Curves with variable coefficient!

[jimbo385]

This is an interesting one!

Is it possible with the current firmware (2.0.12) to set up curve and then use a pot to change the coefficient?

It would be handy for tuning a throttle curve for instance!

Cheers.

[rcgyuk]

I do something similar to fine tune Throttle to elevator mixing.

I set uo a custom function to Adjust GV2 with TrimT

(could use any GV)

Throttle doesn't use throttle trim, as electric motor.

Then I add a second line to the elevator, source Thr, weight GV2

In this instance, I set up a 3 point curve, -100,0 0,50 100,100 and then use the GV to change how much of the curve I use.

I trim the model (very floaty piper cub) to glide with motor off, using elevator trim, then with power on, I use throttle trim to change elevator compensation until it doesn't climb or dive under power.

Turns out I needed 12%

Is that the sort of thing you had in mind?

Regards

[jimbo385]

Not quite!

I currently fly multirotors. I have a couple if throttle curves setup on a switch. Both are setup with 17 points one with a coefficient of 90% and the other with 80% so that I can see which gives me the fine control around the hover.

It would be great if I just had one curve but could change the coefficient via a pot.

Cheers

[Kilrah]

What do you mean as "coefficient"?
You can multiply and/or add an offset to the output for example, which might be what you're looking for.

[jimbo385]

Not quite!

Within the curves tab of Companion 2.0.12, I set the following;

Number of points to 17
Symmetrical f(x)= f(-x)
Then a coefficient of 90

This gives me a really nice curve that I can apply to throttle.

However, 90 is way too much!

Would like to keep all other parameters but use a pot to adjust the coefficient to make the curve variable. Then I can test this at the field. I tried to change at the field but I'd have to adjust each of the 17 points individually on the TX!

Cheers.

[Helle]

Hy,

you use a curve and a weight of 90% I think ?
then yes you can change the weight variable by using a Globale Variable GV at weight

But a GV normaly has -100% to +100%,
so you have to precalculate the Range for this
GV from 60 to 90% for example
and then use it as GV-Weight at your Mixer with the Kurve

here an example in three steps:

picture 451: Input I10: Precalculation S1 with weight 15% and offset 75% makes range 60% to 90%
calculation of weight: from 60% to 90% is 30 30/200= 15% ( -100% to +100% = 200 )
calculation of offset: middle from 60% to 90% is 75%

picture 452: Spezial Funktion: GV1 get the value from Input I10

picture 453: Mixer channel: Gas with Kurve 1 and weight with GV1


thats all,
you got what you need

The output at the channel is variabel with S1 60% to 90% and depending from the Gas-Kurve

Outputvalue = (Gasstick * Kurve-position) * S1-Range

Helle

[jimbo385]

I'm afraid that really doesn't make any sense to me!

I am just trying to change a curve variable with a pot!

[MikeB]

I think the problem is the coefficient you are talking about is only available in companion, and what it does is calculate the curve's points for you just to save you needing to enter them all 1 by 1. This coefficient is not available on the radio itself.
With the settings you are using, the curve you get is very like that when you set expo up.
I think you would get the same effect if you apply expo to the throttle, then you could use a global variable to adjust the amount of expo you use.

Mike.

[jimbo385]

Now that makes sense!

Thanks Mike

[Helle]

Hy,
example
Expo as Global Variable
Expo 0% to 50% with S1
Mixer Gas at channel 8

in three steps
S1 precalculation 0% to 50%
GV1 from S1
Mixer with Expo from GV1
Helle

[jimbo385]

Hi Hele,

Thanks for the example. I think that it was difficult to understand because of the language!

I'll have a look in companion.

Cheers