Many applications of multibody dynamics to real-world systems require the modelling of contact mechanics. In order to simulate the contact of bodies in a multibody system it is necessary to determine the contact points and to model the contact forces. The contact points may be calculated analytically or numerically during time integration.
All contact forces are unilateral.
A new description is presented which comprises all possibilities of constrained and not constrained motion in one set of equations. The corresponding forces can be activated and deactivated easily. The procedure yields an advantage in finding a compatible set of constraints and applied forces after a contact event resulting in a discontinuity. The contact events are indicated by switching functions. It is necessary to formulate the constraints on position, velocity, acceleration and velocity variation level.