Performance Evaluation for Model-Based Networked Control Systems

The performance of a class of Model-Based Networked Control System (MBNCS) is considered in this paper. A MB-NCS uses an explicit model of the plant to reduce the network bandwidth requirements. In particular, an Output Feedback MB-NCS is studied. After reviewing the stability results for this system and some lifting techniques basics, two performance measures related to the traditional H2 performance measure for LTI systems are computed. The first H2 like performance measurement is called the Extended H2 norm of the system and is based on the norm of the impulse response of the MBNCS at time zero. The second performance measure is called the Generalized H2 norm and it basically replaces the traditional trace norm by the HilbertSchmidt norm that is more appropriate for infinite dimensional operators. The Generalized H2 norm also represents the average norm of the impulse response of the MB-NCS for impulse inputs applied at different times. Examples show how both norms converge to the traditional H2 norm for continuous H2 systems. Finally, with the help of an alternate way of representing lifted parameters, the relationship between the optimal sampler and hold of a sampled data system and the structure of the Output Feedback MB-NCS is shown.