喷管轴线、摆角等参数的红外光电探测

提出了一种基于多目视觉红外光电探测和圆锥曲面拟合的喷管轴线、摆角等参数估计方法.假定前端装有红外LED发光板和红外滤光片的4台高速相机实现了同步数据采集,且已完成标定.以红外反光标记球贴着喷管表面移动的大量三维坐标采样为基础,采用圆锥曲面拟合的方法求取喷管轴线的向量表示以及喷管圆锥曲面的虚拟顶点.通过喷管摆动的大量瞬时转轴拟合得到最小二乘意义上的摆动轴.将喷管轴线和摆动轴的公垂线与喷管轴线的交点作为摆心.喷管在摆动前后任意两时刻间的摆角可以用喷管上标记点的前后坐标到摆动轴的垂线向量的内积求得.摆角变化量除以时间间隔可得摆动角速度.摆动角速度的变化量除以时间间隔可得摆动角加速度.使用双轴摇摆-直线升降运动校准装置模拟喷管运动,摆心位移、摆角、摆动角速度和角加速度的测量误差分别为0.17mm、0.03°、0.12(°)/s、0.4(°)/s2.实验结果证明了算法的可行性.

Estimation of nozzle axis and vector angle by infrared photoelectric measurement technology

An innovative axis of nozzle estimation method from multi-camera stereo image sequences based on IR reflective markers is presented in this paper. It is assumed that four high speed cameras fixed IR LED board and IR filter have been calibrated previously. Firstly, the coordinate of several markers for each stereo pair is determined from the sequences of stereo images, and then the correspondence between markers is established by relations of markers' coordinate. Secondly, the axis of nozzle is fitted based on a large amount of sample of IR markers coordinates, and the cone apex and the vector of cone axis are estimated. Thirdly, a mass of axis of rotation of nozzle are estimated and used to fit the optimized axis of rotation by least square method, and then the common vertical line between nozzle axis and axis of rotation. The pivot point is obtained from the intersection point of nozzle axis and the common vertical line. Finally, the vector angle, angular velocity and acceleration of nozzle rotation are estimated by the relation between these markers coordinates and the time instant. The virtual simulation experiment is conducted using synthesized stereo image sequences based on 6-DOF motion platform and the experimental results prove the validity of our approach.