Network attack detection is a crucial issue in cyber–physical systems. One classical type of network attack is the replay attack. Although the watermarking scheme has proven to be effective in detecting replay attacks, it may confront numerous challenges when applied to process control systems. The watermarking signal, which consists of independent and identically distributed Gaussian noise sequences, responds slowly to industrial process control systems. To address this issue, two novel smooth watermarking methods are proposed. The smooth watermarking signals exhibit low-frequency characteristics, enabling them to effectively handle large inertia processes. The proposed schemes are validated through two simulated examples. These examples indicate that the proposed methods can significantly enhance detection efficiency while minimizing additional control performance loss.

A robust resilient H-infinity control and MRS codesign is studied in the paper. The problems, such as time-delay, medium access constraint, system disturbance and controller perturbation, are solved by the co-design. An improved MRS scheme is adopted to reduce the conservative property of the MRS scheme. Meanwhile, the effect of the weighted matrix on the performance of the MRS scheme is studied. The performance of the NCS with MRS scheme can be improved furtherly if we choose the proper parameters of the weighted matrix. Finally, a numerical example is used to demonstrate the effectivity of the codesign method proposed in the paper.

In this paper, a generalized model-reference scheduling (GMRS) scheme is proposed for a networked control system (NCS) with guaranteed performance control and medium access constraint (MAC). The GMRS presented reduces conservatism to some extent, and its performance is improved by adjusting the weighted gain. In addition, two cases of uncertainty existing in the system matrix and control matrix are considered. For the first case, a co-design of guaranteed performance control and the GMRS is studied for the NCS with and without zero-order hold mechanism. For the second case, the uncertainty induced from time delay is considered in the guaranteed performance control and the GMRS co-design. Finally, illustrative examples are given to demonstrate the effectiveness of the proposed co-design schemes.