SCM terrain

[Davide]

Hi all,

I'm focusing on the demo of a tire test rig on a SCM terrain, in particoular on the forces exchanged between tire and ground. While examining the longitudinal tire force as a function of longitudinal slip, I observed that the tire force shows a negative value when the longitudinal slip is zero. Could anyone explain why this occurs? How is this handled in Chrono? Is there any paper I could consult on this topic?

Tahnk you in advance for any help!

Davide

[Dan Negrut]

Hi Davide,

The wheel will sink in a bit. As such, it’ll experience some bulldozing force. You then typically need to push it a bit to maintain that zero slip. In general you’ll see some slip before you generate positive traction.

 

You asked for some literature:

 

@inproceedings{Krenn2008SCM,

       booktitle = {11th European Regional Conference of the International Society for Terrain-Vehicle Systems - ISTVS 2009},

           month = {October},

           title = {{SCM} -- {A} soil contact model for multi-body system simulations},

          author = {Rainer Krenn and Gerd Hirzinger},

            year = {2009},

        keywords = {Multi-Body System Simulation, Contact Dynamics, Soil Contact Model},

             url = {http://elib.dlr.de/60535/}

}

 

@article{chronoSCM2019,

  title   = {Deformable soil with adaptive level of detail for tracked and wheeled vehicles},

  author  = {Tasora, Alessandro and Mangoni, Dario and Negrut, Dan and Serban, Radu and Jayakumar, Paramsothy},

  journal = {International Journal of Vehicle Performance},

  year    = {2019},

  volume  = {5},

  pages   = {60--76},

  number  = {1}

}

 

@article{chronoSCM_JCND_2023,

  title={Real-Time Simulation of Ground Vehicles on Deformable Terrain},

  author={Serban, Radu and Taves, Jay and Zhou, Zhenhao},

  journal={Journal of Computational and Nonlinear Dynamics},

  volume={18},

  number={8},

  pages={081007},

  year={2023},

  publisher={American Society of Mechanical Engineers}

}

 

I hope this helps.

Dan

---------------------------------------------

Bernard A. and Frances M. Weideman Professor

NVIDIA CUDA Fellow

Department of Mechanical Engineering

Department of Computer Science

University of Wisconsin - Madison

4150ME, 1513 University Avenue

Madison, WI 53706-1572

608 772 0914

http://sbel.wisc.edu/

http://projectchrono.org/

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[Davide]

Hi Dan

Thank you for your explanation, it’s very helpful!

However, I’m still a bit unclear about the "pushing force" you mentioned. Is it an external force that must be applied, or is it related to the internal dynamics of the wheel and terrain interaction?

[Dan Negrut]

Davide – to get zero slip for a wheel, you actually need to push the wheel a bit (apply a translational force on it).

In general, at high slip, the wheel will pull you. Not at zero slip – you have to push it in that case.

That’s what I meant by “push”.

 

Dan

---------------------------------------------

Bernard A. and Frances M. Weideman Professor

NVIDIA CUDA Fellow

Department of Mechanical Engineering

Department of Computer Science

University of Wisconsin - Madison

4150ME, 1513 University Avenue

Madison, WI 53706-1572

608 772 0914

http://sbel.wisc.edu/

http://projectchrono.org/

---------------------------------------------