Lie Group Variational Collision Integrators for a Class of Hybrid Systems

TL;DR

This paper introduces a Lie group variational collision integrator for 3D convex rigid-body collisions, effectively handling corner impacts and preserving key physical properties over long simulations.

Contribution

It develops a novel symplectic integrator based on variational principles that accurately models collisions, including corner impacts, without nonsmooth convex analysis.

Findings

The integrator preserves momentum and energy well over long simulations.

Corner impacts are effectively handled using $psilon$-rounding on the SDF.

Numerical experiments confirm the integrator's conservation properties.

Abstract

The problem of 3-dimensional, convex rigid-body collision over a plane is fully investigated; this includes bodies with sharp corners that is resolved without the need for nonsmooth convex analysis of tangent and normal cones. In particular, using nonsmooth Lagrangian mechanics, the equations of motion and jump equations are derived, which are largely dependent on the collision detection function. Following the variational approach, a Lie group variational collision integrator (LGVCI) is systematically derived that is symplectic, momentum-preserving, and has excellent long-time, near energy conservation. Furthermore, systems with corner impacts are resolved adeptly using $\epsilon$-rounding on the sign distance function (SDF) of the body. Extensive numerical experiments are conducted to demonstrate the conservation properties of the LGVCI.