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Fix the traction control...
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(32 posts, started )
Fix the traction control...
I spotted an error with the way the traction control in LFS works. Currently, you set a 'minimum speed' for the traction control to turn on. Unfortunatly, this does you no good when trying to get out of a gravel trap. The traction control minimum speed reads the speed relative to the track. The traction control should be reading the wheel speed instead. How else would TC work in real life? That is how my dads FWD Saturn SL2 works. This should be easy to fix in the next test patch. Except, the traction control on the BMW Sauber might be different IRL, and actually read the relative speed. Anyway, I hope I have provided a improvement suggestion that is an actual improvement. Comments please! I don't think the devs even read this forum section though.
Reading the wheel speed would seem to make sense, if indeed the TC doesn't do that already (I wouldn't have a clue as I haven't raced any LFS TC-equipped cars for a while).

OT: TC in a FWD Saturn? Seems a bit like overkill to me. But then, TC in a RWD 3.8L V6 Holden Calais seems OTT to me

P.S. If the devs don't read this section very much I don't blame them tbh - general comment btw, nothing to do with you hummer
Quote from Hankstar :OT: TC in a FWD Saturn?

It was useful today when me and my dad had to drive through 3in of sleet, snow and ice. We barely made it. My sister has a saturn with 20HP less, and no TC. She couldn't make it out of our driveway. And even in the one with TC, we still had to use a decent amount of gas, and then slide over the big pile of snow from the snow plows. Go too fast, and you end up ass in a ditch. Don't go fast enough, and you get stuck in the snow!
Quote from wheel4hummer :It was useful today when me and my dad had to drive through 3in of sleet, snow and ice. We barely made it. My sister has a saturn with 20HP less, and no TC. She couldn't make it out of our driveway. And even in the one with TC, we still had to use a decent amount of gas, and then slide over the big pile of snow from the snow plows. Go too fast, and you end up ass in a ditch. Don't go fast enough, and you get stuck in the snow!

You must live somewhere that doesn't get much snow? I currently have at least 24 inches of snow in my driveway (half from the wind) and I could almost get my FWD Altima out of it . You don't need traction control, you need more snow in your area so you know what it's like, hehehe. 3 inches and I wouldn't even bother locking the hubs on the truck.
I guess it'd be useful in snow - looks like it's been snowing like a mofo in the US right now too! Doesn't snow here in Melbourne, but we're only a few hours from the ski slopes. Got a 4WD for that :up:

Locking hubs mrodgers? Dude, ol' skool I remember always being hub-monkey when dad got his 1983 Nissan Patrol
Quote from Hankstar :Locking hubs mrodgers? Dude, ol' skool I remember always being hub-monkey when dad got his 1983 Nissan Patrol

Darn right bud! A true 4x4 enthusiast doesn't go for that "auto locking" weak crap!

Actually, I traded the truck in for something for the wife. Not only does it not have manual hubs, but the 4WD is completely automatic. It switches between FWD and 4WD at any sense of slippage. I hate it . Give me a hub to turn, a lever to yank, and a stick to put it in gear!!!
Dang! I can relate. We only have one car right now, an '04 Subi Forester. Bloody good car I must say - no mere station wagon should handle like it does - but Mrs H can't drive a manual. I'm stuck with a slush-box until I get my Mini sorted
I miss dad's Patrol come to think of it (he retired and got an auto Pathfinder). Anything with TWO gear levers is a big bunch of manly toughness

OK, probly enough OT action! ^_^
Quote from wheel4hummer :It was useful today when me and my dad had to drive through 3in of sleet, snow and ice. We barely made it. My sister has a saturn with 20HP less, and no TC. She couldn't make it out of our driveway. And even in the one with TC, we still had to use a decent amount of gas, and then slide over the big pile of snow from the snow plows. Go too fast, and you end up ass in a ditch. Don't go fast enough, and you get stuck in the snow!

Well the problem here is that your sister is driving a saturn. Very poor car in the snow.

The forester in the snow on the other hand
Bleh, one can drive almost anything on the snow if you know how, although ice is more fun.

Give me a piece of crap explorer, a honda, or whatever, I'll make it go if need be. I'd rather stay home and play LFS, though!
how would traction control work if it judged it on wheel speed? There would be no comparison element - think of it as comparing driven and non driven wheel speed in this case.
#11 - Woz
For BMW road cars the TC uses the ABS sensors to determine what state the car is in. It measures the rotation speed of each wheel and makes assumptions from that data. I think the higher spec system has a gyro as well for rotation of the car but dont quote me on that one.

The puncture indicator works off the same sensors as well. I had a BM Mini Coop with run flats and so didnt notice when I got a puncture but the sensors picked up the change in wheel rotations.
Quote from Blowtus :how would traction control work if it judged it on wheel speed? There would be no comparison element - think of it as comparing driven and non driven wheel speed in this case.

In F1 traction control systems are banned at low speeds (bellow 40mph) to prevent launch control.
In this topic was discussion about TC, and you have answer at the end wheel4hummer.
Quote from ajp71 :In F1 traction control systems are banned at low speeds (bellow 40mph) to prevent launch control.

It's banned under 100kph but only off the starting grid.

The FIA look at the telementary data to see if anything is fishy.
It's banned while the pit limiter is on as well, which is why they all wheel spin away from pit box
Quote from mrodgers :You must live somewhere that doesn't get much snow? I currently have at least 24 inches of snow in my driveway (half from the wind) and I could almost get my FWD Altima out of it .

It isnt just 3'' of powder. It was 3'' of sleet and ice now, anyone who hasn't cleared their driveway, has one solid 3'' sheet of ice.
TC is rubbish on snow and ice. My brothers AMG Merc is useless with it on (and even if semi-off). But take the fuse out (so it's 100% off) and the huge tyres find enough grip evenutally.
Depends on the implementation surely? TC systems vary lots I would imagine, some are developed for use on snow and ice. I doubt those system would be much use around a racetrack. Although in theory the mechanical parts would be the same, it's just the software, so it mode could be selectable via the dash if they so wanted.
Quote from wheel4hummer :The traction control minimum speed reads the speed relative to the track. The traction control should be reading the wheel speed instead.

We should make it a bit more clear. Which wheels are you talking about? I would say, any basic TC systems works as an comparison between wheel speed of the unpowered wheels and the powered wheels. So, for the sauber and the fz5, the front wheels are the benchmark. This should be (in most situations) proportional to the speed relative to the track.

We could try to give 100% brake on the frontwheels to get them blocked - so their speed should be 0. The TC should then think that the speed of the car relative to the track is also 0 - and if your minimum TC speed is 0, it should take you alle your power I hope you did understand me...

How else should it work, if not based on front wheel speed? Another possibility would be an wheelspeed acceleration based limiter, but that wouldn't be a simple TC as used in LFS. You would have to get a complete acceleration/gear/speed characteristic map to implement something like that. Then you could compare wheelspeed of the powered wheels in t=0 width wheelspeed in t=1... and judge about to much slip or not on that...

Greets warper

Edit: Btw, until now i thought that the minspeed for TC was only implemented for getting better out of the dirt - because the TC would cut you all of your power. You need much more slip to get some power on the track while beeing on something like sand or gravel...
traction control on FZ sux, so fix it
#21 - Woz
Quote from Warper :How else should it work, if not based on front wheel speed?

As I said earlier, it works out difference in rotation speed between all 4 wheels. It does not favour driven or non-driven for this checking because ALL it is interested in is loss of grip in ANY of the wheels. TC helps with under and overtseer along with general car stability.

Given the rotation speeds of the wheels it is able to calculate which wheels have lost grip and which might loose grib so it can take action. Most TC tries to bring the car back to stability using a combination of application of brakes to individual wheels coupled with override of the driver throttle and sometimes brake input.
I think TC would read the acceleration, not the speed. If the acceleration is greater than expected, the impulse supplied is limited to compensate, through throttle cut(LFS, saturn mentioned in first post), brakes (gm cars like grand-ams for example), or by altering the differentials electronically (F1, WRC, ..).

TC is pretty crap in the snow, I haven't found a use for it
#23 - Tege
Because on snow/ice (British snow and ice, where we get slushy mess, not the nice grippy snow you get ) the TC tries to stop wheelspin by cutting power or applying the brakes, but you actually want a little bit of wheelspin sometimes, and you definately don't want braked wheels 99% of the time.

Maybe in Finland the conditions make TC appropriate, but speaking from my own experiences here TC makes things way more difficult.
Quote from Warper :We could try to give 100% brake on the frontwheels to get them blocked - so their speed should be 0. The TC should then think that the speed of the car relative to the track is also 0 - and if your minimum TC speed is 0, it should take you alle your power I hope you did understand me...

this is indeed what happens ... well not quite because you cant set those values but if you lock the front wheels the tc will never cut in

Quote from tristancliffe :Maybe in Finland the conditions make TC appropriate, but speaking from my own experiences here TC makes things way more difficult.

there are a few rare occasions where tc has its merrits ... like stading on a slope with solid ice underneath while youre late already in a car with an unfamiliar clutch
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Fix the traction control...
(32 posts, started )
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