Studying The Effect of Sampling Time and Network Load on Wireless Networked Control Systems.

Abstract

Wireless networked control systems (WNCS) are considered one of the main attracting topics in the control, communication and computing domains. One of the main problems that face these systems is the various time delays which occur in the measurements. The control design process would be complicated if there is a time delay in the feedback loop.  Moreover, this delay affects the system performance in terms of instability. The literature of WNCS shows that the available controllers can deal with a limited number of nodes. Beyond this limit, the system becomes unstable. In this paper, an optimized Particle Swarm Optimization (PSO)-based PID and FOPID controllers are proposed for WNCS to control the plant wirelessly. The proposed controllers aim at minimizing the time delays and can make the system remains stable when the network tackles a large number of nodes with variable length packet sizes. The performances of the proposed optimized controllers are compared to show which one of them can be more robust against the challenges of WNCS, namely varying time-delays, to handle a greater number of nodes. The results show that the FOPID is more powerful than the PID controller.