Design of 6 degree-of-freedom micro-positioning mechanism for optical elements

For requirements of high-precision displacement compensation of components in optical system, a 6 degree-of-freedom (6-DOF) displacement adjustment mechanism is presented in this paper. The composition and working principle of the mechanism are expatiated. The output compliance and the input stiffness model of the mechanism are established. The results obtained by the finite element analysis (FEA) are compared with that got by the compliance matrix method (CMM). The displacement Jacobian matrix of the mechanism is established according to the FEA results. The output compliance obtained by the FEA and the CMM are 16.081um/N and 14.138 um/N, respectively, and the deviation is 12.083%. The input stiffness got by the FEA and the CMM are 22.483 N/um and 22.127 N/um respectively, and the deviation is 1.605%. The FEA results show that the translation and rotation stroke of the mechanism are larger than 50 um and 200 urad, respectively. The maximum stress on the mechanism is less than 50 MPa when the full stroke is reached. The surface figure introduced by adjusting the lens element is less than 1nm. The results show that the method is feasible and provides the design basis for 6-DOF optical elements.