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

An important aspect in recycling and reuse for environmentally conscious manufacturing is disassembly. Although disassembly systems contain the same basic elements as assembly systems, the disassembly problem differs significantly from the assembly problem due to the fact that the incoming disassembly product is not controlled. In addition, complete dismantling of products is not necessarily required for disassembly, whereas assembly builds a product completely. This paper describes a model for automated disassembly that accounts for workcell interaction and used product constraints. The model provides an essential means to determine, in real–time, the next component for disassembly using the knowledge of the product design and sensor feedback minimizing the steps to remove goal components. Sets of components for removal were resolved by minimizing setup time for disassembling the component. Given the model, a controller for product disassembly is defined that can account for missing and known replacement components. The controller can recover from unknown replacement components and jammed components when alternate removal sequences exist to meet the cell goal. Two case study examples are presented and experimentally simulated. Simulation results based on real product, vision sensor measure, and process input are presented and discussed. It is expected that the concepts demonstrated through these case studies can provide useful insights into other mechanical assemblies.