摘要
工业机器人完成工件的拾取、分拣与装配等任务,需要获得准确的位置信息。而目标检测算法的回归损失函数的设定会直接影响预测框的定位准确性。针对SSD原始回归损失函数忽略4个边界信息的相关性及与评价指标IoU变化不匹配等问题,提出了一种基于改进SSD的工件定位算法。所提算法以高效交并比(EIoU)为SSD的回归损失函数,将4个边界信息作为一个整体,并添加了中心点损失和边长损失2个惩罚项分别表征预测框与真实框的中心点相对距离和边长差异,解决了边框回归不准确的问题。实验结果表明:所提算法能把定位平均误差控制在0.18 mm以内,误差峰值控制在0.76 mm以内。所提算法能有效提高工件的定位精度,适用于不同类型的工件或其他类似的定位任务,具有良好的工业应用前景。
Accurate position information is essential for the robots to complete tasks such as picking,sorting,and assembling workpieces.However,the location accuracy of the prediction box is sensitive to the design of the loss function of the object detection algorithm.The four boundary information's correlation is disregarded in the SSD original regression loss function,which also does not account for changes in the evaluation index IoU.In response to the above problems,a workpiece location algorithm based on improved SSD is proposed.To address the problem of inaccurate bounding box regression,the suggested algorithm uses efficient intersection over union(EIoU)as the regression loss function of SSD.To represent the closeness of the center points and the difference in side length between the prediction box and the ground truth box,respectively,two penalty terms representing center point loss and aspect loss are added to the four boundary information as a whole.Experimental results demonstrate that the average location error is no more than 0.18 mm and the peak error is below 0.76 mm.The proposed algorithm not only can effectively improve the accuracy of the workpiece location but also work well in different kinds of workpieces or similar location tasks,which is promising for industrial applications.
作者
李琳
符明恒
张铁
邹焱飚
LI Lin;FU Mingheng;ZHANG Tie;ZOU Yanbiao(School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510006,China)
出处
《北京航空航天大学学报》
EI
CAS
CSCD
北大核心
2023年第6期1260-1269,共10页
Journal of Beijing University of Aeronautics and Astronautics
基金
广东省科技计划(2020A0103010)。
关键词
工件
定位
损失函数
单步多框目标检测
高效交并比
workpiece
location
loss function
single shot multibox detector
efficient intersection over union
