一种基于压电驱动器的新型高速激光扫描器的研制和测试

Study and Test on a Novel Fast Laser Scanner Based on Piezo-Actuators

激光扫描器是激光雷达、激光检测和激光加工等系统的重要部件,现有激光扫描器难以实现低惯量高频率匀线速扫描。设计了一种基于新型压电驱动器的激光扫描器,该扫描器的机械扫描角度可达±0.35°,一阶谐振频率达1872 Hz。利用有限元分析软件对扫描器结构进行了设计。频率响应曲线显示扫描器具有较复杂的模态,测试了多个频率(100,400,700 Hz)下的三角波驱动扫描波形、频谱和扫描线照片,结果显示压电迟滞效应和扫描器机械谐振对扫描线性度的影响很大。设计了软件补偿迟滞效应和串联硬件陷波器抑制谐振相结合的开环控制方法,加控制器后的100 Hz和400 Hz三角波扫描非线性度分别从6%,27%减小到了2%,7%,实现了高速线性扫描。

Laser scanner is one of the most important components in lidar, laser detecting, laser processing, and so on. Existing scanners are difficult to realize fast linear scanning with low moment of inertia. A fast laser scanner based on novel piezoelectric actuators is designed, which has mechanical scanning angle of ± 0. 35° and first resonance frequency of 1872 Hz. Finite element analysis is used to design the scanner structure. Measured frequency response curve shows that the modes of the scanner are complicated. The scanning waveforms, spectrums and scan line images of triangle waveform actuated scanning at several frequencies are tested. The test results show that the hysteresis behavior and the resonances affect scanning linearity seriously. An open loop control method is designed, which consists of a software hysteresis compensator and notch filters in serials. The comparison of scanning waveforms and scan line photos of triangle waveform actuated scanning with and without open loop controller shows that the scanning linearity is improved effectively. The scanning nonlinearities of 100 Hz and 400 Hz triangle wave scanning reduce to 2 % and 7 % respectively from 6 % and 27 %. The scanner realizes fast linear scanning.