In rational mechanics, the kinematic chain is the union of several members obtained with kinematic pairs, so that, fixed the relative velocity of a member to any other, result univocally determined the relative velocities of all other members, i.e. fixed one of the members, the system has only one degree of freedom.
When the kinematic pairs are coupled in such a way that the last link is joined to the first link to transmit definite motion (i.e. completely or successfully constrained motion), it is called a kinematic chain.
The degrees of freedom, or mobility, of a kinematic chain is the number of parameters that define the configuration of the chain.
- Kinematic link