Low acceleration
Meninstick
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?
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 <projec...@googlegroups.com>
Sent: Thursday, October 12, 2023 12:29 PM
To: ProjectChrono <projec...@googlegroups.com>
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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