The Degree of Freedom of Parallel Robots: A Group-Theoretic Approach

Current interest in the design of novel architectures for parallel robots with less than six degrees of freedom (dof) has called for a revisiting of the dof determination of a multiloop kinematic chain. The paper attempts to shed some light on the issue by resorting to the theory of groups, as first proposed by Hervé in 1978. The concepts, illustrated with various examples, should help robot designers produce novel architectures that would be difficult to devise otherwise.