Unable to perform stable flight with indoor drone (without GPS)

🧪 Flight Testing & Log Analysis v1.13
1

Hi,
I am making this drone for indoor use (without GPS) and I got a positioning camera.
I am trying to the PID Tuning manually, but still unable to perform that also.
Any help will be appreciated.

Problem:
Upon taking off, the drone starts to go away on 1 side and after a few seconds, it started coming down (even on 100% throttle), then touches the ground and then try to takeoff, but couldn’t make it.

Setup:

  • QuadCopter
  • Pixhawk 6X
  • PX4 v1.13.3
  • Flight Mode: Position

What I observed from logs:

  • Huge volume of vibrations
  • Low power
  • Motors are running at almost 2000
  • Setpoints are not available for Local Position X, Y, Z

What I need?
I need support from experts here, please help me diagnose the core problem and the fix to the issues.

Strange Messages!
I am seeing some strange message which I couldn’t understand in the “Logged Messages” section of the log file.
[vehicle_imu] ACC 1 (2490386) offset committed: [0.016 0.003 -0.059]->[0.076 -0.016 -0.050])
[vehicle_imu] ACC 0 (2424858) offset committed: [0.280 0.071 -0.156]->[0.327 0.034 -0.167])
[vehicle_imu] ACC 2 (2752522) offset committed: [0.001 -0.077 0.042]->[0.063 -0.028 0.058])
[commander] action_request lost, generation 11 -> 13

Logs
Log # 1
Log # 2
Log # 3
Log # 4 (Local Position setpoints were available in this, but the behaviour was same)

2

Yes, I can confirm that. Do you mind sharing a picture of the setup?

3

Sent you the details of the setup.

4

Ok, so the Pixhawk is not in the center of gravity. Have you set the params to account for that offset?

Parameter Reference | PX4 User Guide (etc.)

5

No, when the Pixhawk was moved from center the parameters were not set. I will fix the parameters.

But, when it was at the center of gravity, the result was kind of same.

6

Right, I think you need to get it to fly properly in stabilized and altitude control mode first. If it’s that under-powered, it just wont fly properly at all. Once you have some control margin and it flies properly in these modes, you can move to position control.

7

Can you please shed some light on the power issue!

POWER
I am using a fully (actually over charged) battery (24V - 6S).

The drone starts flying, but as soon as it goes into air, voltages drop around 22V and drone came down after a few seconds. Voltages are going down, but more amps are being consumed.

The behaviour is same even at almost 100% throttle.

Kv (Motor Velocity Constant) → 465 RPM/V

MOTOR
MOTOR1128×228 12.2 KB

VIBRATIONS
And how much vibrations could be fine?

8

If the voltage drops a lot under throttle then it might also be a hint that the battery can’t provide the amount of current you want. Check the continuous and peak ratings of it, and then make sure you stay well below them.