Wobbly S1000

[1Placerville]

She started to do this and I'm not sure where to start..I took off in atti then switched to gps. As you can see its quite the handful..anyone have any ideas? Just not sure where to start...she looks confused or something...
https://vimeo.com/99205522

 

[gtranquilla]

What are your Basic and Attitude gain settings? These defaults for the S800 should get you in the right ballpark.
View attachment 18869


Also you might need to tweak these a bit with your iPad Assistant program or your RC Xmitter LD or RD knobs (assuming they are set up to do that).


If the landing gear is any indication, i.e., bottom rods are not aligned, then there may be other MR airframe alignment issues, e.g., do all motor arms have the 8 degree inversion angle as designed?
And I assume there is no 3 deg inclination angles as for the S1000, i.e., 3 motors @ +3 deg and 3 remaining motors at - 3 deg.

 

[1Placerville]

What are your Basic and Attitude gain settings? These defaults for the S800 should get you in the right ballpark.
View attachment 23196


Also you might need to tweak these a bit with your iPad Assistant program or your RC Xmitter LD or RD knobs (assuming they are set up to do that).


If the landing gear is any indication, i.e., bottom rods are not aligned, then there may be other MR airframe alignment issues, e.g., do all motor arms have the 8 degree inversion angle as designed?
And I assume there is no 3 deg inclination angles as for the S1000, i.e., 3 motors @ +3 deg and 3 remaining motors at - 3 deg.

I've used 150 150 160 on both, 175 175 170 basic 135 135 180 atti and a lot of places inbetween

 

[Benjamin Kenobi]

Hey mate,

Looks like the gains are too high to me. Try lowering them and see what happens.

 

[gtranquilla]

Perhaps some additional info from you might help to get more feedback.... e.g., are you using a WKM or and A2 or Naza?
Can we assume that the C of G on the horizontal plane is at the MR hub dead center?
And is it correct on the vertical plane? Some flyers get the +- sign wrong with the vertical offsets.

 

[JoeBob]

Has your FC become loose? If it's moving around it could be trying to level itself as it wriggles.

 

[kohit7]

Always do an advance IMU calibration and a compass calibration before anything. Could be your gains, also check to make sure that your Gps puck is pointing in the right direction for your part of the world, it's different for each longitude.

 

[1Placerville]

Perhaps some additional info from you might help to get more feedback.... e.g., are you using a WKM or and A2 or Naza?
Can we assume that the C of G on the horizontal plane is at the MR hub dead center?
And is it correct on the vertical plane? Some flyers get the +- sign wrong with the vertical offsets.

Using the A2..yes on C of G..yes on vertical plane...no errors on + - XYZ...took off the A2 and bench tested...everything is fine in the assistant...baffling to me...am wondering if I have a motor issue...with 8 its hard to pin down..all see to work fine on the assistant motor test but I dont have a way to take the arm off and see what sort of out put I get on each motor..that would seem the simplest..thanks for responding

 

[1Placerville]

Always do an advance IMU calibration and a compass calibration before anything. Could be your gains, also check to make sure that your Gps puck is pointing in the right direction for your part of the world, it's different for each longitude.

Thanks...I had done the IMU/compass calibration a couple times as I thought along the same lines...gains are nothing out of the ordinary...I used Bladestrikes 175/175/170 basic, 135/135/180 Atti and went to 150/150/160 for both then went down to 120/120/100..played with it quite a bit but it almost didnt effect that hopping around it does. Puck is normal (forward)

 

[1Placerville]

Checked all connections, looked for wear/bare wires, loose wires, loose connections, reversed connections et al....Thanks.

 

[gtranquilla]

Also note that the A2 manual recommends applying hot glue gun glue to the canbus connectors..... I found them to be too much on the loose side..... and an intermittent GPS signal or IMU signal to the FC spells trouble.

 

[kohit7]

Thanks...I had done the IMU/compass calibration a couple times as I thought along the same lines...gains are nothing out of the ordinary...I used Bladestrikes 175/175/170 basic, 135/135/180 Atti and went to 150/150/160 for both then went down to 120/120/100..played with it quite a bit but it almost didnt effect that hopping around it does. Puck is normal (forward)

I hope you know that the IMU and the compass are separate from each other and calibrate differently. IMU is the gyroscope the A2 uses to stay level and adjust motor speeds to keep it level in ATT/GPS mode.

Also puck shouldn't point straight forward, there is a calculation to get it in the exact position you need for your part of the world. For instance, here in California, the pucks arrow should point at the 1 O'clock position. If it isn't correct then you can get a "toilet bowl" effect. A small amount of toilet bowling can be mistaken for being wobbly.

The should be the only factors in a wobbly copter with the exception of malfunctioning parts or improper assembly of the copter (sorry to say). ESC could be bad, could have a bad motor, check all props... The list could go on.

 

[gtranquilla]

The DJI A2 GPS does not need to be adjusted for the angle of declination (mag versus tru north) as does the previous DJI FC systems.
It automatically adjusts for that by flying it back and forth several times in Attitude mode.

 

[kohit7]

The DJI A2 GPS does not need to be adjusted for the angle of declination (mag versus tru north) as does the previous DJI FC systems.
It automatically adjusts for that by flying it back and forth several times in Attitude mode.

That's not true. I think you need to read the A2 manual again as it does state that it needs to be positioned correctly in regards to location.

 

[gtranquilla]

GPS module orientation

That's not true. I think you need to read the A2 manual again as it does state that it needs to be positioned correctly in regards to location.

See box at bottom of page 12 stating "The GPS arrow must point directly towards the MR nose."!

Also my MR with A2 FC flies straight by following DJI instruction above. I no longer have to rotate the GPS module to account for Mag versus true north.:tennis: