Switching-like event-triggered tracking control for UAH/UGV systems
under external disturbance and DoS attacks
Abstract
In this paper, by considering the existence of unavailable state,
external disturbance, and denial of service (DoS) attacks, an
anti-disturbance trajectory tracking controller is proposed for the
air-ground system composed of unmanned autonomous helicopter (UAH) and
unmanned ground vehicle (UGV). Initially, by combining the advantages of
conventional event-triggered scheme (ETS) and memory ETS, a
switching-like event-triggered mechanism is put forward, which can cause
less data transmissions without reducing control performance, and
effectively restrain the DoS attacks. Secondly, by dividing the DoS
attacks into active intervals and sleep ones, the concept of
acknowledgement character technology (ACK) is presented to determine the
suitable type of time intervals. Thirdly, the switching-like dynamic ETS
is introduced for the sleep intervals of DoS attacks while the ETS with
fixed triggered-threshold is exploited for the active intervals.
Fourthly, based on the occurrence of the DoS attacks, a switching-like
observer and a normal one are respectively proposed to estimate the UGV
state, the UAH state, the reference input of the UGV, and the
disturbance of the UAH, which are utilized to design the
anti-disturbance tracking controller. Fifthly, an augmented closed-loop
system consisting of observation errors and tracking error is
established and its stability is analyzed by using Lyapunov stability
theory. Then, a sufficient condition on co-designing the parameters of
switching-like ETS, observers, and tracking controller is presented in
terms of linear matrix inequalities (LMI). Finally, the validity and
superiority of the proposed control scheme are verified by resorting to
simulations and comparisons.