A new stability and time-delay tolerance analysis approach for Networked Control Systems

The key feature of Networked Control Systems (NCSs) is that the information is exchanged through a network among control system components. So the network induced time delay is inevitable in NCSs. The time delay, either constant (up to jitter) or random, may degrade the performance of control systems and even destabilize the systems if the systems are designed without considering the effects of the time delays properly. Once the structure of a NCS is confirmed, it is essential to identify what the maximum time delay is allowed for maintaining the system stability which, in turn, is also associated with the process of controller design. Some studies have been reported in estimation of the maximum time-delay allowed for maintaining system stability. However, most of the reported methods are normally over complicated for practical applications. A new finite difference approach is proposed in this paper for estimating the maximum time-delay tolerance, which has a simple structure and is easy to apply.