A novel compliant linear-motion mechanism based on parasitic motion compensation

In this paper, the center shift of the generalized cross-spring pivot is taken advantage of to compensate for the inherent parasitic motion of the compliant parallel four-bar mechanism. So the rectilinear motion of a linear-motion mechanism, which is constructed by several leaf springs or cartwheel flexural pivots, is improved. The compliant linear-motion mechanism is firstly modeled by making use of the building block method. Then the compensation condition for the parasitic motion is obtained. Meanwhile, the approach to large stroke and small parasitic error is proposed, for the sake of achieving a high performance rectilinear mechanism. Furthermore, the validity and effectiveness are verified by finite element analysis (FEA). Finally, both the qualitative and quantitative analyses show that the advantages of this linear-motion mechanism are remarkable, and the application prospect in precision engineering is promising.

► Parasitic motion of a parallel four-bar mechanism is diminished by the center shift of a generalized cross-spring pivot.
► Primary motion and parasitic motion of the mechanism is modeled.
► The farther the two pivot points on a kinematic chain are, the lager motion range the mechanism achieves.
► Payload influences parasitic motion significantly, but affects primary motion slightly.