Issues of identifying, estimating and using delay times in telecontrol systems based on TCP/IP networks

Today's performant equipment and high speed connections make network control systems a reality. For a series of teleoperation applications like the ones from network control systems domain it is essential to estimate the time delay between the acquisition moment of primary data that needs to be sent and the moment it is available for the receiver's use. This paper presents a methodology for estimating the time delay from experimental measurements, while also taking into account the information loss during transmission. A series of unwanted exceptions that may occur in signal transmission are identified and solution methods are proposed. Based on the above study, three real scenarios were designed for three TCP/IP network types. These scenarios were implemented through simulations for a telecontrol system that uses adaptive PD compensators for the time-varying delays. Finally, the improvement in the system's performances with the PD compensators were validated using real life scenarios.