[Simscape Multibody Contact Forces] Fluctuations in Normal & Friction Forces
6 visualizaciones (últimos 30 días)
Mostrar comentarios más antiguos
Marzieh Zamani
el 9 de Dic. de 2020
Respondida: Yifeng Tang
el 30 de Abr. de 2021
I am working on a Simscape 3D model of a 2-wheels robot moving inside a rolling pipe:
Pipe is rotating along its own central axis (z);
Robot is also moving around (not along) pipe central axis (z);
Therefore, both robot and pipe are rotating along axis z;
The model is built using multibody and contact block
The contact forces between robot wheels and pipe are modeled using contact block (Sphere to Tube Contact Force (3D));
1_ The problem is that the robot is supposed to be moving only in the plain perpendicular to z axis so the velocity along z axis is supposed to be zero
However, there is some velocity along axis z(vAxis); The values are low but with high-frequency fluctuations. Since friction force is a function of relative velocities, it is also suffering from same fluctuations
2_ Penetration velocity (vrad) is also considered and it has low values but with high-frequency fluctuations. Normal force is defined as a function of pentation velocity and so it is also suffering from same fluctuations.
Has anyone had similar experince?
Any explanation or suggestions in this regard would be highly appreciated.
0 comentarios
Respuesta aceptada
Yifeng Tang
el 30 de Abr. de 2021
The contact force, when in contact, is modeled as a stiff spring and damper to prevent the penetration and calculate the normal and friction force. So the parameters for the spring and damper can play a role in the vibration you see. From your description, sounds like the spring is stiff enough, but the small magnitude motion isn't damped enough.
You may also consider add a planar constraint to your robot to get rid of the along-axis motion.
0 comentarios
Más respuestas (0)
Ver también
Categorías
Más información sobre Assembly en Help Center y File Exchange.
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!