Design and analysis of flexible decoupling mechanism for rotating nanomotion

Due to the problem that the parallel flexible mechanism used in micro and nano positioning occasions is difficult to decouple the rotational motion from other degrees of freedom to form an independent drive unit, this paper extends a rotational motion decoupling mechanism based on an orthogonal combination of spring-beam parallelogram mechanisms by replacing the spring beams with arc beams. A series of flexible decoupling mechanisms based on arc beams are designed, and their stiffness modeling and performance are tested. First, four configurations of flexible decoupling mechanisms with different arc beam heights are introduced. These mechanisms, composed of two identical orthogonal parts, utilize the arc beams' stiffness to achieve decoupling for multiple coupled degrees of freedom, including translational motion. Theoretical modeling using the stiffness matrix transfer method determines the mechanism dimensions and output stiffness. Finally, the accuracy of the theoretical model is verified through finite element analysis, and the decoupling capabilities of the mechanisms are compared. Results show that the errors between the finite element and the theoretical model are within 10%, and the decoupling performance is proportional to the height of the arc beams. These mechanisms can be applied to flexible mechanism design in multi-degree-of-freedom parallel micro-nano positioning platforms.