Hi everyone--a bit new to FPV but a happy owner of the DJI FPV.  I am trying to understand the difference between how DJI and other drones handle controller rates.
In the DJI interface, the rates setup looks like this:



In a normal drone (using Betaflight) they look like this:



RC Rate (Betaflight) seems to be the same as Center Sensitivity (DJI) where a setting of 200 gives a linear output of 200 deg/sec at full stick.  So far so good.

Super Rate (BF) and Max Rate (DJI) are related, but wheras in Betaflight max rate is a function of both RC Rate and Super Rate, DJI lets you pick the max rate regardless of RC Rate slope and backsolves the curve.  This is actually a lot more intuitive, but essentially the same math.  So I think I get this.

However, RC Expo (BF) and Expo (DJI) seem totally different.  Whereas RC expo pulls the cuve down for values above zero (but leaves the Max Rate the same), the DJI expo seems to be totally different.  You can see this in the app for the Mavic:



Although there is no such graphical interface to the DJI FPV I'm assuming this is the same thing.  As you can see, an Expo of 0.5 is linear and equivalent to an RC Expo of zero in Betaflight.  Less than 0.5 increasingly pulls down the curve, and above 0.5 pushes the cuve above the line.  I have never seen anyone do such a thing in an FPV rate setup, and I'm not even sure this is possible with Betaflight at all.  (If you want to play with a rate calc online see here: https://erikspen.github.io/betaflightratestuner)

So my questions here are:

1. Is this analysis correct?
2. Is there any way to do a 1:1 mapping of a Betaflight setup and DJI FPV setup?  What is the math used to turn the DJI Expo value into a curve?
3. Why would anyone want a superlinear setup?  I see a number of FPV fliers running 0.55 or 0.65 Expo, but this would seem to make the stick more sensitive right at the middle which is totally counter-intuitive.

Any insight here would be great.  Thanks, -ch

the latest version of the DJI Virtual Flight app shows graphs for the rates/exp for M mode
(so, hopefully we can see this in the next DJI FPV firmware ?  ... also have profiles which would be awesome on the FPV !)

in virtual flight, it shows exp flattening out the curve , so just like betaflight.

so increasing exp will  means less movement in the centre.
exactly how this feels, also depends on centre sensitivity.

to some extent increasing exp, or reducing centre senstivity achieve a similar result

but all 3 parameters are part of an equation, which to some extent affect each other.
(e.g. if you increase your rate, you may find yourself wanting to adjust exp/centre sensitivity)

the new graph in dji virtual flight (or your betaflight graphs) are a good way to see the effect of changing parameters will have.
but of course, ultimately you have to fly a few packs, and feel what works for your style of flying

I've also found as Im improving, Im now increasing the rates, and then re-adusting exp/centre.
upshot is , there are no 'perfect' rates , just ones that suit you.

(though, I think many do thing the intial dji rates are a little twitchy for when you start out)

thetechnobear Posted at 5-1 05:07
the latest version of the DJI Virtual Flight app shows graphs for the rates/exp for M mode
(so, hopefully we can see this in the next DJI FPV firmware ?  ... also have profiles which would be awesome on the FPV !)

Ah super helpful.  Didn't know about the graphs in DJI Virtual Flight, that makes it a lot more clear what is going on.  Good to know that the Expo behaves like Betaflight.

I really wish they had the graphical curve display in the standard settings as well, without having to use the simulator app. It's so vague what everything does else.
And more than one custom preset you could save settings in, so you could switch between more freestyle-ish or more cinematic behavior, or just test some settings out, without going through all the tedious adjusting.

It is really difficult to "imagine" these connections, but there are Excel sheets that can help with this ...

frankymusik Posted at 2021-9-8 23:41
It is really difficult to "imagine" these connections, but there are Excel sheets that can help with this ...

Hey, do you have these Excel sheets for me?

Thomass_H- Posted at 2-24 10:28
Hey, do you have these Excel sheets for me?

... I was able to watch them "back then" in a video, but unfortunately I don't have these links at hand (anymore) at the moment...

Very different than the rates for my jet

Thomass_H- Posted at 2022-2-24 10:28
Hey, do you have these Excel sheets for me?

Try this tool:
https://www.desmos.com/calculator/gttf4kscxp

I've tried to addjust simmilar curves:
RC (Betaflight) - red
a=0.8
b=0.72
c=0.19

Actual (DJI FPV/Avata) - blue
d=100
f=540
g=0.5

If you use Betaflights actual rates, they look a lot more like the DJI stuff ...