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PostPosted: Sun Aug 21, 2011 2:49 am
by Haruna
This is a short guide on how to setup a USR AI driver's setup parameters, as well on how to set up his or her car.

We will go over the private section first because this tweaks the basic way the driver drives his or her car. Unlike SIMPLIX which only has around 15 parameters, USR has nearly double that amount and none of this is documented :!: , therefore this guide is here to document all the parameters.

List of Parameters you can Modify
"min corner inverse", "increase corner inverse"
- Both parameters increase USR's turning circle, when the values are increased. Advise is to set these two values to zero, or a very very low decimal. Lower values result in smoother steering inputs.

"avoid speed factor", "avoid brake factor"
- Avoid Speed Factor controls how quickly USR will try to go through corners when other cars are nearby. Higher values will mean that USR will try to take corners faster, lower values slow it down.
- Avoid Brake Factor controls how short USR's braking distance will be - higher values will mean USR will brake later and more, shortening the braking distance. Be warned - if you have the brake bias set very loose or very tight, you'll either spin or slide off the track!
- Set both of these parameters lower than their base factors, because this will be how hard they'll push when trying to avoid other cars, and thus, be off their ideal line.

"base speed factor", "base brake factor"
- Like Avoid Speed Factor, Base Speed Factor will control how fast USR goes through corners - however, this is when USR is by itself rather than in a pack. Higher values will mean that USR will try to take corners faster, lower values slow it down.
- Base Brake Factor is the same as Avoid Brake Factor, except when USR is on it's own.
- Leave both of these parameters at 1 - these are multipliers for "base speed" and "base brake" respectively.

"base speed", "base brake"
- Base Speed is how fast USR will go through corners. Higher values mean USR will try to corner faster. Higher values are not necessarily better. Start at 14 and raise by 1 if you feel USR is too slow.
- Base Brake is how hard and short USR will brake before and during cornering. Higher values mean USR will stop later and also use more brake power. High values (30+) will make USR abuse trail braking a lot. Start at 20 and raise by 2 if you feel USR doesn't use enough brakes.

"turn decel"
- Put it at 0.5 and forget it.

"revs change up"
- Choose at what % of the powerband should USR shift up a gear. Higher values will mean USR shifts later or at redline; lower values mean USR will short shift (shift up a few hundred RPMs early).

"revs change down max", "revs change down"
- Choose at what % of the powerband USR should shift down, at most. Higher values mean more engine braking, lower values mean less.
- Revs Change Down is the same but it's the minimum RPM USR should be at to shift down.

"steer skid"
- How much USR will try to make the tires skid. Usually not needed, but cars which have a tendency to oversteer on corner entry (for instance, rear-heavy cars) should have it set to a very low decimal (not more than 0.5 for most cars).

"steer gain"
- How much USR will "cut" the apex of corners. Higher values mean more cutting. A setting of 1.5~2.5ish will make USR drop two wheels into the inside grass or dirt on very tight corners, so be careful.

"max steer time"
- How much time before USR reaches the maximum steering angle if on the racing line. Lower values make USR go to maximum lock faster, higher values make USR smoother in long turns. A value of 4~6.0 is fine.

"int margin"
- Again, how much USR will cut the apexes of corners. Higher values mean LESS cutting. Range of 1.2~1.5 should be okay.

"ext margin"
- Same as Internal Margin, but now for the outside of the track. Lower values mean USR will try to run corners wide more. Range of 1.0~1.3 should be okay.

"no team waiting"
- Choose whether or not drivers using this setup will wait for their teammates.

"overtake caution"
- How often USR will try to overtake.

"abs slip", "tcl slip", "skid correction"
- ABS Slip controls how precise USR's braking capability is. Lower values will make USR very sensitive to changes in balance under braking.
- TCL Slip controls how precise USR's throttle use is. Lower values make USR very sensitive to changes in balance under ACCELERATION.
- Skid Correction controls how precise USR's counter steering instinct is. Higher values make USR try to counter-steer more. More isn't always good.

"bump caution"
- How sensitive USR is to height changes, banking, bumps of the track, etc. Higher values will make USR try to slow down on steep inclines, especially uphill ones; lower values will make USR interpret the track more as if it were flat.

"x bgn", "x end"
- x being a number, this is usually 0 since USR usually only has one trouble section to deal with on a track. As the names imply, these mark out specific distances of track. When USR is in between these distances, it will change driving parameters.
- To use these two parameters, you can add any of the above parameters, but with "x" before it. For example: "0 base speed" means the "base speed" when in "0".
- You only see these parameters in track-specific setup files.
NOTE: The "bgn" and "end" distances are about half of the "DfS" (Distance from Start) number, displayed by one of the F5 modes. Thanks Simon.

Correcting Driving Errors
USR spins at the entry of turns
- Increase brake bias ("front-rear brake repartition")
- Decrease base brake
- Increase rear wing angle

USR slides off the track at corner entry even though he is using full steering angle
- Decrease brake bias
- Decrease base brake
- Soften suspension springs
- Decrease rear wing angle

USR spins on corner exit
- Decrease base speed
- Increase rear differential's "max slip bias"
- Soften rear suspension springs and/or rear anti-roll bar
- If hitting bumps, try softening suspension or increasing fast bump
- If at speeds above 80 km/h, try increasing rear wing (very effective on TRB1s and LS-GT1s)

USR bumps into everyone
- Decrease avoid speed and avoid brake factors.
- Decrease overtaking caution.
- Do the above plus decrease base brake.

USR goes flying off hilly sections when it shouldn't
- Increase bump caution.
- Increase wing angles, both front and rear.

Hope it helps.


PostPosted: Thu Oct 20, 2011 5:09 pm
by mungewell
I just started my adventures with making a profile for USR robot. Having got a driver/car defined I can change the parameters and 'he' drives reasonably, but I am seeing the robot crashing out at a particular corner (Brands Hatch - Sheene Curve).

I know I can change the parameters on a track by track basis, but can I make the robot spacually aware? ie. know that 'he' should slow in a particular area of a particular track, without slowing him down for the whole track?


PostPosted: Thu Oct 20, 2011 8:36 pm
by Haruna

I've updated the guide to answer your question.

You could check out the brondehach setups for the SC or 36GP cars - they have code specifically for dealing with a trouble section.



PostPosted: Fri Oct 21, 2011 5:06 am
by mungewell
Thanks for the tips, 'Crazy Eddie' can now constantly hit 1:32.8 around Brondlehach in his Kenji - faster than me!!!

One comment though, the value for the distance appears to be 1/2 the debug's 'Distant from Start'. I found it easiest to set a very low speed value for each section so I could be sure I was adjusting in the right place. I then change this to the appropriate parameter/value.



PostPosted: Thu Oct 27, 2011 8:25 pm
by mungewell
So I have another question.... How can I make 'Crazy Eddie' a little less crazy in the rain? Are there any methods of adapting driving behaviour with changing conditions?



PostPosted: Thu Oct 27, 2011 9:00 pm
by Haruna
USR was not designed for rain, so I can't say much on how to adapt the setup to a wet one.


PostPosted: Wed Apr 25, 2012 11:11 am
by Corvettegtp83
Where are the settings held for the robot ie which directory in linux. tried looking found once but cannot find again. also only have a couple of robots working not sure whether this is from installing from ppa source


PostPosted: Wed Apr 25, 2012 1:39 pm
by mungewell
Each robot has a directory, ie:

The 'simplix_sc.xml' lists the drivers and the '0..X' directory contains driver specific settings. The '<car>'/default.xml' contains tuning of the cars and the 'tracks/<trackname>.xml' fine tune behaviour on a specific track.


PostPosted: Mon Sep 17, 2012 9:41 am
by rajonmestra
Well, i have seen different setting on the video shared to me by my buddy and i guess it will depend on how you have that set up.There are those mods did in some AI car such of SC or 36GP cars like being a huge factor in the USR games. On the same way, i have seen some bugs triggered on other programs still even following similar settings.


PostPosted: Tue Sep 18, 2012 3:11 pm
by mightymariner
Every time I try to make my own setup of this, the car never changes past 2nd gear. It starts, shifts up, then does the rest of the lap at a near constant speed. Can anyone help me with this?