Conclusions

Abstract

This book presented a systematic study of the type synthesis of PMs. The major contributions are highlighted below:

• 1. Representation and classification of motion patterns. With the introduction of the concept of virtual chain, motion patterns can be represented in a rigorous way. A number of motion patterns having practical application potential have been identified.

• 2. The virtual-chain approach to the type synthesis of PMs. Based on the concept of virtual chain and screw theory, PMs can be constructed using several of the seven compositional units via the construction of the multi-DOF single-loop KCs in four steps: (1) the decomposition of the wrench system of a parallel kinematic chain associated with a virtual chain (V= PKC), (2) the type synthesis of legs, (3) the assembly of legs to generate V= PKCs, and (4) the selection of the actuated joints. Once a PM is constructed, part of one or more of its compositional units may be invisible due to the removal of the virtual chain in the process of type synthesis. It is observed that [80]:

  • The virtual-chain approach requires fewer derivations than the approaches proposed in [13, 33, 65, 79].

  • The virtual-chain approach is conceptually simpler and therefore easier to understand than the method proposed in [58].