Abstract: One of the major tendencies towards the devel- opment of parallel kinematic machines (PKM) is to make full use of its reconfigurability and multiple-functionality. Modul- arity is the key enabling technology of reconfigurability. A set of criteria for the conceptual design of reconfigurable PKM modules is presented. The composition principle of sub-6-DOF parallel mechanisms is revisited using the theory of linear algebra, resulting in three classes of parallel mechanisms which can be generated by four types of limbs in terms of actuation and constraints. Considering the performances in terms of reconfigurability, speed, rigidity and accuracy, it concludes that the parallel mechanisms with simple proper-constraint limb whose degrees of freedom and type are exactly the same as those of the mobile platform would be the most suitable candidates. Consequently, a novel 5-DOF hybrid PKM module named TriVariant is proposed and its reconfigurability is demonstrated via a few examples for potential applications.

Key words: Modular design, Parallel kinematic machines, Reconfigurability