基于激光测距仪的视觉对准技术研究

Visual alignment technology based on laser rangefinder

针对机械臂末端视觉系统的姿态校正问题,提出了一种借助激光测距仪实现视觉对准的技术。首先建立了相机成像模型和手眼关系模型,利用标定方法分别求解了相机标定和手眼标定;然后建立了机械臂末端激光测距仪位置标定模型,利用基于平面约束的非线性优化算法,求解了机械臂末端法兰坐标系下激光源坐标和激光光束的单位方向向量;最后建立了视觉对准模型,对投射到目标平面上的激光点拟合了平面方程,并获得了平面单位法向量;结合手眼关系和对准关系,运用优化算法求解了机器人姿态修正角,将该姿态角发送给机器人,使其调整末端位姿,最终实现了相机平面与目标平面的对准。研究结果表明:相机姿态在10°范围内校正误差为0.6°以内,相比于基于PNP原理的姿态校正方法,该技术具有更高的精度和更好的稳定性。

Aiming at the posture correction of the vision system at the end of the manipulator,a technique of vision alignment with laser rangefinder was proposed.Firstly,the camera imaging model and the hand-eye relation model were established.Then the position calibration model of the laser rangefinder at the end of the manipulator was established and the nonlinear optimization algorithm based on plane constraint was used to solve the laser source coordinates and the unit direction vector of the laser line in the coordinate system of the end flange of the manipulator.Finally,a vision alignment model was established.The plane equation was fitted to the laser points projected on the target plane and the plane unit normal vector was obtained.Combined with the hand-eye relationship and the alignment relationship,an optimization algorithm was used to solve the posture correction angle of the robot,and the posture angle was sent to the robot to adjust the end pose to finally align the camera plane with the target plane.The results indicate that the camera attitude correction error within 10°is within 0.6°,and it has higher precision and better stability compared with the posture correction method based on PNP principle.