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Traction and launch control

PostPosted: Mon Sep 01, 2008 7:16 pm
by TimoK
Hello,

Since I'm new to the Motec and haven't been tuning this kind of traction control before (PID control) I'd like some basic tips and procedures how to start. Before the Motec I've been running a system that only cuts out fuel and is tuned only with few different parameters so the Motec is quite a bit more complex and therefore hopefully much better. The car is a Formula FSAE racing car with Yamaha R6 engine. I've read the help files and manuals but couldn't find enough information about the tuning.

-Timo

Re: Traction and launch control

PostPosted: Wed Sep 10, 2008 10:47 am
by MarkMc
Hi Timo,
The first thing you need to establish is how much slip you need for maximum acceleration and the easiest way to do this is with a longitudinal G sensor. In I2 you can set up a X-Y graph of slip vs acceleration. You will then have your slip table for acceleration in a straight line.

Next I suggest starting with a P setting of 1and I and D to 0 and the power reduction table can start at 100 and just one value rather than a table. This will at least give you a starting point for getting the traction control to do something. You can forget about the Gain Comp and Slip Comp tables for now.

Cut is the most instantaneous Control Method as it is quite simply the cylinder is not fired. %0% cut means that over 1 second, say, half of the firing events are canceled giving roughly a 50% cut in power. Ignition retard is reducing the ignition advance, the cylinder still fires but the torque produced is less. Using any retard you will need to test on the dyno what retard gives what power/torque reduction.

TC needs a LOT of testing to get right as it can be highly driver dependant and a motor sport system is not designed to just allow the driver to hold 100% throttle everywhere and let the ECU work it out.

Start with some basic logging first and the settings I have suggested. You are more than welcome to send me your logging for advice. Make sure you log the Slip, Wheel Speeds, G Froce and Cut at a high rate like 50Hz and also include things like Aim Slip, TPS, RPM, etc.