Adaptive Secure Control for Leader-Follower Formation of Nonholonomic Mobile Robots in the Presence of Uncertainty and Deception Attacks

This paper addresses an adaptive secure control problem for the leader-follower formation of nonholonomic mobile robots in the presence of uncertainty and deception attacks. It is assumed that the false data of the leader robot’s information attacked by the adversary is transmitted to the follower robot through the network, and the dynamic model of each robot has uncertainty, such as unknown nonlinearity and external disturbances. A robust, adaptive secure control strategy compensating for false data and uncertainty is developed to accomplish the desired formation of nonholonomic mobile robots. An adaptive compensation mechanism is derived to remove the effects of time-varying attack signals and system uncertainties in the proposed control scheme. Although unknown deception attacks are injected to the leader’s velocities and the model nonlinearities of robots are unknown, the boundedness and convergence of formation tracking errors of the proposed adaptive control system are analyzed in the Lyapunov sense. The validity of the proposed scheme is verified via simulation results.

Algorithm of phase-frequency distortion adaptive compensation for broadband signals during propagation through transionospheric channels.

The models of distortions of digital broadband signals during their propagation through transionospheric channels which are equivalent to a linear filter with an impulse response determined by a number of parameters, in particular, the central frequency of the signals, are presented. Distortions of the phase-frequency characteristics of digital broadband signals due to the dispersion properties of the ionosphere causes time scattering and the appearance of interference noise which reduces the reliability of information systems and with certain characteristics of the radiochannel destroys their operation. This determines the relevance of developing computational procedures for processing digital signals that reduce the effectiveness of this type of interference, a characteristic property of which is the linear dependence of their power on the power of information signals. The description of the algorithm for adaptive compensation of these distortions based on the use of information signals and the formation of an inverse filter is given, which corresponds to the general concept of "blind" processing. The possibility of the considered distortion compensation for digital wideband signals with phase shift keying and achievement of probabilistic characteristics of erroneous reception providing an acceptable quality of a radiochannels for information systems has been shown by means of computer simulations.