Autonomous Robotic Disassembly in the Blocks World

Abstract

This article describes a fully functional autonomous system with two cooperating robots that disassembles complex Duplo 1 structures in a restricted environment. The system operates on a table-top world with any number of Duplo structures for which object models have been given. The structures are disassembled down to individual parts, using basic operations of single part removal, object partitioning, and the addition of stabilizing supports to structures that would otherwise fall over. All aspects are automatically planned, including operation selection, path and grasp planning, and simultaneous cooperative robot motion. Operations are chosen so as to not create unstable structures and to not risk breakage in areas of low structural integrity. Overall planning is done with a process mechanism that heuristically generates efficient disassembly sequences, without searching a space of all possible operations. Several examples of actual system operation, using real robots, are presented.

Modeling and supervisory control of a disassembly automation workcell based on blocking topology

“…Spath [10] outlined an information system for disassembly. Schmult [11] created a complete system for disassembly of block structures, which simplifies the domain of possible motions to disconnect parts. Little work, however, has been done on modeling and control of an automated disassembly system which takes into account the product configuration variations or uncertainties, particularly in the context of real-time supervisory control.…”

An intelligent disassembly assistant for man-machine demanufacturing

“…Schmult [4] implemented stability analysis in the automated system to prevent a disassembly operation that leaves the product unstable. A similar stability analysis is performed in the combined man-machine system.…”

“…In block structures, these individual center of mass coordinates are compared to the maximum X and Y extents of the feet structure to determine stability [4]. The block with its center of mass farthest from the feet is chosen for removal because it results in the most stable structure.…”

“…In the previous work [4] that focused on automated disassembly, the stability analysis can determine the entire disassembly sequence prior to disassembly because it is assumed that the robot will remove items in the appropriate sequence. In the case of human directed disassembly, the human operator may not perform the directed task.…”

“…Schmult [4] developed a system for automated disassembly of block structures for a fully automated system. This system addresses the general problem of acquiring desirable or undesirable material from a product, or segregation of dissimilar materials.…”