高速CCD激光位移传感器

Development of high-speed CCD laser displacement sensor

介绍了一种用于高速测量的CCD激光位移传感器测量系统,可用于高速、实时地测量运动物体的位移或高速振动。传感器测量系统由光学系统7、500像元的高速线阵CCD、转换速率达40 MHz的高速ADC、高速缓存FIFO、比较器筛选电路、CPLD时钟驱动电路、像元脉冲计数器和数字信号处理器(DSP)构成。系统采用自适应控制方法,通过调节激光的发射频率和输出电流强度来调节发射激光光强,从而适应各种被测对象和外界环境条件。采用特殊设计的比较器筛选电路来控制FIFO对高速A/D采样数据的存储和DSP对高速FIFO中数据的读取,使FIFO只存储CCD输出的有效像元信号,从而减轻DSP数据处理的负担,实现对CCD传感器信号的采集与处理同时进行,满足高速测量的需要。实验结果表明,数据转换速率可达40 M,最小采样间隔时间为0.1 ms,位移分辨率为0.01 mm,重复性为±0.01 mm。

A new kind of Charge Coupled Device（CCD） laser displacement sensor for high-speed measurement was introduced to measure the displacement or high-speed vibration of moving object by the mode of high-speed and real-time. The sensor system is composed of optical system, linear CCD with 7 500 pixels, high-speed Analog-to-Digital Converter （ADC） with convertion.rates up to 40 MHz, high-speed First-In, First-Out （FIFO） memories with clocked reading and writing controls, comparatot selecting circuit and Digital Signal Processor （DSP）. An adaptive control method was adopted to control the light intensity of laser by modulating separately the oscillation frequency and output current of the laser, which made the system suit various specific object or situation. Additionally, the storage data from high-speed A/D converter and the read data from high-speed FIFO could be controlled by a comparator selecting circuit, then only useful pixel signals from CCD were memorized by FIFO. Therefore, the burden of DSP was alleviated, and both acquisition and process for CCD sensor signal could be carried out simultaneously. The experimetnal results show that this system can be used in the field of high-speed measurements of displacement and vibration and can obtain the velocity of data acquisition up to 40 M, minimum sampling interval of 0.1 ms, displacement resolution of 0.01mm and the repetition of ±0.01 mm.