Soft Robots Cable Actuator with Neo-Hookean Material

[subella]

Hello,

I am trying to get the cable actuator to work with a finger using the TetrahedronHyperelasticityFEMForceField. However, the results are unstable and the simulation is not converging. Has anyone experienced this or know a solution?

Thank you

[hugtalbot]

Hi @subella
the Neo-Hookean material is a hyperelastic one (non-linear) which makes the whole system to solve non linear.

1. One thing, would be to use a NewtonRaphson method to make sure your solution at the end of the time is well converged.

Are you using a dynamic or a static solver?
The StaticSolver in SOFA already includes NewtonRaphson iterations.
In dynamics, such a NewtonRaphson is only available in the Caribou plugin for now.

2. you should also maybe make sure the mesh, time step and other numerical settings (e.g. linear solver data) are correctly set, to ensure the best convergence