Automatic Assembly Feature Recognition and Disassembly Sequence Generation

Abstract

This paper describes a system for the automatic recognition of assembly features and the generation of disassembly sequences. The paper starts by reviewing the nature and use of assembly features. One of the conclusions drawn from this survey is that the majority of assembly features involve sets of spatially adjacent faces. Two principle types of adjacency relationships are identified and an algorithm is presented for identifying assembly features which arise from “spatial” and “contact” face adjacency relationships (known as s-adjacency and c-adjacency respectively). The algorithm uses an octree representation of a B-rep model to support the geometric reasoning required to locate assembly features on disjoint bodies. A pointerless octree representation is generated by recursively sub-dividing the assembly model’s bounding box into octants which are used to locate: 1. Those portions of faces which are c-adjacent (i.e. they effectively touch within the tolerance of the octree). 2. Those portions of faces which are s-adjacent to a nominated face. The resulting system can locate and partition spatially adjacent faces in a wide range of situations and at different resolutions. The assembly features located are recorded as attributes in the B-rep model and are then used to generate a disassembly sequence plan for the assembly. This sequence plan is represented by a transition state tree which incorporates knowledge of the availability of feasible gripping features. By way of illustration, the algorithm is applied to several trial components

Design of adaptive function blocks for dynamic assembly planning and control

“…The existing assembly feature definitions in the literature are also domain specific. Sung, Corney, and Clark [8] concluded that what these definitions have in common is that assembly features are the regions of an assembly that help improve the efficiency for the assembly planning. Assembly features can be classified based on different criteria, such as mating relationship, number of connecting form features (surface, edge, corner, etc.…”

Assembly planning and evaluation in an augmented reality environment

“…Assembly features have been widely used to improve the efficiency of the assembly design and planning process (Sung, Corney, and Clark 2001;van Holland and Bronsvoort 2000). In this research, only the geometric attributes of a part are considered as assembly features.…”

Interface Management for Automating Finite Element Analysis Workflows

“…Shahwan [16] extracted interfaces using bounding boxes of components in a DMU to filter non-adjacent components and subsequently check for geometric interactions. Sung [19] used an octree approach to locate assembly interactions for disassembly sequence generation. These interfaces are readily available in the non-manifold cellular model.…”