Control Of Cyber-physical Systems Research Articles

ТРЕБОВАНИЯ И НОРМЫ ИСПЫТАНИЙ ПО РАДИАЦИОННОЙ СТОЙКОСТИ ИНТЕГРАЛЬНЫХ СХЕМ К ЭФФЕКТАМ ВОЗДЕЙСТВИЯ ТЯЖЕЛЫХ ЗАРЯЖЕННЫХ ЧАСТИЦ

The paper presents an analysis of existing approaches to estimation of single event rate (SER) in integrated circuits under effects of charged particles of space radiation environment. These issues are of significant importance in the light of the expansion of the scope of practical application of cyber-physical control systems for space objects, since it is mainly due to the SER that information is lost in the register elements and in the memory cells of the electronic blocks of spacecraft. It is shown that existing models based on energy deposition in fixed sensitive volume are not applicable for SER estimations in case of high threshold linear energy transfer (LET) values. An alternative approach is proposed. It is based on diffusion charge collection model, which can be used to estimate the SER cross-sections in isotropic particle field. A universal dependence for SER estimation in integral circuits (ICs) at geostationary orbit is proposed and used as a basis for establishing classification of devices based on hardness assurance levels. The obtained results provide the grounds for setting test requirements that has to be met during single event effects testing of ICs.

Survey on Unmanned Aerial Vehicle Networks: A Cyber Physical System Perspective

Unmanned aerial vehicle (UAV) networks are playing an important role in various areas due to their agility and versatility, which have attracted significant attention from both the academia and industry in recent years. As an integration of the embedded systems with communication devices, computation capabilities and control modules, the UAV network could build a closed loop from data perceiving, information exchanging, decision making to the final execution, which tightly integrates the cyber processes into the physical devices. Therefore, the UAV network could be considered as a cyber physical system (CPS). Revealing the coupling effects among the three interacted components in this CPS system, i.e., communication, computation and control, is envisioned as the key to properly utilize all the available resources and hence improve the performance of the UAV networks. In this paper, we present a comprehensive survey on the UAV networks from a CPS perspective. Firstly, we respectively research the basics and advances with respect to the three CPS components in the UAV networks. Then we look inside to investigate how these components contribute to the system performance by classifying the UAV networks into three hierarchies, i.e., the cell level, the system level, and the system of system level. Further, the coupling effects among these CPS components are explicitly illustrated, which could be enlightening to deal with the challenges in each individual aspect. New research directions and open issues are discussed at the end of this survey. With this intensive literature review, we try to provide a novel insight into the state-of-the-art in the UAV networks.

Purposeful ensuring energy efficiency and environmental friendliness of waste and review of used local conservation laws

The constant improvement of technologies is accompanied by an increase in requirements for the energy efficiency of industrial and residential facilities and the environmental friendliness of waste. The existing standards clearly formulate the concepts and limitations in this problem area. The developing class of cyber-physical systems accumulates the capabilities of cybernetics for modeling and controlling physical environments. Building on their basis not only monitoring systems, but also technology management is especially important in energy and ecology. When creating cyber-physical technology control systems, it is necessary to correctly formulate the goal. The article proposes the use of conservation laws in the format of their local forms. It shows how differential equations corresponding to these forms, transformed into an input-output form, are used to control the energy efficiency and environmental friendliness of waste and emissions from enterprises and other technogenic facilities.

Supervisory Control Synthesis for Safety PLCs

Abstract The development of supervisory controllers for cyber-physical systems is a laborious and error-prone process. Supervisor synthesis enables control designers to automatically synthesize a correct-by-construction supervisor from a model of the plant in combination with a model of the control requirements. Subsequently, the controller code can be generated from the supervisor model such that it can be implemented on a programmable logic controller (PLC). In industry, supervisors have to adhere to strict safety standards. To achieve these standards, safety PLCs (SPLCs) are used. For SPLC implementation, the supervisor has to be split into a regular part and a safety part. This paper presents a method to automatically splits a supervisor model for this purpose. To validate the method, a case study on a rotating bridge has been performed. The result is compared to a splitting result made by experts. Furthermore, the supervisor has been implemented to control the real bridge.

Switched-Based Resilient Control of Cyber-Physical Systems

We present a control-theoretic approach to achieve Cyber-Physical Systems (CPS) resilient designs. We assume situations in which the CPS must maintain the correct operation of a set of crucial functionalities despite ongoing adversarial misbehavior. The approach is based on a moving target defense paradigm, driven by a linear switching of state-space matrices, and applied at both the physical and network layers of a networked-control system. We show that the final system maintains stability. We also evaluate, via simulation, a step-by-step procedure that takes a transfer function, representing the dynamics of the physical process. As a result, we obtain a resilient CPS design structured around a topology of decentralized controllers. Results show that the obtained approach is both innovative and promising.

Formalization of target and assessment of quality of the cyber-physical control systems for emissions reduction technologies

Monitoring and inventory is a necessary but not sufficient condition to reduce emissions in the energy and industry. The ultimate task of controlling air purification technologies in combination with monitoring is effectively achieved while minimizing the human factor. The creation and application of cyber-physical technology management systems provide a solution to a set of related environmental problems. In addition, the development of models based on cyber-physical systems forms new requirements for the development of technologies for their creation. A special feature of such technologies is close interaction between computing methods with design and production facilities. These issues have not been sufficiently reflected in publications. The article presents the target setting for the creation of cyber-physical technology control systems based on local laws of preservation and the decomposition of the target into macroscopic quality assessments. A mathematical model and methods of quality assessment at the life cycle stages of such systems based on recalculation of probability densities of a priori data are presented. Examples of cyber-physical emission reduction systems in the energy and industry developed under the nature-technology concept are given.

Contention-aware optimal scheduling of real-time precedence-constrained task graphs on heterogeneous distributed systems

Abstract Real-time applications in today’s distributed cyber-physical control systems are often represented as Precedence-constrained Task Graphs (PTGs) and increasingly implemented on heterogeneous platforms to cater to their high performance demands. Optimal scheduling solutions for such systems can provide advantages in terms of performance, reliability, cost etc. However, existing research works dealing with the optimal scheduling of PTGs, typically assume platforms consisting of homogeneous processing elements which interact through a fully connected network of homogeneous communication channels. In this work, we propose an Integer Linear Programming based optimal solution strategy for scheduling PTGs executing on a distributed platform composed of heterogeneous processing elements and inter-connected through a set of heterogeneous shared buses. Through the real-world case study of an automotive cruise controller, we generate an optimal schedule using our proposed scheme in order to demonstrate its generic applicability. Conducted experiments on benchmark PTGs reveal the practical efficacy of our scheme.

Experience Report: Towards Moving Things with Types - Helping Logistics Domain Experts to Control Cyber-Physical Systems with Type-Based Synthesis

One of the ultimate goals of software engineering is to leave virtual spaces and move real things. We take one step toward supporting users with this goal by connecting a type-based synthesis algorithm, (CL)S, and its IDE to a logistics lab environment. The environment is built and used by domain experts, who have little or no training in formal methods, and need to cope with large spaces of software, hardware and problem specific solution variability. It consists of a number of Cyber-Physical Systems (CPS), including wheel-driven robots as well as flying drones, and it has laser-based support to visualize their possible movements. Our work describes results on an experiment integrating the latter with (CL)S. Possibilities and challenges of working in the domain of logistics and in cooperation with its experts are outlined. Future research plans are presented and an invitation is made to join the effort of building better, formally understood, development tools for CPS-enabled industrial environments.

Electrical Method for the Cyberphysical Control System of Non-Electrical Objects

Wydawnictwo SIGMA-NOT wydaje czasopisma fachowe informujące swoich czytelników o najnowszych osiągnięciach naukowych i nowoczesnych rozwiązaniach technicznych w Polsce i na świecie, popularyzuje problemy techniczne oraz poszerza wiedzę i kulturę techniczną.

Performance, Security Tradeoffs in Secure Control

This letter summarizes the established vulnerability analysis techniques for cyber physical control software and highlights the possibility of employing lightweight security measures in conjunction with reachability analysis for such systems. We propose a possible cyber physical control system implementation methodology, which leverages the dependence of control performance on the choice of security measure adopted and the resulting platform level vulnerability.

Cyber-physical control system for integrated material flows

The article is devoted to the development of applications for Industrial Internet of Things and their integration with Enterprise Resource Planning and Customer Relationship Management systems. This brings to a higher level interaction both of enterprises with each other and with consumers. These processes are most clearly revealed in commercial structure network. The prerequisite for IIoT implementation was the need to determine by the code of the goods not only the destination, but also the storage conditions and the period of realization. An important feature is the necessity to take into account a very short period between the production date and the Expire Date, during which Supply Chain Management is performed, generating storage, distribution, logistics and marketing problems.

Intelligent robust control for cyber-physical systems of rotary gantry type under denial of service attack

This paper presents an approach for tolerant control and compensation of cyber attacks on the inputs and outputs of a cyber-physical system of rotary gantry type. The proposed control schemes are designed based on classic–intelligent control strategies for trajectory tracking and vibration control of a networked control system, which are developed for tip angular position control, while the system is prone to cyber attacks. The malicious attacks are assumed to be of denial of service (DoS) kind and cause packet loss with high probability in the two signals; control input and sensor output. In this paper, several classic and intelligent control strategies are studied in terms of robustness and effectiveness to attacks. Based on the results, a new hybrid control scheme is designed using linear quadratic regulation, sliding mode control, and artificial radial basis function neural network to alleviate the effect of DoS attacks and maintain the performance of the cyber-rotary gantry system in tracking applications. The neural network controller is trained during the control process. Its learning algorithm is based on the minimization of a cost function which contains the sliding surface. The hybrid control system is analyzed from the stability perspective. Moreover, the efficiency of the proposed scheme is validated by simulation on MATLAB Simulink platform.

Robust Design and Validation of Cyber-physical Systems

Co-simulation--based validation of hardware controllers adjoined with plant models, with continuous dynamics, is an important step in model-based design of controllers for Cyber-physical Systems (CPS). Co-simulation suffers from many problems, such as timing delays, skew, race conditions, and so on, making it unsuitable for checking timing properties of CPS. In our approach to validation of controllers, synthesised from their models, the synthesised controller is adjoined with a synthesised hardware plant unit. The synthesised plant and controller are then executed synchronously and Metric Interval Temporal Logic (MITL) properties are validated on the closed-loop system. The clock period is chosen, using robustness estimates, such that all timing properties that hold on the controller guiding the discretised plant model also hold on the original case of the continuous-time plant model guided by the controller. Benchmark results show that real-time MITL properties that are vacuously satisfied or violated due to co-simulation artefacts hold correctly in the proposed closed-loop validation framework.

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

This paper is concerned with the security state estimation and event-triggered control of cyber-physical systems (CPSs) under malicious attack. Aiming at this problem, a finite-time observer is designed to estimate the state of the system successfully. Then, according to the state information, the event-triggered controller is designed through the event-triggered communication. It is proved that the system is uniformly and finally bounded. Finally, the effectiveness of the proposed method is verified by a simulation example.

Adaptation in network control systems with hierarchical scheduling

The analysis and synthesis of cyber-physical systems (CPSs) require an integrative approach of the study of the underlying physical and cyber components and their intricate and interactive interconnections. Their implementation using distributed embedded systems (DESs) requires the modelling and control of the entire CPS, where uncertainties may occur both in the physical and in the cyber parts. The focus of this study is on the adaptive control of such CPS. When multiple applications have to be controlled using a DES, often the underlying resources are shared. One of the main implications of this resource contention is the introduction of delays in the control messages reaching their intended destination. The specific set of problems the authors consider here are those where a control implementation leads to delays that are unknown. By separating the known part of the delay from the uncertain part, the authors propose a delay-aware design for the controller. They derive the underlying models, the requisite adaptive control designs, and the stability of the adaptive system. The authors showed effectiveness of the result and its improvement over non-adaptive designs using simulation.

Performance and Resilience of Cyber-Physical Control Systems With Reactive Attack Mitigation

This paper studies the performance and resilience of a linear cyber-physical control system (CPCS) with attack detection and reactive attack mitigation in the context of power grids. It addresses the problem of deriving an optimal sequence of false data injection attacks that maximizes the state estimation error of the power system. The results provide basic understanding about the limit of the attack impact. The design of the optimal attack is based on a Markov decision process (MDP) formulation, which is solved efficiently using the value iteration method. We apply the proposed framework to the voltage control system of power grids and run extensive simulations using PowerWorld. The results show that our framework can accurately characterize the maximum state estimation errors caused by an attacker who carefully designs the attack sequence to strike a balance between the attack magnitude and stealthiness, due to the simultaneous presence of attack detection and mitigation. Moreover, based on the proposed framework, we analyze the impact of false positives and negatives in detecting attacks on the system performance. The results are important for the system defenders in the joint design of attack detection and mitigation to reduce the impact of these attack detection errors. Finally, as MDP solutions are not scalable for high-dimensional systems, we apply ${Q}$ -learning with linear and non-linear (neural networks-based) function approximators to solve the attacker’s problem in these systems and compare their performances.

Centralized, decentralized, hybrid principles of cyber-physical systems control of the Industry 4.0

The task is to develop a control system for multi-agent cyber and physical systems in the Industry 4.0 production. The company control systems components are cyber and physical systems of production purpose, cloud services and applications, server equipment and industrial data transmitting channels based on the protocols of Ethernet and Internet of Things. Three scheme options are available for cyber and physical systems control: a centralized control, a decentralized control and a hybrid one. There are schemes ready for implementation into exploitation of control system different options in cyber and physical production. Advantages and disadvantages of each option are described for the computerized control system building.

A System-Level Approach to Controller Synthesis

Biological and advanced cyber-physical control systems often have limited, sparse, uncertain, and distributed communication and computing in addition to sensing and actuation. Fortunately, the corresponding plants and performance requirements are also sparse and structured, and this must be exploited to make constrained controller design feasible and tractable. We introduce a new “system level” (SL) approach involving three complementary SL elements. SL parameterizations (SLPs) provide an alternative to the Youla parameterization of all stabilizing controllers and the responses they achieve, and combine with SL constraints (SLCs) to parameterize the largest known class of constrained stabilizing controllers that admit a convex characterization, generalizing quadratic invariance. SLPs also lead to a generalization of detectability and stabilizability, suggesting the existence of a rich separation structure, that when combined with SLCs is naturally applicable to structurally constrained controllers and systems. We further provide a catalog of useful SLCs, most importantly including sparsity, delay, and locality constraints on both communication and computing internal to the controller, and external system performance. Finally, we formulate SL synthesis problems, which define the broadest known class of constrained optimal control problems that can be solved using convex programming.

Reliable control of cyber-physical systems under sensor and actuator attacks: An identifier-critic based integral sliding-mode control approach

This study focuses on reliable control problems for cyber-physical systems (CPSs), described by linear continuous time-invariant systems, under a class of time-varying state-dependent sensor and actuator attacks. According to the state-dependent property of sensor attacks, the original reliable control problem is converted into a problem to stabilise a completely unknown time-varying system with the actuator attacks. Firstly, a dynamic neural network (NN) identifier with an indicator-function term is developed to model the unknown system dynamics. Due to the indicator term, the input distribution matrix of the identifier is guaranteed to be of full column rank. It provides a technical condition for designing an effective identifier-based integral sliding-mode (I-SM) attack compensator. It is shown that, under the proposed adaptive law, the identification errors and NN weight estimation errors are uniformly ultimately bounded. Furthermore, an identifier-critic based I-SM controller, which consists of an ADP-based controller and an adaptive I-SM attack compensator, is online learned using real-time control input and compromised sensor data, such that the unknown dynamics with the actuator attacks is stable with a nearly optimal performance. Meanwhile, it is shown that, the developed control approach ensures that the states in CPSs under sensor and actuator attacks converge to a compact set around zero. Finally, the effectiveness of the proposed one is verified by two illustrative examples.

Fractional Order PIλDµ Control Design for a Class of Cyber-Physical Systems with Fractional Order Time-Delay models

The control of cyber-physical systems (CPS) is a great challenge for researchers in control theory and engineering mainly because of delays induced by merging computation, communication, and control of physical processes. Consequently, control solutions for time-delay systems can be applied efficiently for many CPS system configurations. In this article, a fractional order PIλ and PIλDµ control design is investigated for a class of fractional order time-delay systems. The proposed control design approach is simple and efficient. The controller parameter's adjustment is achieved in two steps: first, the relay approach is used to compute satisfactory classical PID coefficients, namely kp, Ti and Td. Then, the fractional orders λ and µ are optimized using performance criteria. Simulation results show the efficiency of the proposed design technique and its ability to enhance the PID control performance.