A new stability analysis and time-delay tolerance estimation approach for output feedback networked control systems

Networked Control Systems (NCSs) has been recognized as an area where theory is behind the development of technology. The defining feature of NCSs can be considered as the information is exchanged through a network among control system components. So the network induced time delay is inevitable in NCSs. This 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 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. In this paper, a new finite difference approach is proposed for estimating the maximum time-delay tolerance in output feedback NCSs. The method is applied to dynamic feedback controller NCSs and the results are compared with the ones published in the literature.