Hello again. Sorry for leaving out vital information about the tire and 
terrain model. I was using rigid tire and terrain and there was very little 
slip. Turns out the problem was an axle with very high inertia in the rigid 
suspension I hadn't taken into account.

Thanks!

söndag 15 oktober 2023 kl. 18:55:34 UTC+2 skrev Radu Serban:

> You don’t say anything about the tire model and terrain model you use.  
> You cannot leave that out when doing such a back of the envelope 
> calculation.
> You are assuming rolling without slip.  First thing I would do is monitor 
> the longitudinal slip at each wheel.
>
>  
>
> --Radu
>
>  
>
> *From:* 'Meninstick' via ProjectChrono <[email protected]> 
> *Sent:* Thursday, October 12, 2023 12:29 PM
> *To:* ProjectChrono <[email protected]>
> *Subject:* [chrono] Low acceleration
>
>  
>
>  Hello, I am currently modelling a simple vehicle, using the simpleEngine, 
> AutomaticTransmissionSimpleMap and SimpleDriveline templates.
>
> Using 40Nm tourque on the engine and a 1:1 gear ratio, 0.5 Front Torque 
> Fraction I get only about half the excpected acceleration. Are there any 
> losses I havn't acounted for?
>
>  
>
> For the acceleration test the throttle is set to 1, resulting in instant 
> maximum tourque.
>
> The graph shows an acceleration from 0 to 1.03 m/s in 0.57s. Resulting in 
> a = 1.807 m/s^2.
>
> Using the effective mass (taking wheel inertia into account), F = m*a 
> results in F = 125N, 31.5N per wheel.
>
> With a tire radius of 0.165m I get 5.2N/wheel. Not the 10N/ wheel expected.
>
>  
>
> Total mass: 66.3kg
>
> Tire radius: 0.165m
>
> Tire inertia: [0.015, 0.019, 0.015],
>
> Wheel inertia: [0.002, 0.004, 0.002]
>
> Effective mass: 69.8kg
>
>  
>
> Any answers are appreciated :)
>
>  
>
> tldr:
>
> Are there any losses between SimpleEngine, AutomaticTransmissionSimpleMap, 
> SimpleDriveline and the ground?
>
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