Sim Racing servo ffb systems : OSW & Bodnar

Adrian, do you have a copy of those JSON file changes.
Hopefully my Bodnar wheel should be available this week, I just keep pestering poor John until it is!

Thanks Mark.

 

From JSON file i changed update rate and resistance coefficent and saturation. I didn't change anything else.

Could you give an examble of some settings you had to change?

I bought this as a kit from http://ib-reimer.de/index.php/en/ For some reason he doesn't offer mige kits anymore.
I have tried to change granity settings also, but didn't find any setting that would make it possible to use higher update rate. I also use lowish TBW 220 hz.
CIS fixed all my problems but it also adds 6 ms of delay. I tried it, but i thought that the delay is notable.

With 133 hz update rate from json and 220 hz TBW from granity i have been very pleased. It doesn't feel like i would be missing any information that i would be feeling through steering in real life.

Do you get grinding feeling with your lenze if you try mmos deskop effect damper without filtering?

 

Drill a couple of holes in the steering wheel and you'll have your answer The difference between the Lenze and and the big Mige is the equivalent of lightening your wheel by 100 grams or so.

 

You'll laugh, but i am going to drill a few holes in my GT2-Fanatec rim, as it is heavy as hell!

 

With belt driven wheels wheel rims weight has big effect especially if belts aren't well tightened. After tightening belt of my TX i was able to use little pit heavier wheel rim without losing much details. Have to say TX with tightened belt and g27 rim was pretty good combination.

 

Your AF "industrial servo/marketing" reference seems a little bit too dismissive based on the large set of opinion and testing I have read. I am in the market and have read just about all the iRacing Forum posts and communicated directly with several people who have tried OSW and AF as well as at least one who has tried those two plus Bodnar (and was in Barry's review). Whatever differences a manufacturing guru would see when comparing the AF motor to the others doesn't amount to a huge difference in sim racing.

The OSW and Bodnar wheels are, however, superior regarding torque-- that seems clear. Noticeable? Yes, in certain conditions. Significant? It can be but specifically in a few situations where you are using the wheel set at full or close to full torque and driving a high downforce open wheel car. In these situations it is most noticeable when you are hitting a curb or in a very high speed turn with bumps. In these situations the AF is a step behind in FFB immersive-ness.

The AF has narrowed the gap a bit in recent Simexperience tests unleashing higher torque levels. These have been conducted with users via the forum. The gap was not fully closed, however, according to one well informed AF owner who has participated in the tests. As I was told the AF still fails to match the others with regard to extra torque headroom in those situations I mention above. But the new settings bring it closer and improve it. And it also has become more clear that the AF in Barry's excellent review was not adjusted optimally. This comes from one of the participants who later tried another AF and felt it was clearly better then Barry's AF. This of course is a pro and con of the AF-- software gives huge adjustments but can be confusing and actually screw up the feel. Apparently SimExperince have already worked part of the solution for this and are continuing on with new default settings and processes to eliminate user error for those of us who want less adjusting.

Key to consider for those of us planning to upgrade is that most people who have tried all wheels thoroughly say: 1) any of them is far far better than the lower tier wheels and will make us very happy, 2) the high torque benefits of the OSW/Bodnar are real vs the AF but few users actually seem to set their wheels while racing at a level that fully realizes that benefit due to the forces at play (10 minutes lapping at full torque is one thing, a 40 minute race is another). So, I think, some of the other pros and cons are also valid decision points (price, support levels, software, delivery time, etc).

 

hiya mark

yes I'll do,a bit more to it so its presentable & post it , I only amended it quickly few days ago as I installed rf2 for first time in about a year, I had a perfect profile before but all the .ini
( now Json ) file seems to have changed so new one needed


traind
-quick answer : the servo systems are superior in every way to the AF but what ever your opinion respect to you etc ( quickly read some of yr post etc ) a few that I've had corraspondance with who were selling their AF's said they were disappointed with it but both were servo users ( one with bodnar one with a OSW) I have no idea why they ordered a AF in the 1st place and not surprised by their opinion, the AF is a great ffb wheel though & better than CSW / t500s etc

 

For sure, knowing what we now know, the AF cannot compete with the Bodnar or OSW but not technically or necessarily because it's not a "high grade servo system" for numerous reasons previously explained (e.g. servo or not, makes absolutely no difference). You should be more specific by what you mean "high grade" too because it's rather ambiguous as to what/which attributes you are referring to that you think are the reason for the performance difference. For instance, i'm pretty sure it's not because the bodnar uses higher quality alloys in its construction.

You could make the argument that it's because the bodnar and OSW motors are more powerful and you would be most likely right in making that analysis to some extent for the following reasons.

The bodnar motor is rated at a maximum capable power output of up to 2000 Watts (based on the stated voltage, amperage and wattage ratings on the motor label from Barry's bodnar wheel review video part 1). However, we don't actually know what the true max power output of the bodnar and osw motors are in practice because there are no stats on what their respective psu's are supplying (or maybe someone here knows and would be kind enough to share please?). I'll assume for the moment it's at least half or else i can't see good reason for opting for such a motor with such high ratings in the first place but without solid fact on it, it could be anything. We simply don't know unless someone has tested/measured with a wattage meter.

Now what we know of the AF Pro motor (provided it's the same as this motor: here) is that it's recommended max is 60V at 10A which means it's rated at a maximum capable power output of up to 600 Watts. That alone is significantly less that the bodnar's rating. But worse yet, the AF's power supply is supplying the motor with only 24V at 10A which is only 240 Watts.

So what does the power output difference translate to in physical performance? Well, power = torque x speed. So one can see that for the same torque output from the AF Pro and bodnar motors, the maximum speed at which that same force/torque can still be delivered is going to be lower for the motor with the lower peak power output potential. This perfectly explanations the observations made by various AF users that the motor is lacking in responsiveness which occurs at high rotation speeds (e.g. when hitting curbs, etc) when compared to the bodnar/osw. It is because at these speeds, the AF motor is unable to maintain the torque demand.

However, knowing that it's psu is limiting the AF Pro to 240 Watts when the motor is capable of up to it's recommended 600 Watts should mean it still might have a chance of performing comparably with the bodnar and OSW (at least up to 13Nm). Barry himself said that if the problem is down to power, then they could increase the psu's voltage output to 36V which would increase the max power output a further 50%. It would be interesting to see if that would resolve the issue completely or not, though thinking about it, that would only raise it to 360 Watts which still sounds far short of what the bodnar and OSW motors are probably running at.

So the AF cannot/does not compete/compare with the bodnar and OSW wheels due to there difference in max power output. However, if you could provide the motors the same exact power output potential, they should perform identically since the motor type is not the issue here (as explained before...for example, all these motors are PMSM motors, etc). Though I wonder even if the AF had access to it's full 600 Watt recommended limit, could it perform identically to the bodnar/osw's within the performance envelope operated in (i.e. within the torque-speed curve) when used for sim racing. It would be interesting to see if an increase to 36V on the AF Pro would be enough to do the trick or not.

So yeah, when you boil it down to it's most basic parts, it comes down to a simple Power = Torque x Speed issue.

 

Thanks everyone, especially Adrian, for the info. I think I'm going to make my decision and buy one once you, Adrian, get yours and give us some great info regarding the big MiGe compared to your particular Kollmorgen model.

DrR, are you saying that the total power of the OSW, Bodnar, etc. is the only thing that makes it better (for simracing use) than the SimX AF? So if the OSW, Bodnar, etc. were ran at 13 Nm (or 16 Nm or whatever the AF's max is) then they wouldn't be superior to the AF with regards to, well, anything regarding FFB (clarity/detail, "quality", acceleration, response times, speed, etc.)?

 

nothing to do with power, urbsurd , total nonsense

but whatever it's like a broken record now

 

@Spin

So, lowering the peak torque output of the bodnar/OSW motors to 13Nm to match the AF Pro will not also match limit it's power output.

Remember, power = torque x rotational speed. So if say for example the bodnar/OSW motors had 4x higher power output potential than the AF Pro then for the same torque output the bodnar/OSW motors can sustain it at up to a 4x higher rotational speed than the AF Pro motor can.

If however you limited the power and torque of them to the AF Pro though, they should all perform identically.

 

Really? Power has no impact on the performance of a motor? Do you understand what power is and how that translates to the output performance of a motor?

If you truly believe it has no bearing, then you're ignorant of the last 400 years of applied physics.

If you had to choose between two identical cars to race in, both having the same everything, same weight, same peak motor torque output, etc, with the exception that one cars motor has more horsepower.....which would you choose? Clearly the one with more horsepower. Why? Because it will have a higher top speed.

When comparing the available power output from an electric motor, the exact same principle applies.

If however you don't agree that the difference in power is the reason for the observed difference, fine but a) don't say power makes no difference to performance because you'd be making a giant fool of yourself in making such a demonstrably false claim and b) please explain why you believe it's not the reason. Would be good to hear your thoughts on what you think is actually causing the performance difference then but please no more of the "...because it's not a high grade servo motor" responses because it's not a valid answer by any standard.

 

Spin, can you share/send stats on the different OSW motor and psu power outputs that your interested in. It's another factor to maybe consider.

 

In-terms of simracing tried and tested brands - the Lenze is too much, same with the Kollmorgen. Unless I'm mistaken, doesn't that just leave me with the MiGes?

With regards to the MiGes, I always see the same 2 mentioned ("small" and "large") but there's two others that stand out for me.


MiGe Models for SimRacing

[TABLE="class: grid, width: 1287, align: left"]
[TR]
[TD]SimRacing Name[/TD]
[TD]Model[/TD]
[TD]Rated Power[/TD]
[TD]Rated Current[/TD]
[TD]Peak Torque[/TD]
[TD]Holding Torque[/TD]
[TD]Electrical Time Constant[/TD]
[TD]Motor Weight[/TD]
[TD]Motor Inertia[/TD]
[TD]Torque Coefficient[/TD]
[TD]Rated Speed[/TD]
[/TR]
[TR]
[TD]"Small"[/TD]
[TD]130ST-M10010[/TD]
[TD]1.0 kW[/TD]
[TD]4.5 A[/TD]
[TD]20 Nm[/TD]
[TD]10 Nm[/TD]
[TD]3.26 ms[/TD]
[TD]11.5 Kg[/TD]
[TD]19.4 kg cm^2[/TD]
[TD]2.2 Nm/A[/TD]
[TD]1000 rpm[/TD]
[/TR]
[TR]
[TD]"Medium-Small"[/TD]
[TD]130ST-M10015[/TD]
[TD]1.5 kW[/TD]
[TD]6.0 A[/TD]
[TD]25 Nm[/TD]
[TD]10 Nm[/TD]
[TD]3.93 ms[/TD]
[TD]11.5 Kg[/TD]
[TD]19.4 kg cm^2[/TD]
[TD]1.67 Nm/A[/TD]
[TD]1500 rpm[/TD]
[/TR]
[TR]
[TD]"Medium-Big"[/TD]
[TD]130ST-M10025[/TD]
[TD]2.6 kW
[/TD]
[TD]10.0 A
[/TD]
[TD]25 Nm[/TD]
[TD]10 Nm[/TD]
[TD]3.36 ms[/TD]
[TD]11.5 Kg[/TD]
[TD]19.4 kg cm^2[/TD]
[TD]1.0 Nm/A
[/TD]
[TD]2500 rpm[/TD]
[/TR]
[TR]
[TD]"Big"[/TD]
[TD]130ST-M15015[/TD]
[TD]2.3 kW[/TD]
[TD]9.5 A[/TD]
[TD]30 Nm[/TD]
[TD]15 Nm[/TD]
[TD]4.05 ms[/TD]
[TD]14.4 Kg[/TD]
[TD]27.7 kg cm^2[/TD]
[TD]1.58 Nm/A[/TD]
[TD]1500 rpm[/TD]
[/TR]
[/TABLE]



1. The "small" and the "big" are the ones almost everyone uses but what about the "medium-small" and the "medium-big"? It confuses me because the two "medium" models have the benefit of the "small's" lower motor inertia yet they provide 25 Nm of peak torque as opposed to the "small's" 20 Nm. Therefore, don't the two "medium" models make the "small" completely redundant (the price differences are minor)?

2. The holding torque, weight, and motor inertia of both "medium" models are identical to the "small". To me, this suggests that all three models are actually the same identical motors. Do the "medium" models just come with better electronics in order to handle higher current, peak torque, and rpm?

3. How much benefit is the speed (rpm)? For example, there is an even bigger "big" model (130ST-M15025) which - while it doesn't have a higher peak and holding torque - is capable of 2500 rpm rather than 1500 rpm.

4. Acceleration is way more important than top speed for simracing in my opinion. Why don't these motors come with specs on acceleration? For example, the time it takes every model to go from 0 rpm to 500 rpm.

5. Same question as Q #4 but regarding initial response time. Would that be the "Electrical Time Constant" measurement in the chart above?

 

I believe they have already experimented with this power bump within the SimExperience user forum. I am not sure of the details but one owner who comes across as having very little bias and has also tried and enjoyed the OSW said he had the beta upgrades including the more power option. His comments were essentially: 1) the power increase to the AF increased the strength, 2) for him it seemed to narrow the gap to the OSW but he did not have an OSW at his house to compare back to back so exactly how close it got was unclear. He guessed that the gap was not closed, only narrowed. 3) at the end of the day he felt the OSW remains more immersive than the AF if you use the higher torque settings and are driving a high downforce open wheel car. With other car options or lower torque settings the difference is not as clear between the two. He thought the AF could have a few advantages for some users who like to tweak settings and are seeking absolute lap times instead of absolute, high torque immersion.

A

 

a lot of over analysation exists for sim racing vs high spec servo systems
( I guess this will happened as people are parting with monies )

order pretty much any of those Mige servos & you'll be heaven, any of the bodnar options same ( or lienze servos ) same
(I've gone for the 30Nm Mige to compare to my bodnar more out of curiosity than anything else ....hoping my pre conceived ideas are wrong but I don't hold out much hope, I'll end end up selling one)

win win

we live in very privileged times, now we have phonimal hardware options ( only available to us very recently ) the pressure is on software devs to further developed ffb to utilise this ktype of hardware
ISI IMO already offer super fantastic ffb already that really brings these high spec systems to life
( but in rf2's case we have to manually change the Json file so they actually work .......doh! )

good news all round

was using the f1 round interlargos earlier in a 4hr practice session & I get blown away every time I get into a practice session like that & iracings ffb is no where as near as good as ISI's

p.s some only pick on overall power ratings because it's a simple measure, a higher figure is one we understand right?
like the more the better? lol if only hey .... what a simplistic potential consumer base


it's system grade that's king here , for simracing stick with pretty much any of the high grade servo system options & completly sidestep the hype & Google posts

& you'll not go wrong -claw onto which ever random info you think suits you & you'll still be safe +not go wrong, there will be no future upgrade path & you'll need no repairs replacement or service ( if you stick with the servos)
(although been an interesting subject in past I'm kind of fed up of writing this so hopefully last time I'll bother lol )

 

Exactly, it's not just about power, if it was I'd simply pick the 130ST-M15015 ("big") MiGe and be done with it. Since I wont be buying another one for a long time, if ever, I'd really like to know more.

Don't the two "medium" MiGes essentially render the "small" MiGe completely redundant since (according to the specs) they're almost identical but with a higher peak torque for the two "medium" models?. If someone didn't want the "big" MiGe, why is the "small" one the go-to model by just about everyone when the two "medium" models are essentially a "small" MiGe but with a sort of 5-Nm-of-torque bonus? It's baffling to me. What am I missing here??....

I'm glad to hear about your results. I remember reading somewhere that iRacing's FFB only falls behind other sims when used with "regular" wheels and that it's because the FFB is so good and realistic that you need to have a high-end wheel therefore, when used with a high-end wheel, iRacing's FFB becomes the best of the bunch with others lacking. I'm glad to hear that's not the case since RF2 (and SCE to a certain extent) are my go-to sims.

 

Spin:

First up, I saw a discrepancy in the numbers you gave for the 130ST-M10025 so i doubled checked them and it's rated power is 2.6kW not 2.0kW and rated current is 10A not 7.8A and torque coefficient is 1.0 not 1.67 Nm/A. The way you can tell is to take the rated speed (in this case 2500 RPM) and convert it into radians/s first which equals (2500*2*π/60=) 260 rads/s. Then multiply it by it's rated torque which is the torque the motor can sustain at rated speed (both found/measured empirically by the manufactures via motor testing) which in the case of these MIGE motors is 10Nm. Which gives you (260*10=) 2600 Watts = 2.6kW. Rated power = rated torque * rated speed. For example, Bodnar's kollmorgan motor's rated torque is around 6.5Nm at its rated speed of 3000 RPM which equals (6.5*3000*2*π/60=) 2kW.

Regarding your questions:

Ok, so all the 130ST-M100XX motors all appear to be identical (at least in spec) with the only differentiator being their respective rated currents. It's likely that they are slightly different to one another in coil/winding construction whilst things like it's rotor is identical for each, hence the exact same motor inertia rating for each (though it should be called rotor inertia). For example, the coil windings maybe thicker for the 25Nm motors to permit more current flow, etc, hence the different current ratings and then between the two 25Nm motors the one with higher rated speed maybe also uses a different coil material, etc, to minimise inductance time-lag thereby permitting higher rotation speed. Also agreeing with my suspicion it's a difference in coil/winding construction is their difference in resistance, inductance and electrical time constant that i found on what looks like an official chart (in the description): http://www.aliexpress.com/store/pro...-WITH-DRIVER-AND-CABLE/917944_1668202556.html

Yeah, this puzzled me also. I don't know where you got these numbers from but from my own search, i couldn't find any official spec for the holding torque of these motors, only their rated torques. Which makes me think maybe you've gotten these numbers from someone else who has quoted the motors rated torque as its holding torque without realising that they're not the same thing. Based on the difference in current that can be supplied to each motor if coil construction varies between them, then the motors with higher peak torque should also have a higher holding torque as every time i've compared motors these spec differences have always gone hand in hand.

If the AF is truly suffering in comparison to the bodnar and OSW because it is unable to maintain the delivery of 13Nm of torque at certain steering rotation speeds found ingame, then speed potential of the motor matters much. However, the question is how much is enough and even if the motor has the potential to provide enough, it doesn't necessarily mean it will deliver it. That comes down to the power supply and controller driving the motor as well. For example, using the IONI looks like it would fall woefully short of allowing the mige motors to operate at their full potential since it's limited to 52V out where-as the MIGe motor's are rated at 220V but the argon can power up to 380V motors. So going with the IONI may limit it to rotation speeds like the AF Pro

I can only provide you with my guess on whether 10Nm at 1500 RPM would be enough or not and my guess would be that it's exceedingly more than enough. I mean, 1500 RPM = 25 revolutions per second. That's insanely fast and far higher than the theoretical speed limit that the AF Pro can continue to deliver 13Nm if we work it out backwards. The AF Pro power is 24V @ 10A = 240 Watts. 240 Watts / 13Nm = 18.5 rads/s = 2.9 revolutions per second.

My point in all this is that the rated RPM is not the differentiating performance factor between all the MIGE motors for sim racing (if powered/driven appropriately). It'll be the difference in peak torque output instead.

Well, they kinda do. The combination of the torque rating and rotor inertia gives you all the information you need to determine relative rotational acceleration rates between motors. Simply divide the motor torque by it's rotor inertia to literally work out rotational acceleration rates. For example the small mige, 10Nm torque and 1.94 kg.m^2 rotor inertia = 515 rads/s^2 = 81 revolutions/s^2. In other words, the motor can reach rated speed in a completely load-free scenario (e.g. no steering wheel and no-one adding resistance to the rotation of the motor...i.e. hands-free) in around 0.3 seconds. But imo with such powerful motors, these stats are pretty meaningless. The differentiator you will notice if comparing should be in the peak torque output.

Electrical time constant is not something you need to worry about. It's just the time it takes to reach 63% of the change in electrical current from some initial value to the desired/target value. These numbers are truly irrelevant to how the motor will perform in sim racing.

 

Very interesting. I'd be curious to know if the AF Pro motor at it's recommended upper limit of 60V would even be enough to satisfy the steering speeds expected in game.

Also, do you know which OSW motor he is comparing to? I mean, if it's also higher in torque, that will ofc produce a stronger feel by nature of it's greater torque output. If only someone could compare them torque for torque, then see if upping the voltage up to 60V would be enough to resolve the speed issue or not.

 

I think so. If i were you, i'd go with the 130ST-M10015. You get the benefit of 5Nm higher peak torque but you do lose the 2500 RPM for 1500 RPM but i really doubt you will ever notice that difference, ever. Also, even if you opted for the 2500 RPM motor, you may not even be able to drive it up to such a speed if you wanted since the Argon is supposedly only able to power up to 1.5 kW motors which makes it a perfect match for the M10015 that's rated at 1.5kW.