Implicit Frictional Dynamics With Soft Constraints

IEEE Transactions on Visualization and Computer Graphics, vol. 30, pp. 7776–7787

Abstract

Dynamics simulation with frictional contacts is important for a wide range of applications, from cloth simulation to object manipulation. Recent methods using smoothed lagged friction forces have enabled robust and differentiable simulation of elastodynamics with friction. However, the resulting frictional behavior can be inaccurate and may not converge to analytic solutions. Here we evaluate the accuracy of lagged friction models in comparison with implicit frictional contact systems. We show that major inaccuracies near the stick-slip threshold in such systems are caused by lagging of friction forces rather than by smoothing the Coulomb friction curve. Furthermore, we demonstrate how systems involving implicit or lagged friction can be correctly used with higher-order time integration and highlight limitations in earlier attempts. We demonstrate how to exploit forward-mode automatic differentiation to simplify and, in some cases, improve the performance of the inexact Newton method. Finally, we show that other complex phenomena can also be simulated effectively while maintaining smoothness of the entire system. We extend our method to exhibit stick-slip frictional behavior and preserve volume on compressible and nearly-incompressible media using soft constraints.

Authors 5

1. Egor Larionov

   University of British Columbia

   Affiliation as printed

   Computer Science, University of British Columbia, Vancouver, British Columbia, Canada

2. Andreas Longva Aachen Computer Science

   RWTH Aachen University

   Affiliation as printed

   Computer Science, RWTH Aachen University, Aachen, Germany

3. Uri M. Ascher

   University of British Columbia

   Affiliation as printed

   Computer Science, University of British Columbia, Vancouver, British Columbia, Canada

4. Jan Bender Aachen Computer Science

   RWTH Aachen University

   Affiliation as printed

   Computer Science, RWTH Aachen University, Aachen, Germany

5. Dinesh K. Pai

   University of British Columbia

   Affiliation as printed

   Computer Science, University of British Columbia and Vital Mechanics Research, Vancouver, British Columbia, Canada