mcx / contact_models

Fork of https://bitbucket.org/pchorak/contact_models

Description

Examples and methods to simulate inelastic rigid-body contact dynamics with Coulomb friction. Companion to the paper: P. C. Horak and J. C. Trinkle, "Comparison of Complementarity and Convex Contact Models," arXiv:TBA [cs], May. 2018.

Contents

• experiments - scripts to run the simulation experiments (depend on timestepping)
  • generate_results.m - reproduces plots from the results section of the paper
• plotting - animate results from the experiments
• solvers - solve generic contact dynamics problems
• timestepping - simulate the dynamics for the experiments (depend on solvers)

Solvers

The solvers are based on or discussed in the following papers:

• solver_blcp.m - K. Erleben, “Velocity-based shock propagation for multibody dynamics animation,” ACM Trans. Graph., vol. 26, no. 2, pp. 12-1–20, Jun. 2007. (sections 2-3, no velocity-based shock propagation)

• solver_ccp.m - A. Tasora and M. Anitescu, “A matrix-free cone complementarity approach for solving large-scale, nonsmooth, rigid body dynamics,” Comput. Methods in Appl. Mechanics and Eng., vol. 200, no. 5, pp. 439–453, Jan. 2011.

• solver_convex.m - E. Todorov, “Convex and analytically-invertible dynamics with contacts and constraints: Theory and implementation in MuJoCo,” in 2014 IEEE Int. Conf. Robotics and Automation, 2014, pp. 6054–6061.

• solver_lcp.m - D. E. Stewart and J. C. Trinkle, “An implicit time-stepping scheme for rigid body dynamics with inelastic collisions and coulomb friction,” Int. J. Numer. Meth. Eng., vol. 39, no. 15, pp. 2673–2691, Aug. 1996.

• solver_ncp.m - Y. Lu, “A framework for comparison of methods for solving complementarity problems that arise in multibody dynamics,” Rensselaer Polytechnic Inst., Troy, NY, 2016. (see prox_NCP.m from the RPI-MATLAB-Simulator)

• solver_qp.m - E. Todorov, “A convex, smooth and invertible contact model for trajectory optimization,” in 2011 IEEE Int. Conf. Robotics and Automation, 2011, pp. 1071–1076.

Optional Dependencies

• lemke.m from the CompEcon Toolbox
• The PATH Solver

Tested Environments

• Ubuntu 14.04, MATLAB R2017a