Precision Analysis and Error Compensation of a Telescope Truss Structure Based on Robotics

Abstract

We propose a new secondary mirror support structure assisted by multi-robotics to improve the observation performance of vehicle-mobile telescope systems. A mathematical model of the displacement at the end of the robotic and the variation of telescope pitch angle is established, then the posture of the robotic is optimized by the Jacobian matrix iteration inverse kinematic problem method. Based on the new support structure, a high-order sensitivity matrix is proposed to establish the mapping relationship between the robotic misalignment and the Zernike coefficient, with the accuracy verified via the Monte Carlo method. The method of adjusting the secondary mirror to compensate the aberration caused by the primary mirror is proposed, and the relationship between the primary mirror surface error and the system error is established under different pitch angles before and after compensation. The experiment and simulation results showed that the adjustment calculated by the high-order sensitivity matrix method can effectively compensate for the misalignment caused by the robotics and the primary mirror surface error to a certain degree. After multiple iterations, the root mean square of the wavefront aberration was better than λ/15. This conclusion provides an engineering application reference value for the secondary mirror support and aberration correction technology of the vehicle telescope system.

Optical Pupil Shift Correction Method for Large Ground-Based Optical Telescopes

“…For the coma, an additional term 131 () (20). If the deviation is small, the on-axis field-of-view (FOV) image dispersion increment term will be negligible relative to the coma increment term.…”

“…The overall optical model of the telescope was used to calculate the degrees of bending and sinking variation at different elevation angles and calibrate the optical axis, which helped eliminate the effect of optical pupil shift on the adaptive optical imaging system. This method not only improves the calibration accuracy but also reduces the number of calibration iterations needed to improve the system efficiency [19,20].…”

Positioning Accuracy and Numerical Analysis of the Main Casting Mechanism of the Hybrid Casting Robot

“…Wang et al [9] studied the thermal deformation of a truss secondary mirror support structure and proposed a high-order sensitivity matrix method to compensate the thermal deformation error of the truss, which compensated the secondary mirror error caused by thermal deformation to a certain extent, but the compensation accuracy cannot meet the accuracy requirements of the telescope system. Li et al [10] applied finite element analysis method to analyze the steady-state deformation law of thermodynamic coupling in two directions of large span beam of large truss extubation robot and optimized the structure.…”