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  • #1321
    Profile photo of Kevin
    Kevin
    Participant

    I thought I would contribute to the forum on one possible solution (you can do it however you want) for mounting the BlueRobotics OpenROV Compatible Kit to a v2.7.

    As you can see from the attached pictures, I deviated from the posted tutorial and mounted my horizontal thrusters to the top of the ROV frame instead of on the sides. I was concerned with “rolling” the ROV if they were mounted on the side walls. Luckily the v2.7 allows one to do this, not the v2.6.

    I started by positioning one thruster at a time using just the back screw hole. I also used calipers to ensure both thrusters were placed the same by making light etchings in the frame.

    After I was satisfied, I drilled one hole for the back screw and mounted each thruster. I then installed the inner frame and checked to see if the thruster was straight adjusting as necessary and then marking the remaining three holes for each thruster.

    As you can see, I got very good results and I am confident the thrusters are mounted straight even if they were “eyeballed” in.

    I’ll be working on the vertical thruster next!

    • This topic was modified 2 years, 2 months ago by Profile photo of Kevin Kevin.
  • #1329
    Profile photo of Rusty
    Rustom Jehangir
    Keymaster

    Kevin,

    Thanks so much for posting your progress. This looks excellent. I really like the idea of mounting the thrusters to the top. I’m not too familiar with the v2.7 kit but it looks like this is the way to go.

    Please keep us up-to-date on the rest of your build! Do you mind if we include some of these images in our tutorial?

    Best,

    Rusty

  • #1330
    Profile photo of Kevin
    Kevin
    Participant

    Rusty,

    Of course! Let me know if you need any more shots and I can work backwards the best I can. It mounts very easy and I have no problem taking it apart.

    The vertical thruster is going to need some work so it doesn’t hit the E-tube, but I have some ideas. I only need to raise the propeller a few millimeters and it should clear it.

    Kevin

  • #1342

    Dave Sirak
    Participant

    I just bought OpenROV Compatible Kit (#OROV-KIT-R1) for my 2.7,  I expect to have to some modifications.  are these thrusters different than the ones you showed??

    • This reply was modified 2 years, 2 months ago by  Dave Sirak.
  • #1344
    Profile photo of Kevin
    Kevin
    Participant

    The attached picture is everything I got in my kit: 2 Standard T-100’s, 1 M-100, Propeller and assorted mounting hardware.

    I actually finished work on my 2.7 yesterday and everything works perfectly. After I get my endcap replacement set (yes, I messed one up), I’ll put up some pictures. I haven’t water tested it, but I know it is going to be stern heavy so I’m looking at flotation options.

    The only other major modification is to find a new place for the IMU as it won’t fit on the top anymore due to the thruster cowlings. I’m going to make up something for it and mount it on one of the old motor mounts.

    Attachments:
  • #1346

    Dave Sirak
    Participant

    Thanks for the excellent information, I am wondering if I could create a platform for IMU protruding off the back.  Let me know if the larger motors and magnetic field interfere with the compass.  My ROV had her maiden run this morning and she was already a bit tail heavy.  I am interested in installing a GoPro topside.  Have you heard or seen anyone doing this?  I was thinking I would add an addition vertical threaded rod forward to bring the bow down.  Please let me know what you do.

  • #1356
    Profile photo of Harry Franklin
    Harry Franklin
    Participant

    Just a thought…  I like the idea of the thrusters mounting to the top, but the original thrusters are mounted much lower.  I am assuming they need to be mounted close to the center of gravity in order to maintain level forward travel.  I am thinking that with the thrusters mounted so high, it may tend to force it down while moving forward.  Perhaps a small spacer to drop the thruster down lower closer to the CG would help?  This would also help clear the preferred IMU mounting location.  I could be way off base with this.  Please let me know if anyone has any knowledge of the subject.

  • #1383
    Profile photo of Kevin
    Kevin
    Participant

    Dave,

    You should be good to add the IMU off the back, but you just want to be careful you don’t knock it off in transit. And I think the magnetic compass was disabled on the current software release. I think it’s Inertial only right now.

    For the GoPro, my friend Scott added one like this to the bottom. He uses it for making up wreck mosaics, but it can certainly be turned forwards. I think slinging it to the bottom is the best way as it adds a sort of “keel” to the ROV to balance it out.

    Harry,

    I was thinking about the thruster placement as well and I went into my copy of The ROV Manual to check to see if there was anything on the subject and there is not for how high or low thrusters should be placed on the frame. Center of Gravity (CG) is not the only factor in ROVs, there is also a Center of Buoyancy (CB), which I am taking into consideration.

    I have a thought going that the closer to the CB the thrusters are, the more stable it will be. Is it true, I don’t know, I haven’t done the math, but I keep looking at the larger ROVs and all their horizontal thrusters are placed pretty high on the frame and very close to the floatation. The most I can do is try it!

  • #1402
    Profile photo of Kevin
    Kevin
    Participant

    As promised, attached are a few of my completed shots of my OpenROV.

    You will notice that I made a little platform for the IMU that simply screws into the starboard motor mounting holes.

    The functions and water integrity tests were SAT. I still have to go about adding buoyancy to the stern as it was pretty back heavy with the new thrusters.

  • #1414

    Dave Sirak
    Participant

    Kevin,

    Thanks for the excellent photos and info. My thrusters arrived today and I thinking of installing the main thrusters on spacers made of a material with positive bouancy to offset the weight. I am also hoping the spacer will allow clearance of the installed IMU. I am thinking of a PVC cap filled with bouyant material… I will post and share what I try.

  • #1436

    Dave Sirak
    Participant

    Here is a link to the trial and error working with buoyancy in the pool: http://youtu.be/3EIQV_ZH8yI

    I used 4 nylon bolts as spacers to allow the thrusters to clear the IMU with no issues.  The main thrusters went in without any issues, make sure you leave about 12 inches of cable to allow you to disassemble the frame from the main ROV body.  I had more difficulty with the vertical thruster.  I made a motor mount out of surplus acrylic and glued it to frame.  The motor mount plate is strengthened when the motor hardware runs thru it and is installed to the motor.  I had purchase longer M3 stainless screws of varying lengths to accommodate the spacers on the main thrusters and some small spacers I made to accommodate the different lengths of the screws thru my homemade vertical thruster mounting plate.

    My next step was to work on a buoyancy solution to make up for the heavier thruster in the stern.  I used different sizes and lengths of PVC pipe figuring I could cut to length depending on the correct buoyancy. The larger PVC sections installed above and below served as unintended control surfaces and really had a negative impact on the control of the ROV.   I found 2 lengths 3/4 of PVC pipe cut 15″ running along the top and with the direction of travel worked well and the bouancy was pretty close.

     

    • This reply was modified 2 years, 1 month ago by  Dave Sirak.
    • This reply was modified 2 years, 1 month ago by  Dave Sirak.
  • #1447
    Profile photo of Kevin
    Kevin
    Participant

    Looks great Dave! I can also see you had some fun with this!

    I took your advice and moved the thrusters down so that they are now inline with the old motor mount holes and it runs perfectly straight.

    I also had it out in the ocean this weekend and it ran great even if it did get beat up with the current a bit. We were just drifting in about 200 ft of water.

  • #1451

    Dave Sirak
    Participant

    Excellent solution, where can I get some of the foam? Is that high density foam found at craft stores??

  • #1452
    Profile photo of Kevin
    Kevin
    Participant

    It was like a 2×2 foot piece of Foamular XPS foam I picked up at Home Depot. I’m not sure on the density. It’s pretty rigid but will probably get crushed at about 20-30 feet, but it works well for testing in shallow water.

    Let me know what you find. I’m on the hunt for some good stuff that will work down to 300 ft. So far, I would have to custom order a pretty large piece from General Plastics.

  • #1453

    Dave Sirak
    Participant

    I found this on syntactic foam: http://www.synfoam.com/products.html

  • #1461
    Profile photo of Harry Franklin
    Harry Franklin
    Participant

    Kevin – What was your reason for initially mounting to the top of the outer shell, rather than the side.  If I can’t come up with another solution for buoyancy,  I will need some foam as well.  Perhaps a few of us could split a piece to help keep costs down.  How much better are these thrusters performing over the original OPENROV thrusters?  I have not had a chance to work on this, but I m starting to wonder if it is worth the effort.

  • #1462

    Dave Sirak
    Participant

    My experience with the Blue Robtics thrusters has been very good initially and well worth the modifications. I plan to use my ROV in salt and fresh water.  I also fly RC planes and the Turnigy motors are at the bottom of the food chain and should be fine for occasional use but I would suspect frequency salt water use could be problematic.  It is a very good choice in terms of an entry level motor and perfect for new users.

    I would be interested in sharing notes and costs of a foam order. I was thinking of  covering foam with fiberglass resin for water proofing. I am thinking of making a couple of horse shoe pieces of foam covering with fiberglass resin to account for saltwater, freshwater and different payloads.  I am thinking of installing lengths of surgical tubing to allow stainless bolts to pass thru for installation.

    Craft stores sell foam used for artificial plants that is easier shaped and cut which might be a good foam candidate.

    Dave

     

     

     

     

     

  • #1476
    Profile photo of Rusty
    Rustom Jehangir
    Keymaster

    Kevin, David, and Harry,

    I was just pointed to some fishing net floats, which come in hard plastic and hard foam varieties. These might work great and I’m sure they are more pressure resistant than the XPS insulation foam. The four blocks that Kevin is using are probably providing about 1.4 oz (40 g) of buoyancy each. You could replace those with four of these foam floats or plastic floats.

    They are definitely a little larger for their buoyancy than the insulation foam.

    We’d be happy to place a bulk order on foam if you guys can agree on a size. Kevin and I talked about the General Plastics R-3300, which is pretty well priced in quantity.

    -Rusty

    • This reply was modified 2 years, 1 month ago by Profile photo of Rusty Rustom Jehangir. Reason: missing links
    • #1499

      Dave Sirak
      Participant

      I ordered 2 of each of the suggested net buoys from Memphis Net,  I want to have a set for fresh water and another for salt.  Depending on how the net buoys work out and if I mess it up I would be interested in getting in on an order with General Plastics.  I am looking to shoot a grouper spawning event which happens every full moon.  We plan to dive, place and tether the ROV on a ship wreck at approx 160 feet and wait for sunset.  100’s of Grouper are known to appear but it has never been recorded.

      Dave

      • This reply was modified 2 years, 1 month ago by  Dave Sirak.
  • #1483
    Profile photo of Kevin
    Kevin
    Participant

    Harry,

    I originally mounted them to the top because that is where the shell is the most rigid and would still allow the installation of the poly-fin. I’m fine with the changes and the extra holes on top. Lesson learned.

    Before we dive into the R-3300, let me try some of those foam floats Rusty found. Cutting one of the “hot dog” looking ones in half might work out pretty well and be more “off the shelf”.

  • #1501
    Profile photo of Harry Franklin
    Harry Franklin
    Participant

    That’s amazing Dave.  Where are you located?  Keep us updated on the foam and be sure to share that video if it works out.  I may consider making some syntactic foam metioned in another thread on here.

  • #1502

    Dave Sirak
    Participant

    I am in Orlando – I am the co-founder of Formula H20, an underwater racing league.  We have a race this weekend in Weeki Wachee Florida.  I plan to use the ROV to shoot the races and the mermaid shows.

    Here is a link to a show featuring one of races.

    The wreck with the Grouper spawning in called the USS Muliphen of the coast of Stuart Florida.

    I will post some video this weekend of the ROV in action at the races.

     

    Dave

     

  • #1525
    Profile photo of Kevin
    Kevin
    Participant

    So I ordered twelve (12) of the 1-1/4 inch foam floats, so I’ll see how they do.

    Another option I was told about was the use of Divnycell Foam, which seems to be what a lot of the scuba divers use for their equipment. I bought some of the H-100 foam, so I’ll have to do some pressure testing, but I can at least order this foam without having to get a custom quote. The H-250 looks to be way overkill for my needs.  http://www.aircraftspruce.com/catalog/cmpages/divinycellfoam.php

    • This reply was modified 2 years, 1 month ago by Profile photo of Kevin Kevin.
  • #1530
    Profile photo of Harry Franklin
    Harry Franklin
    Participant

    I am thinking of a slightly more elaborate solution.  My thought is to design and 3d print a mold that will fit above, and contour to, the thruster.  Once I have that mold ready, I can fill it with  syntactic foam that is discussed in another thread on here.  Unfortunately I have more ideas than time and don’t know 3d design/cad programs quite well enough to pull this off yet.  If anyone else thinks this may work and wants to contribute, let me know.  I think this could be a really clean solution, or I could be totally wrong.

  • #1533
    Profile photo of Rusty
    Rustom Jehangir
    Keymaster

    Harry,

    I think that could work really well. With the 3d printed shell for structure, I think you could use a very low density foam instead of syntactic foam. You might be able to use an expanding insulation foam.

    -Rusty

  • #8930
    Profile photo of TCIII
    TCIII
    Participant

    Hi Kevin,

    I know that this thread is over a year old, however I am interested in how well the T100 Thrusters worked with your OpenROV 2.7 Controller Board as the T100 Thrusters draw about double the current that the OpenROV brushless motors do. Also, I think that OpenROV reduced the current carrying capacity of the ESCs on the 2.8 Controller Board which further acerbates the higher current consumption of the T100 Thrusters issue.

    Did you adjust the value of the Thrust parameter in the OpenROV cockpit down to say 2 – 4 to prevent over current damage to the Controller Board ESC power circuitry?

    Regards,

    TCIII AVD

  • #8932
    Profile photo of Kevin
    Kevin
    Participant

    I never had an issue with the 2x T-100s and 1x M-100 on my 2.7. I simply dropped in the new BR hardware and it’s been working fine. I used it on power settings 2-4, not necessarily because of overload, but because at 5, it was too powerful and would pitch a bit downward. 2-4 kept it nice and straight.

    Actually, it’s still working like a champ and was just loaned out for helping to film a TV show for 4 weeks and the users had no complaints.

    Also of note, my large 6 thruster ROV used a 2.7 board with 6 thrusters and I didn’t (surprisingly) blow anything up. https://forum.openrov.com/t/work-class-openrov/674/101

  • #8938
    Profile photo of TCIII
    TCIII
    Participant

    Hi Kevin,

    Thanks for the information, much appreciated.

    It is hard to believe that you were able to get 6 of the BR Thrusters to work with the OpenROV 2.7 Controller Board without having an over current event during operation.

    Your 6 thruster design is most impressive. I am attaching a picture of my vectored 6 thruster ROV for comparison. It uses a BBBMINI as the navigation controller and has a separate battery WTC.

    Regards,

    TCIII AVD

     

    • This reply was modified 9 months, 3 weeks ago by Profile photo of TCIII TCIII.
  • #8986
    Profile photo of TCIII
    TCIII
    Participant

    Hi Kevin,

    Did you build the navigation controller WTC for you 6 thruster ROV from scratch or did you cut down an existing OpenROV WTC and chassis?

    The charges to laser cut the Topside Adapter case and the controller support structure in the Electronics Tube is about $70USD and that does not include the WTC water tight end-caps which I do not need in my design.

    Comments?

    Regards,

    TCIII AVD

  • #9003
    Profile photo of Kevin
    Kevin
    Participant

    I used a stock OpenROV 2.7 Tube and 2x endcap kits. I doubled up one side with 6mm flanges so I was able to pot 6 more servo wires into the end cap. Seen here: https://forum.openrov.com/t/work-class-openrov/674/69 I originally built it for 3 thrusters, and while fine, I wanted to experiment with 6. I had the foresight to pot the extra servo wires, which I thought might have been used for 6x T-100s with BlueESCs, but I was cautioned against that as I would draw too much power and the ESC’s would be powered when the battery tubes were sealed up. Too many issues, not enough low cost solutions.

    At the time I was building it, the BR 4″ WTCs were just coming out and it was a bit late to change my design. I had considered upgrading, but when I was shown the BlueROV2 prototype, I ceased all R&D work of my own. The BlueROV2 has far more power and is more maneuverable than anything I could build.

    Yep, I’ve been following your design for some time…what are you building now with the OpenROV stuff?

  • #9008
    Profile photo of TCIII
    TCIII
    Participant

    Hi Kevin,

    Thanks for the information on your build, but I am still a little confused on how you constructed your Controller WTC. I understand about using the OpenROV WTC and End Caps.

    Did you have the Controller Electronics Tube acrylic support hardware cut from the OpenROV laser patterns or did you have previously existing Controller acrylic support hardware?

    Presently I am putting together a three thruster ROV using the OpenROV 2.8 Controller and am thinking about duplicating the OpenROV WTC Controller housing instead of putting the Controller in a WTC that is parallel to the ROV sides and not perpendicular.

    Regards,

    TCIII AVD

  • #9018
    Profile photo of Kevin
    Kevin
    Participant

    My mistake on the understanding. So it’s a bit of a weird story on the E-Chassis…As you saw from this thread, I completed a stock OpenROV 2.7 kit #1790 in March 2015 with the additional BR thrusters.

    I bought a new E-tube and endcaps for my new 3 thruster design and once that was complete, I transplanted the whole E-Chassis from #1790 into the larger frame 3 thruster variant. The two were interchangeable so I had no need to build a new chassis at the time. When Walt sent me the prototype 6 thruster Controller Board, it was an easy swap out. When I visited OpenROV HQ in January 2016, Brian G was kind enough to give me a spare 2.7 chassis kit so I had two fully functional ROVs again.

    Hope that makes a bit of sense. Best of luck with your new design, should be an interesting build.

  • #9020
    Profile photo of TCIII
    TCIII
    Participant

    Hi Kevin,

    Thanks for the clarification, much appreciated. That is what I figured you did, but wanted to be sure.

    If I do duplicate the OpenROV WTC I will have to have the Controller chassis supports laser cut, however if I go with a configuration that has the WTC parallel to the ROV chassis sides I will have to make my own Controller chassis supports.

    I plan to use a BR 4″ diameter WTC and BR O ring flanges and end caps no matter what configuration I build.

    Regards,

    TCIII AVD

    • This reply was modified 9 months, 2 weeks ago by Profile photo of TCIII TCIII.
  • #9046
    Profile photo of Kevin
    Kevin
    Participant

    Concur with using a BR 4″ WTC, those things can go deep and it was pretty fun when we personally tested to 200m. Besides hydrodynamics, what is your reason for wanting the WTC parallel to the sides? I’ve seen plenty of ROVs with it perpendicular (Outland 1000/2000, Teledyne Mini Rover come to mind).

  • #9047
    Profile photo of TCIII
    TCIII
    Participant

    Hi Kevin,

    You will notice that all of the BR ROVs have the WTCs parallel to the sides of the ROV so there must be some advantage to this kind of configuration.

    The OpenROV ROV is one of the few hobby ROVs, that I have seen, with the WTC perpendicular to the sides of the ROV which, in my opinion, appears to make that ROV harder to balance fore and aft. I have had no problem easily balancing my vectored 6 thruster ROV chassis and it has two WTCs that are mounted parallel to the ROV sides and are centered over the center of the ROV chassis.

    The Teledyne Mini Rover’s WTC appears to be small in relation to the overall chassis so putting it perpendicular to the sides of the ROV chassis and right up front probably has very little effect on the ROV COG which is what I am looking for in a ROV configuration.

    Regards,

    TCIII AVD

  • #9049
    Profile photo of Rusty
    Rustom Jehangir
    Keymaster

    @tciii and Kevin,

    I think both options can work well. There are a few disadvantages to the lateral tube configuration that have led us toward the longitudinal design with a dome.

    1. The air-acrylic-water light path causes the camera’s field of view to decrease when you have a flat acrylic plate in front of the camera. The difference can be pretty dramatic (like 110 deg reduced to 65 deg if I recall correctly). In our design, we use a dome, which fixes this entirely and has no distortion.

    In the lateral-tube design, you can mount the camera close to the acrylic, but your field of view will be reduced, or you can mount it close to the center of the tube, but then the image will be distorted. It’s distorted because in this position it is basically a dome shape vertically but a flat plate shape horizontally.

    2. With our enclosure and penetrator design, you need a lot of space at the end of the tube for the cable penetrators. That means that for a reasonable sized tube you need a very wide ROV.

    For us, the longitudinal-tube design works out better.

    -Rusty

  • #9051
    Profile photo of Kevin
    Kevin
    Participant

    Thanks for the technical pros/cons Rusty, I didn’t realize the field of view changed that dramatically. I guess it’s just in the way manufacturers build things then.

  • #9053
    Profile photo of TCIII
    TCIII
    Participant

    Hi Kevin/Rusty,

    I just received a OpenROV Controller chassis acrylic components quote from Polulu and it turns out that the Controller Chassis end plates are only 3.66 inches in diameter which is over a 1/4 inch smaller in diameter than the inside of the OpenROV acrylic Tube which is supposed to have a 4 inch diameter inside. What gives?

    Regards,

    TCIII AVD

  • #9054
    Profile photo of Rusty
    Rustom Jehangir
    Keymaster

    Hi Tom,

    Did you check the dimensions on the “Preview” PDF from Pololu before ordering? Sometimes the sizes of things in DXF files don’t get translated very well. The files you have might be set up with strange units.

    -Rusty

  • #9066
    Profile photo of TCIII
    TCIII
    Participant

    Hi Rusty,

    Yes I did and I figured that I might have to adapt the Controller Support Frame End Caps to the WTC which will not be that difficult. The Frame End Caps are not the same as WTC End Caps that have the rubber O ring seals and I think are smaller in diameter than the WTC End Caps.

    Polulu can only work with the DFX files and the DFX files are one of three available for the OpenROV 2.8.

    As far as I can tell, there are no OpenROV frame component dimensions available to use for comparison.

    Regards,

    TCIII AVD

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