Design, modelling and analysis of a completely-decoupled XY compliant parallel manipulator

This paper deals with the design, modelling and analysis of a new XY compliant parallel manipulator (CPM). This XY CPM is composed of identical compound basic parallelogram modules as non-under-constrained compositional compliant modules, which is completely-kinetostatically decoupled. Based on an improved topology structure, a new XY CPM is proposed, which arranges each pair of prismatic joints on the base in two non-adjacent legs to be rigidly connected. Two analytical models, static approximate and static accurate, are derived for all translational displacements of rigid stages, and compared to a finite element analysis (FEA) model and experimental results for a case study. Detailed performance characteristics of the new XY CPM are analysed and compared with those of a corresponding XY CPM without the connection bars. The proposed new XY CPM has no under-constrained motion mass with a compact configuration. It is able to effectively constrain the parasitic rotation of all rigid stages and the cross-axis coupling of the motion stage. The cross-axis coupling motion of the actuation stage can be completely eliminated, and the lost motion between the actuation stage and the motion stage can be significantly reduced.