Design Of Networked Control Systems Research Articles

A Lyapunov-based control design for centralised networked control systems under false-data-injection attacks

ABSTRACT A central processing unit receives data from all agents and transmits control commands in a Networked Control System (NCS) which is centralised. Centralised NCSs have numerous applications in industrial settings due to their efficiency, simplicity and cost-effective design. However, centralised NCSs are vulnerable to false data injection (FDI) attacks. Despite the fact that researchers have developed detection and mitigation defense mechanisms during past several years, most of these methods have focused on systems with linear dynamics. Furthermore, the existing literature only assumes the injection of FDI attacks on measurement signals. In this paper, we assume that an adversary has injected the FDI attack into both state measurements and control signals with nonlinear dynamics while considering communication noises and disturbances. We propose a secure nonlinear control design that mitigates FDI attacks in real time by combining learning and model-based approaches. We used Lyapunov stability analysis to design the controller, estimator and updating laws of the neural network (NN). In addition, we selected a network of two robots with Euler–Lagrange dynamics to illustrate the robustness of the proposed controller and estimator.

Differential Entropy-Based Fault-Detection Mechanism for Power-Constrained Networked Control Systems.

In this work, we consider the design of power-constrained networked control systems (NCSs) and a differential entropy-based fault-detection mechanism. For the NCS design of the control loop, we consider faults in the plant gain and unstable plant pole locations, either due to natural causes or malicious intent. Since the power-constrained approach utilized in the NCS design is a stationary approach, we then discuss the finite-time approximation of the power constraints for the relevant control loop signals. The network under study is formed by two additive white Gaussian noise (AWGN) channels located on the direct and feedback paths of the closed control loop. The finite-time approximation of the controller output signal allows us to estimate its differential entropy, which is used in our proposed fault-detection mechanism. After fault detection, we propose a fault-identification mechanism that is capable of correctly discriminating faults. Finally, we discuss the extension of the contributions developed here to future research directions, such as fault recovery and control resilience.

H∞ Controller Design for Networked Systems With Two-Channel Packet Dropouts and FDI Attacks.

In this article, the stochastic analysis and H∞ controller design problems of networked systems with packet dropouts and false data injection attacks are investigated. Different from the existing literature, we focus on the linear networked systems with external disturbances and both sensor-controller channel and controller-actuator channel are studied. First, we present a discrete-time modeling framework that leads to a stochastic closed-loop system with randomly varying parameters. To facilitate the analysis and H∞ control of resulting discrete-time stochastic closed-loop system, an equivalent yet analyzable stochastic augmented model is further constructed by matrix exponential computation. Based on this model, a stability condition is derived in the form of linear matrix inequality (LMI) with the aid of a reduced-order confluent Vandermonde matrix, Kronecker product operation, and law of total expectation. Specifically, the dimension of the LMI obtained in this article does not increase as the upper bound of consecutive packet dropouts does, which is also different from the existing literature. Subsequently, a desired H∞ controller is obtained such that the original discrete-time stochastic closed-loop system is exponentially mean-square stable with a prescribed H∞ performance. Finally, a numerical example and a direct current motor system are exploited to substantiate the effectiveness and practicability of the designed strategy.

Design and implementation of computer network security detection and control system

With the widespread application of computer network technology, computer network security defense capability has become a focus of attention in various industries. The extensive use of computer information systems in various sectors has significantly improved work efficiency but has also introduced security risks and management issues. The deployment of network security detection and control systems allows for effective security monitoring and management of computer operations and real-time network information. This paper presents a computer network security detection and control system based on human-computer interaction, which enables users to handle daily key business processes. The work principles and overall architecture of the network security detection and control system are analyzed and demonstrated. It offers functions such as filtering options, address rules, network security detection, network unreachability, overall traffic analysis, subnet definition, fault diagnosis, and security analysis. Testing and analysis indicate that the systems design achieves the intended goals. In the application of network security features, it can effectively combine various forces to enhance the quality and efficiency of network security, making it widely applicable in various industry units.

Novel Dropout Compensation Control Design for Networked Control Systems With Mixed Delays

Novel Dropout Compensation Control Design for Networked Control Systems With Mixed Delays

Robust control design of a nonlinear liquid-level networked control system: a comparative study between STR and Kharitonov analysis

Robust control design of a nonlinear liquid-level networked control system: a comparative study between STR and Kharitonov analysis

Event‐triggered networked cascade control systems design subject to hybrid attacks

This paper deals with the design problem of networked cascade control systems (NCCSs) with two different event‐triggered mechanisms (ETMs) for the feedback loops. A combination of stochastic denial‐of‐service (DoS) attack and deception attack has been considered for the communication network. To comply with the practical point of view, the primary and the secondary systems have been considered with distinct disturbances. First, the closed‐loop system with state feedback controllers is provided in a unified stochastic delayed system. Then, the Lyapunov–Krasovskii stability theory and stochastic analysis techniques are employed to derive and formulate control design conditions in terms of linear matrix inequalities (LMIs). Finally, a superheater steam temperature control is utilized to assess the applicability of the proposed method.

An improved event-triggered control method for fuzzy systems under membership functions online learning

This paper is concerned with the problem of adaptive event-triggered (AET) based optimal fuzzy controller design for nonlinear networked control systems (NCSs) characterized by Takagi–Sugeno (T–S) fuzzy models. An improved AET communication scheme with a memory adaptive rule is proposed to enhance the utilization of the state response vertex data. Different from the existing ET based results, the improved AET scheme can save more communication resources and acquire better system performance. The sufficient criteria of performance analysis and controller design are presented for the closed-loop control system subject to mismatched membership functions (MFs) and AET scheme. And then, a new MFs online learning algorithm on the basis of the gradient descent approach is employed to optimize the MFs of fuzzy controller and obtain optimal fuzzy controller for further improving system performance. Finally, two simulation examples are presented to verify the advantage and effectiveness of the provided controller design technique.

Discrete‐time modelling methodology of networked control systems under packet delay and dropout

AbstractModels and control techniques for networked control systems (NCSs) can be divided into continuous‐time and discrete‐time types. Unlike the continuous‐time analysis, literature on discrete‐time analysis and control of NCSs under packet delay and dropout shows a variety of different models. However, a systematic study of these models is absent in the literature. This article is a methodology for these models. Different factors involved in making this variety are discussed. The models are described and it is shown how they are different or related to each other. The models are from the existing literature. However, to complete the methodology some of the models are introduced by the authors. Furthermore, the concept of sequence matrix is introduced which helps to differentiate some models and should be considered when NCS is analysed as a switched linear system. This methodology can be used as a basis for selecting the suitable model in analysis and design of NCSs. Denial of service (DoS) attack and time delay switch (TDS) attack can be considered as packet dropout and packet delay respectively. Thus, this methodology can also be used in analysis and design of NCS under these cyber‐physical attacks.

Secure Control Design for Networked Control Systems With Nonlinear Dynamics Under Time-Delay-Switch Attacks

A continuous controller is developed for a centralized network control system (NCS), which is composed of agents with nonlinear dynamics subject to a time-delay-switch (TDS) attack and additive disturbances. Since the state tracking error is unmeasurable during TDS attacks, controllers cannot use the state tracking error to coordinate the NCS. Therefore, a novel error signal is designed to address this unique challenge and enable the NCS to achieve a formation control objective. Furthermore, a TDS attack mitigation strategy is developed, which uses both learning- and model-based approaches to estimate an agent’s state for TDS attack detection and compensation. Lyapunov–Krasovskii functionals are used in the stability analysis to prove that the tracking errors converge to a steady-state residual, which is a function of the system uncertainty and TDS attack properties. The leader–follower formation control problem for unmanned aerial vehicles based on a pure pursuit guidance law is selected for a simulation study to validate the performance of the proposed method.

DEID-Based Control of Networked Rapid Control Prototyping System: Design and Applications

This article presents a novel networked rapid control prototyping (NRCP) system, which can significantly facilitate the theoretical analysis and product design of networked control systems (NCSs). The NRCP system consists of a PC controller equipped with MATLAB/Simulink software and an embedded target designed with open-source hardware, e.g., Raspberry Pi and STM32. Therefore, it benefits from the following advantages, such as simple structure, low cost, convenient deployment, and robust scalability. In order to verify the effectiveness and superiority of the proposed NRCP, a networked magnetic levitation control system (NMLCS) is developed on the basis of this NRCP system. Furthermore, a discrete-time equivalent-input-disturbance (DEID)-based model predictive control approach is proposed for NMLCS to deal with the common practical issues in NCSs, such as time delay and disturbance. Specifically, the time delay is modeled as delay-induced disturbance (DID), whose influence is effectively estimated and eliminated by the designed controller. Several experimental case studies are performed to verify the effectiveness of the NRCP, the DEID-based control algorithm, and the analytical method of DID.

Decentralized Resilient Output-Feedback Control Design for Networked Control Systems Under Denial-of-Service

This article deals with the problem of decentralized resilient observer-based output-feedback control design for networked control systems (NCSs). The proposed scheme considers both network imperfections and security issues. It is assumed that the NCS is suffering from time-varying network-induced delays and time-varying transmission intervals. Moreover, data transmission is performed over a nonsecure network that suffers from a denial-of-service (DoS) attack. The DoS jamming attack has affected the network by the occurrence of consecutive packet dropouts, which result in attack-induced packet dropouts. Based on the fact that packet dropouts caused by DoS attacks naturally do not follow a specific statistical pattern, the attack-induced packet dropouts are modeled as an extension of time-varying intervals with no probability distribution. Sufficient conditions are provided to guarantee the uniformly globally exponential stability of the NCS in the form of linear matrix inequalities. Finally, the effectiveness and applicability of the proposed method are demonstrated by simulation results.

Networked control system stability analysis of pipeline system with networked-induced delay

This paper presents the design of Networked Control Systems (NCS) for pipeline systems. NCS plays an important role in controlling and monitoring large-scale systems such as pipeline systems. To implement the NCS, one must derive the pipe model and consider the network communication constraints. Here, the pipeline model is divided into two sections for simplicity. For example, in a long pipeline system, one can use a higher number of sections in order to give a better result for the analysis. Then let’s consider a networked-induced delay as the network communication constraint. The discretize pipe dynamics model is derived to support the NCS scheme in the pipeline system. The stability analysis of the proposed NCS is derived by taking into account the small and the large networked-induced delay. Then the optimal LQR control is designed for both stabilizing and tracking. The stability region of the pipeline system in the NCS scheme with networked-induced delay is derived and depicted to provide stability information. The design of the proposed controller under network constraint (networked-induced delay) must consider the stability plot that is divided into the stable region and unstable region. In this research, let’s assume that it is possible to measure the exact time delay and then consider the allowable sampling time for the controller. The proposed controller is designed by considering the NCS scheme with time delay both for regulator and tracking problems. By using the proposed controller, the pipeline system can be controlled in the presence of network-induced delay, which commonly occurs in a distributed system. The simulation verifies the stability analysis of the proposed optimal control for the pipeline systems with the NCS scheme under networked induced delay

Multi‐loop networked control system design subject to interchange attack

AbstractThis paper deals with the design problem of multiloop networked control system (NCS) under interchange attack. This is a new type of attack where the transmitted data are swapped between different control loops which can be more destructive than other types of attacks, such as denial‐of‐service (DoS) attack. In this context, multiple sampled‐data control loops are first considered that use a shared communication network for data transmission. Then, the overall closed‐loop systems with the proposed attack are formulated in a unified stochastic delay system. The proposed framework is also applicable to DoS attack. Based on Lyapunov–Krasovskii theory and stochastic analysis techniques, some conditions in terms of linear matrix inequalities (LMIs) are derived for the control design problem. Finally, two inverted pendula are utilized for simulation to show the effectiveness of the proposed method. Also, the effects of DoS attack and interchange attack are compared.

Optimal Transmission Power and Controller Design for Networked Control Systems Under State-Dependent Markovian Channels

This article considers a codesign problem for industrial networked control systems to ensure both stability and efficiency properties of such systems. This problem is particularly challenging due to the fact that wireless communications in industrial environments are not only subject to shadow fading, but also stochastically correlated with their surrounding environments. This article first introduces a novel state-dependent Markov channel (SD-MC) model that explicitly captures the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">state-dependent features</i> of industrial wireless communication systems by defining the proposed model’s transition probabilities as a function of both environments’ states and transmission power. Under the SD-MC model, sufficient conditions on <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Maximum Allowable Transmission Interval</i> are presented to ensure both <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">asymptotic stability in expectation</i> and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">almost sure asymptotic stability</i> properties of a nonlinear control system with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">state-dependent fading channels</i> . Based on these stability conditions, the codesign problem is then formulated as a constrained polynomial optimization problem (CPOP), which can be efficiently solved using semidefinite programming methods for the case of a two-state SD-MC model. The solutions to such a CPOP represent optimal control and power strategies that optimize the average expected joint costs in an infinite time horizon while respecting the stability constraints. For a general SD-MC model, this article further shows that suboptimal solutions can be obtained from linear programming formulations of the considered CPOP. Simulation results are given to illustrate the efficacy of the proposed codesign scheme.

Design of gas drainage pipe network regulation and control system based on PLC

In order to improve the regulation efficiency of the coal mine gas drainage pipe network, reduce the labor intensity of workers, and ensure the safe production of coal mines, a gas drainage pipe network regulation and control system is designed. The system adopts Siemens S7-1200 series PLC as the core control unit of the gas drainage pipe network. Through the explosion-proof treatment of the PLC control box, it meets the special requirements of PLC used in the coal mine environment. Through the design and selection of flow sensors and methane sensors it improves the flow and methane sampling accuracy of the gas drainage regulation system. By writing local control strategies and remote control strategies in PLC, the automatic regulation of the gas drainage pipeline network is realized.

Event-based security tracking control for networked control systems against stochastic cyber-attacks

This paper investigates the security tracking controller design for discrete-time networked control systems (NCSs) with stochastic cyber-attacks via dynamic event-triggered communication approach (DETCA). The DETCA is introduced to adjust the amount of data transmission in the network based on variation of the tracking error while keeping the tracking performance of the system. Stochastic cyber-attacks such as the denial-of-service and deception attacks are assumed to be encountered during the signal transmitted in the network. A sufficient condition to guarantee the asymptotical stability of the tracking error system is achieved with the Lyapunov stability theory. The tracking controller gain and the event-triggering parameter are co-designed by solving a linear matrix inequality. Finally, two simulation examples are given to verify the availability of theoretical results.

Fault-tolerant control design for unreliable networked control systems via constrained model predictive control

This work deals with the problem of passive fault-tolerant control (FTC) for discrete-time networked control systems (NCSs). Network imperfections such as random time delay and packet dropout are modeled as a Markov chain that results in a Markovian jump linear system (MJLS). Some of the elements in the transition probability matrix (TPM) are supposed to be unknown so as to address network complexities. In addition, a comprehensive and practical fault model that considers the stochastic nature of networks is employed. By utilizing this fault model, the closed-loop NCS model is obtained by means of state augmentation technique. Then, a constrained model predictive control (MPC) is proposed to develop a fault-tolerant control strategy in which all these issues are considered as well as input constraint. Sufficient conditions to design the proposed reliable controller are derived in terms of linear matrix inequalities (LMIs). Finally, two examples are utilized to demonstrate the validity of the proposed FTC. The simulation results show that the proposed strategy works well, and results in more effective responses compared to state-of-the-arts studies.

Specified QoS based networked observer and PI controller design with disturbance and noise rejection under random packet dropout

In this paper, a novel observer based networked PI controller has been designed by considering bounded disturbance and measurement noise under specified probability of random packet dropouts in networked control systems (NCSs). Lyapunov stability condition of the NCS with an observer and PI controller has been derived using an asynchronous dynamical system (ADS) approach as a linear matrix inequality (LMI) with nonconvex constraints to improve its quality-of-service (QoS) and quality-of-control (QoC). In order to improve QoC and QoS for NCS under process and measurement disturbance, we have used H∞ norm bound, and random packet drop rate in the NCS design. The algorithm has been tested and validated on four test-bench models of energy conversion systems. Confidence intervals and the mean responses of the state variables, state estimation errors of the observer and control signals have been reported using 100 Monte Carlo simulations. Our proposed NCS with PI controller and observer design method can be employed on a wide range of state space models of energy conversion systems. The specified probability of packet dropouts in the communication network between the sensor, observer, PI controller and actuator has been considered in the design which allows design of the NCS with guaranteed Lyapunov stability. We consider a switched linear dynamical system structure of the NCS with bounded noise and disturbance inputs while jointly searching for PI controller and observer gains. Using the controller and observer designed with 90% packet drop rate, we show the system performance degradation at 97%–99% QoS using phase portraits of the error dynamical system around the equilibrium as well as through univariate and multivariate hypothesis tests for equal dispersion around the equilibrium of the error dynamical system.

Adaptive event-triggered [formula omitted] fuzzy filter design for nonlinear networked systems via asymmetric LKF approach

This paper studies the problem of the fuzzy H∞ filter design for nonlinear networked control systems through event-triggered communication (ETC) scheme. Firstly, an improved adaptive ETC scheme is proposed to save communication resources. Secondly, an asymmetric Lyapunov-Krasovskii functional (LKF) method is introduced in the H∞ performance analysis of filter error systems. Then, a new sufficient condition is obtained to meet the H∞ performance by combining the method with membership-function-dependent approach. Further, a relaxed co-design method of the corresponding filter and event-triggering parameters is obtained. Finally, two numerical examples are provided to verify the advantage of the new approaches.