Enhancement of WNCS response using packet priority

Abstract

The Wireless Network Control System (WNCS) is a new field that merges between wireless sensor network (WSN) and motor control system, this merge has all the advantages of the two fields. But on the other side, will create a new challenge because it accumulates the disadvantages of both. In these systems, sensors and actuators are connected to the controller by a wireless network that presents an additional delay. This delay has a negatory effect because it increases the actuator steady state time. This paper studies the effect of packets delay caused by wireless sensor network (802.11b) on the plant response using TrueTime. The study shows wireless network rapidly raise the steady state time of the actuator when the wireless channel loaded, also it shows that sensor packets delay have more impact on the control system than controller packets. Preemptive schedule type is used to enhance the motor response based on packet priority. Increasing the priority of the sensor packets is a solution that will reduce the steady state time of the motor and increase of the stability time of the system in a wireless network without any additional cost or hardware.