Automatic Generation of Hierarchical Exploded View Based on Recursive Iteration Method

Abstract

Abstract：A method for generating hierarchical exploded view automatically for complex product using the strategy of recursive iteration and depth-first searching hierarchical assembly sequences is proposed. To meet the requirements of assembly sequence planning (ASP), assembly reconstruction function that can conveniently define subassembly and edit assembly tree is designed. To avoid repetitive interference detection, the method of merging interference matrix based on assembly tree is studied, which can flexibly generate hierarchical structure-oriented assembly relation matrices by integrating the original ones. To reduce the complexity of large-scale ASP, the whole ASP task is divided into sub-tasks of hierarchies according to assembly tree. Within each sub-task, multi-rule screening (MRS) algorithm is applied to circularly construct a sequence, taking interference matrix-based geometric feasibility as precondition while parallelism, continuity, stability and directionality as optimization screening criterions. The proposed recursive explosion algorithm iterates depth-first searching hierarchical assembly sequences and real-time calculating the accumulative bounding box of exploded components to decide the displacement vector of each exploding component. The generated exploded view is full of sense of hierarchy, uniform in interval and compact in structure. An assembly planning system "AutoAssem" is developed on Siemens NX, and a gear reducer and big parts of a car are taken as examples to verify the effectiveness of the method and algorithm.Key words：assembly sequence planning；hierarchical exploded view；recursive iteration；extended interference matrix； accumulative-bounding box 0 前言 *

Intelligent planning of product assembly sequences based on spatio-temporal semantic knowledge

“…An advanced CAD-assisted immune-based strategy has been introduced to obtain an optimal feasible assembly sequence for a given assembled product using assembly attributes . Yu and Wang (2016) designed the reconfiguration function of the assembly structure that can easily define the sub-assembly and edit the assembly tree. A unique assembly sequence generation deterministic method has been proposed to avoid redundant data collection and calculation, which can organize the assembly operations as linear or parallel progression to complete assembly tasks in a minimum number of stages (Bahubalendruni et al, 2019).…”

An Automatic Generation Method of Exploded View Based on Projection

“…Furthermore, the exploded distance and the perspective of the exploded view directly affect the visualization expression of the assembly sequence. Yu Jiapeng et al [6] successively proposed an exploded distance algorithm based on axis aligned bounding box (AABB) and oriented bounding box (OBB); Zhao Hongfei et al [7] adopted fixed direction hulls(FDH) makes the exploded distance of the parts more compact; Li et al [8] proposed the exploded view with dynamic perspective, which enables the exploded view to switch the local exploded position with the movement of the view angle. In addition, considering that it is difficult to express all the details of complex product assembly by single exploded view.Agrawala et al [9] proposed the design rules of step-by-step assembly guidance view; Vieilly et al [10] used the bounding sphere to calculate the exploded distance of parts to generate hierarchical exploded view; Tatzgern et al [11] expressed the corresponding assembly details through the enlarged local exploded view.Through the analysis of the above literature results, we can see that there are still two points to be improved in the problem of automatic generation of exploded view: first, only using bounding box to calculate the exploded distance can obtain a relatively compact exploded view, but due to the lack of consideration of the perspective of the exploded view.Therefore, the generated exploded view often appear the phenomenon that parts block each other in some given view angles (such as equiaxed or oblique axis side views), and this kind of "axonometric view" is usually the most concise and three-dimensional product assembly auxiliary drawing in engineering.…”