Fault Tolerant Control in NCS Medium Access Constraints

This paper deals with the problem of fault-tolerant control of a Network Control System (NCS) for the case in which the sensors, actuators and controller are inter-connected via various Medium Access Control protocols which define the access scheduling and collision arbitration policies in the network and employing the so-called periodic communication sequence. A new procedure for controlling a system over a network using the concept of an NCS-Information-Packet is described which comprises an augmented vector consisting of control moves and fault flags. The size of this packet is used to define a Completely Fault Tolerant NCS. The fault-tolerant behaviour and control performance of this scheme is illustrated through the use of a process model and controller. The plant is controlled over a network using Model-based Predictive Control and implemented via MATLABcopy and LABVIEWcopy software.