A trade-off model for performance and security in secured Networked Control Systems

Networked Control Systems (NCS) is a fast growing technology that integrates distributed sensors, actuators, and computing processors over a communication network for a vast amount of applications. However, the NCS can be vulnerable to various network attacks when the network used is insecure (e.g., Internet). Thus, secure NCS need to have embedded security mechanism to ensure its security operating requirements, which may sacrifice its performance due to limited system resources. This paper addresses the trade-off between NCS security and its real-time performance and use a secured networked DC motor system for illustration. This paper will present a trade-off model for system dynamic performance and system security. This model can be used to adapt security configurations to provide sufficient protection and satisfy real-time dynamic performance requirements of the NCS simultaneously. The construction of this model includes the development of a set of metrics to quantitatively measure the performance and security levels of NCS and the development of a trade-off objective function incorporating performance and security. A Simulink based test-bed implemented to control the speed of the DC motor is used to illustrate the effectiveness of this model.