Camera Mount Rolling Off To The Right Problem

[Ollie332]

Hello everybody,

I am using the Pro Mount 200 camera mount. The first flight with it on went good however, every flight after that I get the camera mount wanting to roll or lean off to the right. I don't know if something accidentally got changed or what but Photo Higher said I should check to make sure the gear is not slipping on the pot shaft. I checked that and everything is fine. They also mentioned it could be the FC but I have the MK leveled off, and camera mount and camera plate level too but cant seem to figure out what else could be causing this. Any suggestions are appreciated. Thank you!

Kyle

 

[Droider]

Hi Kyle.. familiar story.. check out this..

and this

Is this whatt you mean?

 

[RTRyder]

Hello everybody,

I am using the Pro Mount 200 camera mount. The first flight with it on went good however, every flight after that I get the camera mount wanting to roll or lean off to the right. I don't know if something accidentally got changed or what but Photo Higher said I should check to make sure the gear is not slipping on the pot shaft. I checked that and everything is fine. They also mentioned it could be the FC but I have the MK leveled off, and camera mount and camera plate level too but cant seem to figure out what else could be causing this. Any suggestions are appreciated. Thank you!

Kyle

On the AV130 I have I had to use a couple drops of CA to secure the gear to the pot shaft, it was loose enough to be able to slide it back and forth toward the body of the pot so I can't imagine that would not slip in direction of rotation, the glue fixed that.

I have a similar issue with 2 different MK flight controllers, no matter how well I level the platform each one always winds up off a bit to one side or the other in flight. My solution has been to watch the video, see which way it wants to lean, and the incrementally add a little offset to the center point in the camera tab until the horizon is level on the video. There has to be a reason for it but my solution seems to work OK and I'm too busy/lazy to tear into it and find out exactly why it happens.

Ken

 

[jes1111]

Just because I'm curious at the moment about camera stabilisation, I went to look at the MK documentation on the settings. Could someone please explain what they mean, particularly the first two? And there only seems to be Tilt compensation - nothing about Roll.

EDIT: just found a newer page (why don't remove the old one?) http://www.mikrokopter.de/ucwiki/en/MK-Parameter/Camera - I see there that it has Tilt and Roll. The first two parameters are still a mystery to me, though. I'm hoping that understanding the settings migt give some clues about the OPs problem.

 

[Ollie332]

Yes RTRyder that is exactly what I am mean. Do you have any type of fix for this problem?

 

[jes1111]

UPDATE: I found the code that calculates the required servo positions for Tilt and Roll on MK. Not much help though - as with all the MK code, it's so convoluted that I can't figure out what he's trying to do. Having said that, it's fairly obvious that he's trying to do something pretty strange - the calculation involves Integrals and Cosines and other gritty stuff. I thought the calculation should be rather simple: if the aircraft is rolled 5 degrees to the right, roll the gimbal 5 degrees to the left. Apparently not in the MK world

I've seen so many people reporting odd camera behaviour (and yet not all users) - something fishy in there, for sure - but someone who's familiar with the code needs to have a look.

 

[Buzzed]

Pretty sure I also read somewhere that if a servo plug is pulled off the FC while the MK is still powered that it damages one of the components on the FC. Maybe someone else can verify.

 

[Ollie332]

That is a good point. Yes, would be nice if somebody can verify this. If in fact it did damage a component, wouldnt it show up in MK Tools?

 

[RTRyder]

Yes RTRyder that is exactly what I am mean. Do you have any type of fix for this problem?

Yes, mine tend to lean the same direction and the same amount every time no matter how carefully I level it on the bench, apparently its a "feature" of the MK software. If that's the case forget about trying to level the camera platform on the ground because obviously the flight controller has a different idea of what level should be when its off the ground.

What I do is see which way it leans by watching video I've recorded in flight and then change the setting for the center point of the roll axis in the software to make it lean a bit in the opposite direction. The goal is to use the setting in the camera tab of Mk tool to set the camera platform to where the MK thinks level is when it's flying which will usually not be where actual level is when the MK is sitting on the bench.

The end result is the horizon looks flat and level from the camera and the camera platform looks like its out of level when the MK is parked because it is, or the short way of saying the above is I intentionally set the camera platform off level on the ground so that it will become level in flight.

It takes a bit of trial and error doing test flights but eventually you get to a point that looks good and you can live with it, or at least its worked that way for me.

The only other way I know of to do it is if you have a spare slider you can assign to an unused channel on the TX and a video downlink, then you can assign the poti for the slider to the roll axis in the software and then look at the video downlink while adjusting the slider so that the view is level but you'll need to do that everytime you fly.

That is a good point. Yes, would be nice if somebody can verify this. If in fact it did damage a component, wouldnt it show up in MK Tools?

No, MKtool doesn't have that level of diagnostic ability to know if a single component is damaged. If this were the case that removing the connector did damage I would think that servo output would just stop working or if it didn't that the symptom would be something that made it obvious there was a problem like the servo going full lock to one side each time you applied power to the flight controller.

Ken

 

[Ollie332]

Ok, I will do a little trial and error and try to get it level like you did. I appreciate all of the help. Thank you.

 

[Crash]

The first two parameters are still a mystery to me, though. I'm hoping that understanding the settings migt give some clues about the OPs problem.

The first parameter sets the servos position. IOW, as it changes the servo changes position.

The compensation parameter is similar to a multiplier. It increases or decreases the amount of movement to compensate for different setups. IOW, If you were to tilt the craft, 20 degrees, the linkage geometry or mount mechanics may not tilt the camera 20 degrees. The compensation factor will need to be adjusted to put it at 20 degrees.
Did I explain that so it makes sense?

Re the code: Perhaps all the extra math in the servo code is to accommodate the MK's ability to alter it's as-built orientation? You can alter the front of the craft in software without moving the board or motors and additionally care free mode will do it in flight. The camera mount however does not follow that orientation change.

 

[jes1111]

Thanks, Crash. So the first param is for setting the "home" position of the servo on that axis? And the second one is a scaling factor. Looking some more at the code, the calculation of each axis involves a "factor" from the other axis, i.e. in writing the formula, I believe the programmer does not have access to an absolute "current attitude" expressed in degrees (probably, as you say, because of the carefree mode) and must therefore (re)calculate based on some PID-like stuff. This could easily account for the infamous "lean" - i.e. if there's some anomaly in the FC's idea of "level aircraft" and "level gimbal" then the pitch estimation (of the aircraft) will "feed into" the roll estimation (of the gimbal). That might be "findable" by examining the aircraft's settings for something that "seems to work but isn't actually the right way to do it" - it might well be the source of the gimbal's bias.

 

[Crash]

Yes, scaling factor. That's the term.

Perhaps you guys with tilt problems should try out FC version .78F as a test to see if it makes a difference.

 

[jes1111]

I've been thinking some more about this issue. I'm convinced that it's either a bug in the version you're using or, assuming this is being widely reported by all users of this version, a rogue setting (for the aircraft, not the gimbal) that is feeding a bias into the gimbal's calculation.

What is the airframe itself doing whilst this gimbal problem is showing? Behaving normally in attitude, response to inputs, etc.? My best guess, knowing the nature of the higgledy-piggledy MK code, is that there is a setting somewhere (for the airframe) which is clipped when applied to the airframe calcs but not when calculating for the gimbal. For example, "X" is the setting in question and it has a range of 0-255. In the flight calcs, it is clipped to 200, say - i.e. even if you set it to 255, the value used will be 200. (The MK code is littered with this kind of stuff.) So you set it to 255, 200 is used in the flight calcs and all is well. But when it comes to calculating the gimbal, the 255 value is used, hence the software's idea of "level aircraft" and "level gimbal" will be different. Since the bias is on the gimbal's roll axis, the flight setting must be something related to aircraft roll.

Try returning all the settings to default and see if the bias still exists, or review/question/verify every setting in the flight section.