushless DC motors used in the thrusters, along with waterproof (IP67: 1 meter submersion) servos from Hitec. (The thrusters themselves have been tested to 3000 meters depth (4500 p.s.i.) by Woods Hole Oceanographic Institute.)
Anyone who's done marine ROVs knows how limited the choices heretofore have been for thrusters: i.e. bilge pump motors with improvised props, Minn Kota electric trolling motors, or very expensive commercial ROV thrusters. BlueRobotics thrusters are filling a glaringly empty middle gap in this market.
The company has obviously adopted (perhaps without realizing it) the Parallax model for responsiveness to customer needs, and I can recommend them without reservation.
-Phil
Anyone who's done marine ROVs knows how limited the choices heretofore have been for thrusters: i.e. bilge pump motors with improvised props, Minn Kota electric trolling motors, or very expensive commercial ROV thrusters. BlueRobotics thrusters are filling a glaringly empty middle gap in this market.
The company has obviously adopted (perhaps without realizing it) the Parallax model for responsiveness to customer needs, and I can recommend them without reservation.
-Phil
Comments
Now you have me thinking about a one-servo ROV. Hmmm.
Is it hard to control an ROV using two vectored thrusters instead of four fixed?
Two of these, some PVC pipe, glue, Propeller, La Jolla Cove, I can see it now.
Now to go explore some swamps...Sounds like a good way to loose a thruster!
Thanks for the heads-up.
These thrusters are a low cost breakthrough in the field of underwater robotics.
They are just what I have been hoping for!
Now for someone to breakthrough in low cost underwater sonar!
Whit, how ever are you going to get that thing to sit still long enough to attach the thrusters?.. Video would be awesome, probably NSFW I think, but still awesome...
-Tommy
@Tommy - LOL!
-Phil
That would be good but generally brushless motors have a minimum speed they will run at.
BTW, my students determined that a small (<20 lb.) ROV propelled by two thrusters could achieve speeds in excess of 5 mph. Maximum speed is not, however, the most efficient point on the power curve.
-Phil
That's exactly what I tried to tell all my previous employers... I should put that on a Tee Shirt!.
I bet that was a fun day for them. :thumb:
-Tommy
If I still lived in San Diego, I'd be all over this (I've spent many many days in the La Jolla Cove and the surrounding area).
Here in Chubbuck Idaho, all I've got near by are some irrigation canals. I need to figure out some way to justify getting a couple of these thrusts.
I recall seeing these when the KickStarter was still active. IMO, this is a perfect KickStarter project. People who knew what they were doing leveraging the power the bulk purchasing. (I'm not always so impressed with what I see churn through KickStarter.)
Let's see. . . there is a reservoir not too far away. I'm sure there's some important and practical reason why I need to explore its depths with a ROV.
The thrusters will run down to about 300 RPM. Below that the speed controllers have trouble sensing the back-EMF field and running the motor. At that speed they get almost neglible thrust, around 0.03 lb.
-Rusty @ BlueRobotics
Reservoirs used to be fun to dive in.
Old open pit mines can be interesting. Sometimes there is interesting stuff to explore that was left over from the mining operations. They can often be relatively clear water also since all the dirt is long gone and you are down to rock and any silt is from runoff water after it became a body of water.
Reservoirs caused by damming rivers are always exciting. The water is generally murky and since they often don't clear the area before damming things up, you can find all kinds of things. Lots of trees to run into and get tangled up in. This would be a great opportunity to try SONAR in addition to you cameras.
You can always mount a scrubber brush and offer to clean the local pool!
Thanks for the info, and welcome to the forums!
Jim
Thanks, good to know. One further question, any plans to offer a symmetrical prop? For my purposes I would need equal thrust in both directions.
Welcome to the Parallax Forum! I'm glad you found your way here. (Was it the photo link from here in your server's log file that tipped you off?
__________________
I went with a couple of my students down to a local dock to test their ROV under both RC and GPS control. RC control worked fine. Under GPS control, it was programmed to go out to a racing buoy and back. I had tuned it via the GPS/Google-Earth simulation I wrote awhile back. But the simulation dynamics didn't come close to matching the real thing, and the ROV just spun in circles -- grossly over-correcting I guess. With new GPS data coming only once per second and a very responsive differential drive (thrusters are only 12" apart), I will probably have to adjust the programmed velocity profile -- especially when turning.
-Phil
This is one made from a dam. It would be very interesting to see what's down inside the reservoir.
http://en.wikipedia.org/wiki/American_Falls_Dam
I'll probably resist purchasing the thrusters unless erco decides I need them. He can make me buy just about anything. I have a 4" blue hamster ball sitting in front of me to prove it.
@Duane, my young Padawan: These Are the Thrusters You're Looking For!
Take two Blue Robotics thrusters, put on the blue hamster ball and call me in the morning.
Maybe it's just me, but I struggle to find a practical use for these. You could
- make some sort of human puller, but then you'd probably need SCUBA gear to make it worth while.
- make a tethered rover. But where would you drive it? Unless you have a boat to get to interesting places (shipwrecks?), you're pretty limited. I'd imagine silt gets old pretty fast.
- make a powered surface boat. But then why not just buy and convert an RC model?
- ???
Especially complicating the whole system is the lack of suitable underwater sensors or navigation solutions (except possibly a compass?).
I think these are really cool, and definitely appeal to the geek side of me, but I'm not sure what I'd do with one (or six).
Boats really aren't that uncommon. I just sold my larger boat recently to replace it with a simple small 14ft aluminum, the intention is to use it in conjunction with my autonomous solar boat - and maybe an ROV. It only cost me $300, and that's with electric motor and trailer.
[video=vimeo;116122593]
My students have a "contract" with the Port Townsend Marine Science Center to assist with their sea star survey. Their ROVs (a.k.a. "ASVs" autonomous surface vehicles) will be dispatched to nearby tide shallows to photograph the bottom (through the transparent polycarbonate waterproof box) from the surface, guided by GPS waypoints. Here's a photo of one team's full-sized model (the one alluded to above):
I also have a friend who does eelgrass surveys. Occasionally there are areas that he cannot survey (e.g. tide flats and estuaries) due to their being too shallow for his vessel. A GPS-guided, shallow-draft ROV such as these would be ideal for such an app.
-Phil
I've also written a Spin driver for the ESCs that pulses the motors on and off when the programmed pulse width is between 1450 and 1550 usec, in order to make sure that "slow" is really slow. This still ignores inertial effects, which can be significant with a craft that skims across the surface.
-Phil
This video above is very interesting. It was on a thread that may be made inactive.
See more about the SeaDrone here. An article is also here on IEEE Spectrum about the idea's developement (Stanford brains again!).
It really might be fun to develop an inexpensive hobby/educational bot (ala Phil Pilgrim's work here) - like the ELEV-8 for underwater use.
This fits Parallax's mission. The SeaDrone seems to have the "right stuff" for such an idea/concept - revised, of course, and made available in an ELEV-8 sort of package. We need Parallax Control (brains) and the educational materials - but this could be really fun!
In Louisiana, this could be a natural with our rivers, lakes and bayous - a wonderful educational opportunity... This really has me thinking about an area of robotics that would be interesting to more fully explore - practical - and educational for students of all ages!
What do you think Phil, Ken, others?
See my post about this at my blog - Robotics Under the Stole - http://roboticsunderthestole.blogspot.com/2016/05/underwater-robotics.html
"I have been experimenting with a common EMax BLHeli ESC and the EMax Program card. I have found that the ESC can be programmed quite easily to be bidirectional, and it works very smoothly and robustly.
This is great news and it means that small bi-directional brushless motors can easily be used for land wheeled robots and water robot thrusters!"
Did not know about this either - Looks like Blue Robotics has already made a really nice underwater platform! See - http://docs.bluerobotics.com/bluerov/
Blue Robotics is a great company. They handled their KickStarter campaign very well (as opposed to these guys: http://hackaday.com/2016/05/11/peachy-printer-collapses-investor-built-a-house-instead-of-a-printer/ Buyer beware!), and continue to deliver great products.
The seaweed thing is an issue, though. For surface vehicles, and based on this year's class project, I'm becoming convinced that paddle wheels are the way to go. Okay, they're much slower and less efficient than a prop-driven craft. But for underwater photography, you don't need speed, just reliable navigation. And they don't seem to have as many problems with seaweed fouling.
-Phil