rec.autos.simulators

What started as a short experiment finally ended in frustration many hours
later in the wee hours this morning. I'm no closer to understanding the
settings in core.ini, and now don't recall what I had them set to. What do
you use for your MSFF?

Michael.

Slot

This is normal.  When I first started racing karts, my lower arms would
absolutely kill after just 15 mins of racing.  Just imagine hauling around
an F1 car with 1 turn lock to lock and no power steering.

I still use the original ff settings because I don't really understand what
affects changing those numbers will have, and I don't have the time to try
all the different combos.  If anyone could suggest a 'realistic' set of
numbers to use, that would be great.

I'm using a latency of 0.010, and a damping force of 35.0. Max torque is
commented out. I'm looking for best feel for road conditions, without
inviting repetitive stress injury.

Before, the forces were high enough that my hands and wrist were still sore
the next morning. Two weekends ago, I ran a full GP at Spa plus the second 2
hr practice before that, about 3 hours of actual track time in one sitting.
(I finished 5th, and was pleasantly pleased, if tired and drained. I had
only recently made some strong breakthroughs in lap times.) I think damping
force was 85, and possibly the initial default 0.035 latency; max torque was
still commented out at the time, I believe. Part of the problem is I didn't
make note of how it was set before I started making changes (who would think
you would so easily forget 3 little numbers?). The wheel was heavy, and
kicked strongly from time to time; road feel was very good, and the shaker
let me know when I was running right out to the pavement edge.

Anyway, I've since tried changing the FF numbers to see if I could get a
lighter feel without losing too much feedback. I never did find a good value
to use for max torque. It would either shimmy strongly, or was too light to
be of much use. By shimmy, I mean the wheel would slap back and forth if I
let go, even at slow speed. At one point, I could distinctly smell the ozone
of an overstressed electric motor. I realize that the shimmy is an artifact;
not finding resistance, the aligning forces would quickly turn the wheel
until it reversed, and then it would feedback the other way. However, I
never did find a balance that I liked.

So, that's why I'm asking. Last weekend, I thought I would amuse myself by
taking a break from struggling around Rouen, and take a few turns around Spa
while loaded up on a half bottle of Merlot (Lynfred Winery 1999 Private
Reserve; absolute nectar if you like this kind of thing!). My second lap
out, I turned a PB of 3:21, 0.8 seconds faster than ever before. It was at
this point that I started to monkey with the FF numbers, and things haven't
been right since. Even if I can't improve on it, I'd like to at least get
things back to where they were. Hence my appeal for your help. My lap times,
at both Rouen and Spa, are now almost 2 full seconds slower than at that
peak of ***ic bliss. The only changes were to the FF settings.

Michael.

: Anyway, I've since tried changing the FF numbers to see if I could get a
: lighter feel without losing too much feedback. I never did find a good value
: to use for max torque. It would either shimmy strongly, or was too light to
: be of much use. By shimmy, I mean the wheel would slap back and forth if I
: let go, even at slow speed. At one point, I could distinctly smell the ozone
: of an overstressed electric motor. I realize that the shimmy is an artifact;
: not finding resistance, the aligning forces would quickly turn the wheel
: until it reversed, and then it would feedback the other way. However, I
: never did find a balance that I liked.

  As I understand it, the "shimmy" you describe is a result of having
the latency set too low.  As I understand latency it is a measure
of "how far ahead you want to predict the wheel setting" - you can't
get the "force" to the wheel instantly, there is a certain delay.
Therefore, GPL predicts what the force WILL be in a certain amount of
time and sends that to the wheel in the hope it will get there.

  A lot of GPLers simply assume "low latency is good" (right) and
therefore set the latency as low as possible (wrong).  

  As I understand it, if you set the latency too low, once the force
gets to the wheels, it "lags" what the wheels are actually doing.
Imagine you are travelling down the straight, your wheel is slightly to
the right - there should be a restoring force to move your wheel to the
centre.  Therefore, GPL sends a "move wheel left a bit" message to your
wheel.  However, if the latency is set too low in GPL then by the time
the message gets to your wheel and moves it left your on-screen wheel is
straight.... as I understand it, this rocking from side to side is a
problem of low latency setting up a non-linear dynamic system (to borrow
a phrase from my work).  Try popping the latency up a bit higher and see
if it helps.

  Richard.

  Disclaimer: other people on this group probably understand the FF
settings much better than me and might find flaws in my reasoning.

--
Richard G. Clegg       Only the mind is waving
    Networks and Non-Linear Dynamics Group
      Dept. of Mathematics, Uni. of York
    www:  http://manor.york.ac.uk/top.html

--
Olav K. Malmin
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Try these settings, what have you got to lose?
Damping=4000
Steering_torque=1800
Change the torque to 2000 and then 1500 and try those as well. Let me know
how it works on your wheel.

Slot

Michael.

I'm not sure that I agree. While I still don't understand how the numbers
change what, setting a much higher damping value cured this. Looking at the
effect, I would guess that this value is properly named: under-damped
systems oscillate; higher damping fixed the problem. I agree with you about
latency, though, since my reaction to any delay is probably typical of
everyone else. :-) It seems just as driveable at 0.01 as 0.05. I haven't
tried values outside that range.

Michael.

What settings for MSFF do you use in control panel?

[ Joy ]
allow_force_feedback = 1                        ; Use FF if device has
it
force_feedback_damping = 25.000000              ; force feedback
damping coefficient (org)
force_feedback_latency = 0.085000               ; force feedback
latency (secs) org Sierra
max_steering_torque = 225.000000                ; steering torque in
N*in giving max device force

Never played around much with them though. A bit more damping, a bit
more torque, but didn't really test much.

Ruud van Gaal
MarketGraph / MachTech: http://www.marketgraph.nl
Art: http://www.marketgraph.nl/gallery

Slot