针对大功率半导体直接输出激光加工系统的应用, 本文搭建了由大功率半导体激光器、工控机、机械手运动系统、测温仪和WAGO通讯模块等组成的激光加工系统的硬件平台, 提出了大功率半导体激光直接输出加工过程中激光加工温度的控制方法, 设计了基于Lab Windows/CVI交互式软件开发环境的PID和模糊控制算法, 并且通过现场实验对两种控制算法的各个参数进行了精确整定。整定后的PID和模糊的温度控制效果良好, PID控制的温度峰值时间只有0.45 s, 最大超调量为3.28%, 稳态均方根误差为1.01 ℃; 模糊控制的温度峰值时间为0.93 s, 最大超调量为1.5%, 稳态均方根误差为2.22 ℃。为了对比两种控制策略的实际控制效果, 以设定温度为1 250 ℃, 启动功率为500 W, 45#钢基体为实验条件, 分别对整定后的PID控制和模糊控制以不同的扫描速度进行激光相变硬化实验, 实验发现随着扫描速度的增加, PID控制与模糊控制的稳定性都有所降低, 但是在相同扫描速度下, 模糊控制的超调量较小, 温度控制更稳定。因此模糊控制策略更适合于本控制系统, 最终本系统采用模糊控制作为激光加工的温度控制策略。

For the application of high power semiconductor direct output laser processing system, a laser processing system platform was built composed by high power semiconductor laser, industrial host, robot motion system, thermometer and WAGO communication module. A method of the temperature control in high power semiconductor direct output laser processing was proposed, PID and fuzzy control algorithms were designed which were based on Lab Windows/CVI interactive software development environment, and the parameters of the two control algorithms were adjusted accurately through field experiments. PID control and fuzzy control which were adjusted worked well, PID control of temperature peak time was only 0.45 seconds, the maximum overshoot was 3.28%, the RMSE was 1.01 ℃; Fuzzy control of temperature peak time was 0.93 seconds, the maximum overshoot was 1.5%, the RMSE was 2.22 ℃.To compare the effects of the two control strategies in actual processing, laser transformation hardening experiments were carried out at different scanning speed based on the PID control and fuzzy control. It was found that the stabilities of PID control and fuzzy control were reduced with the increasing of scanning speed, but at the same scanning speed, the processing temperature of fuzzy control had a smaller overshoot, temperature controlling was more stable. So fuzzy control strategy was more adaptive to the system, and finally the system chose fuzzy control as the strategy of laser processing temperature control system.