TITLE:
Wireless Fault-Tolerant Controllers in Cascaded Industrial Workcells Using Wi-Fi and Ethernet
AUTHORS:
Tarek K. Refaat, Ramez M. Daoud, Hassanein H. Amer
KEYWORDS:
Fault Tolerance; Networked Control Systems (NCS); Industrial Informatics; Wi-Fi; Ethernet
JOURNAL NAME:
Intelligent Control and Automation,
Vol.4 No.4,
November
13,
2013
ABSTRACT: A Wireless Networked Control System using 802.11b is used to model fault-tolerance at the controller level of an industrial workcell. The fault-tolerance study in this paper presents the cascading of two independent workcells where each controller must be able to handle the load of both cells in case of failure of the other one. The intercommunication is completely wireless between the cells and this feature is investigated. The model incorporates unmodified 802.11b and 802.11g for communication. Sensors send sampled data to both controllers and the controllers to exchange a watchdog. The fault-free and faulty models are both simulated using OPNET Network Modeler. External interference on the critical intercommunication link is also investigated. Results of simulations are presented based on a 95% confidence analysis, guaranteeing correct system performance.