I have tested a lot in first person and continually observe that when the bike is at very low lean angles under acceleration lateral oscillations set in. Increasing the lean slightly, raising the bike to vertical will cause them to cease.
Very noticeable of very long curves where you have to hold slight lean angles but you can also sense it on the rumble every time the bike passes through the low lean angle to a higher angle.
Not sure if its related but there does seem an issue with calculating the rear suspension mechanical damping;
setting 'RearLatDamping' to a lowish value (2 or 3) gives rise to huge non resolving oscillations even with the bike just rolling slowly in a straight line with no power.
setting it 20 seems to give a reasonable damping and a much reduced tendency for oscillations to build at low lean angles, going to 30 (over the top - i know) the bike explodes on the grid as soon as you leave the garage and 'core.exe'.
The 'FrontLatDamping' seems OK and you can set a low value with no problems
i've experienced this as well - possibly why i spend much more time on the Varese than the Mura....
I spent the evening tuning the Yohji V1 config and its improved the situation greatly - its a fun ride now especially in 1P, much less prone to the shakes. You do need to try a few setups with the Yohji model as the garage settings are more effective for each different track but give it a go - not many bikes to try with B7 anyway
What do you call "lateral oscillations" exactly ?
Because RearLatDamping does not relate to the rear suspension, it's the chassis/swingarm flexibility model damping.
I know - which is why it seems so strange. The lateral oscillations can start at a very small lean angle and just keep building. You can take the same turn, different line with silly throttle settings and it will be OK though if you are carrying more lean.
Try setting RearLatDamping to 2 or 3 if you want a laugh - barely moving and the bike shakes itself to bits and does not decay - does not seem possible
It is very possible: if one changes (significantly) the bikes structural parameters, the virtual rider may no longer grant stability.
I dunno what causes it but I can concur it is very annoying. Lots of people online talking about it. I think we all wait for B8 with fingers crossed.
Quote from: HornetMaX on November 29, 2015, 07:16:42 PM
It is very possible: if one changes (significantly) the bikes structural parameters, the virtual rider may no longer grant stability.
Very evident on the stock bike since b7 and its horrible - it is what set me on my current quest :)
Try the first straight on spa after eau rouge with stock 990. Riding the long gentle curve in the track, tiny constant lean leads to big vibes. :(
and exiting onto the last long back straight bit near what looks like a lake - same problem
It just feels like a bug somewhere in the system.
Bit like the.. exit the pit garage, turn left into pit lane, Wobble wobble wobble.. Straighten up away you go.. Thing.
Almost like the virtual rider is confused.. Steer, no.. counter steer. Steer, counter steer.
At very low speed the bike seems to lean instead of just turning. Could it be related somehow??
At very low speed the bike dynamics are very different and it is very likely that the virtual rider is not doing the right thing.
I don't think it's a big problem as it is unrelated to the issues we experience at higher speed.
It could probably be solved at the price of some additional complexity in the virtual rider (like a dedicated low-speed controller plus some smart-ass way to switch between the low-speed and high-speed controller).
I have not read everything, but you refer to it? Just happened in the Monza Race tonight...
https://www.youtube.com/v/3J9N0am_dY8
Quote from: HornetMaX on November 30, 2015, 07:43:42 AM
At very low speed the bike dynamics are very different and it is very likely that the virtual rider is not doing the right thing.
I don't think it's a big problem as it is unrelated to the issues we experience at higher speed.
It could probably be solved at the price of some additional complexity in the virtual rider (like a dedicated low-speed controller plus some smart-ass way to switch between the low-speed and high-speed controller).
I think something might have been tried already, been playing with the config and increasing kdamping1 hugely improves low speed virtual rider control but also seems to confuse him (overreacts) at speed and under braking (which is odd). spg0 effects low speed sensitivity, more negative = more sensitivity, spg1 effects high speed sensitivity the same way. I have jiggled it so its reasonably balanced but its not 'right' under braking as the rider seems to be the input to the oscillation. Still trying to figure sig0 and sig1.
@ Blackheart - the shakes look familiar ;)
Quote from: h106frp on December 01, 2015, 12:49:11 AM
Quote from: HornetMaX on November 30, 2015, 07:43:42 AM
At very low speed the bike dynamics are very different and it is very likely that the virtual rider is not doing the right thing.
I don't think it's a big problem as it is unrelated to the issues we experience at higher speed.
It could probably be solved at the price of some additional complexity in the virtual rider (like a dedicated low-speed controller plus some smart-ass way to switch between the low-speed and high-speed controller).
I think something might have been tried already
No, I don't think it has been.
Quote from: h106frp on December 01, 2015, 12:49:11 AM
been playing with the config and increasing kdamping1 hugely improves low speed virtual rider control but also seems to confuse him (overreacts) at speed and under braking (which is odd). spg0 effects low speed sensitivity, more negative = more sensitivity, spg1 effects high speed sensitivity the same way. I have jiggled it so its reasonably balanced but its not 'right' under braking as the rider seems to be the input to the oscillation. Still trying to figure sig0 and sig1.
spg0, sig0 and sdg0 are the parameters of the PID controller stabilizing the "target lean to steering" part of the bike. The "1" gains (spg1, sig1, sdg1) are the gains that adapt to speed, e.g. spg = spg0 + spg1 * speed (same for sig and sdg).
Kyaw, Kdamping0 and Kdamping1 are (probably, has we have no official confirmation) the gains of the "yaw controller", the thing that tries to have the bike "tracking correctly", i.e. keep neutral steering behavior, no oversteer, no understeer.
From what I've seen, you'd better focus on the spg, sig, sdg gains and leave Kyaw, Kdamping0 and Kdamping1 alone (even if you put them at zero, the bike is still rideable).
But knowing that is not enough if you don't know what you're actually trying to control.
Tuning this by trial and error is borderline impossible: the two controllers interact, the bike characteristics vary with the bike speed, the bike has a "non minimal phase" behavior (I won't go into details but essentially the fact that to lean left you have to initially steer right, it makes things harder), the non-minimal phase thing is there only above a certain speed (that's why at very low speeds the current virtual rider sucks). It's a complex control problem: even taking a huge simplification (linearize at different bike speeds and try to find an LPV controller that stabilizes all the resulting systems) is hard without proper tools.
I don't know how Piboso does all this, but if I had to do it first thing I'd do is to buy a Matlab license (with a few toolboxes on top).
Quote from: HornetMaX on December 01, 2015, 08:18:31 AMI don't know how Piboso does all this
Sadly, probably not as you would.
Anyway, I also think that the virtual rider is the source for most physics problems we have currently (apart from the missing swing arm pivot adjustment on the stock bikes).
Quote from: vin97 on December 01, 2015, 08:34:46 AM
Anyway, I also think that the virtual rider is the source for most physics problems we have currently (apart from the missing swing arm pivot adjustment on the stock bikes).
But keep in mind that on a real bike, the pivot adjustement is only a few mm (+/- 2-4mm), I'm not sure that would make an huge difference.
Easy to test tough: stock 990, add/subtract 4mm to the pivot min/max. Not sure if it's worth though, as we'll have beta8 someday.
Thanks for the info - I'm not trying to make a physics mod with this stuff, just playing around out of curiosity to see how it works.
The huge default value for spg1 is not good though, I am quite convinced that it causes the rider to overreact at speed, and the low value for kdamping1 causes the 'jagged' low speed steering - spg1 seems to be trying to compensate for this. With a modest increase in kdamping1 (0.5) and reducing the magnitude of spg1 (-150) you can get really nice smooth low speed handling without the erratic (jagged) steer inputs.
The steering damper (damper, damper power) is bugged and as far as i can tell does not work at all in any conventional sense (for a steering damper) that i can fathom, trying to use it too calm high speed handling is a waste of time.
It does encourage me that the virtual rider model is capable of doing what is required though, it just seems to need a bit of tuning to finish it. I think i have also come to the conclusion that the virtual rider issues make any attempts at tuning the bike physics very difficult as its difficult to separate bike physics and the virtual rider control loop.
@vin97 - totally agree about the rider - i altered the bike so that it was super stable under power and braking with really nice high speed handling, low speed handling then gets a lots of high frequency vibration, but this get magically fixed by raising the control loop gain but then the high speed handling gets a bit 'flappy' - but our bike model has not changed only the rider inputs and the bike suddenly appears to have poor high speed stability ;)
I know this is all very 'trial and error' and probably a waste of time but it has kept me amused and given me a reason to do lots of practice laps if nothing else. ;D
@MaX - starting to think that unless the 'dev diary' shows some work on virtual rider tuning B8 will not be much fun :(
I think PiBoSo is doing that at the moment (uphill/downhill fix and general lean angle change).
Combined with the improved rear suspension simulation, we might get surprised by beta8.
Quote from: h106frp on December 01, 2015, 08:53:59 AM
I know this is all very 'trial and error' and probably a waste of time but it has kept me amused and given me a reason to do lots of practice laps if nothing else. ;D
Totally agree that its fun to learn about this stuff. My only concern is that if figures and changes are made to make the bikes work, but which don't reflect real life measurements and physics, then all we are doing is creating arcade bikes. Good for interim fun of course while the man is fixing the simulation but I think it is important not to get frustrated thinking he can fix it by just doing this or that (an unrealistic change).
Having said that you may know my stance on any simulation is that it will be totally impossible to reflect real life physics, so some compromise can (and must) be made.
Don't get me wrong, fiddling with this stuff is good fun and interesting to learn about I just worry that people start to think "well we can fix it so why can't PiB" and get frustrated ::)
The problem is that all this stuff works together: the stabilizing controller, the yaw controller, the steering damper ... What one typically does when dealing with multiple control loops, is to try to separate them, i.e. having one controller acting over a frequency range that is different from the one of the other controllers. This greatly simplifies the tuning.
If you want to dig into all this stuff, I'd suggest to start removing the steering damper (Damper = 0) and the yaw controller (KYaw = KDamping0 = KDamping1 = 0) and try to play with the stab controller (spg0/1, spi0/1, spd0/1) first.
The steering damper is only supposed to help in dealing with wobble (wobble, not weave). Wobble is essentially an oscillation of the front, weave is more an oscillation of the rear (you can have a look here (http://www.dinamoto.it/dinamoto/8_on-line_papers/wobble-weave/wobble-weave_eng.html)). Also, the stab controller should not interfere with the steering damper: I'm not sure that's the case today, as the stab controller seems to have no explicit rolloff (it doesn't cut its action at high frequencies).
The yaw controller is a bit of a mystery to me. I'd need to play with it more, but it seems to me it mainly help exiting a turn on the throttle (it avoids lowsiding when accelerating and/or picking the bike up).
Quote from: HornetMaX on December 01, 2015, 08:48:10 AM
Quote from: vin97 on December 01, 2015, 08:34:46 AM
Anyway, I also think that the virtual rider is the source for most physics problems we have currently (apart from the missing swing arm pivot adjustment on the stock bikes).
But keep in mind that on a real bike, the pivot adjustement is only a few mm (+/- 2-4mm), I'm not sure that would make an huge difference.
Easy to test tough: stock 990, add/subtract 4mm to the pivot min/max. Not sure if it's worth though, as we'll have beta8 someday.
lol yeah seen a pivot kit from yoshimura $266 for 2mm adjustment lol!!
@Nick, one conclusion i have arrived at is we cannot fix it by tinkering, its down to PB. We can only throw values at the control loops but we cannot control the way they interact and this seems to be the problem area :(
@Max, sort of where i had got to, steering damper off, yaw off. I will have a go with kdamping off, it will be interesting how this impacts the stab controller as its seems at the moment to be the only way to get the rider to work on low speed turns.
@Bob Maybe it just means the pivot position is way out on the stock bike, revised location in B8 and we may only need a few mm :)
Well whatever the reasons its still nice to have a play around and see what's what.. If anything it shows piboso is not far away really!
Obviously real bikes are ''complete'' lol
So yeah when everything else is done, moving the pivot 2mm should have the right effects.
It really is amazing the level of detail going into every aspect of these virtual bikes!
Puts things into perspective... Lets be honest it would be alot easier to make a bike in a game/sim ''feel'' realistic.. But to simulate everything is like piecing together a never ending jigsaw.
Im looking forward to beta8.. Especially the improved front end on banked turns.
From my amateur dabblings i have pretty much decided the bike physics are handled quite well if the model is good.
The real failing is the rider, he currently struggles to discern between low speed steering, high speed turning and just steadying and guiding the bike (this is definitely missing - the VR seems to address all bike attitude changes caused by whatever reason with a steer solution however inappropriate i.e. I am making no controller steer input but the VR gives it a huge steer input and i would rather he just steadied the bar torque) when braking or accelerating hard.
You seem to be able to choose one area of riding that you can get really nice and the other areas suffer often in quite erratic ways.
this lateral 'oscillation' as i like to call it, i found to be very apparent in the (brand?)new MotoGP Yammie M1, for example - most significantly at low lean angles at relatively low speeds.
almost as if something in the physics is constantly causing a tank slapper effect at these points... come to think of it, maybe it's not as bad in b7, but b6 felt as if it was obsessed with doing tank-slappers constantly, as well.... :P
QuoteThe yaw controller is a bit of a mystery to me. I'd need to play with it more, but it seems to me it mainly help exiting a turn on the throttle (it avoids lowsiding when accelerating and/or picking the bike up).
Indeed it is.
After testing a bit i agree that it does what you described.
I could not see another effect but changing value from 0-10 makes a stabilizing effect on the turn exit at throttle.
Testing on the Monza 2nd chicane. (yaw conroller=0, steering damper =0)
Set to 0 leads to a strange (better say an expected) behavoir on turn exit. The front shakes on a very high frequency from left to right (no youtube account...otherwise i would upload the video). It was not controllable hitting the rear brake.
Set to 10 decreased the shaking left to right on the turn exit but it´s still visible and leads to crash.
Normal value is 20-25 ?!
I agree on h106frp that the VR is a problem.
Better to say the interaction of the VR and the bike.
You can mess up real good bike physics with the behavior of the VR.
Quote from: CapeDoctor on December 02, 2015, 08:24:52 AM
this lateral 'oscillation' as i like to call it, i found to be very apparent in the (brand?)new MotoGP Yammie M1, for example - most significantly at low lean angles at relatively low speeds.
Yep... the aprilia too! maybe all?
really bad at monza on the fast sections too where you have slight lean angle.. on the straights and at full lean angle its fine! ???
BOBR6, yes, the Aprilia too - seems they all share a common physics atm.... :P
and yes, it seems more to happen on straight sections - done a few laps at Mugello, and it doesn't seem to happen (much) on the inclines.
(http://www.lequipement.fr/produit/vie-de-la-redac/divers/photos-redac_2013-09-28-motogp-video-angle-maxi-001__800.jpg)
Quote from: CapeDoctor on December 02, 2015, 08:24:52 AM
this lateral 'oscillation' as i like to call it, i found to be very apparent in the (brand?)new MotoGP Yammie M1, for example - most significantly at low lean angles at relatively low speeds.
almost as if something in the physics is constantly causing a tank slapper effect at these points... come to think of it, maybe it's not as bad in b7, but b6 felt as if it was obsessed with doing tank-slappers constantly, as well.... :P
Video or it didn't happen. I need to be 100% sure if it's wobble or weave. The remedies are not the same.
Quote from: C21 on December 02, 2015, 08:26:00 AM
Testing on the Monza 2nd chicane. (yaw conroller=0, steering damper =0)
Set to 0 leads to a strange (better say an expected) behavoir on turn exit. The front shakes on a very high frequency from left to right (no youtube account...otherwise i would upload the video).
Get one, it's free :)
Or send me the replay file and I'll make and upload the video.
I'm not sure if its just a bug rather than a physics problem, if you have the rumble on at low speed you can sense the rumble triggering as you lean through a small lean and back to vertical although visually you do not see a large reaction it appears to be the the same source of the more extreme issue at speed.
Those 'random' wobbles that happen at the Monza or Magnycourse back'straight's (probably better called tank slappers) can be avoided if you are extremely (unrealistically) smooth on the steering.
The wobbles you get when accelerating out of a corner while straightening the bike up are different and unless you can keep the front wheel in the air until you are well out of the corner there is nothing you can do about it.
I have tried very gentle steering but for this it does not help, with a small lean you get a very small initial vibration that will gradually build until it throws the bike of the track, it more like the reaction you get from an underdamped control loop when the input is very small and the control loops starts to oscillate.
There are known issues with control loops; Best to solve the problem of the initial source first i.e. the vibration for no obvious reason then tune the loop
Wiki..
Applying too much impetus when the error is small and is reducing will lead to overshoot. After overshooting, if the controller were to apply a large correction in the opposite direction and repeatedly overshoot the desired position, the output would oscillate around the setpoint in either a constant, growing, or decaying sinusoid. If the amplitude of the oscillations increase with time, the system is unstable. If they decrease, the system is stable. If the oscillations remain at a constant magnitude, the system is marginally stable.
QuoteOr send me the replay file and I'll make and upload the video.
Will do it tomorrow.
Quote from: h106frp on December 02, 2015, 06:59:43 PM
I have tried very gentle steering but for this it does not help, with a small lean you get a very small initial vibration that will gradually build until it throws the bike of the track, it more like the reaction you get from an underdamped control loop when the input is very small and the control loops starts to oscillate.
I
have managed to ride the long rider hander at the beginning of Magnycours without any wobble which I thought was impossible but that was only once or twice and as I said it is unrealistic how careful you have to be.
Does not really change the situation but maybe it's important to know that it's not some more fundemental bug.
Hockenheim 97 on GPBOC 1 server really highlights the small lean/oscillation problem due to the tracks long, fast sweeping curves.
Buckaroo. :(
BUMP - this problem is still present in Beta 8 and is a game killer. :(
https://www.youtube.com/v/5aYtId8bViE
You can say that again Nick, This and Core problems are not being worked on, or at least never says about it in daily update.
DD
Watching the suspension motion, here is the problem, are moving in a completely abnormal way :o
I would suggest this could be a bike physics problem rather than core GPB physics problem? In which case it would be the bike physics author to sort it out. We all know that the bikemods are better setup physics-wise than the default bikes, right. :-X ;)
Hawk.
But as the video says it applies to all bikes including the stock ones. I just tried it on the Murasama too, to double check. If it only happened on some Mod bikes or only happened on the stock bikes then I would agree, but it affects all of them. :(
Look to 0.53 in my video with Varese, is definitely less than in the Nick clip, but is present. :P
https://www.youtube.com/v/kFuf-974ix8
Quote from: Napalm Nick on February 23, 2016, 07:33:51 PM
But as the video says it applies to all bikes including the stock ones. I just tried it on the Murasama too, to double check. If it only happened on some Mod bikes or only happened on the stock bikes then I would agree, but it affects all of them. :(
It's still present in the updated
beta 8 mod bikes too? Sorry, I haven't had chance to test any yet. :-[
Hawk.
It is and it is even worse than on the Murasama.
Even a heavy tank won't stabilize the front and avoid wobbles.
Quote from: Hawk on February 23, 2016, 07:44:38 PM
It's still present in the updated beta 8 mod bikes too? Sorry, I haven't had chance to test any yet. :-[
Hawk.
I don't know about the updated Beta 8 bikes because we don't really have any fully released ones yet , only the stock bikes and Beta 7 Mods. If it is not present on the Beta 8 bikes then that will be a small Triumph (geddit?) but only means the problem at the heart of the bike has been tuned out.
Just been taking the Varese around the A1 Ring and its a wobble fest :-X
Quote from: Napalm Nick on February 23, 2016, 08:34:54 PM
Quote from: Hawk on February 23, 2016, 07:44:38 PM
It's still present in the updated beta 8 mod bikes too? Sorry, I haven't had chance to test any yet. :-[
Hawk.
I don't know about the updated Beta 8 bikes because we don't really have any fully released ones yet , only the stock bikes and Beta 7 Mods. If it is not present on the Beta 8 bikes then that will be a small Triumph (geddit?) but only means the problem at the heart of the bike has been tuned out.
Just been taking the Varese around the A1 Ring and its a wobble fest :-X
Got it. Lol ;D
Unless it is an inherent physics issue, I'm pretty sure it can be tuned out in the bike physics files with some good testers providing feedback.
A good point for Piboso to note, and let's wait and see what the bikeMODS bring on. :)
Hawk.
;) Bring em on!
Well i do agree it is a big problem, but at A1 ring with Mura in the race, i must admit that i thinking riding style and setup could help it a lot since i didn't feel big difference from start to end. I was doing better laps average in last part of the race than in the start, so it might be helped by setup work :)
Just my opinion as a calm and smooth racer lol
Mind uploading an onboard lap with 4 liters of fuel then?
Are you using TC or AW?
I really don't think those kind of wobbles could have been completely avoided but of course it would be nice :D
Not completely avoided no, but i didn't feel any trouble going low to mid 1.27 all the race, was fastest in sector 1+2 at the end of the race and just a tad slower in 3 + 4, but mainly due to my own riding and not setup wise.
Not too good with the video uploads, haven't done any yet.
you could also just upload the GPB replay file which you find under documents\piboso\gp bikes\replays
hard to know what you are talking about without video.
well, said it wrong. of course i could have avoided them by almost never going flat out but if i wanted to get half decent acceleration on the straight, I couldn't do it.
there was no way to push the bike without losing a lot of time.
so what about traction control and anti-wheelie?
Yeah i understood what you mean, will try to make a replay for you :) otherwise take a look at last laps of the mura race from yesterday? :)
I have 0 AW and 0 TC.
I was doing pretty much low-mid 1.27 all race without problems, and i didnt feel big difference in wobble from start to finish, might be my riding, might be setup or might just be luck.
Quote from: Meyer#12 on February 23, 2016, 10:59:20 PM
Yeah i understood what you mean, will try to make a replay for you :) otherwise take a look at last laps of the mura race from yesterday? :)
Thanks!
I am afraid it will be too laggy because somebody else recorded the replay.
You don't have to record and upload a video, the rpy file should be sufficient.
Otherwise it's not possible to tell how much you had to push the bike to make it wobble.
Just take any bike and lean it at 30 degrees , the faster you go the worse it is obviously. Do the Hockenheim 79 thing you cant mistake it!
I agree nick, with throttle and lean all the bikes do wobble quite a bit, but as i hear it, it got worse and worse and almost unrideable for people, i didn't see that big change in my race, that is why i wonder what the problem is.
As soon as i have time to do a few laps i will upload the replay for you Vin. Just few laps, 4l fuel and hard tyres fine?
Perfect, thank you very much!
Would be good if you could do one smooth lap (like you did in the race) and one where you purposely ride a little more aggressively.
all seems (to me ;D) related to how the bikes turn in general in GPB.. like the post/thread from janau about the dodgy dragging front end.. like walken pointed out about how the bike/tyres interact with the track.. iv'e always had the feeling that the bike wants to stay pointing forward, and when you tip into a corner the front drags sideways instead of ''tracking'' the track surface and ''looking'' natural..
so maybe these wobbles/oscillations with small lean angles has something to do with the bike wanting to point forwards instead of tracking the surface naturally..?? some conflict somewhere maybe?
just finished a nightshift.. be kind ;D :P
Hi guys, well I dont know about you but I get this with most bikes for the last x number of betas. I thought I would do a video with 4 cam views so we could see the way the front is acting. I did not push it and purposely rode slower as it is to do with a lower angle of lean and defo seems to be around the 30 degree mark. Best watched in 1080p full screen on YouTube.
Well see what you recon. Love this GP15 though, I gonna have sex with it later lol.
https://www.youtube.com/v/en5WvqaI50w
DD