Secure estimation for cyber‐physical systems with adversarial attacks and unknown inputs: An L₂‐gain method

Abstract

Summary This paper investigates the attack‐resilient state estimation problem for linear systems with adversarial attacks and unknown inputs, where the upper bound of the unknown inputs is unknown. It is assumed that the attacker has limited resources and can only manipulate a certain number of sensors. In most of the existing observer design approaches for the systems with unknown inputs even in the absence of attacks, the observer matching condition should be satisfied. To overcome this restriction, a novel switched observer is proposed, where the matched unknown inputs will be completely compensated by means of the outputs and the mismatched part will be suppressed in terms of L2‐gain rejection property. Meanwhile, the observer can provide an attack‐resilient state estimation. Compared with the existing results, the proposed observer can guarantee that the resulting observer error system is stable with unknown input attenuation level γ that can be optimized. Finally, a simulation example of an unmanned ground vehicle is provided to show the effectiveness of the proposed approach.

Secure interval observer for linear continuous-time systems with discrete measurements subject to cyber-attacks

“…Remark 3. Since the matrices ∆ • are nonnegative which implies that ∆ ∆ ∆ ∆ is also nonnegative, it is always possible to enhance the interval observer dynamics at jumps in (16) by reducing the matrix (18) to its optimal realization Γ(L, L).…”

“…ILLUSTRATIVE EXAMPLES In order to illustrate the performance of the proposed observer, we consider the following examples. Example 1: Unmanned Ground Vehicle (UGV) system borrowed from [18] and [11]: where x 1 (t) and x 2 (t) are the UGV position and the linear velocity, respectively. m and b are the mechanical mass and the translational friction coefficient, respectively.…”

State Estimation and Event‐Triggered Control for Cyber‐Physical Systems under Malicious Attack

“…S e Fτ S exists. en, (12) defines a finite-time observer for the system (1) and the observer estimates the exact state of system (1)…”

“…However, the above algorithmic method has the disadvantage of losing the correctness guarantee, while the observer-based method has a fast response and saves the computing resources. A novel state observer was proposed in [12,13]. Lu and Yang studied the problem of security state estimation of network physical systems and proposed a new security Luenberger observer in reference [14].…”

Adaptive control for nonlinear cyber‐physical systems under false data injection attacks through sensor networks

“…Considering the attacks on communication links from controllers to actuators, the observer‐based attack‐resilient control architecture for linear systems was proposed in the work of Xie and Yang . In addition, the state estimation problem against sensor attacks was considered in the works of Yang et al However, these methods are mostly implemented for linear systems.…”