高精度表面粗糙度外差干涉仪信号处理系统的研制

针对用于磨床加工的光外差表面粗糙度在线干涉测量仪，文中介绍了整机的信号处理系统，着重讨论了两项关键技术。即宽动态范围测量信号的自动控制和高精度动态相位测量，系统的测量精度达２．６°（相当于３．２ｎｍ），允许测量中最大多普勒频移±２０ｋＨｚ（对应高度的变化率±８．７５×１０－３ｍ／ｓ），完全满足磨床加工中表面粗糙度在线测量的要求。现场测试证实了这一点，这对于精加工、超精加工表面粗糙度的在线质量控制、提高加工精度等非常重要。

Research on signal processing system of heterodyne interferometer instrument for measuring surface roughness with high accuracy

To develop a practical, economical and precision heterodyne interferometer instrument for measuring surface roughness on line, the signal processing system is described and two of key technologies, i.e.automatic voltage controlling with broad range and phasemeter with high dynamic accuracy are discussed. The accuracy of the system is 2.6°(3.2nm) and the maximum Doppler frequency shift allowed is ±20kHz(±8.75×10 -3 m/s). The system meets the demand of the measurement in process or on machine and it was verified by practice, which is very important in fine machining or extra fine machining.