A Precise Method for Computing the Delay Margin of a Networked DC Motor Controller

The recent developments in computing and communication networks paved the way to the Industry Revolution 4.0. In this paradigm different devices are communicating using cheap communication networks to form a networked control system. Networked control systems have two problems, which are data loss and time delay. Not considering these imperfections result in a poor performance or losing the system's stability. Determining the delay margin for the networked control system is a vital step in the controller design. In this paper, we present an accurate method for determining the time delay for a networked control of a DC motor. The transcendental characteristics equation is converted to a frequency-dependent polynomial. Then the the binary iteration algorithm and sweeping test are used to determine the crossing frequencies and hence the delay margin is accurately computed. The results are compared with the results of the latest papers and the sweeping test and the binary iteration prove to give exact values for the delay margin with less computation.