结构件构形与图象编程智能化研究

On Feature Modelling and Intelligent Graphics NC Programming

本文对结构件构形与图象编程智能化作了一些研究。在构形方面提出以平面约束法作为结构件特征造型的实现手段,在数控编程方面提出以加工单元实现为总目标,并将总目标的实现归结为寻求八个子目标的解。在这个智能化系统中,知识模型用概念空间来表示,在概念空间中,推理是概念之间的一种联想,根据概念的抽象度不同,联想可分为纵向、横向、回溯三种方式。文中侧重讨论了自动产生加工单元模式这个子目标。

This paper discusses three aspects of CAD/CAM of aircraft structural components: (1) feature modelling (2) graphics NC programming (3) schema of machined unit and automatic recognition. For convenience, previous research will be separately and briefly reviewed and then new contributions of this paper will be explained. 3D model of aircraft structural component must be constructed before NC programming can start. Current modelling methods[1-3] appear to be unsuccessful because the geometry of aircraft structural component is too complicated. The present paper improves the plane-constraining method of the 1st author [12] and the result, feature modelling, is believed to succeed where references [1-3] fail. Feature modelling can be essentially summed up as follows: keeping geometrical details in mind, we define a set of halfspace planes, which are used to construct the 3D model. References[4-6] discuss two kinds of NC programming methods after 3D model for non-aircraft structural component was constructed, but they do not consider process planning; as a result, the degree of automation is relatively low. The intelligent graphics NC programming method presented in this paper integrates NC programming with process planning and thus attains a relatively high degree of automation. In references [8-9], machined unit can be abstracted from 3D model and contains only geometric information, so it is not useful in process planning. The machined unit employed in this paper contains not only geometric information but also processing information, making it possible to achieve integration of 3D model, NC programming, and process planning. In this paper are given details about schema of machined unit and about rules for automatic recognition.