Non-Planar-Surface-Contacts

An algorithm to model the non-planar frictional surface contacts

1. Surface contact generation, including:

• 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/

2. 6D friction computation for non-planar surfaces

• 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

3. Fitting limit surface models

The fitting can apply to both planar and non-planar surfaces with two models:

• 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

4. Mulit-contact modeling

• 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

License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.