针对高功率激光系统中传统小工具抛光方式带来的较大中频误差影响高功率激光系统稳定性和可靠性的问题,提出了基于简谐运动的复合摆动轨迹抛光方法,并建立了数控多杆机构复合摆动轨迹抛光系统;根据小工具抛光基本原理可知,规则、有序的平转运动轨迹是引入中频误差的重要原因之一。为了提高生成去除函数轨迹的复杂性,提出了基于复合摆动轨迹的去除函数模型,研究了复合摆动轨迹抛光的基本过程和离散化计算方法;选择合适的工艺参数和去除函数轨迹,进行了基于复合摆动轨迹的去除函数与基于传统平转运动的去除函数的对比加工实验。结果表明:通过干涉仪测量可知,复合摆动轨迹加工方法得到的面形干涉条纹比平转运动的更光顺,且无毛刺;在50 mm×50 mm范围内,复合摆动轨迹加工面形的功率谱密度曲线低于平转运动的功率谱密度曲线,整体加工效果优于传统平转运动;基于复合摆动轨迹的数控多杆抛光系统相对于传统平转工艺能有效抑制中频误差。

In high-power laser systems, traditional small-tool polishing results in significant mid-spatial-frequency errors, which reduce the stability and reliability of such systems. In this study, we propose a polishing method that uses the compound swing trajectory (CST) based on a simple harmonic motion and demonstrate a polishing system that employs the CST of a multi-link mechanism. By analyzing the basic principle of small-tool polishing, we observe that the regular and orderly trajectories of traditional translational motion (TM) polishing are important causes of the mid-spatial-frequency errors. Further, we propose a function model based on a CST, study the basic polishing process, and perform the discretization calculation for such trajectories to improve the complexity of the trajectory of the removal function. We conduct a processing experiment by selecting appropriate process parameters and trajectories for the removal functions to compare the CST with the traditional TM. Subsequently, we measure the wavefronts using interferometers and observe that the interferometric fringe patterns obtained using the CST processing method are without burrs and smoother than those obtained using TM processing method. The power-spectral-density curve obtained using the CST processing method is lower than that obtained using the TM processing method in 50 mm×50 mm, displaying a better overall processing effect. These experimental results denote that a polishing system using the CST of a multi-link mechanism exhibits a significantly greater capability in suppressing mid-spatial-frequency errors when compared with the TM method.