The decision-making of process sequence in CAPP is the key problems that have not been solved properly until now.A new decision method of process sequence was proposed based to Petri nets using T_invariant.First of all,a Petri net process sequence model based on rule was built according to the principle of Petri net and the production rule.Then,a alternative process plans T-invariant creating algorithm was given considering process constraints.Finally,a case was studied to verify the reason and validity of the algorithm.The results show that the decision-making of process sequence with the proposed method herein can obtain the best/hypo-best process plans in alternative process plans.

针对计算机辅助工艺设计中一直没有解决的加工顺序决策问题,提出了一种新的基于Petri网T_不变量的加工顺序决策方法。首先根据Petri网原理和产生式规则建立了一个基于规则的加工顺序决策Petri网模型;然后在考虑工艺约束的条件下,给出了可选工艺路线T_不变量的生成算法;最后通过一个实例验证了该算法的合理性和有效性。实例结果表明,所提出的决策方法能够实现从可选工艺路线中得到最优/次优的工艺路线。

 

Petri网, T_不变量, 工艺约束, 加工顺序, 决策方法, CAPP