How does rapid acceleration effect RADIAN ?

Discussion in 'Radian' started by TROU BAYLISS, Mar 23, 2013.

  1. TROU BAYLISS

    TROU BAYLISS Member

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    0 TO 60MPH 4 seconds . decel is even more rapid ..this is a cablecam type app ..
    cheers trou
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Trou: If you asking about the upper bound on the Radian sensor's capabiilities, I recall JohnC, the designer saying it was about 500 degrees per second. If that's not what you're asking, could you restate your question, please?

    Thanks
    Andy
     
  3. TROU BAYLISS

    TROU BAYLISS Member

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    OK ...can rapid acceleration effect radians ability to mantain level on a gimble thats accelerated in a strate line ..EXQUZ spelling i cant see what im typing its to faint ..
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Good question: I'm afraid I don't know the answer. I'll see if I can find out.

    By the way, when you go to reply to a posting and have clicked on the "Reply" button, click and drag through the entire text, then change the font color to black by clicking on the "A" to the left of the Smiley face. You can also increase the font size if you wish (as I have done for this reply).

    Andy.
     
  5. TROU BAYLISS

    TROU BAYLISS Member

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    thanks mate ima machinist nota typissed ..now thatts funny . SOOO do RADIANS have accelerometers inim ?? Because my ROLL is misbehaving when im going 0 to 60 mph in3seconds with the gimble oriented so the tilt axsis is the direction of travel ie a profile shot . savy ?? roll is horizon .cameras moving left and right NOT PANING ..cheers in advance TROU BAYLISS
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Trou: I'm pretty sure that the Radians have accelerometers in them -- but JohnC is the man to ask. I'll contact him to confirm this and let you know.

    Andy.
     
  7. TROU BAYLISS

    TROU BAYLISS Member

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    if they do.. on an AV200..mounting the PAN RADIAN as far away from the pan axsis as u can .slows down PAN DRIFT a lot ..got mine 12 inchz out ...bit more than a cinestar ..It throws the PAN radian a greater distance ie moves it more due to the incresed radius ...radians sence movement .hopefully using accelerometers..pizo gyros..and magnotometers. all having a chat about what just happened ..howam i doing ANDY ......
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Sounds like valid advice, Trou. I don't have an AV200, but I'm sure others who do can verify what you're finding.

    Andy.
     
  9. John Cunningham

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    The Radians do have accelerometers inside : it's the only way it can know what 'level' is on your roll axis.

    The accelerometers are mixed with gyros to make it more stable (it would be unusable with just accelerometers). This is all done inside the IMU software.

    All IMUs which work this way are affected by accelerations and it depends on the software by how much. If you just use gyros, acceleration won't affect the angles - but the lack of a proper IMU means the roll axis can move all over the place and the cameraman must make it level. Look at the horizons on some zenmuse videos to see what I mean : they can be way out.

    Accelerometers cannot be used for the pan axis - and a magnetometer is very sensitive and would not work very well down in the middle of a camera mount. Hence pan relies on the gyro sensor stability for minimal drift. The Radian uses some of the newest technology which has very low drift compared to other gyros.
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Thanks for the peek inside the Radian's, JohnC.

    Andy.
     
  11. Tim Joy

    Tim Joy Active Member

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    If you use a stabilizer like the radian on a cablecam setup, unless you have a mechanical gyro stabilizer like the Kenyon gyro, the tilt/roll axis will cause a swinging and oscillation of the whole rig.
    In my experience, as long as you can start and stop smoothly without jolting the cable, you don't really need any stabilization. If you can get a Kenyon gyro on there, it's all you'll need.
     
  12. Tim Joy

    Tim Joy Active Member

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    But relating to acceleration using the Radians, they definitely tend to lean into the movement on acceleration. It's most noticeable on the roll because we are so sensitive to seeing a horizon off level. I can pretty easily see down to about a half of a degree off.
     
  13. TROU BAYLISS

    TROU BAYLISS Member

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    TIM are u seeing any horizon shift on DECCELERATION . ?? .. im turning roll stab off at the begining of the move ....that is the acceleration part ..then on for the middle TROU
     
  14. Tim Joy

    Tim Joy Active Member

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    I don't think that will be successful. The radian will not turn on smoothly. And with it off, you will have no control to move the gimbal.
    Your best option for cablecam is a KS-2 or KS-4 gyro, depending on the weight.

    Here are some cablecam shots I did without stabilization, no gyro, and with bumps in the line and jerky starts. Max speed was about 25-30 mph and it eats up the cable fast. (400'in this one) You will need a LONG cable to get to 60 and slow down before crashing.

     
  15. TROU BAYLISS

    TROU BAYLISS Member

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    Tim ill have ROLL seperate with its own receiver not connected to PAN+TILT... to be con trolled by the dolly opperator ... nice trackin shot .. did u have much rehersal ttime ??? ..I got 1800 ft of 12mm string .. cheers TROU BAYLISS
     
  16. Tim Joy

    Tim Joy Active Member

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    No rehearsal time. They sent each heat down so fast that we barely had time to get back to the top for the next run. Doing it again this year with some improvements. :)
     

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