C300 mounting

Discussion in 'Radian' started by Colin, Dec 18, 2012.

  1. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Hey guys. Just new to this forum and of course aerial filming. We have several projects ahead of us which require the use of the Canon C300. We purchased the SkyJib 8 with the Cinestar 360 mount. Legs have been extended using 12mm ali tube for clearance. Extra long arms installed to allow for tilt up.
    Now the issue. Shaky video footage. Its poor, nothing steady about it at all and requires lots of post production. Props are balanced. We have the radian on all three axis with the gains set to 100%. Do we have to increase gain to carry the weight of the C300. The gimbal is sitting on top of 6 silicone mounts and cable tied to the airframe. Please help a troubled producer.
     
  2. Brad McGiveron

    Brad McGiveron Active Member

    Joined:
    Jul 7, 2012
    Messages:
    396
    Likes Received:
    65
    Is the gimbal and each axis completely balanced for the camera? Is the Multi balanced perfectly with the gimbal and the camera? Are all of the belts nice and tight? The default settings are not good for all axis as you'll find if you browse around the forum.The list of things to do goes on and on.
    Post some footage so folks here can try to help.
     
  3. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Hi Brad, The camera and gimbal are as best balanced as I can get. The only axis out is pan because the C300 is much heavier then the other rear mounted components and I have it pushed back toward centre as far as possible. All belts are tight. My gimbal settings now are Pan 45, Tilt 10 and Roll 45. That in itself would seem to be rock solid compared to what it was like at everything at 100. I did look at you tube to see what should be happening. Alls left now is to do is to try some new footage. But do keep advice coming. Thank you. Colin
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Colin:
    Now that I've got an extra moment, some additional thoughts:

    1. Typical gains that people are using are Pan 55-80, Roll 130-150, Tilt 150-180 -- these are only typical and depend on many factors (such as payload, ambient temperature -- which alters the flexibility of the vibration isolators). At the settings you've presently got I'm not sure to what degree the Radian's will be active -- you can, of course, assess this by suspending the Skyjib so that it can twist freely and then hand-inducing yaw, roll, and tilt deflections.

    2. Have you done any experiments with the Radians off or in Stabilized fixed mode? The first thing I would try to do is determine whether the vibration is being caused by the Skyjib or the Radian sensors' settings.

    3. There is some additional rearward movement that you can get by shifting the entire gimbal backwards if you move the clamp that holds the gimbal's down post outwards on the boom to which its clamped (see the red arrow in the image).

    Hope this helps
    Andy.
    3-Axis Gimbal down-post clamp.png
     
  6. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Hi Andy. Thank you for your post. We have already been there and the clamp is about 1cm rom the back. It will take time to completely sort the issues out to a result Im happy with. Why are the gains so high. If I put ours there and do the tap test it bounces??
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Hi Colin:

    Good question. I don't have a very satisfactory answer beyond: Other folks are finding that they can set them that high without incipient oscillations when they do the tap test.

    Did I mention it wasn't a very satisfactory answer? :)

    A more interesting question is why you're seeing the incipient oscillation at lower gains. What voltage are you feeding to the Radians and the servos, please?

    Also, if you connect up to a Radian sensor, are you seeing lateral "jitter" on the slew input? (Which would indicate that you have electrical noise on the Slew control input that might add to the incipient oscillation when you do the tap test.)

    Andy.
     
  8. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Andy, you're getting very technical now. We had our unit professionally built for us, apparently, but i wonder now why i just didn't do it. Im sure youve gathered my knowledge is very limited. As for voltage I connect a 11.1v battery to the gimbal. I do know there is some electronic component inside the side arm before going to the radian. This battery also supplies power to the camera control and 5.8 video Tx. Other than that I don't know. What do you mean by lateral jitter?
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Apologies, Colin. If you bring up the Radian software connect up the programming cable to a Radian sensor, click Connect, and then Read, in the Diagnostic window there is a horizontal bar marked Slew that corresponds the motion you're commanding via the transmitter to one of the Radian sensors (which one depends on which one you've connected up the wire from the computer to a Radian sensor).

    If there is electrical noise in the system, it sometimes shows up as the sliding indicator in the Slew horizontal bar waggling left and right a bit without any control input by you on the transmitter -- "jitter" is the name for this.

    Do you happen to know whether the Radian sensors are running the latest firmware, version 1.03? If not, then you should upgrade to that version on all three Radian sensors as this may reduce the problem you're seeing.

    You can see which version of firmware they are running when you connect up to a Radian sensor. It shows up in the software Configuration window.

    Hope this helps.
    Andy.
     
  10. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Andy, got it now. I certainly haven't witnessed any movement within the diagnostic window. I'll check in the morning what version we are running with. Hopefully it will be 1.03 as we only received the unit two weeks ago. You help and information is greatly appreciated and certainly we look forward to some exciting projects once we have the unit corrected. Our first video is hosted here http://vimeo.com/skylinephotography on my sons site.
    Regards Colin
     
  11. Brad McGiveron

    Brad McGiveron Active Member

    Joined:
    Jul 7, 2012
    Messages:
    396
    Likes Received:
    65
    Colin, if you are still having issues it would be helpful to see footage thats not post stabilized and as well some of the footage should be with the Radians switched off so you can see what the multirotor is doing by itself
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Colin: That bridge sequence is impressive -- and very smooth. The mood is sombre, though -- seems slight at odds with a Peace Bridge concept, or was the point of the piece -- I don't know the context. Where's the bridge, by the way? I know there's a Peace Bridge in Londonderry, but it doesn't look like that one.

    Thanks
    Andy.
     
  13. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Andy, The smoothness is via either FCP or A Effects. Its for a new tourism advert in which you'll see about 2secs of a clip. It is in Londonderry spanning the Foyle and was opened only this year. Goggle doesn't have it on the map yet.
    I've tried to upload a .mov file for Brad but it won't take that. How do we upload a video file. Colin
     
  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Colin:
    Still nice work even if you got a little help in post.
    The best way to deal with movies is to upload them to Vimeo or YouTube (Vimeo preferably if you want to keep them private with password) and then insert a link into a posting (click and drag to select one or more words in the posting and then click on the chain link icon just below and to the right of the smiley face in the second icon bar above the posting message window).

    Andy.
     
  15. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Andy, from bad to worse. Today I drove 100's of miles to a commission only to return empty handed. Issue, when we connect the gimbal it will initialise or seem to. Tilt and Roll steady green so I assume not an issue. When it comes to Pan green flashing, the gimbal slowly rotates either to the left or right. It will then stop where upon I have no control. After a few seconds I can see minor movement like a gentle shake which will gradually turn into an oscillation as the unit tries to correct itself. All I can do is to disconnect the battery before the machine shakes itself to death. Any ideas. I cant see anything in the forum
     
  16. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Hi Colin:
    How bloody frustrating for you. I hate it when this kind of thing happens. Grrrr.

    If you have the copter on the ground and you turn on the Radians, the booms and hub will rotate slowly in one direction or another. This is a mechanical side effect of having the bird on the ground and not having any gyroscopic effects from the motors spinning the props.

    So, first thing: Do you have the bird on the ground or are you suspending it from the battery plate so that it can twist in the breeze?
    Even if it is suspended you will see a tendency for the upper part to rotate -- you have to gently resist that with one finger (well you can use more, but the point is that you don't need much force).

    Secondly, the oscillation you're seeing is a sign that the Radian gain is set too high. On my bird I have the gain around 60.
    If you're already set around that, can you connect up the Radian software to the pan sensor, click on Read and then upload a screen capture showing the diagnostic and configuration window.

    You mention that the Pan sensor has a flashing green LED -- is it a slow flash (meaning that Mode is OFF), or a fast flash (meaning the IMU is still trying to initialize)?

    Hope this helps
    Andy.
     
  17. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Andy, Thanks for the reply. Our system is the SkyJib 8 with the cinestar gimbal with radian, purchased for its stability! With the SJ on the ground the A/C is static and the gimbal free to rotate 360 as it is held on with cable ties to the A/Frame. As a last resort today we changed the gains from 45 and added values between 5-200 it didn't make any change whatsoever. When I get the chance I'll upload the screen shot from the radian software.
    Tonight I've tried it again. Tilt and Roll lock on first, Pan takes a few seconds longer then the green goes static. Seconds later the oscillations start. It is very minute to start with but as the radian senses movement and the need to correct itself it gets stronger and stronger until the gimbal almost shakes itself apart. Its a mad grab to disconnect the power. We couldn't get the bird in the air as I'm sure the shaking gimbal would effect the flight sensors and dear knows what would happen. Having a C300 in below we weren't taking any chance. Hopefully Phil has sent Tabb an email directly.
     
  18. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Yeah, a C300 dangling does "focus the mind" on certain decisions.
    It'll be interesting to see the Radian software's diagnostic/config windows while the pan starts to oscillate....

    Andy.
     
  19. Colin

    Colin Member

    Joined:
    Dec 18, 2012
    Messages:
    87
    Likes Received:
    1
    Hi Andy, still working on this damn uav. Are you aware of the skyjib set up to carry the cinestar gimbal. If so how should it be attached to the airframe. Ours is sitting on silicone mounts and just tied on using cable ties. Im just wondering should they be bolted through the airframe very tightly. Vibration still an issue. I think I read somewhere else the roll is the most likely to cause issues.
     
  20. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
    Staff Member

    Joined:
    Jul 31, 2012
    Messages:
    10,369
    Likes Received:
    1,162
    Hi Colin:
    Hmmmm. I'm afraid I don't know about the Skyjib.
    I just did a quick search of the forum and there are three other members who apparently have Skyjibs.

    Here are the threads:
    http://forum.freeflysystems.com/index.php?threads/epic-on-the-cs-3-axis-gimbal.515/#post-5699
    http://forum.freeflysystems.com/ind...oftware-problem-on-my-pc.187/page-3#post-2868
    http://forum.freeflysystems.com/index.php?threads/introduce-yourself.2/#post-3 (Message #2).

    As you say, vibration is indeed an issue. As Tabb once wrote: If it flies it vibrates! It's a problem one just has to gnaw away at...

    Sorry I cannot be of more help!
    Andy.
     

Share This Page