Modeling and analyzing the dynamics of an electric-motor brush

This paper briefly presents the Pfeffer-Glocker formulation for the multibody dynamics of rigid bodies with unilateral contacts. The multiple, concurrent contact situations of stick-slip, detachment and impact with friction are solved as a linear complementarily problem. The theory is extended toward the discretely defined bodies of complex body shapes with nonlinearities. As shown in the numerical example of the electric-motor-brush dynamics the presented extensions can be used to simulate the influence of a detailed geometry, including surface roughness. The influences of brush-wear and brush-stiffness on the dynamic stability are presented from more than 40 parameters that define the brush system.