Basic ETB Traction Control with Lua

[NormanAlphaspeed]

Hi

I made a type of traction control using LUA for ETB-equipped vehicles. It is quite basic, works well in my book, but it could use a phase-in/out timer to smooth transitions into/out of traction control events.

current code is

Code: Select all

	-- traction control
	local slipRatio = rvss / fvss
	if slipRatio > 1.1 and tcState == 0 then
		setEtbAdd(slipRatio * - 40)
	else
		setEtbAdd(0)
	end

Where
slipRatio = a simple division of driving/driven wheel speeds (in this car, car is RWD, so rvss = rear vss). If one of the rear wheels is going faster than one of the front ones, we are probably slipping
tcState = a traction control on/off button

I noticed in my case that noticeable slip happens after a ratio of about 10% deviation (which is what the 1.1 represents). I multiply this by a constant -40 so if we have minimal slip, we reduce TPS by 40%, and gets multiplied by the amount of slip to compensate for more slippery situations.

image.png

The arrow indicates where slip was detected, and ETB target changes from 100% to ~50%

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At the top of second gear we are starting to actually have grip, and once we shift into 3rd, we can see that slip% is small enough to where we can target 100% TPS

[AndreyB]

My Nissan SUV has four wheel sensors look how left and right wheel speeds are 20% off during intense acceleration. Per-axis average difference is below that.

image.png

[NormanAlphaspeed]

My Nissan SUV has four wheel sensors look how left and right wheel speeds are 20% off during intense acceleration. Per-axis average difference is below that.

image.png

That's because open diff. In this case it would be very benificial to do front vss average / rear vss average

[AndreyB]

I've implemented something similar under https://github.com/rusefi/rusefi/issues/5843 someone would have to give it a try

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