AC-3.1 autotune support discussion

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- - - Developer
      
      leonardthall > Brandon Clifford December 13, 2014 at 2:04pm
      
      Hi Brandon,
      
      Thanks for your help on this! While it always sucks when someone crashes. Your help has meant that a whole heap of people won't crash for the same reason.
      
      https://github.com/diydrones/ardupilot/pull/1684
    - Josh Welsh > Brandon Clifford December 13, 2014 at 1:36am
      
      I have been having bad luck with my GPS and that was actually a brand new unit in order to prevent any issues.
      
      Apologies if I missed it... are you running FPV, and by chance is it 1.2/1.3GHz?
- Developer
  
  leonardthall > Brandon Clifford December 12, 2014 at 3:26am
  
  Hi Brandon,
  
  Looks like you had a GPS fail safe event and it went into auto land.
  
  Sorry to hear about your crash!!! Hope you didn't do any major damage!!
  - Brandon Clifford > leonardthall December 12, 2014 at 6:37am
    
    Hi
    
    After I looked at the logs it seems that All of the sudden I got massive vibrations causing the alt to be off from what it is. This alt controller is in serious need of a redesign something as easy as if vibes past limit only use gps and baro alt. It seems so primitive to rely on the accels So much when we have so much more info.
    
    Now I am just wondering what caused the vibes all of the sudden, I think the gps failsafe happened after as I was in alt hold during autotune...in gps failsafe would it still auto land even though not in a gps mode
    - Developer
      
      leonardthall > Brandon Clifford December 12, 2014 at 4:15pm
      
      Brandon, first up, I don't see the massive vibration you are talking about. Secondly suggesting that the work of the devs needs to be thrown out and done again without any explanation of how it could be improved or even why it is bad is not a way to motivate people to help you.
      
      I think the vibrations you see are where it hits the house.
      
      I am trying to work out why it went to maximum throttle though. I will get back to you.
      
      Again, sorry for the crash.
      - Brandon Clifford > leonardthall December 12, 2014 at 4:38pm
        
        Hi Leonard,
        
        I may have been mistaken, but was there a vibrations on the Z accel? on the line 33? I compared IMU1 Z accel to my Current, I will double check this later tonight.
        
        I am not saying the work of the devs needs to be throw own, I did mention a fix (a check of the vibrations and if the IMU is experiencing +- 30g then It should be thrown out of the equation, Even if this crash wasn't caused by vibes I did have issues with them before where my quad would go straight up and I think having an If statement to check if there is to many G forces to not use the accels as this (normally?) doesn't happen, on a regular flight(?) would be a good idea.
        
        It is possible that the vibrations is when it hit the house, I will take another look and try to remember the time line. I do know it throttled up before It hit anything so if I compare current to the Z chart that should help..
        
        Thanks for the help, sorry if I came across rude but I did think it was a valid point? I don't have any experience in designing the FC calculations but please point out any issues with the idea I had(I guess CPU payload?)
        
        Developer
        
        leonardthall > Brandon Clifford December 12, 2014 at 6:01pm
        
        Hi Brandon,
        
        No problem mate. We already do that and in the latest EKF it is the most robust way we possibly can do it. The EKF will reject impulses like that amazingly well. We also compare two imu's sampled at different rates to remove high offsets or spikes from noise or vibration aliasing.
        
        I will get back to you on the throttle thing when I get to the bottom of it.
Marc December 7, 2014 at 12:01pm

hello randy,

does autotune work on the apm 2.5 and 2.6 or is it only for pixhawk?

many thanks
Rob Burrows December 7, 2014 at 10:22am

George, Are you in both autotune AND alt hold? I have each function set up on a different switch. So I'll switch into alt hold first on the 3 position switch, leave it there, and then switch to autotune on a 2 position switch. Hope that helps!
George Roberts December 5, 2014 at 8:12pm

Can't get autotune to start!

My quadcopter flies but I want to try autotune now. I have a 3 position switch that should be able to swtich from stabilize to alt-hold to autotune but autotune never starts. Instead I tried having ch7 enable autotune and I checked in "radio calibration" that the PWM goes over 1800 (about 1850) but again - no autotune mode. Should the log show it in the mode display? The log shows text for "stabilize" mode and "alt-hold" mode but never shows any other mode. The log definitely shows nothing with the ATUN tag.

I have apm2.6. And firmware 3.1.5. I have reduced vibrations quite a bit - I think all 3 axes are under 1 in the graph from top to bottom in the noise (with no props it's about .5 from top to bottom for the noise). I don't think it's the noise - would that not allow it to go into calibration?

When copter is on USB only mode should I be able to get it to go into "autotune" in the GUI? It shows stabilize mode and "armed" but never autotune. I assumed the motors actually needed to be turning but if not I could maybe debug this without even turning on the motors?

What should I try next?

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AC-3.1 autotune support discussion

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