Multicopter PID Tuning Guide Rate Controller

PX4 Autopilot
1

Hi Folks,
I am part of a team that working on a prototype for a heavy lift drone. I am using the Holybro Pixhawk 4 FC and I am having trouble trying to fly the prototype. I am thinking that problem is in the air frame mixer, I am using the generic 500 mm X quad air frame, the prototype is 14 in diameter. Big difference, so I am thinking that I need to reduce the Gains in the rate controller a lot and start over bringing them up very slowly. I have done all of things that the article talks about on getting ready to tune the drone.
Any thought would be great.

Mike

2

Hi Folks,
I just noticed that editing on the last post is not that great! Hi! The Prototype Drone is 14 feet in diameter, not 14 inches real big difference!
One of the team members is sick so I have not had a chance to try out my ideas yet.
Thanks Mike

3

Hi Mike,

Have you tried performing a test flight? I am working on a similar size octo coax and have experienced some diagonal oscillations upon takeoff.

4

@hilltopmike

I found a solution. You have to set up PID. In my case it was mostly MC_ROLL_P and MC_PITCH P and MC_PITCHRATE_P and MC_ROLLRATE_P

5

Hi Dusan,
Sorry I missed your first post on Sep 2. I have been fighting a number of problems and then one of the team members has been real sick for over a mouth, so progress has been very slow.
Great on finding a solution, in setting up the PID did lower the gains to zero and then bring them back up slowly with a test flight for each change? I have not been working with this for awhile, so will have to brush up on the PID section again. I will working on the drone later this week, and update what is going on.
Thanks
Mike

6

Hi Dusan,
Again my editing is not so great!

Great on finding a solution, in setting up the PID did you lower the gains to zero and then bring them back up slowly with a test flight after each change? I have had some flight tests but it was so unstable we have not had it in the air yet for more then a few seconds.
I have not been working with this for awhile, so will have to brush up on the PID section again. I will working on the drone later this week, and update what is going on.

Mike

7

Hi Mike,

What I did is lower drastically gain values. Not to 0 but for about 40%. From there I finetuned by further decreasing or increasing gains by small amount.

Dusan