  In this paper, we consider a class of denial-of-service (DoS) attacks, which
aims at overloading the communication channel. On top of the security issue,
continuous or periodic transmission of information within feedback loop is
necessary for the effective control and stabilization of the system. In
addition, uncertainty---originating from variation of parameters or unmodeled
system dynamics---plays a key role in the system's stability. To address these
three critical factors, we solve the joint control and security problem for an
uncertain discrete-time Networked Control System (NCS) subject to limited
availability of the shared communication channel. An event-triggered-based
control and communication strategy is adopted to reduce bandwidth consumption.
To tackle the uncertainty in the system dynamics, a robust control law is
derived using an optimal control approach based on a virtual nominal dynamics
associated with a quadratic cost-functional. The conditions for closed-loop
stability and aperiodic transmission rule of feedback information are derived
using the discrete-time Input-to-State Stability theory. We show that the
proposed control approach withstands a general class of DoS attacks, and the
stability analysis rests upon the characteristics of the attack signal. The
results are illustrated and validated numerically with a classical NCS batch
reactor system.

Systems and Control;Systems and Control