Petri Net Approach of Collision Prevention Supervisor Design in Port Transport System
AbstractModern port terminals are equipped with various localtransport systems, which have the main task to transport cargobetween local storehouses and transport resources (ships,trains, trucks) in the fastest and most efficient way, and at thelowest possible cost. These local transport systems consist offully automated transport units (AGV- automatic guided vehicle)which are controlled by the computer system. The portcomputer system controls the fully automated transport units inthe way to avoid possible deadlocks and collisions betweenthem. However, beside the fully automated local transportunits, there are human operated transport units (fork-lifttrucks, cranes etc.) which cross the path oftheAGVfrom timeto time. The collision of human operated transp011 unit andA GV is possible due to human inattention. To solve this problem,it is necesswy to design a supe1vismy control system thatcoordinates and controls both human driven transport unit andA G V In other words, the human-machine interactions need tobe supen·ised. The supen•ising system can be realized in the waythat the port terminal is divided into zones. Vehicle movementsare supen•ised by a video system which detects the moving ofparticular l'ehicles as a discrete event. Based on detected events,dangerous moving of certain vehicles is blocked by the supe1visi11gsystem. The paper considers the design of collision preventionsupen•isor by using discrete event dynamic themy. The portterminal is modeled by using ordi1za1y Petri nets. The design ofcollision prevention supe1visor is cmTied out by using the P-inl'ariantmethod. The verification of the supervisor is done bycomputer simulation.
(1] Desrochers, A. A., Al-Jaar, R. Y.: Applications of Petri
Nets in Manufacturing Systems. IEEE Control Systems
Society, IEEE press, 1995, New York.
(2] Haoxun, C.: Control synthesis of Petri nets based on
S-decreases. Discrete Event Dynamic Systems, KJuwer
Academic Publishers, val. 10, no. 3, Netherlands 2000,
(3] Harustak, M., Hruz, B.: Supervisory control of Discrete
event systems and its solutions with the Petri net P-invarijants,
IFAC Conf. on Control Systems Design (CSD'
/2000), Bratislava, Slovak Republic 2000, pp. 390-394.
(4] Kezic D., Peric N., PetroviC I.:An Iterative Siphon Control
Algorithm for Deadlock Prevention Based on Petri
net, Automatika, vol47, no. 1-2/2006, pp. 19-30.
(5] Kezic D., Antonic R., Racic N.: Automatic Supervisory
System Synthesis for Port Cranes Collision Prevention by
Using Petri Net, Pro met, vol18, no. 3/2006, pp. 143-150.
Lee, J. S., Yhou, M. C.: An Application of Petri Nets to
Supervisory Control for Human-Computer Interactive
Systems, Automatica, IEEE Transactions on Industrial
electronics, vol. 22, no. 5, 2005, pp. 12201226.
(7] Murata, T.: Petri Nets: Properties, Analysis and Applications,
in Proc. ofthe IEEE, 77(4), 1989, pp 541-580.
(8] Yamalidou, K., Moody, J., Lemmon, M., Antsaklis, P.:
Feedback Control of Petri Nets Based on Place Invarijants.
Automatica, val. 32, no. 1, 1996, pp.J5-28.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).