Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Gimbal calibration and gains questions

Discussion in 'Zenmuse H3-2D GoPro Gimbal' started by ChinaWarrior, Sep 30, 2013.

  1. ChinaWarrior

    Joined:
    Sep 18, 2013
    Messages:
    4
    Likes Received:
    0
    In the past two weeks I installed the H3-2D gimbal and bound a Graupner MX-16 transmitter to the phantom. The gimbal and transmitter work great even though it was my first time soldering and there were a few hiccups. Yesterday I went out for the first test flight after installing everything. The Phantom flies, the gimbal is steady, and the graupner allows me to control the gimbal tilt, but I did notice a few issues.

    1) After powering on the phantom the gimbal does not position itself completely level with the ground. To be more specific: when looking at the front of the camera, the left side droops slightly. Is there a way to calibrate the default position of the gimbal?

    2) Should I adjust the motor speeds after installing the gimbal? It seemed like the Phantom had a harder time getting off the ground than before. When taking off on my 3rd battery it slumped forward causing 2 of the props to hit the ground (though this might be my fault for not giving it more power during lift off). If I should adjust the motor power/gains/idle are there recommended settings?

    Finally some things I noticed and learned after yesterdays test flights.

    Stock batteries (the only ones I have) last a maximum of 8:30 minutes. As soon as the LED on the phantom starts flashing red I have a lot less time to land than before installing the gimbal. The phantom seems to become very sluggish when the leds flash red. Before installing the gimbal I still had plenty of time to land after seeing the leds.

    Everything looks a million times better with the gimbal. I realize this isn't news to anyone, but I am still blown away by just how much better everything looks when properly stabilized.

    The Graupner MX-16 is wonderful. Works just as well (if not better) as the stock TX and it has a proper gimbal tilt dial. I still have a lot to learn with the MX-16 considering for now it's calibrated according to a YT video I found (i haven't mapped IOC controls yet).
     
  2. MrMediaGuy

    Joined:
    Jul 31, 2013
    Messages:
    171
    Likes Received:
    1
    Have not seen that before -- are you absolutely sure the mounting plate and all four dampers are installed correctly? If the mount is level, the IMU in the Zenmuse should level it correctly unless there's something wrong internally. For example, if you had a left or right damper that wasn't fully seated, that could cause a tilt. There's not a user-accessible calibration that I'm aware of. [EDIT: One thought -- have you done a NAZA advanced calibration lately? The IMU does get data from the NAZA so if that was off, maybe it would cause the gimbal to be out of level with the Phantom frame.]

    No you should not. Just take off at 100% full throttle and hold tight until it pops off the ground. You may try taking off in ATTI mode and then switching back to GPS (if you were using it) once you're in a hover. But don't adjust motor speed or gains just to compensate for takeoff.

    That's to be expected -- not only are you hauling more weight, meaning more power to the motors just to hover, meaning faster depletion of battery, the gimbal and GoPro are drawing a fair amount of current that's pulling your voltage down even more across the board. You might want to go into NAZA Assistant on the Voltage tab and set the "Loss" a bit higher than the 0.60V default -- maybe something like 0.65V or 0.7V. That will in turn cause the "Loaded" voltages to be a bit lower, which will give you a bit more flight time. If you wish, you can then set the first-level warning 0.1V *higher* than it is now. That means the light will flash sooner, but you'll have more time before auto-land kicks in.

    However if you adjust the voltages or the loss factor, you *must* ensure that you're not depleting your battery by more than about 80%. Do you have a good computerized charger to show you how much you're charging the pack after, or are you using the stock charger?
     
  3. Dizzy Lizzard

    Joined:
    Aug 23, 2013
    Messages:
    15
    Likes Received:
    0

    I'm having the exact same problem.....

    [​IMG]

    Yes I know I left the darn lens cover on for that photo.... I just forgot to remove it for the pic. I do not fly with the lens cover on and have not added anything to the GoPro per the H3 2D Owners Manual.

    The mounts are solid and level, I even took everything apart and re-assembled just to be sure there was no operator error. I can say that the problem was not there when I first got the gimbal it has only appeared in the last few weeks. When I push up on one of the rubber dampeners I can get the gimbal to go level but the mount is clearly not level.

    I have a Version 1 gimbal which version do you have?

    So I wrote DJI about the problem and they wrote back....

    "Our technician has determined the case above is a possible warranty issue. I have issued RMA#XXXXX. Please be sure to write the RMA number clearly on the outside of the box you are shipping with permanent marker. If we cannot find or read the RMA number, the package will be refused."

    The real bummer is I'm going to have to take the Phantom apart and de-solder the power connections. Really wish I didn't have to do all that.

    Then just tonight I ran into an RC store owner and told him about the problem he says there is a way to adjust the Zenmuse Gimbal left/right alignment in the "Dealer Version" of the Nazam Assistant Software. Going to his shop in the next few days to check it out. Anybody else here about a different version for dealers of the Nazam Software?

    I'll keep you informed with what I find out.
     
  4. ChinaWarrior

    Joined:
    Sep 18, 2013
    Messages:
    4
    Likes Received:
    0
    Unfortunately I only have the stock charger. I never realized just how important battery care was with RC. I'll look into getting a better charger.

    Could you go into a bit more detail regarding the "Loss" and "loaded" voltages. I can make the changes you mentioned, but I don't fully understand why I would be making them. I'll go ahead and change the warning level for now.

    This is very interesting. Please do keep us informed, though I doubt I would have access to a dealer version of the Naza software here in Poland.
     
  5. MrMediaGuy

    Joined:
    Jul 31, 2013
    Messages:
    171
    Likes Received:
    1
    Sure, I can try. It's definitely confusing until you understand what's going on. The basic principle is that a LiPo battery will show a different voltage depending on what load is placed across it. So your fresh pack might read 12.6V or so "open circuit," meaning just putting a voltmeter across and taking a reading outside the Phantom.

    Once you install the battery, the Phantom starts drawing current. Just a little at first -- maybe only a few hundred milliamps until you start the motors. That might drop the voltage to 12.3V or so. Then you start the motors, and at that point you are pulling anywhere from a few amps just before takeoff, all the way up to 30 or more amps in extreme flight. If you could see the votage the NAZA is reporting at that point it might be as low as 11.5V at first, going down to about 10.3V or lower as the pack depletes.

    With all of that context, the Phantom can only "see" or read one kind of voltage -- the voltage of the pack *under load* while you are flying. When you land and take out the battery, the voltage will immediately read higher again because the load is gone. But the loaded voltage is all that matters. The "Loss" value is the average difference in "normal" flight between what the NAZA measures under load and what the unloaded voltage would be.

    In truth, there is absolutely no reason to worry about the "Loss" setting -- all the NAZA pays attention to is the Loaded voltage in the third box. You can set Loss to 0.0V if you want and just enter a No Load value equal to what you want the Loaded value to ultimately be.

    There is a method to estimate the Loss more or less accurately. Set your Loss to 0.0 and set the first-level alarm to something arbitrary like 11.3V. Put in a fresh pack and fly "normally" until the red light comes on, then land immediately. Quickly remove the pack and measure the voltage. Now you know "when the NAZA saw 11.3V under load, the unloaded voltage was _____" That number is your Loss. You can then enter that number and put in whatever you think is reasonable for No Load levels, and the software will calculate the Loaded voltage based on the Loss you entered.

    There is a ton of debate and opinion on "how low you can go" without damaging your packs. There is a common 80% rule that says you don't want to take more than 80% of the capacity out of the pack because you risk damage, but with well-made packs many people routinely take out 90% or even a bit more, although I wouldn't recommend that.

    Conservatively, your first-level Loaded voltage should be no lower than about 10.6V, although I routinely fly down to 9.9V with no damage at all to the packs. Just try with maybe 10.5V to start and measure how many mAh your charger is reporting putting back in. (Invest in a good computerized charger if you don't have one!) If you're recharging more than 80% or 85% of the total rated capacity, raise your voltage levels by 0.1V and try again.

    Once you get comfortable with the right warning level and how long you can fly afterward, you should probably "turn off" the auto-land feature by setting the second level to a very low value. Generally, you don't want the Phantom to auto-land into a pond when you *could* have manually brought it back in another 30 seconds. Better to burn up a $30 battery than lose the Phantom in a river. :)
     
  6. Dizzy Lizzard

    Joined:
    Aug 23, 2013
    Messages:
    15
    Likes Received:
    0

    So after some digging I'm starting to think this dealer is getting the Phantom Zenmuse and the S800 Zenmuse mixed up. The Zenmuse Z-15 for the S800 has adjustments on all axis's the Phantom H3-2D does not. So I stripped down the Phantom tonight and shipping off my tilting gimbal to DJI to see what's wrong.

    I'll let you know what happens
     
  7. OneJoe

    Joined:
    Sep 21, 2013
    Messages:
    16
    Likes Received:
    0
    Location:
    Fonthill ON

    So after some digging I'm starting to think this dealer is getting the Phantom Zenmuse and the S800 Zenmuse mixed up. The Zenmuse Z-15 for the S800 has adjustments on all axis's the Phantom H3-2D does not. So I stripped down the Phantom tonight and shipping off my tilting gimbal to DJI to see what's wrong.

    I'll let you know what happens[/quote]

    Sorry for resurrecting an old thread but what was the final outcome on this, or are you still waiting for it to come back?
     
  8. ChinaWarrior

    Joined:
    Sep 18, 2013
    Messages:
    4
    Likes Received:
    0
    Thank you for taking the time to explain this. I don't fully understand everything, but that has more to do with my ignorance of batteries, voltage, and electricity in general. I'll keep learning as much as I can and try to put your advice to good use.
     
  9. sevenclouds

    Joined:
    Oct 10, 2013
    Messages:
    9
    Likes Received:
    0
    What ended up happening with this? Did they fix it for you?

    I am having the same issue, I can fix it in post but why can't I calibrate the Zenmuse myself??? it seems like an obvious thing to be able to do...and im not talking about up and down, I mean its tilted to one side so it makes the horizon level as if I was on a ship at all times...rather disappointing
     
  10. Andre B Grove

    Joined:
    Mar 23, 2014
    Messages:
    1
    Likes Received:
    0
    same problem cannot get the go pro perfectly level but this was only after a crash. just some useless advise - you can take off fast but do not come down fast - you can come down fast if you are flying side ways but not straight down. I have come short a few times doing this.. Please if anyone has any info on levelling the go pro please advise
     
  11. FangsCPO

    Joined:
    Apr 7, 2013
    Messages:
    793
    Likes Received:
    3
    Location:
    Chula Vista, CA
    I can say that once I added my gimbal and GoPro, I would have to give it full throttle for my Phantom to get off the ground. After that it was fine flying aournd. The other thing I learned rather quickly is that once the secondary warning kicked in, the Phantom would come down a heck of alot faster due to the extra weight of the gimbal and GoPro. The best flight times I could expect with my Dronefly LIPO (2250 mAh 45C 3S) was about 6 minutes.

    As for the Gimbal calibration, I had a minor crash and after that my gimble would never look straight ahead. I tried everything but nothing worked so I e-mailed DJI Los Angelos and they sent me a RMA# number to send them the gimbal. It's been about 2 weeks now and nothing yet. I'm still waiting but I got tired of not having my gimbal so I purchased another one. I'm impatient and I missed flying around and not being able to see from above. :lol:
     
  12. FangsCPO

    Joined:
    Apr 7, 2013
    Messages:
    793
    Likes Received:
    3
    Location:
    Chula Vista, CA
    FYI - I just received an e-mail from DJI Lost Angelos that my gimbal has been fixed and is being sent to shipping. The best part, "No Charge"...........nice!!! Not bad, it only took two weeks.