激光结构光测量连续调节智能光源控制器设计

Continuous smart light source controller design for laser structure light measurement

激光结构光视觉测量过程中被测物体的表面材质差异、表面几何曲率大小均会影响到实际采集的激光光斑图像质量,从而影响到测量数据处理的精确度和准确性。为了适应工业测量中多变的被测对象特性和使用环境,对结构光源的激光二极管进行电流控制。在分析m W级别小功率激光二极管工作特性的基础上,提出了一种使用上位机和ARM微控制器的微小功率半导体激光器智能控制器的低成本设计方案。研究了数字PWM信号驱动激光二极管的技术,使用ARM微控制器生成PWM信号输出,然后PWM数字信号通过光电隔离的阻容滤波电路、运放电压跟随、调理电路以及压控恒流源电路(V-I)驱动半导体激光二极管的电流大小。激光控制器的PWM信号的占空比、基准频率通过上位机串行Modbus协议通讯进行快速设定。系统经过激光结构光投影成像实验进行验证,适时调整激光结构光输出强度大小,可优化激光视觉测量系统的测量输出和适应性。通过实验验证的结果表明,系统可以稳定运行。

During the measurement procedure of laser structure light vision,the measurement object material surface difference and geometric curvity would both affect the laser light-spot image quality,and influence the precision accuracy of measurement data processing.For adapting to application various circumstances of industrial measurement,the current controlling of laser diode of structure light was adopted.A low cost miniwatt semiconductor laser controller design solution was submitted based on the analysis of laser diode performance.The PWM signal driving technique was researched in this paper,which applied ARM MCU to generating PWM output signals,and then signals were transformed into analog laser controlling signal by cascade circuits of the resistance-capacitance filter circuit with optoisolator,operational amplifier follower and voltage controlled constant current source(V-I)circuit.The ratio and reference frequency of PWM signal could be set by the modbus serial agreement between host machine and laser controller.A series of imaging experiments with laser structure light projection were be done,which indicated adjusting laser structure light output at the right level would be able to optimize the measurement result and improve the adaptability of laser vision system.The experimental results show that the system can run stably.