Research on position and posture measurement system of body and cutting head for boom-type roadheader based on machine vision

Aiming at the problem of measuring the position and posture of the body and cutting head for boom-type roadheader in underground coal mine,the position and posture measurement system of the boom-type roadheader was proposed,which were based on the laser beam and infrared target.Three laser orientation instrument were installed at the top of the roadway of the driving face,and the image of the laser beam were collected by the explosion-proof camera mounted on the machine body,and the laser beam were detected by the improved random Hough transform.A two-point and three-line algorithm model was established to calculate the position and posture of the machine body in roadway coordinates.Meanwhile,the image of light spot were collected by the other explosion-proof camera，the central position of the light spots were ascertained by using the algorithm of gaussian surface fitting.The calculation model of the posture and position of the cutting head was established based on dual quaternions,which was used to complete the calculation of the position and posture of the cutting head.Combined with the transformation relation between the machine body coordinate system and the roadway coordinate system,the central point position of cutting head in roadway coordinate system were obtained.Finally,vision measurement platform for the boom-type roadheader was set up，and simulate the position and posture of the body and cutting head in actual working condition,the experimental results show that the posture measurement error of the cutting head in roadway coordinates is within 0.5°,and the position measurement error of the cutting head in roadway coordinates is within 40 mm,which can meet automatic,accurate and real-time measurement requirements of boom-type roadheader.