Kiss Airmode HELP!

[Bromego]

Kiss FC / LittleBee 30A OPTO / RS 2205 2300KV

(On the bench) When i flip the arm switch to go into air mode all motors start to twitch until i give power and then all motors spool up.

But when I come back down to zero throttle on the sticks, motors 3,4,5 still spin (I assume at my min throttle) but motor 2 will 2 or not spin. Is this normal? Shouldn't all motors be spinning at the same speed at this point?

 

[Craftydan]

They should all be running . . . but all the same speed? No. The whole point of airmode is the control loops will continue to function at minimum throttle. Even just sitting at the table, I would expect to see the control loops attempt-yet-fail to keep the airframe stable, even with the vibration noise, and that would lead to slightly different throttle settings among the motors. It's not "land mode" after all -- expect it to behave a little erratically on land.

Erratic or not, none of the motors should shut off in airmode. I'm not familiar with the details of the KISS FC, but sounds like your min Throttle is set too low. Might be called something else on a KISS, but it's effectively the "minimum throttle signal that all of the motors will still spin at" . . . and clearly it's set lower than motor 2's "idle" throttle level. Re-calibrating sometimes fixes this, but if you have the min throttle setting it's the easier way to keep all the motors running.

 

[Bromego]

My thought exactly, coming from cleanflight while in airmode, the all the motors are still spinning. And agree some should spin faster than others ( and I can see this in the GUI) but still get nothing from motor 2.

This is why I made the min throttle 1150, well above what it should take to get them spinning just on the table and no luck, same result.

 

[PsyBorg]

I think you are confusing min throttle and min command on the Kiss FC. Min throttle is the minimum range for sticks. Basice setting there is 1000. Some people fine tweak that after seeing where all motors start and setting that just a hair below the slowest one. Min command is what you set to spin the motors when armed. Usually ranged between 1040 to 1070 pre Dshot. I set mine to 1060 and they idle nicely with the heavier Dal triblades on them.

 

[Craftydan]

Funny . . . those definitions are exact opposite on the *flight roms.

not saying it's wrong, just weird.

 

[Bromego]

I think you are confusing min throttle and min command on the Kiss FC. Min throttle is the minimum range for sticks. Basice setting there is 1000. Some people fine tweak that after seeing where all motors start and setting that just a hair below the slowest one. Min command is what you set to spin the motors when armed. Usually ranged between 1040 to 1070 pre Dshot. I set mine to 1060 and they idle nicely with the heavier Dal triblades on them.

To enable airmode doesnt min command need to be at 1000?

On your Tx have you bumped the min command up as well? (almost like a faux idle up)

Or is bottom 1000

 

[Bromego]

Please see the attached photo, for whatever reason, motor 2 will not spin up to meet the rest of the motors

 

[PsyBorg]

My apologies I said what I meant backwards.. here is a screenie of what I run with Dshot.



The guys who raise min command above 1000 fly in idle up mode. These are pids Steele posted a while back pre Dshot.

 

[Bromego]

well I have component swapped 1 new ESC with the old motor and got no where, and then swapped a new motor and old ESC and nothing, and swapped for both a new ESC and motor and still have PWM2 idling 20 under all the rest

I think my FC is bad... BUT ITS BRAND NEW UGH.

 

[PsyBorg]

Soooo Here's the weird thing. I had a situation where I went to fly and got all set up. Hit the arm switch to take off and only 3 motors would run. Just like yours. The only thing was I think it was motor number 3. I removed the top plate and un bolted the FC to check connections and found nothing wrong. I powered the quad up to take some voltage readings on the test points and all 4 motors armed. I could not get the problem to repeat.

I have since flown several sessions with multiple batteries each time with no problems. I went out to fly on Saturday morning and the same thing happened only this time it was motor number two. This time I have it all opened up and the motor still would not spin. the number two esc light would come on when the FC was powered and then immediately go out. I wiggled wires checked solder joints did continuity tests no answer as to what the problem was.

I just went to flyduino web site and read the ESC manual. It lists that specific issue and what to do to fix it. It says it is either a bad connection on one of the signal wires or it has lost track of where min throttle and max throttle is so you should do a calibration even though it is not a necessity for when Dshot is running. I did the calibration several times and no change. The esc would light up and then go out and not arm or spin under any condition.

Well I forgot the flight battery was plugged in and started reading some more. The quad went into that inactive for so many minutes alarm condition and when it did that the esc rebooted itself and now works again as it is supposed to.

Try doing what I just did and maybe yours will wake up as well. Do this with NO PROPS on the quad.

1. Turn on your transmitter.
2. Connect the FC to your computer and connect.
3. Go to data output page and click the test motors box and check each motor so they will spin.
4. Set the throttle to full on position on the transmitter.
5. plug in the main battery and drop throttle back to zero when you hear a beep.
6. Check light on the esc in question. If it is on arm the quad and make sure it all works properly again.
7. If no light after re-calibration just let it sit there until it goes into inactive alarm state and the esc reboots and the light stays on.
8. Once that happens and the esc light is back on power the quad down and disconnect it all. Unplug it from the computer and try a normal start up like you were going to fly and confirm it all works again.

Post back here if you were able to repeat this process with success and we can submit this info to Flyduino to investigate.

 

[Bromego]

The only issue is I assume you are using kiss ESC? I have little bee 30a. But I will try it tomorrow. The fiancé said no more drones for tonight.

Thanks again for the lengthy and very thorough reply! It really helps to bounce ideas off others

What I don't get is why One motor is idling at min throttle 20 below the others per my picture.

 

[PsyBorg]

I would assume since the likelihood of what ever you have the quad sitting on is not perfectly level the FC has decided that is the correct speed needed to be at idle. Remember once you arm it the FC thinks it is flying and will adjust things to keep itself stable. The good thing is your set up is stable enough that vibrations are not making the FC think it is moving so it keeps changing to correct for level.

As long as when you spin up the throttle the four bars move evenly thru the range with no quad movement it should be OK. As long as motor direction is correct and all motors start at the same time then it should fly.

Edit: you did not by chance bump a trim button did you? check to make sure your channel centers are at 1500 within + or - 1. It looks like your yaw center is 1496 which could possibly cause that slight change in speed as well.

 

[Bromego]

Ill have to check, this is actually a really good find. Just need to figure out why my pitch and roll are also at 1511. Could be a combination of everything that's throwing it off.

I did copy the profile on my Taranis. Maybe Ill start a fresh one.

 

[Bromego]

Indeed my pitch was trimmed forward and roll to the right. Makes sense why motor 2 was constantly spinning less. Just need to verify with the computer. Super great find!