Analysis of the displacement of complaint double parallel four-bar mechanism

The compliant double parallel four-bar mechanism is a classical parallel guiding mechanism. Two mathematic models of double parallel four-bar mechanism were built based on pseudo-rigid-body model and elastic beam theory. The elastic beam theory was used to analysis the effect of axial deformation on the displacement of moving plate at large displacement. Effect of compliant guiding beam geometric parameters on moving plate and the accurate of two models were discussed. Results showed that moving plate displacement is proportional to the force. Meanwhile, the axial deformation of guiding beam and its width/thickness ratio of the rectangular cross section have significant effect on the displacement of plate. The displacement of plate increases rapidly with the decrease of cross section width/thickness ratio, in other words, the system sensitivity increase rapidly. Finally, the FEM (finite element method) was used for comparison with the mathematical model, and similar results were obtained. This research has significant practicality for further analysis the displacement of compliant double parallel four-bar mechanism, optimizing the mechanical structure, and improving the comprehensive performance.