  This paper proposes an active attack detection scheme for constrained
cyber-physical systems. Despite passive approaches where the detection is based
on the analysis of the input-output data, active approaches interact with the
system by designing the control input so to improve detection. This paper
focuses on the prevented actuation attack, where the attacker prevents the
exchange of information between the controller and actuators. The proposed
scheme consists of two units: 1) detection, and 2) control. The detection unit
includes a set of parallel detectors, which are designed based on the
multiple-model adaptive estimation approach to detect the attack and to
identify the attacked actuator(s). For what regards the control unit, a
constrained optimization approach is developed to determine the control input
such that the control and detection aims are achieved. In the formulation of
the detection and control objective functions, a probabilistic approach is used
to reap the benefits of the \textit{a priori} information availability. The
effectiveness of the proposed scheme is demonstrated through a simulation study
on an irrigation channel.

Systems and Control;Systems and Control