A Deadlock Prevention Policy Based on Complementary Places

For Petri net models of flexible manufacturing systems,this work proposes a method to design liveness-enforcing supervisors based on complementary places.Firstly,a finite-capacity net珦Nis obtained from a given Petri net N by adding a capacity function K.Then,by increasing K to Kmax,the maximal reachability set of live finite-capacity net珦Nis computed and the complementary-place transformation is used to obtain the live system N′.Finally,an example of S3PR net is provided to compare with some other approaches proposed in prior work.Comparison results show that the liveness-enforcing supervisor obtained by the proposed method has simpler structure and more permissive behavior in some cases.Furthermore,another example of S3PGR2net shows that the proposed method can be applied to the general Petri nets.