Ive recently switched form Super X to MK 2.5, I've done some reading on tuning and managed to get it flying a lot smoother than the stock settings. But its still jittery in Alt Hold, it just jumps up and down a bit, even when sitting in hover with no wind. Its almost as if its floating on choppy water. What settings could effect this? It was doing this before i started tuning it. I raised the Barometric D up to 50 from the stock of 40, which helped with the large high fluctuations. I also raised Min Gas to 90. Maybe altitude P is the setting I should adjust ? Cheers Ryan
Ryan, it should work well even with stock settings. If your FC is placed on soft rubbers, you should change them to harder ones, this might help. Once i had an alt hold issue and changing the standoffs to harder one improved the alt hold. And also, you are using vario alt hold, right?
Im using the recommended 15mm stand offs from Mikrokopter https://www.mikrocontroller.com/index.php?main_page=product_info&cPath=77&products_id=391 Are you meaning shorter ones are harder?
It should not create a problem. And also, I would recommend you to revert back to stock settings. We need to check everything to find the source of the problem. A video and GPX file would help to diagnose the problem. Does she fly smooth when AH is off? Are there vibration sources coming through the motors or props?
Its flying really nice in manual mode, super smooth. Nicer than when i had Super X on it. The props are all balanced and so are the motor bells. I tested for vibes with Super X and they were very low. Is there a way to see vibrations in Mk GPX tool? The vibes are only up and down, its not shaking. Il try and get a video next week when the weather clears, a storm has just set in here so it looks like it might be a week before i can test again.
I haven't been able to get a video of it, but its not bad enough to worry about for now. I was test flying in some wind this morning, and really had to fight it in alt hold to keep the height, when it was gusty, it was dropping altitude by 3 meters(maybe more), and it was tricky to control the height. Its almost like manual control. I also notice the yaw is not that locked in, it moves around a bit. It makes me feel a little nervous. What parameters would i adjust for tuning yaw?
Ryan, can you confirm that you are using parameter set #3 -- look at the bottom of the MK Tool screen near the triangle with the exclamation mark in it and you should see 3. Can you also verify the settings in the Channel command to ensure that you really are turning on Altitude Hold -- it almost sounds like it is not actually being enabled....weird though that is. Also check what settings you have in the Altitude window of MK Tool. Andy.
Ryan, do you know how to get a GPX file from the Navigation board? If you put a 2GB (max) microSD card in there formatted for DOS, the board will save a record of every flight. There is some software that'll let you inspect every little detail of you copter's performance. In your case, as Andy pointed out, I'd be curious as to whether you're actually engaging Altitude Hold. The GPX file will tell. And there's a ton of additional data in there.
Ryan: The 2GB microSD card must be formatted as FAT16 otherwise it will not record the GPX file. Andy.
Im using parameter 3, I have changed some settings to get my x8 fly smooth. Its flying pretty good, just alt hold doesn't work great.It is defiantly on and working just not as good as it should. I have flown it in calm weather and it was holding with in 30cm, but with a light gust it would drop 5-1m (then raise back up). I just check in MK tool, and I could see the altitude readings (0.1m), moving from 0 down to -2 and all the way up to 20, with in the space of 30 seconds, it just moves around, even though the machine is sitting firmly on my desk. The reading mainly hovered around -1 to 3. Could I have faulty sensor? And with regards to the loose yaw, i have the external compass with readings of 100, 101, 100, so its not emi.
Heres the GPX file of a short flight today, this was the first time i had the GH3 on there since moving to MK, it flew well considering the wind. It was gusting 30km. Mk tool has been really useful so far, just being able to check amp draw of all motors easily.
At least one forum user (@Dave King) had a similar problem and it looks like he may have a bad flight control board. He has another board which works perfectly in the same copter. If you have another flight control board, you should swap it out. Otherwise, maybe it should go in for repair.
Could it just be the pressure sensor? Or is the whole board possibly dodgy? I dont have another board, I just changed over to MK
We used to see this with the FC 2.1 that used the old circular/multi-legged pressure sensor when there was a wind gust, but the 2.5 FC uses a very different sensor, so given what Ryan's saying, I'd be very suspicious of the FC itself. Andy.
I noticed a couple things. your current draws are quite high. are you flying with a simulated payload? what's your power system (ESCs, motors, etc.)? you were hovering at around 1-2 meter, which may not give you a good hover because of ground effect. I'd change the MK params back to defaults and see if you can hover better at 5-10m altitude.
Im running kw10 motors, which are 500kv 3515s, with 15" fox tech supreme light props. Herkules III esc, freefly 9000mah 6s batteries. That was with the gh3 and brushless gimbal, the weight has added up since the original build, which didn't included a brushless gimbal and retractable landing gear. I want to do a test with the 16" props at least on the bottom and then switch back to xoars and see what the amps draws are like. I did actually notice the amp draws go up recently, after adding the extra weight of the retracts. I think the motors have just been pushed out side the efficiency window. Its annoying but there aren't any amp draw charts on the kw10s, so I'm not sure what the amp draws are meant to be, so I'm just going off the 400kv 3515s chart to get an estimate. It was also quiet windy and the motors were battling that, which wouldn't have helped. Il have to go testing when its calm weather again. That was meant to just be a really quick flight with the camera to check everything was ok before doing anything else, but the rain came in and i didn't get to fly again.
Ryan I changed flight control boards and found a noticable improvement. I also covered the sensor completely with velcro loop material all around the sensor and it seemed to do the trick. I haven't had a chance to fly the X8 since then as I have been using the flat 8 for my shoots.
I heard back from Mk support yesterday, they seem to think its fine and i have a tuning issue. I hope that is the case. Il give it ago this weekend, hopefully i can get it tuned. I added heat shrink to the sensor, which should help. I might try the velcro mod.
Try hooking it up to MK Tools and see what you get for a Altitude reading on the bench. Once you calibrate the gyros it should stay at 0 plus or minus 1-2. Also please take off props for bench testing. Cheers, Jeff
Hi jeff, Thats what i did, it moves more than that, +6 and -6 and then some times more. Don't worry props are always off for testing.