Is Auto tune mandatory?

ArduCopter Copter 4.0
1

Hello everyone!!

I have the following doubts?

  1. Is it mandatory to do autotune for all the different frame types?

  2. Or Is it okay to go with by default PID values?

  3. Does it affect the flight duration?

  4. Can do auto tune separately for ROLL and PITCH and YAW or all should do together?

Please let me know.

Thanks.

2

  1. Autotune helps with tuning the copter’s PID values and is recommended to do

  2. As a base for when everything is ready for first flight = yes, after first flight the PID’s will most likely need to be changed for better stability

  3. Yes, if the motors are working harder by making the copter wobbly this means it is often pulling more amps. Bad PID values can also make the motors/ESC’s hot which means they are alot less efficient.

  4. You can do them separately but doing them all at once is fine, all it does is JUST pitch then once its finished pitch it will then do roll ect. The reason why you can do each individually is if your copter cant complete all axis’s in the one flight (or if you only need to tune pitch/roll and not yaw)

1 Like
3

Thanks Lachlan.

I have one more query,

But the Drone should take off automatically and go to the last waypoint and continue the mission without arming again from TX or Mission planner after changing the battery.

Will it happen? If I keep the flight controller power ON even when the battery is getting swapped automatically.

( Battery changing also automated by battery swapping machine)

Normally we arm the drone and put into auto mode using the the TX or GCS.

In my case at the beginning only I will setup everything and arming, changing the flight mode into auto mode, then when the battery failsafe triggered during the mission drone will come to the Docking station, battery change will happen then the Drone also should take off automatically and continue the mission.

I am not good at programming language. What to do to achieve the above scenario?

Thanks.

4

You already got suggestions in the the thread you started about changing batteries

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5

Hi Shawn,

You are correct, But stillt I got no idea how to achieve my task.
I am not good at writing programe. I need some more guidance to acieve my task, that is reason again i am puuting tha issues here.

I dont know how to start the cripting using LUA. Could you point me in the write direction to start writing the script for Drone with battery swapping project?

Thanks.

6

https://ardupilot.org/copter/docs/common-lua-scripts.html?highlight=lua%20scripting is a good starting point.

1 Like
7

In the old days machinists would use Smoak to fine tune manifolds. So the idea to fine tune is not new. For some people they can fine tune by moving some of the pids around manually it’s really up to the user. I have good luck using the stock tuning as a base point then if i get a odd shake just address the bad pid axis. For example a typical twitch for me comes from at roll I able to reduce that manually within a few seconds. One of the big issues is to test the firmware and or hardware like frames your using to eliminate any major change Auto tuning will not solve. Also there is a in-between using the PID slider in MP very handy.

8

The default PIDs basically work well on a 3DR X4 (something like 400mm, 2Kg, 10" props, 800kv motors). The further your copter is away from that configuration the worse the performance is likely to be. If you copter is much smaller then its almost certainly unflyable and likely dangerous for both you and your vehicle. If your copter is much bigger I suspect it will fly but feel pretty sloshy.

1 Like
9

Thanks Andyp,
So it’s better to go for Auto tune write?

10

Yes absolutely you should

11

I made a lot of smaller crafts and i don’t understand you making it a safety issue. In order to auto tune you need a stable craft in the air this can be adjusted manually sliding the PIDs and then auto tune. Auto tune if done wrong can also make for a unpleasant flight as documented. Honesty your going to know something is wrong the first one sec in the air…

12

Autotune or manual tune, some kind of tuning is necessary on these copters

13

Agreed Andy 100% true.

14

Do remember to change the INS_POSn_XYZ values before autotune if the FCU is not at the same CG of the airframe.

Particularly for a taller drone, you will experience different roll and pitch with default ins_pos values and configured ins_pos values.

1 Like
15

Hi Jay.

I have fixed my FC at center of my quad on top. Should i need ot change INS_POSn_XYZ values?

Please let me know…

Thanks.

16

Regarding the INS_POSn_XYZ parameter, how sensitive is the flight controller to not being at the center of gravity? Mine is a pixhawk and seems like I remember from taking the cover off the IMU’s are more towards one end of the board. Is it precise enough that I should try and locate the IMUs to CG? I’m thinking it could be off by maybe 1.5" vertically and horizontally, is it worth measuring and updating that param?

17

.

Not very sensitive.