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Throttle Issue, MK Electronics

Discussion in 'Electronics' started by Adam Koontz, Oct 20, 2014.

  1. Adam Koontz

    Adam Koontz New Member

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    Hi Everyone,

    Interesting issue over the weekend in relation to my throttle. I've been flying a CS8 with MK FC2.5 and a Double Quadro Cool V3 with no GPS//NaviCtrl in a plan to really get to know how to fly the copter (also helped not having to buy everything straight away). I've had it up for about 2 months with no issues in flight, long flight times and feel totally in control of the copter. Over the weekend I decided it was time to install the Navi and GPS. I connected everything up and updated the Navi/GPS firmware. With light getting low and needing to use my batteries I figured I would leave setting the compass until the next day, so I disconnect the Navi/GPS and made sure all my settings were back to where they were before I had ever touched the Navi/GPS.

    Upon takeoff I immediately noticed change in my throttle and how I was about to take off. I will first describe the "BEFORE" flights, which was before I ever connected the Navi/GPS:

    Power up, and go through the normal preflight checks. Upon take off and throttle increase, I would not hear or see any change in motor RPMs until I reached the middle of the throttle. In other words, there seemed to be dead space until I hit mid throttle. Motors would increase and I would take off. Even with the dead space on takeoff, during flight the throttle was proportional to copter reaction. If throttle was increased slightly, I would have a small controlled increase in altitude. Same for descent and same for large increases/decreases. Hover was easily obtained just above mid-throttle.

    For the "AFTER" (still with NO Navi/GPS connected!), I powered up and went through the same preflight checks. Upon takeoff and throttle increase, I would immediately hear and see motor speed changes. Once throttle left the bottom stick, I the motor would react and would stay corresponding to throttle position. I did not fly at this moment, as I knew something had changed. After going back into MKTool and checking all settings and firmware and even reinstalling it, I went back out to test. Same "AFTER" symptoms occurred. Although it may have been risky, I did take a quick flight. Throttle was super sensitive. After takeoff it was VERY difficult to find a good hover throttle, and any hair above that line I would rise in altitude fairly quickly and if I went below that line it felt as if the copter was in free fall. There were no controlled descents, which obviously made for an interesting landing.

    Part of me does not know which throttle is correct, as the BEFORE situation doesn't really make that much sense with the 'dead space' in throttle on take off. Yet flight was 300% easier BEFORE compared to with the AFTER symptoms and touchy throttle. I am obviously used to flying before this happened and maybe I just need to get used to the new throttle, but the real question then is WHY? What made this change happen and why was it the way it was during my first 50 flights? Again, neither the before or after situations had the Navi/GPS connected for either flight. Makes me worried that more changes will start to happen and we all know these aren't cheap investments, plus the cameras we're flying. I suppose I'm luckily this change happened on land..

    Just as a note, I'm using a Futaba 14SG, but I know there weren't any changes made on the transmitter.

    If anyone has had a similar issue, any thoughts or comments would be greatly appreciated. This is my first copter and only one I've seen in person so I'm not sure which situation relates to how everyone else flies, but as I said previously, this drastic and unaccounted for change is quite baffling. I'm at a loss to what is correct and how to reassure myself that I can fly without doubts of problems (at least the same problem ;))

    (I believe I have a video of the "BEFORE" takeoff's so I will post if I have it available)

    Thanks in advance,
    Adam
     
  2. Ozkan Erden

    Ozkan Erden Distributor

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    When you connect the MK to KopterTool, check the mode at the bottom of the screen. Here is the screen:

    [​IMG]
    At the bottom, you see "3" near "Lesen"(Read) button. Can you confirm that it's at 3 with your chapter?

    I suspect you changed the mode from transmitter by mistake. Also check the "Sticks" tab. IF you want your copter to behave smoothly and not wildly, set them to 3.

    http://wiki.mikrokopter.de/en/MK-Parameter/Stick

    If you can post a video, it would be more helpful.
     
  3. Adam Koontz

    Adam Koontz New Member

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    Hey Ozkan thanks for the reply. Yes, I can confirm it is still on 3. I understand the sticks tab and its a good thought, however the issue is solely on the throttle. I have not had a chance to get post the video, its been one of those days.. I will double check the transmitter again but when I set up the Navi/GPS the other thing I did was turn the transmitter on so it would be hard to believe I changed anything that significantly.. At least i hope its not that easy to mistakenly change something :eek:

    As far as the 'dead space' or lag on the throttle that was happening before the change, does this seem correct? or should it have been more in correlation as seen in the after situation? I have run two FC's (both 2.5) and they both had the same 'lag' during takeoff. I am going to switch them again tomorrow and see if it still persists. Is there anyway this could be related to power distribution or draw through the BL's? Just trying to think of any and all possibilities
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I've not heard of this kind of issue before, Adam.
    Is there any chance you accidentally selected a different Model in the transmitter? You don't say what Transmitter you're using but, for example, the Graupner transmitters permit you to select specific throttle curves -- that is exactly to control what you are describing. The throttle curve alters the relationship between the throttle stick movement and the transmitter signal to the copter.

    Andy.
     
  5. Adam Koontz

    Adam Koontz New Member

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    Hi Andy - I snuck it in there on the first post, it was definitely out of place tho: I'm using a Futaba 14SG. I went back again through the settings and am confident nothing has changed. The profile mode I have been using is still selected and to confirm this there is a running time from last reset/mode change, which is at 17hrs (time in use). Throttle curve is still a straight line from bottom left to top right. I didn't change anything to begin with so I know this is correct.

    Going to start switching out my FC's right now to see if that's the issue. I know they both responded the same when they were both connected up the first time..
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Ooops, sorry, Adam. My mistake.

    Ah well, another of my elegant hypotheses crashes to the ground.... :)

    Let us know what you find with a different FC, please.

    Thanks
    Andy.
     
  7. Adam Koontz

    Adam Koontz New Member

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    After connecting up my backup FC the throttle is consistent with the 'after' scenario of any increase corresponds to instant increased rpm's. So it either has to be with the BL? or something on the transmitter that is being overlooked. I'm not counting it out but I am having a hard time at this point thinking its on the transmitter.

    Right now however, I'm starting to think the "issue" was there when I first started and it has finally worked itself out (sort of mind blowing considering I've taken 50 or more flights :confused: ). Here is a video from a month or two ago, obviously I didn't know I would have this problem so the transmitter/visual of the throttle isn't present, but I added in some titles to note where the throttle was at. At 25% there are a few beeps, and then again right before 50% when I takeoff. I fee like this could be something worth asking about?



    pw: copter

    (Feel like I should note the wheels have been removed. They were to just add some mental confidence when perfecting my landings ;))
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Can you hook up to the MK flight controller board using MK tool, and look at the Channels window -- does the throttle control appear to advance smoothly and correspondingly to the stick movement?

    The only other place that "non-linearity" might be coming from is the Brushless Controllers....
    Andy
     
  9. Adam Koontz

    Adam Koontz New Member

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    Andy - yes for both situations the throttle advanced smoothly and corresponded to where the throttle was percentage wise. What's the best way to check the brushless controllers?

    Also- in the video does the beeping sound normal? That was before the change. After the change there are 0 beeps

    Thanks again. Much appreciate.
    Adam
     
  10. Jason Smoker

    Jason Smoker Active Member

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    Adam you should hear three beeps after your initialize your gyros.

    I cant hear any beeps before the engines start in the video
     
  11. Adam Koontz

    Adam Koontz New Member

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    Hey Jason - the video starts after the gyros were initialized and motors were already running. My concern was during throttle increase to take off there was a 'dead space' of no motor reaction even though I was moving the throttle. Around 25% throttle you can hear a series of beeps, almost like a ticking. Only after 50% throttle would the motors begin to spin faster. This was how I was flying before working on hooking up the Navi/GPS. After hooking it up, I experience the change in throttle.

    After the change, I still have three beeps for the gyros, but on take-off the throttle instantly causes a reaction to motor speed even at 1%. The ticking beeps (that are audible in the vide) are no longer present. I cannot figure out why the change, nor do I know which situation is correct. Even if something has changed in respect to throttle curve, why has the series of beeping on take-off stopped? Very confusing..
     
  12. Jason Smoker

    Jason Smoker Active Member

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  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yeah, let's see the GPX file from that flight. It might have a clue -- certainly it would show if there are any I2C bus errors.

    As you say, it's more like a ticking than a beeping. Something is very evidently wrong. I wouldn't do any serious flying until you understand what's going on...

    Andy.
     
  14. Adam Koontz

    Adam Koontz New Member

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    I know its the golden rule to have the GPX file, but the ticking beeps occurred before I had the GPS/Navi connected... Wanted to keep it as simple as possible to learn how to really control this bird, which is obviously backfiring.. AFTER connecting the GPS/Navi the 'ticking' beeps have stopped, as well as the 'dead space' // lag in throttle has disappeared during takeoff. It's raining here today, otherwise I would take a quick low flight and get a GPX file to at least see where I stand at now. I suppose i could still do it without props?

    Thanks for the link Jason. The beeping from the MK link does sound very similar to what had been happening, although I would not say 100%. The ticking had slowed down as I continued to increase the throttle, perhaps I can assume that if I left the throttle exactly when it started beeping it may have been more constant..? Now that it no longer ticks, I will have to get a file on what is happening now and hope the problem has been solved..

    Appreciate you help guys, I will update once I get that current file.
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    If you take the props off, you can "fly" indoors. The GPX file starts when you hit 40% throttle.
    The GPX file will show whether or not there are I2C bus errors and other useful data.

    Also, with the props off, you can use MK Tool's Motor Test to spin up individual motors or all of them and see whether or not the motors are responding normally or not.

    Andy.
     
  16. Dave King

    Dave King Well-Known Member

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    WE can get a pretty good idea of what your response should be if we know the following info such as what motors, props, payload, copter weight etc. From this we can get a pretty good idea of how much throttle it should take to lift it. The video sounds pretty normal to me. It sounds like the motors are a little undersized for the flying weight.
     
  17. Gary Haynes

    Gary Haynes Administrator
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  18. Adam Koontz

    Adam Koontz New Member

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    Haven't had the chance to run a GPX file yet.. been a busy few days. Unfortunately might not be after the weekend as well :(

    I'm running off of what Quadrocopter offers. Overall setup:
    -MK Electronics, FC 2.5, 2XQuadro Cool V3
    -TigerRC MN4012 480KV motors, 15*5CF props
    -QC 10,000mAh 6s battery

    My maiden flight had 0lbs payload (no camera/gimbal) and it sill sounded just as it does in the video. 'Ticking' beeping and delayed/dead space throttle.

    Setup in the "Before" and "After" scenarios are the same - 3-axis gimbal, 5Dii
    Copter weight - 9lbs
    Gimbal/Cam - 6.9lbs
    Total - 15.9lbs --> 7,212.12grams. Looking at the tables on the TigerRC site I should be fine with weight. Especially after talking a lot before the purchase with the guys at QC plus seeing others on here using a similar setup. Hover-throttle is just a bit over 50% with this setup.
     
  19. Adam Koontz

    Adam Koontz New Member

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    Hey guys,

    So after a few out of state travels for work and waiting for my 2gb microSD card to arrive (who knew no one sells them locally under 2gb anymore :eek:) I've finally gotten the GPS connected again and did a grounded 'test-flight'. The GPX file returned no errors, even with the "new throttle curve". I am going to assume that I had been flying with an I2C error this whole time, only for it to be solved after connecting the GPS/Navi up for the first time. I'm still not sure what caused the error to be solved. I will be taking a few easy, low altitude flights in the coming days to make sure everything is still OK. Until I have more info, thanks for all your help. I'll update if anything new (or strange) happens.

    -Adam
     

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