基于机器视觉的斜齿轮螺旋角在线检测方法研究

Research on on-line detection method of helical gear helix angle based on machine vision

针对斜齿轮螺旋角测量难度高、测量装置复杂、测量耗费工时过多、难以实现在线测量等问题,以斜齿圆柱齿轮为研究对象,提出了一种结合曲线拟合的斜齿轮螺旋角机器视觉测量方法。首先,设计并搭建了与端面测量系统相结合的斜齿轮螺旋角视觉测量系统,使用双远心镜头相机采集了斜齿轮侧面图像,对齿形进行了建模与分析,验证了方法的可行性;然后,采用统计结构元素的方法判定了斜齿轮的旋向,先后利用结合同态滤波的canny算子以及基于改进的击中击不中变换的斜率筛选算法,对斜齿轮侧面图像进行了处理,得到了齿线边缘图;最后,通过拟合得出单条齿线的解析式,再利用其余齿线边缘点与解析式坐标的方差优化解析式,得到了斜齿轮的螺旋角,结合设计值对实验结果进行了验证。实验及研究结果表明:该方法测量速度约1 s,斜齿轮螺旋角测量误差可达4.38′,斜齿轮旋向测量准确;该方法的测量系统能够在测量齿轮的齿数、齿顶圆直径、分度圆直径等参数的同时,测量斜齿轮的螺旋角和旋向,满足工业快速在线检测的要求。

Aiming at the problems of helical angle measurement of helical gear,such as high difficulty,complex measurement device,too much measurement time and difficulty in realizing on-line measurement,helical cylindrical gear was taken as the research object,and a machine vision measurement method combined with curve fitting was proposed.Firstly,a helical gear helix angle visual measurement system combined with the end face measurement system was designed and built.The side image of helical gear was acquired by using a double telecentric lens camera.The tooth profile is modeled and analyzed to verify the feasibility of the method.Then,the rotation direction of the helical gear was determined by the method of statistical structural elements;the rotation direction of helical gear was determined by the method of statistical structural elements.The canny operator combined with homomorphic filtering and the slope screening algorithm based on improved hit miss transformation were used to process the side image of helical gear,and the tooth line edge map was obtained.Finally,the analytical formula of a single tooth line was obtained by fitting,and then the analytical formula was optimized by using the variance between the edge points of the other tooth lines and the analytical coordinates to obtain the helical angle of the helical gear.Combining with the design value,the experimental results were verified.The experimental results show that the measurement speed of the proposed method is about 1 s,the measurement error of helical angle of helical gear can reach 4.38′,and the rotation direction of helical gear is accurate.The measuring system of the proposed method can measure the number of teeth,the diameter of tooth tip circle,the diameter of indexing circle and other parameters of the gear,and measure the helix angle and direction of helical gear at the same time,which can meet the requirements of industrial rapid on-line detection.