Autonomous flying with Pixhawk 6x has uneven motor speeds

ArduCopter Copter 4.5
1

Hi everyone,

Our team is participating in a competition where we need to demonstrate the autonomous capabilities of our quadcopter.

The objective is to make the drone autonomous after receiving a command from a laptop. Once in autonomous mode, the UAV should perform a stable vertical takeoff at a constant velocity, ascend to a height of 3 meters, hover for 30 seconds, and then land at the exact takeoff position this should happen without gps.

For this, our team has purchased SimonK 30A ESCs, 1000KV BLDC motors, a Pixhawk 6X flight controller, a quadcopter frame, and a Raspberry Pi.

We are facing issues with uneven motor speeds, causing the UAV to crash. We have already disabled RC, GPS, and other unnecessary failsafe parameters, but we are still unable to get the drone to reach the desired height and hover for 30 seconds.

Any guidance or suggestions to resolve this issue would be greatly appreciated.

Thanks in advance!

2

Here are some suggestions:

  1. Do not disable ANY failsafes, they are there for a reason.
  2. Check that you are not using hardware that should be avoided
  3. Make sure to follow these hardware best practices
  4. Enable RC, mount the GPS and configure the vehicle correctly
  5. Tune the PIDs
  6. Once that is done and the drone operates reliably, remove the RC and the GPS and try again.

I edited the title of your post to better reflect the content

1 Like
3

Could you please guide us on how to tune the PID controller? As undergraduate students, we are in the learning phase and would greatly appreciate your assistance. Additionally we also have pixhawk 2.4.8 with us.

4

Install the software that is mentioned on point nr 4.
And follow the painfully detailed instructions.

5

OK sir we will do that but we only left with 5 days to deadline of submitting this demonstration sir.

7

Sure sir we start it right now. I forgot to mention that we have did calibration before in qground control for pixhawk 6x but without gps. For pixhawk 2.4.8 we have did all the necessary calibrations sir!

8

What position sensor do you have if not GPS to “land at the exact takeoff position”?

9

We planned to relay on inbuilt imu

10

That is a poor plan. Connect a GPS or go here Non GPS Navigation.
Optical Flow would be the easiest to implement.

11

Thank you so much for your words sir

12

Sir will a single point lidar helps us to estimate the position since our requirement is only to go vertical

13

No, Lidar is a rangefinder. But, you need one of those also for Optical Flow.

14

This is probably only theoretically true.
In reality, the drone will actually drift somewhat, more or less, due to internal and external influences.