Analysis and calculation for compensation force in axial support system in φ 1.2 m primary mirror optical fabrication

Dealing with some non-rotational symmetrical residual error in low-frequency Zernike polynomials surface is needed in the manufacture of large-reflecting mirror. These errors greatly increase the difficulty of processing. Propose to change the mirror surface for reducing the fabrication difficulty by active support technique. Study the method of compensating some non-rotational symmetrical residual error in low-frequency Zernike polynomials surface by active support technique. Firstly, apply the all-floating support method in axial support system to control the deformation of the mirror's surface. Then, apply force as the control variable in the system. Do the correction process on the solution which can not satisfy the principles of Resultant equal to zero and Total torque equal to zero. Successfully achieve the compensation of low-frequency Zernike coefficient surface by active support technique. The results of simulation by Ansys-Workbench software prove the feasible.