应用卡尔曼滤波技术的激光熔覆宽度检测

Application of Kalman filter in laser molten pool width detection

对金属零件激光成形过程闭环控制系统中,熔覆宽度的检测技术进行了研究,提出了一种基于卡尔曼滤波技术的熔覆宽度检测方法。利用视觉传感系统获取激光加工过程中的熔池图像,经过图像处理与图像标定求熔覆宽度作为参量建立系统状态方程和测量方程,应用卡尔曼滤波算法对图像上的熔宽和熔宽变化进行状态估计,得到最小均方差条件下的熔覆宽度最佳预测值,从而减小过程噪声和测量噪声引起的熔覆宽度测量偏差,测量平均误差由0.028 mm降为0.009 3 mm,实现加工过程熔覆宽度的精确检测。实验结果证明:将卡尔曼滤波技术应用到熔覆宽度检测过程中可以大大提高熔宽检测精度。

The laser molten pool width detection technology of the closed-loop control system in metal parts laser forming process was researched. A method of applying Kalman filtering for molten pool width detection in laser forming process was presented. The vision sensing system collected the images of the molten pool in laser forming process. The molten pool width calculated by image processing was used as a parameter to establish a state equation and a measurement equation. A Kalman filter recursively computed the solution over least squares approaches to equations which were established based on an estimation of the width and the displacement in width. The Kalman filter optimized the estimation of the molten pool width at the next sampling time and reduced the measurement errors caused by the process and sensor noises. Experiment results show that measurement average errors decrease from 0.028 mm to 0.009 3 mm. Experiments demonstrate the effectiveness and great improvement of precision by using the proposed algorithm in the molten pool width detection.