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MATLAB Vehicle Powertrain Model
Hello,

I've found a very interesting video about car simulation. I wonder if LFS engine could run this kind of complex simulation model?



Thank you,
Marino
#2 - Ped7g
? Seems actually lot more simpler than what LFS does internally.

For example this model has very simple "clutch" (torque converter) (no temperature/slipping) and differential (only one generic type, while LFS simulates different designs). The engine itself is some black-box, so hard to tell how detailed that part is, but it's lacking some features of LFS, like starter (in LFS, when you run out of fuel, you can move the car slowly by starter, at least with manual clutch, not sure about automatic).

Another important part is the "solver", in video "ode15s", which can be probably found described in detail in some papers. AFAIK LFS solver is not publicly known (except few details like it does run at 100Hz, so it's delta-time fixed), and it's custom work of Scawen, so hard to tell how those compares. May be more complex or simpler...

Etc, etc... so I'm confused by your question a bit. If I take it literally "I wonder if LFS engine could run this kind of complex simulation model?", then the answer is simple "yes, it's doing more complex simulation already, and that's why the car does move on the track"? Maybe I'm missing your original idea, what made you curious.
I had impression of MATLAB as the most complex software for mathematical simulations, and when I saw this video, I immediately thought of LFS and where LFS engine stands in comparison to MATLAB.
#5 - Ped7g
"MATLAB as the most complex software for mathematical simulations" - probably quite true (*) in general point of view. But it's just tool, framework to base your own calculations/simulations on, it doesn't make them sophisticated complex on its own, serious amount of work must go into the task creation, while the video shows just somewhat simplified clickable widgets, you can hardly compete with such "nice to use" SW with something specialized like car simulator.

*) when considered in absolute values, MATLAB is nowhere near the specialized work of some commercial researchers ... I just guess, but I believe F1 teams would use MATLAB only for some generic overview and early guestimates, but they have much thorough models for example for CFD. working on super-computer grade HW.
#6 - Ped7g
And I'm still a bit confused, what you then see in the LFS... Maybe it "just works" so well, that most of it seems "obvious" and doesn't ring a bell when you see it...

Just a quick recapitulation from top of my head (and most of it guessed, I didn't see sources, so I may be wrong about some), what you can experience in LFS, to give you idea how detailed the model of simulation is:

- the actual simplified model of suspension is simulated, i.e. the wheels don't connect to the car body through some approximation, but the struts/springs are defined of physical features resembling real world, and simulation of those is sending forces between wheels and car body.
- those forces include dynamic centre of gravity (i.e. fuel tank position and it's load does affect forces applied on the suspension during race, dynamically changing setup "feel" as the fuel is burnt away)
- the clutch-driveshaft-ignition-starter is modelled to a level where you can move car by the starter (the most unreal thing about that is, that the battery can't be depleted, other aspects are pretty much correct reproduction of what you can do with real car)
- sounds are dynamically produced according to revs/ignition of combustion engine (i.e. 4 cylinder engine vs 8 cylinder at the same revs produce somewhat different sound in LFS, if I understand correctly how it works)
- the tires do simulate flatspots (both in terms of surface temperature and vibrations/grip anomalies), and latelar deformations (not just as graphical effect, but actually changing the results of force transfers between track, tire and car body)
- you can save the fuel consumption by lift'n'coast like in real car (the fuel consumption is calculated based on ignition in cylinders and the "richness" of mix going into engine ... although probably just represented by some simple linear calculation from gas pedal state, but results are reasonably close to real behaviour)

There are still quite gimmicky parts of LFS simulation using quite basic approximations, or even missing completely (like brakes wear and temperatures), but some parts of the simulation were state-of-art back when introduced, and I guess quite some of them are still on par with commercial packages available today used by some race teams in RL racing. F1 teams have probably better ones, but if you step down to lower classes... I remember times when GT teams were using GTR1 and GTR2 to figure out quickly some insight into how other teams car react to some setup changes, etc.. as the sim, although mostly based on table data provided to developers by some teams, did mostly produce results close-enough to give engineers general idea "what if this", accurate enough to decide for further action (like prioritizing what setup changes they were testing on track in real practice session first)...
Like Ped7 says; Matlab is just a tool/environment that aids your calculations with various ready-made toolboxes, its own high-level programming language and simulink etc. You can do 1+1 and get it right in Matlab, but also build/visualize very complex math applications. The user is the limit.
I dunno.... This MATLAB might help a developer that's in the starting processes of making a game. But with LFS this far along? I don't think it would be of much use. Maybe back in 2002 or something, but not now.
While there's nothing said for the detail of this simulation, I do like the modular nature of connecting anything to anything. It's something I'm trying to do myself if I can get the time. To be able to rapidly prototype new configurations in a simulation environment is very useful. I would hazard a guess that LFS is rather for mixed in it's layout.

MATLAB Vehicle Powertrain Model
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