存在视场丢失的机器视觉精度补偿方法

Compensation method for a robot vision system with an occluded camera field

  • 摘要: 无论Eye-in-Hand或Eye-to-Hand型式的机器视觉控制系统,均存在视场受限、丢失等情况,从而无法在一定距离、角度内对目标进行在线视觉测量,进而无法建立全闭环的伺服控制.基于Eye-in-Hand型式的机器视觉控制系统,以及最短测量距离Lmin,提出一种闭环与开环相结合的伺服控制系统:即测量距离大于Lmin时为位置反馈型闭环控制的原位调姿,在测量距离小于Lmin时为位置给定型开环控制,机器人以相对线性运动进给到目标位置.针对该过程中的偏移问题,提出了前馈补偿模型,即利用前期运动数据对运动误差进行估计.实验证明,该方法能有效地补偿定位误差.

     

    Abstract: In both Eye-in-Hand and Eye-to-Hand robotic visual controls, problems such as limited field of view or tracking target loss remain. Thus, online measurement cannot be performed within a certain distance and a certain degree, and a closed-loop control cannot be constructed. Based on Eye-in-Hand visual control and the theoretical shortest measuring distance Lmin, a visual servo combining the closed-loop and open-loop controls was proposed. When above Lmin, an iterative compensation method was proposed to adjust the attitude with the online measured data. In contrast, when below Lmin, a feed-forward compensation for relative linear motion was integrated to improve the positioning accuracy, estimating the error by the data determined by actually moving the path of the robot record by the visual system. As shown by several experiments, this method can effectively enhance the position accuracy.

     

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