A study of network emulation for IP network-based control system of a small motor

In networked control system (NCS) though IP networks, there are the issues such that time delays, its jitter and packet losses cause control performance degradation. Hence, many control schemes against the issues have been developed. For evaluating the effectiveness of the scheme, control experiments generally need to be done under actual IP networks. However, in actual networks, it is difficult to experiment under various conditions. Hence, the evaluation should be done under networks emulated by emulators because they can make the various realistic conditions. Therefore, it is important to confirm the validity of emulator in the case of using in NCS. In this paper, we discuss the validity of a popular network emulator built-in Linux, called netem, in terms of NCS. As a result, it has been found by experiment that netem in a recent Linux kernel can work well as emulator in NCS.