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Underwater ROV project controlled by BS2 via RS232 from StampPlot GUI. — Parallax Forums

Underwater ROV project controlled by BS2 via RS232 from StampPlot GUI.

StuartttttStuarttttt Posts: 45
edited 2008-01-20 00:23 in Robotics
Hi,
Please take a look at my latest project. This is an underwater ROV·controlled from·the surface PC by a cat 5 cable. The cable transmits RS232 data to and from the BS2 / StampPlot GUI. A bonus is that the BS2 programme can be changed / fine tuned whilst the ROV is in the water. Presently a 12 metre cable is fitted with no problems and I·will fit a 30/40 metre cable soon. One pair of the cat 5 sends the video to the PC which is "on top" of the GUI. I may fit a CCTV sender to improve the picture quality. The ROV has an onboard 12v battery and another·connected in parallel·via another pair on the surface.

Features of the ROV are:
Auto proportional / integral depth control.
Manual depth control.
Proportional forward left right etc.
Depth indication on Stampplot GUI trend.
Leak detector which alarms on GUI.(Hope I won't need that)
Control of LED cluster lights.
·········· more details on the website.··· http://members.aol.com/stuarttttt/index.html

Regards
···· Stuart


·

Comments

  • JDJD Posts: 570
    edited 2007-11-01 16:55
    Congratulations on a nice looking project. Looks like you have some big plans for this project. If you don’t mind me asking; what prompted this project? Are you thinking about using this ROV to explore lakes and/or the ocean?

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    Joshua Donelson

    www.parallax.com
  • steve_bsteve_b Posts: 1,563
    edited 2007-11-01 17:22
    Fantastic....I've bookmarked your webpage in the hopes that you keep it up to date!

    Looks like you still have some work to do on the depth control system (PID-wise).
    On our servo systems, we use a multi-stage sloped feedback. So, when you are really far from where you want to be, you give the error more quantity (not sure what the right word is...).... So, say you are more than 10ft from you desired depth. You would give your error a multiplication of 1.5x. When you are within 5ft, you give it a 1x multiplier....then at less than 1ft you give it 0.8x multiplication. Add a few more stages to prevent overshoot...although it may mean it takes you longer to get to your depth.
    Did that make sense?? lol maybe not!

    Any problems with the tether getting swallowed in your thrusters?!

    Looks great so far!

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    <FONT>Steve



    What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
    Lee Travino after the second time being hit by lightning!
  • StuartttttStuarttttt Posts: 45
    edited 2007-11-01 17:33
    Hi Joshua,
    Thanks for writing. I have used BS2 on several projects, and decided to try something a bit more challenging. As you know it combined programming BS2 and StampPlot, design and construction of something that had to stay watertight be controlled in both planes and from afar. The ROV provided lots of challenges believe me [noparse]:)[/noparse] and I'm still continually trying to overcome / improve them. I'm no BS2 expert so I had to experiment, learn and eventually came up with something that worked. Very enjoyable.

    Next stage is to fit a longer control cable and then yes I will be exploring local fesh water lakes then the ocean. Only the vertical thruster is seawater proof (its a converted bilge pump) so the other two DC motors will be changed out so they work OK in salt water. Also a better cam is on order to improve view.

    Stuart
  • StuartttttStuarttttt Posts: 45
    edited 2007-11-01 17:42
    Hi Steve,

    No your PI details makes perfect sense. I can adjust the P and I settings in the BS2 programme and yes I still have a bit of work to do but it does work when tuned. One problem I didn't foresee was the deadband of the vertical thruster. ie its a 12v motor and at the low ends of forward and reverse (voltage) the motor needs a bit quicker ramping or offset added to get the motor moving when changing direction.
    No chewed up cable...........yet [noparse]:)[/noparse]
    Stuart
  • JDJD Posts: 570
    edited 2007-11-01 18:00
    I look forward to your viewing the new videos, and your learning points. I think that is a good addition to your page, whereas others can see some of the avenues you took but wasn't feasible or accommodating to do so. It’s good to safe success and road blocks with follow enthusiasts. Thanks for posting

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    Joshua Donelson

    www.parallax.com
  • sailman58sailman58 Posts: 162
    edited 2007-11-01 19:15
    on several occasions I have run into folks who operate r/c submarines. They all seem to use 75 mhz r/c gear, and that for fresh water only.



    Ron
  • StuartttttStuarttttt Posts: 45
    edited 2007-11-01 19:23
    Hi Ron,

    I would have preferred an untethered ROV but.........I tried Bluetooth and also 430 Mhz radio data Tx / Rx but soon as it went underwater all communication was lost. I tried a wireless camera in a jam jar as well, same result [noparse]:)[/noparse]

    Stuart
  • sailman58sailman58 Posts: 162
    edited 2007-11-01 21:16
    Lower frequencies have beter penetration into water. That is why 75 mhz gets through better. I am not sure what frequency band blue tooth uses, but it is fairly high also.

    Ron
  • skylightskylight Posts: 1,915
    edited 2007-11-05 19:46
    Some Bluetooth frequency info
  • WhitWhit Posts: 4,191
    edited 2007-11-07 01:24
    Stuart,

    Fantastic project and great site. Keep up the good work.

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    Whit+


    "We keep moving forward, opening new doors, and doing new things, because we're curious and curiosity keeps leading us down new paths." - Walt Disney
  • ProfessorwizProfessorwiz Posts: 153
    edited 2007-11-08 14:47
    Wow, it constantly amazes me what great projects people come up with! Fantastic!
  • bennettdanbennettdan Posts: 614
    edited 2008-01-19 08:48
    Stuarttttt,
    ·· Have you thought about a simple buoy that floats on top of the water that has the tethered link from it to your sub this would allow only enough cable to reach the sub and it would not have to drag along alot of extra and then radios back the data to you wirelessly on the shore also the buoy could have a winch that would alow you to recover the Sub incase of failure.

    Buy the way I love the project and keep up the good work.
  • Shawn LoweShawn Lowe Posts: 635
    edited 2008-01-20 00:23
    Excellent job!! Very motivating! You have obviously put in alot of work.

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    Shawn Lowe


    Maybe I should have waited to do that......
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