Constraints
摘要
The systems we wish to describe are made of particles and rigid bodies that are not totally free to move, but are instead subject to constraintsConstraint, that is, a priori restrictions on the motions allowed. Constraints are in general made of pins and similar devices, although we should make clear that we are not mainly interested in the way they are physically constructed, but only in their mathematical modelling, and especially the consequences they cause on the system’s kinematics.