Time and error recovery with parameterized Petri nets

A new class of Petri nets (PNs) called parameterized Petri nets (PPNs) is proposed and applied for planning and coordination of intelligent systems. The PPN approach uses a hierarchical organization to deal with the complexity characteristic of net representations, through parameterization of transitions and the use of generalized or parameterized places in higher level nets. Time is introduced in PPNs in terms of a parameter. An error recovery controller is then described based on timed-PPNs.