Automatic landing method of a reclaimer on the stockpile

摘要

Large excavation reclaimers are used to dig ore and transfer it tonthe blast furnaces that refine the ore into pure metal form. Thenreclaiming job consists of two operations: (1) landing a reclaimernbucket on the surface of a pile and (2) slewing its boom with rotatingnbuckets to scoop the ore. An automatic landing method for choosing wherento dig in a pile of raw ore is proposed to achieve autonomousnreclaiming. The method comprises detecting the shape of a pile,nextracting contour lines of the pile, obtaining the joint angles of thenreclaimer and determining an optimal landing point. A 3D range findernwas developed with laser radar concepts to detect the shape and heightnof the ore pile. A series of image processing techniques for extractingnthe contour line from the 3D range data of a pile is suggested. A heightnmap is obtained from the acquired range data for a pile and a contournmap is obtained through image processing steps, including interpolationnand edge following. The optimal landing point of the bucket on thencontour line is determined so that an overload problem does not occur innthe slewing operation and the reclaiming efficiency can be maximized.nThe algorithm for finding the landing point requires an inversenkinematics solution for the reclaimer. The forward kinematics of thenreclaimer is first obtained. A constraint equation based on thengeometrical relationship is suggested to solve the inverse kinematics ofnthe reclaimer with redundancy. The proposed method was successfullynapplied to a working reclaimer. An autonomous reclaimer is now beingnoperated in the yards of Kwangyang Steelworks in Korea