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Calculated Brake Pressure
Posted: Sat Jun 17, 2017 12:23 am
by boggie1688
Hi Everyone,
Is it possible to create a calculated brake channel based on negative g acceleration in the forward direction?
I'm open to doing this post run via excel. Or alternatively via a calculated math channel in LUA.
I'm clueless as how I might correlate negative G to brake pressure.
Has anyone tried this?
Posted: Sat Jun 17, 2017 1:28 pm
by Mustangkev
Here is a way that it has been done.
http://www.jameshakewill.com/brake-trace.pdf
I wrote a script that included it which is in the second post here:
viewtopic.php?t=5227
Posted: Sun Jun 18, 2017 1:18 am
by boggie1688
Thank you!!!
Posted: Wed Jun 21, 2017 3:13 am
by boggie1688
I found some time tonight to integrate your brakeg script. I ran into two issues; see bold. The first was the missing parentheses. Easy enough. The second was that brakeG was displaying acceleration Gs. I removed the sign switch and that fixed the issue.
Code: Select all
brakegId=addChannel("BrakeG",10,2,0,1.5,"G")
totalgId=addChannel("TotalG",10,2,0,1.5,"G")
local g1=getImu(0)
local u3=getGpsSpeed()
local b2=([b]-1*[/b]g1)-((u3^2/10000)[b])[/b]
if b2>0 then
setChannel(brakegId,b2)
end
local g2=getImu(1)
local g3=((g1^2)+(g2^2))^(0.5)
setChannel(totalgId,g3)
Now that I have brakeG I assume I point RaceRender at this channel as my brake input. How did you scale it from 0 to 100 for brake input? Can you set 0 Gs = 0 and my highest brake G as 100? This doesn't necessarily represent the brake pedal input. Am I missing something or is this as good as it gets without a brake pressure sender?
Posted: Tue Jul 04, 2017 2:14 am
by Mustangkev
Yes, I did miss a parenthesis.
I haven't really played with this too much but your suggestion of scaling the result from 1-100 seems reasonable.
Posted: Fri Jul 14, 2017 1:44 am
by MrBlahh
boggie what did you decide to do about scaling the data?
Posted: Tue Oct 03, 2017 3:23 pm
by wizrd54
This worked great. Really good document to explain everything as well. Thank you.
I scaled it 0-100 and ended up needing to use 200000 instead of the 50000 called out in the PDF. Our 318ti chump car is a bit less aerodynamic than a Formula Ford used in the documentation haha.