Anisotropic Friction Modelling in Perpendicular Directions of Contact Surface for Snake Robot Locomotion

How can I model an anisotropic friction characteristic (for perpendicular directions of contact surface which can be realized via wheels on modular parts of a snake robot in physical implementation) to make forward locomotion possible by using 'Simscape Multibody Contact Force Library' or 'Spatial Contact Force' block with contact proxies approach or any other method?

Answer 1

[Steve Miller]

The Spatial Contact Force block lets you use your own custom friction force if you set the Frictional Force Method to "Provided by Input". Then you can have the coefficient of friction value depend on any quantity you want. For anisotropic friction, you would need to carefully obtain the direction of the relative velocity, compare that to your field of friction coefficients, and calculate the resultant friction force.

There is an example of a custom friction force in File Exchange submission Spatial Contact Force Examples in Simscape Multibody. It is not as complex as the example you are working towards, but could be used as a starting point.

https://www.mathworks.com/matlabcentral/fileexchange/109680-spatial-contact-force-examples-simscape-multibody

Download the files and try sm_disk_floor_custom_friction.slx

--Steve