Help! PID tuning?

Innaviation

Well-known member
I finished my first FPV drone a few weeks ago and have been flying it around some (See videos for flight footage). I'm pretty new to FPV drones but I'm wondering what kind of PID tuning I need to do.

I also don't quite know how to do PID tuning either so I need some help on that as well.


 

PsyBorg

Wake up! Time to fly!
You got VERY lucky with that crash lil bud.

A few suggestions for you until your skills are trained up a bit is to lower your camera tilt, slow down, mellow out those rates a bit until you have more solid control. Worry about pids AFTER you can fly in a more controlled manor. Right now you are in what i call wet noodle mode. Too high rate not enough super rate where you are over shooting and over correcting as well as flying way to fast to be safe at your skill level. The quad is flying you at this point and you are just reacting to what it does.

For your rates first remove any expo you have set in the radio or the flight controller. Its not needed and just causes over steer issues at full deflection. RC super rate is the expo on flight controllers. It acts to smooth things out. Adding expo after that makes the full stick deflection changes unpredictable and insanely fast in a very short motion range.

Then I would set RC super rate to zero. At this point the FC should be measuring nothing but Rate degree per second movement. Raise or lower that until the degree per second shows 250 on pitch and roll and yaw to about 380 to start. Then you can raise super rate until the DPS is around 700. This should be pretty snappy yet smooth in the center of sticks.

When you test the rates start slow and cruise around in a steady pace and just do laps around the flight area where you can roll and pitch to get a feel for the center stick control. Do this for a few packs THEN adjust to allow yourself time to get used to the new rates. Adjust RC Super Rate up or down to where it feels good and you are not over steering and having to correct a lot on harder turns. Once you have the center feeling good and you think it is smooth you can then start changing max deflection.

The goal here is to hover then tap the throttle to blip the quad up a foot or so drop throttle to zero. Then do a full stick deflection in pitch or roll and immediately go back to center. Return throttle to where it was to catch the quad and hover again. The quad should do one complete flip or roll and come back to level. If it repeatedly goes past a single flip then lower Rate for that axis. If you cant do a complete flip or roll and stop level then add some rate. This will give you maximum resolution and more fine over all control.

Then practice those flips and rolls to where you can repeatedly do them in one place automatically. From there you can move on to freestyle type flight that you have been doing but you will be flying in control instead of the quad flying you and you just reacting to what it does like you are doing now.

Once you have that under control then you can think about pid changes to make it even more stable. For now though there is no sense trying to tune pids if you dont have full control of the quad to be able to "feel" the changes pids make.
 

outthayr

Active member

PsyBorg

Wake up! Time to fly!
Epic fail. Don't push too hard, imagine you were riding on the thing... don't crash. Could have put it through someone's window, or worse into their face. Good skill though, seems like you're gonna be quick to pick up anything you set your mind to.

https://www.getfpv.com/learn/fpv-essentials/fpv-drone-basic-pid-tuning-rates/

https://oscarliang.com/quadcopter-pid-explained-tuning/

https://intofpv.com/t-pid-tuning-cheatsheet

https://myfirstdrone.com/blog/how-to-tune-a-quadcopter


Those are all good "theory" articles but each one of them have one or more practical flaws that get cookie cuttered along the chain of teaching in regards to quads and tuning. They are good for trying to understand what pids are and do but not very practical for real life application.
 

Innaviation

Well-known member
You got VERY lucky with that crash lil bud.

A few suggestions for you until your skills are trained up a bit is to lower your camera tilt, slow down, mellow out those rates a bit until you have more solid control. Worry about pids AFTER you can fly in a more controlled manor. Right now you are in what i call wet noodle mode. Too high rate not enough super rate where you are over shooting and over correcting as well as flying way to fast to be safe at your skill level. The quad is flying you at this point and you are just reacting to what it does.

For your rates first remove any expo you have set in the radio or the flight controller. Its not needed and just causes over steer issues at full deflection. RC super rate is the expo on flight controllers. It acts to smooth things out. Adding expo after that makes the full stick deflection changes unpredictable and insanely fast in a very short motion range.

Then I would set RC super rate to zero. At this point the FC should be measuring nothing but Rate degree per second movement. Raise or lower that until the degree per second shows 250 on pitch and roll and yaw to about 380 to start. Then you can raise super rate until the DPS is around 700. This should be pretty snappy yet smooth in the center of sticks.

When you test the rates start slow and cruise around in a steady pace and just do laps around the flight area where you can roll and pitch to get a feel for the center stick control. Do this for a few packs THEN adjust to allow yourself time to get used to the new rates. Adjust RC Super Rate up or down to where it feels good and you are not over steering and having to correct a lot on harder turns. Once you have the center feeling good and you think it is smooth you can then start changing max deflection.

The goal here is to hover then tap the throttle to blip the quad up a foot or so drop throttle to zero. Then do a full stick deflection in pitch or roll and immediately go back to center. Return throttle to where it was to catch the quad and hover again. The quad should do one complete flip or roll and come back to level. If it repeatedly goes past a single flip then lower Rate for that axis. If you cant do a complete flip or roll and stop level then add some rate. This will give you maximum resolution and more fine over all control.

Then practice those flips and rolls to where you can repeatedly do them in one place automatically. From there you can move on to freestyle type flight that you have been doing but you will be flying in control instead of the quad flying you and you just reacting to what it does like you are doing now.

Once you have that under control then you can think about pid changes to make it even more stable. For now though there is no sense trying to tune pids if you dont have full control of the quad to be able to "feel" the changes pids make.
Well I did everything you said to do. Then once I started feeling comfortable with the new rates I decided to go to a parking lot to fly for a bit but...


So yeah, I'm definitely regretting the flying over asphalt. On the bright side my rates were feeling great up until that flight.