Evaluation and compensation of a kinematic error to enhance prepolishing accuracy for large aspheric surfaces by robotic bonnet technology

摘要

To obtain an economical uniform polishing method, it is effective to combine robot technology with bonnet polishing technology and apply it to the precision processing of large aspheric surfaces. However, the large robotic kinematic error causes significant deterioration to the surface shape of aspheric optics during robotic bonnet polishing (R-BP). To address this problem, research on the evaluation and compensation of the kinematic error was conducted to enhance the prepolishing accuracy on large aspheric surfaces by R-BP. Firstly, a precession control model of R-BP applied to the polishing of large aspheric surfaces was proposed. Then, an evaluation and compensation method of a robot kinematic error was presented based on machining errors. At last, it had been verified by experiments that at the removal depth of 2.5 μm, the variation of surface shape was reduced from 0.42 μm to 0.11 μm after compensation. Meanwhile, the change rate was reduced from 16.8% to 4.4%. Hence, the effectiveness of evaluation and compensation method to improve the prepolishing accuracy was verified, which is beneficial to implement mass production of high-precision large aspheric surfaces with low cost.