Non-Planar-Surface-Contacts

An algorithm to model the non-planar frictional surface contacts

parametric surfaces
discretization of parametric surface
FEM simulation with two types of soft finger
- Objects are discribed with non-uniform rational B-Splines (NURBS) for smooth surface generation
- ANSYS is used to mesh objects and simulate contacts
Code
- createParametricSurface/
- FEMSimulation/
Required external libraries
Create NURBS-based objects
- MATLAB NURBS Toolbox: https://de.mathworks.com/matlabcentral/fileexchange/26390-nurbs-toolbox-by-d-m-spink
- MATLAB IGES Toolbox: https://de.mathworks.com/matlabcentral/fileexchange/13253-iges-toolbox
- MATLAB IGES OUTPUT Function: https://de.mathworks.com/matlabcentral/fileexchange/14470-igesout
FEM simulation
- ANSYS workbench: https://www.ansys.com/

for parametric surfaces: Numerical integrated wrenches with symbolic integrands
for meshed surfaces: Sum of the wrench of all elements
Code
- frictionComputation/
Required external libraries
Visualization: show vector with arrow
- vectarrow: https://de.mathworks.com/matlabcentral/fileexchange/7470-plot-2d-3d-vector-with-arrow?focused=5062305&tab=function

Ellipsoidal model
convex quartic polynomial model
Code
- fitLimitSurface/
Required external libraries
convex optimization
- Convex optimiation cvx: http://cvxr.com/cvx/
Visualization: show vector with arrow
- vectarrow: https://de.mathworks.com/matlabcentral/fileexchange/7470-plot-2d-3d-vector-with-arrow?focused=5062305&tab=function

Sampling the limit surface models
Build the grasp wrench space
Check if a 6D wrench disturbance is inside of the grasp wrench space
Code
- multiContact/
Required external libraries
check if a disturbance is inside of the qull (grasp stability assessment)
- inhull: https://de.mathworks.com/matlabcentral/fileexchange/10226-inhull