模糊约束网络在机床产品协同设计冲突检测中的应用

分析了机床产品协同设计中约束的内涵和特点,并用EXPRESS-G图描绘了约束网络的结构模型.将机床产品协同设计中的约束分为硬约束和软约束,从数学上给出模糊约束和模糊约束满足问题的定义.采用遗传算法作为协同设计过程中模糊约束满足问题的求解方法,在遗传算法的运行过程中对软硬约束分别进行了不同的技巧处理,遗传算法利用硬约束通过前向检查算法随机产生几何可行初始群体来限制设计空间,并给出遗传算法的具体实现过程.提出了基于模糊约束网络的冲突检测系统的体系结构,并对原型系统进行开发.最后,以某车床传动轴的设计为例验证了约束在协同设计冲突检测中的应用.

Application of fuzzy constraint network in conflict detection of machine tool's collaborative design

The connotation and characteristic of constraint in collaborative design of machine tool are analyzed.Conformation model of constraint network is demonstrated using EXPRESS-G.Constraint of collaborative design is classified as two types,hard constraint and fuzzy constraint.Fuzzy constraint and fuzzy constraint satisfaction problem are defined mathematically.Genetic arithmetic(GA) is used to resolve fuzzy constraint satisfaction problem in collaborative design.Hard constraint and fuzzy constraint are managed differently in the process of GA.Feasible and initial population are generated randomly using fore-check arithmetic,so design space is limited using hard constraint.A concrete implementation of GA is described in detail.The three-layer system architecture of conflict detection based on fuzzy constraint network is put forward.A corresponding prototype is developed and its running process is described.Finally,an example of driven shaft is presented to show that the system is effective in conflict detection.