基于振动点云补偿锻件尺寸在线测量系统研究

Online Measuring System of Forging Dimension Based on Vibration Point Cloud Compensation

目的针对高温锻造生产线检测任务中机械振动造成锻件热态尺寸测量误差较大的问题,提出基于加速度传感器的振动点云补偿方法。方法振动点云补偿方法是在激光相机中内置加速度传感器获取振动信号,在检测出相机振动的加速度后,通过二次积分求解出相机在3个方向上的位移量,并通过旋转矩阵变换得到对应点的坐标值,从而对相机振动带来的点云偏差进行补偿和校正。在完成对点云偏差的修正之后,利用Halcon中的模板匹配算法对锻件点云进行匹配。结果搭建了具有加热、镦粗、预锻等工序的汽车轮毂机器人自动化锻造生产线,根据锻造工艺要求,使用所研制方法对高温锻件产品进行了关键尺寸的在线测量。经补偿后,锻件点云尺寸平均测量误差由±0.9 mm降低至±0.1 mm,标准差由0.52 mm降低至0.056 mm。结论采用二氧化硅气凝胶隔层降噪、增加防振结构件及隔热恒温等措施,使用蓝紫线激光3D相机,并通过基于加速度传感器的振动点云补偿算法,可以满足锻造自动化生产线的在线检测要求,能够提高锻造生产线高温锻件尺寸的检测精度、降低尺寸检测的不稳定性。

The work aims to propose a vibration-point cloud-compensation method based on the acceleration sensor to solve the large forging thermal dimensional measuring error in detection task caused by the mechanical vibration in the high-temperature forging production line.First,the vibration signal was obtained through the built-in acceleration sensor in the laser camera.After the acceleration of the camera vibration was detected,the displacement of the camera in three directions was solved by secondary integration.Subsequently,the coordinate value of the corresponding point was obtained by the rotation matrix transformation so as to compensate and correct the point cloud deviation caused by the camera vibration.Finally,the forging point cloud was matched with the template matching algorithm in Halcon.The automatic forging production line of automobile wheel hub robot with heating,upsetting and preforging processes was built,and the key dimensions of high-temperature forging products were measured online with the developed method.After the forging point cloud was compensated,the average measurement error of dimensions was reduced from±0.9 mm to±0.1 mm,and the standard deviation was reduced from 0.52 mm to 0.056 mm.Through the vibration point cloud compensation method based on the acceleration sensor,as well as silica aerogel insulation,vibration structural parts,heat insulation and constant temperature,blue violet laser 3D camera and other measures,the online detection requirements of automatic forging production line can be met,the dimensional detection accuracy of high temperature forgings in the forging production line can be improved,and the instability of dimensional detection can be reduced.