Servers by jDrones

Unstable quadcopter in automode

pixhawk2

(Bharath Chandanreddy) #1

Hello,

This is Bharath. We are working with Pixhawk 2.1 from 2 months and faced an issue

Drone specifications:

  1. Tarot Frame 960mm
    2)T motors 280kv
    3)T motor esc 60A
    4)T motor 22 inch propeller
    5)Tattu battery 6S 22000mah
    6)Horus x 10s transmitter
    7)Rededge-m camera as payload

We faced an issue in autonomous mode survey grid yesterday. We had 5 flights with different auto missions with 2 separate batteries with changing the velocities from 5m/s,6m/s.7m/s. We had a stable flight for first 4 flights
In the final flight drone we changed the battery (Note:there is sudden change in wind speed and drop in temperature around 3-4 degree temperature before 5th flight, which is common weather change in India during summer evenings) drone with velocity 7m/s in auto mode, the drone losses its control and wobbled like hell, expected to have a crash landing.It didn’t come to control even when we changed to manual gps mode, We took around 5 minutes to take control on drone ( to be honest we thought drone would be crashed) and analysed the logs but couldn’t find the exact reason behind it.

Here below drive link directs you to log file.
https://drive.google.com/open?id=1OpjtW0KCLUfB9j-rynKrzwHguaTnxFYi


(Mike Boland) #2
  1. Vibrations:

You have considerable clipping happening, which is not good.
You need to get your Z axis vibrations under control.

2: Too much lift, not enough braking.

You can see here that the FC is shutting down motors to try and get stability back.
Maybe, for the weight/thrust you are using it might be worth considering 20" props.

Have you autotune?


(Bharath Chandanreddy) #3

Hello Mboland,

Thanks for the quick reply. We did autotune for the setup.

Can be power supply noise (Since we faced the problem after battery changed and also we faced this problem before with this battery), mag values problem?

Coming to vibration problem we are using different materials 3dr anti-vibration pads, 3M tape, Dubro foam but none of reached our expectations.

We are testing the drone again today with changing the battery, removing payload, fixing the canopy and planned to the test quad with different velocities and update you with results