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In this paper, the noncooperative optimal control problem is investigated for a class of discrete time-varying networked control systems subject to exogenous nonlinear disturbances. To relive the transmission burden in the sensor-to-controller channel, the Round-Robin protocol is adopted to schedule the sensor transmissions. On the other hand, the controller operates in an event-triggered manner so as to reduce the transmission frequency and thereby preserving the energy in the controller-to-actuator channel. In the presence of the underlying scheduling and triggering mechanism, it is literally impossible to acquire the accurate value of the individual cost function for each controller and, as an effective alternative, a certain upper bound is derived on the individual cost function. Then, in virtue of the completing-the-square technique and the Moore–Penrose pseudo inverse, such an upper bound is minimized at each time instant. Furthermore, a sufficient condition is established to guarantee the boundedness of the derived upper bound over the infinite horizon. Finally, a numerical example on the power grid is provided to verify the validity of the proposed methodology. [ABSTRACT FROM AUTHOR]

The increasing complexity of distributed real-time control systems in the vehicular area has led to the development of new protocols, such as controller area network with a flexible data rate (CAN-FD), that provides high-bandwidth communication with FD rate. Different topologies are used to interconnect electronic control units in safety-critical applications in the automotive area and the applied communication protocols, such as CAN-FD, must comply with reliability requirements. Moreover, the functional operations must be tested to their limits, since they require appropriate assessment techniques for different application scenarios. Recent research has highlighted that power switching systems cause transient faults that affect the communication network. In light of this concern, this paper explores the IEC/TS 62228:2007 and ISO 26262-3/4/9:2018 standards that can act as guidelines for the development of a test method and testing board for evaluating the impact of electrical fast transients on the performance of a distributed automotive control system. Metrics such as difference jitter, average jitter, and packet loss, are used to determine the fault impact on the control law of a critical vehicular control system. The experiments that were conducted show that during the four test scenarios in which the testing board was used, the average jitter increased from 10.41 to 29.05% in the worst case scenario. These results highlight the importance of carrying out consistent tests to prevent critical situations and that these data can be used in software requirements specification phases to improve reliability in vehicular control systems. [ABSTRACT FROM AUTHOR]

This paper studies the codesign optimization approach to determine how to optimally adapt automatic control of an intelligent electric vehicle to driving styles. A cyber-physical system (CPS)-based framework is proposed for codesign optimization of the plant and controller parameters for an automated electric vehicle, in view of vehicle's dynamic performance, drivability, and energy along with different driving styles. System description, requirements, constraints, optimization objectives, and methodology are investigated. Driving style recognition algorithm is developed using unsupervised machine learning and validated via vehicle experiments. Adaptive control algorithms are designed for three driving styles with different protocol selections. Performance exploration method is presented. Parameter optimizations are implemented based on the defined objective functions. Test results show that an automated vehicle with optimized plant and controller can perform its tasks well under aggressive, moderate, and conservative driving styles, further improving the overall performance. The results validate the feasibility and effectiveness of the proposed CPS-based codesign optimization approach. [ABSTRACT FROM AUTHOR]

The amount of electronic systems in agriculture machinery grows, becoming more complex and multifunctional. Due to the increasing number of devices connected to the network and the complexity of their functions, the current controller area network (CAN) becomes overloaded and CAN with flexible data rate (CAN FD) emerges as an alternative. This paper presents the simulation of an agriculture machine vehicular network using the higher layer protocols J1939 and ISO11783 (ISOBUS) and the performance comparison of the network using CAN, CAN FD 8 B and CAN FD 64 B. The presented contribution is mainly twofold: the proposal of an SAE J1939/ISOBUS compliant CAN FD 64 B model for a highly demanding vehicular network, and a detailed analysis of the real-time properties of this model compared to CAN and CAN FD 8 B. In the performed experiments, on the network permanent regime, periodic messages of machine control functions and network management data were sent by the devices connected to the network. The bus load usage, the response time, and jitter of these messages were analyzed to evaluate the real-time characteristics of the network. Compared to CAN, CAN FD had faster object pool transference, lower bus load usage, shorter worst case response time, and lower jitter. [ABSTRACT FROM PUBLISHER]

Remote access laboratories (RALs) are online environments for operating instruments and collecting measurement data over the Internet. Such systems are often deployed by universities to support undergraduate students and generally follow the client–server paradigm. This paper discusses a RAL system that enables peer-to-peer (P2P) experimental design and sharing. For this, a modular design is required, which allows participating nodes to create rigs and host those individually at distributed locations. The proposed architecture is generic and can be used with any distributed P2P network control systems over the Internet. In this paper, a distributed remote control framework is presented with regard to a P2P RAL system. The experiments in the RAL require three subsystems handling the user interface, instruction interpretation, and instruction execution which can be organized and operated in different manners depending upon the experiment. The key component for creating and controlling experiments is the microcontrollers that can be easily obtained, configured, and set up for use over the Internet. The most popular microcontrollers are examined for suitability to the distributed control architecture. The basic layout of a message-based network protocol suitable for programming the devices and communication between peers for remote instrumentation and control is discussed, and queuing and flow control mechanisms are compared and tested for the proposed framework. [ABSTRACT FROM PUBLISHER]

This paper explores the design, online, of an electrical machine's healthy reference by means of statistical tools. The definition of a healthy reference enables the computation of normalized fault indicators whose value is independent of the system's characteristics. This is a great advantage when diagnosing a broad range of systems with different power, coupling, inertia, load, etc. In this paper, an original method called spectral kurtosis with reference is presented to design a system's healthy reference. Its principle is first explained on a synthetic signal. This approach is then evaluated for mechanical unbalance detection in an induction machine using the stator current instantaneous frequency. The normalized behavior of the proposed indicator is then confirmed for different operating conditions, and its robustness with respect to load variations is demonstrated. Finally, the advantages of using a statistical indicator based on a healthy reference compared with a raw fault signature are discussed. [ABSTRACT FROM PUBLISHER]

In a smart grid, fine-grained usage reports of consumers are gathered using some computationally constrained smart measurement devices. One of the most challenging requirements in the data aggregation is how to securely read the consumption data, while putting the least possible overhead on smart meters. For this reason, recently, two efficient security protocols have been proposed to be used for subsequent secure consumption reports gathered from isolated smart measurement devices. Nonetheless, in both protocols, for each key establishment, the smart reader requires to connect to the electricity service provider (ESP) via the Internet. This paper proposes a novel key establishment protocol, which is free from the ESP involvement during the key agreement and benefits from notable reduction in the communication cost. Our thorough efficiency and security analyses indicate the eminence of the proposed security protocol. [ABSTRACT FROM AUTHOR]

Time delays exist in network-connected systems. Especially for vision-based multirobot systems, time delays are diverse and complicated due to the communication network, camera latency, image processing, etc. At the same time, many tasks, such as searching and rescue, have timing requirement. This paper focuses on fixed-time formation control of multirobot systems subject to delay constraints. First, predictor-based state transformation is employed for each robot to deal with the input delay, and the uncertain terms remained in the transformed systems are carefully considered. Then, a couple of nonlinear fixed-time formation protocols are proposed for the multirobot systems with respectively undirected and directed topology, and the corresponding settling time is derived by using the Lyapunov functions. In particular, the upper-bound estimation of the formation settling time is explicitly given irrelevant to the initial conditions. Finally, the protocols are validated through a numerical simulation example and then implemented on an E-puck robots platform. Both simulation and experimental results demonstrate the effectiveness of the proposed formation protocols. [ABSTRACT FROM AUTHOR]

In this paper, a structured methodology is proposed to define the architecture for a communication framework with multiframe capability, which can be embedded in a residential smart meter hardware for smart grid applications. This framework is based on the Transmission Control Protocol/Internet protocol, and it is considered that the data are exchanged via wireless technologies. The architectural model was based upon the state-of-the-art in software engineering, making use of the design patterns and the principles of low coupling and high cohesion, which result in a solution that is both more reliable and maintainable. A security module is also provided and the framework performance is evaluated, in terms of packet throughput and computational effort of the security layer on the processing device, via practical experiments of some laboratory scenarios. Furthermore, errors on some frames are introduced in order to evaluate the feasibility of this framework in real field applications. Results show that this framework architecture supports acceptable transfer rates even with extra computational cost due to the use of data encryption and separated processing modules, making it a feasible proposal for the considered application context. [ABSTRACT FROM AUTHOR]

Reprogramming is a crucial technique for software deployment and update in wireless sensor networks (WSNs). Bulk data dissemination is an important building block for enabling wireless reprogramming. Dissemination for reprogramming is required to be fast and energy efficient. Recent studies show that wireless link correlation can have a significant impact on the performance of bulk data dissemination. In this paper, we propose correlated dissemination (CD), a fast and energy-efficient bulk data dissemination protocol for reprogramming in WSNs. The main contribution of CD is that it disseminates data according to a novel structure called correlated tree, which considers both link qualities and link correlations. The construction of correlated tree is lightweight and allows for more efficient data transmission. Moreover, it selectively and dynamically employs rateless codes to improve the performance, especially in circumstances where link correlation is inherently weak. We implement CD based on TelosB testbed with both TinyOS and OpenWSN (with 802.15.4e MAC). Evaluation results show that, compared with previous works, CD greatly improves the dissemination performance in terms of completion time, transmission cost, and energy efficiency. [ABSTRACT FROM PUBLISHER]

The recent advances in cooperative and bio-inspired computing based on self-organizing sensor networks have been recognized as a very promising enabling technology for future smart grids (SGs). Although many papers outline the important role of these paradigms in decentralized SG monitoring and control, they do not explicitly consider the effect of the uncertainties that characterize the actual power system environment. The effects of these uncertainties could compromise the convergence of consensus-based algorithms in the form of unwanted changes in the convergence time, increasing the convergence errors and compromising the repeatability of the convergence. To address this problem, this paper proposes a new consensus protocol based on the use of affine arithmetic. The application of this reliable consensus protocol to decentralized SG computing is explained in detail. Furthermore, several numerical results are presented and discussed to demonstrate the effectiveness of the proposed methodology. [ABSTRACT FROM PUBLISHER]

This paper is concerned with the output-feedback controller design for consensus of a class of heterogeneous linear multiagent systems with the aperiodic sampled-data measurement. Under mild assumptions that the sampling periods are taken from a given set and the agent systems are time synchronized, an equivalent switched system model is first proposed for the heterogeneous agent system with nonuniform sampling. The overall leader-following tracking control problem (LFTCP) is then formulated as the output regulation of a discrete-time switched system. By using some algebraic manipulations, the control problem under consideration is further decoupled into two control subproblems, i.e., a static output-feedback (SOF) control problem plus a simple feedback control problem related to the communication topology. Based on the Lyapunov stability theory, some sufficient conditions are obtained for the solvability of LFTCP. In our results, the SOF controller gains are determined by solving some strict linear matrix inequalities. Finally, a simulation study on the modified Caltech multivehicle wireless testbed is presented to show the effectiveness of the proposed design method. [ABSTRACT FROM PUBLISHER]

Physical-layer-assisted power management (PA-PM) has great potential for reducing packet delay and lowering power consumption significantly. In PA-PM, the access point transmits the signature of a station to notify it of receiving packets, while the station performs low-power physical-layer correlation operations to detect its signature from the received signal. The detection performance of the signature has a crucial impact on the performance of PA-PM. In this paper, focusing on a polling scheme with PA-PM, we are the first to propose a novel queueing model to study the impact of the detection performance on the packet delay and the power consumption. Our model is applicable to homogeneous and heterogeneous traffic. Based on this model, we can optimize the sleeping interval of a station that minimizes the power consumption while meeting the delay requirement. Extensive simulations verify that our model is very accurate. This study can help system developers choose optimal system parameters (such as the sleeping interval and the signature length) and promote the practicality of PA-PM. [ABSTRACT FROM AUTHOR]

In wireless communication, secure transmission and reception of data are the major concern today. In recent years, Radio Frequency Identification (RFID) has played a vital role in the security system for secured data communication. The main challenge in RFID-based security system is to design a more secure, better area and power efficient encoder architecture for tag-reader mutual authentication protocol. This paper proposes new and efficient encoder architecture for RFID mutual authentication protocol which utilizes 2^n\,- \,2^k\,- \,1 modulo adder for achieving higher security. The proposed architecture is described in Verilog hardware description language and the functionalities are verified and synthesized using Altera Quartus II tool. The architecture is also synthesized using Cadence RTL compiler for 180 and 90 nm technology. Experimental results of the proposed scheme give better performances in terms of area, power, and delay when compared with existing mutual authentication schemes. In addition to that, the architecture is realized as hardware in Altera DE2 Cyclone II (EP2C35F672C6) field programmable gate array and real time verification has been carried out using Logic Analyzer 16851A. Finally, formal security analysis has been performed using the Burrows–Abadi–Needham (BAN) logic to show that the proposed protocol is secure. [ABSTRACT FROM PUBLISHER]

The combination of ultra-low-power wireless communications and energy harvesting enables the realization of autonomous wireless sensor networks. Such networks can be usefully applied in commercial aircraft where wireless sensing solutions contribute to weight reduction and increased ease of installation and maintenance. This paper presents, for the first time, a complete energy-autonomous wireless strain monitoring system for aircraft. The system is based on a multimode wireless time-division multiple access (TDMA) medium access control (MAC) protocol that supports automatic configuration and a time-stamping accuracy better than 1 ms. The energy supply depends solely on an innovative thermoelectric energy harvester, which takes advantage of the changes in environmental temperature during takeoff and landing. The system was successfully integrated and passed the functional and flight-clearance tests that qualify it for use in a flight-test installation. [ABSTRACT FROM PUBLISHER]

In this paper, we use an event-triggered control methode to study the consensus problem for an asynchronous distributed multi-agent system. An integral-type event-triggering condition is proposed. Each agent periodically checks its triggering condition by its own clock. When the triggering condition for an agent is satisfied, then control inputs of this agent and its neighbors are updated. Based on local information, we present the consensus protocol, and using Lyapunov's methods, we show that all agents asymptotically reach an agreement on states. Finally, experiments are presented to demonstrate the effectiveness of our proposed protocol. [ABSTRACT FROM PUBLISHER]

This paper proposes an impulsive framework to analyze the effect of the clustered event-triggered information transmission on the dynamics of multiagent systems. Under this framework, we study three cases and propose different types of event-triggered protocols. First, if agents’ states are available, a clustered event-triggered protocol based on agents’ states is designed, which guarantees all followers to track the leader eventually. Second, the first case is further investigated when the agents’ states are under disturbance. Hence, a modified event-triggered protocol is introduced to reach \mathcal L_\infty leader-following consensus. Third, for the case where agents’ states are not available, a clustered event-triggered observer-type protocol is developed based on the agents’ outputs. It is worth noting that Zeno behavior is excluded in these cases. Finally, some numerical examples and an application of unmanned aerial vehicle helicopters are given to verify our theoretical analysis. [ABSTRACT FROM AUTHOR]

Visual, motion control, and programmable logic controller (PLC) systems are becoming increasingly inseparable and important in manufacturing. However, the types of programs and hardware used in these systems are numerous, and there are many communication protocols and mixed development methods among the systems; meanwhile, the requirements and complexities of these systems are ever growing. All these factors hinder application implementation for users, and very few reported studies have researched the integration of these three systems to ease complexity. Most of these studies have focused on individual applications. In this paper, we propose a multilevel flexible architecture based on a vision control algorithm (VCA) protocol. This multilevel architecture includes a flexible layer, a control layer, and an algorithm layer. The flexible layer is used to seamlessly integrate the visual system and the embedded PLC (ePLC). The VCA protocol is designed for data interactions between the layers. Correspondingly, customized hardware, memory allocation, and Petri-net-based multithreading structure of the proposed architecture are described in detail. Then, two cases are implemented: a winding machine with a visual system that obtains a regular winding effect by correcting $\theta$ , and a binocular catching robot uses cameras to track the trajectory and successfully catch a ball by adjusting speed and position. The results indicate that the proposed VCA-based architecture could easily be applied to two very different scenarios. [ABSTRACT FROM AUTHOR]

Hybrid energy storage system (HESS) consisting of battery and supercapacitor (SC) is an effective approach to alleviate voltage stability problems brought by the fluctuation of renewable resources in a dc microgrid. This paper proposes a novel distributed control scheme for multiple HESSs based on a leaderless consensus protocol to realize the power splitting between batteries and SCs and thus regulate the dc bus voltage. Without assigning leaders among the batteries and SCs, each SC or battery has equal priority in participating in voltage or state of charge (SOC) regulation using only neighboring information exchange instead of global communication. This distributed approach makes the system robust against any physical failure or communication fault only if the remaining communication network is connected. Consensus for the state variable associated with the battery SOC, the SC terminal voltage, and the dc average bus voltage are all achieved in this scheme, and thus the voltage quality and the energy storage lifetime can be improved. In addition, the small-signal stability of a four-HESS system is investigated, and the impact of the control parameters on the system is analyzed. Simulations and experimental studies are conducted to demonstrate the effectiveness of the proposed control scheme in an islanded dc microgrid. [ABSTRACT FROM AUTHOR]

Boundary conduction mode or critical conduction mode is characterized by an inductor current that operates in the boundary between continuous conduction modes (CCM) and discontinuous conduction modes, making the converter switching frequency dependent on the converter operating conditions. The advantage of this operation mode versus CCM is achieving zero current switching (ZCS) conditions for the converter rectifier, which makes it possible to use silicon diode rectifiers without having a penalty due to reverse recovery issues. Moreover, the main switch turn-on loss is decreased due to ZCS conditions and valley switching operation. However, the penalty is an increased current stress in the circuit and an increased main switch turn-off energy loss. Implementation of the synchronous rectifier in boundary conduction mode (BCM) converters makes it possible to achieve zero voltage switching (ZVS) conditions by extending the synchronous rectifier conduction time after zero current condition in the inductor. High power density and high-efficiency MHz implementations have already been demonstrated in the literature; however, none of the proposed solutions solves the controllability issues of the synchronous rectifier switch. This paper proposes and validates a ZVS self-regulating control method for BCM converters operating in the MHz switching frequency range. [ABSTRACT FROM AUTHOR]

This paper investigates the distributed finite-time restoration of inverter voltage and frequency terms in an islanded ac microgrid. Formulating networked inverters of ac microgrids as a cooperative multiagent system, the voltage and frequency restoration can be cast as synchronization problems, while the active power sharing can be viewed as a consensus problem. One popular distributed control approach is the neighbor-based linear consensus protocol, where the consensus at the frequency and voltage set points is achieved over an infinite-time horizon with an exponential convergence. To achieve accelerated convergence and better disturbance rejection properties, a distributed finite-time control protocol, based on feedback linearization approach, is proposed for voltage restoration, which synchronizes the voltage term at each inverter to the reference value in finite time period. Then, a finite-time control protocol for both frequency restoration and active power sharing problems is proposed to synchronize the microgrid frequency to the nominal value, and share the active power among inverters based on their ratings in a finite time. Rigorous Lyapunov proofs are provided to establish the upper bounds on the convergence times. Numerical simulation studies verify the effectiveness of the proposed control protocols. [ABSTRACT FROM PUBLISHER]

Dynamic wireless charging of electric vehicles (EVs) aims at increasing EV range and reducing battery size and associated costs. Moreover, it minimizes the need for recharging stops, thus increasing travel comfort. As electrification of transport ultimately targets CO2 emissions reduction, increased utilization of renewable energy sources is likely to provide the means for reaching the decarbonization objectives. Demand-side management (DSM) enables the increased penetration of intermittent power sources by providing techniques that ensure grid stability. While complete frameworks for DSM deployment in static charging have been designed, these approaches must be re-evaluated with focus on the operational requirements for dynamic EV charging. In this paper, a review of DSM methods targeting static charging is made and one particular case of DSM is simulated in a dynamic charging environment in order to reveal critical aspects towards deployment. [ABSTRACT FROM PUBLISHER]

This paper proposes a new approach for the analysis of consensus of multi-agent systems subject to time-varying delayed control inputs and switching topology. The main contribution is a condition for consensus for a networked system based on linear matrix inequalities that takes into account the joint effect of time-varying delays and switching network topology. Topology changes are modeled using Markov jumps with uncertain rates of transitions. A practical example is shown to illustrate the main result in various scenarios. [ABSTRACT FROM PUBLISHER]

Construction vehicles (CVs) are typically a class of remote mobile objects. Safe, efficient, and low-cost operations of CVs have raised an urgent need for the intelligent remote monitoring system (IRMS) based on the Internet of Things (IoT). The existing technology of remote wireless communication could not meet the requirements of the IoT-based IRMS for CVs on the real time, efficiency, and reliability of data transmission, transmission data types, and the balance between the monitoring scale and costs. This paper proposes a remote wireless transparent transmission protocol, CVDTP. First, all remote monitoring data are abstracted and classified. Then, transmission modes are matched online and optimized dynamically with transmission data types and transmission channel states. The field test and the practical application on the Internet of concrete pump trucks demonstrate that CVDTP could afford an industrial-QoS data transmission on the remote wireless network characterized by low bandwidth and frequent disconnection. The test results also show that CVDTP does not need the support of routing nodes in remote wireless networks; thus, it is easy to be implemented. [ABSTRACT FROM PUBLISHER]

This paper proposes a distributed integral-sliding-mode (ISM) control strategy for cooperative braking control of a connected vehicle platoon with a focus on the car-following interactions between vehicles. In particular, a linear controller considering the position and velocity of the lead vehicle as well as the braking force is proposed for the leader, while a constant-time-headway-policy-based ISM controller incorporating the car-following interactions, the spacing error, velocity difference, and external disturbances is developed for the followers. In addition, the convergence for the ISM controller is rigorously analyzed using the Lyapunov technique. Furthermore, the string stability of the platoon is analyzed using the transfer function method. Finally, extensive analyses are conducted using numerical and field experiments. Results verify the effectiveness of the proposed control strategy with respect to the position, velocity, deceleration, and spacing error profiles. [ABSTRACT FROM AUTHOR]

Real-time switched networks are becoming popular with the growing complexity of distributed embedded systems. There is a practical need to transmit noncritical data including diagnostic and supervising data for cost reduction. To meet hard real-time constraints, the time-triggered method is widely used due to its deterministic property, where both the reliability of the control data transmission and the tolerance of link failures are required. Conventional methods deploy redundant links and transmit frames over multiple disjoint paths. This paper presents a novel schedule method for the time-triggered network without simultaneous transmissions with multiple frames. The fault tolerance protocol is localized for critical data. We harness multiple effective optimization heuristics and strategies to ameliorate the existing schedule model and constraints. The experimental evaluation substantiates that our effective method can considerably improve the bandwidth for noncritical traffics with no link failures. [ABSTRACT FROM AUTHOR]

The extremely constrained resource has hindered the efforts to implement the elliptic curve cryptography (ECC) into a radio-frequency identification (RFID) tag chip. In this paper, an ECC-based RFID digital baseband controller (DBC), which is compatible with ISO/IEC 14443 and Schnorr authentication protocol, is presented. In order to achieve low resources consumption and fast ECC computation speed, some techniques, such as the register reuse, clock multiplexer, and asynchronous counter, are adopted in this design. In addition, a linear feedback shift register-based stream encryption scenario is proposed for the data security. According to the synthesis result, the gate area and power consumption of DBC are 25.7 K and 14.7 \mu\W, respectively, in UMC 0.13 \mu\m CMOS technology. All of those characteristics make the realization of ECC-based DBC for RFID tag chip promising. [ABSTRACT FROM PUBLISHER]

This paper considers the problem of fault-tolerant tracking control for linear and Lipschitz nonlinear multi-agent systems subject to actuator faults and the leader's bounded unknown input. The communication topology is the undirected subgraph with directed connections between the leader and the followers. Based on the relative states of neighbors and a general actuator fault model, an adaptive fault-tolerant control protocol is proposed to compensate for the failure effects on consensus tracking where the feedback matrices update the parameters by the online estimation of actuator faults. The criteria of reaching consensus tracking despite the actuator faults for both linear and Lipschitz nonlinear agents are derived, respectively. Finally, two examples are included to illustrate the theoretical results. [ABSTRACT FROM PUBLISHER]

Advanced metering infrastructure (AMI) plays a critical role in the smart grid. It enables intelligent applications such as load control switching, demand side management, and meter data management by creating a bidirectional communication network for smart meters and utility systems. Consequently, AMI should be strictly protected to ensure reliable and secure operations of smart grid. In this paper, we first show that a recently proposed key management scheme for AMI by Liu et al. suffers from the desynchronization attack, and, at the same time, it lacks scalability due to inefficient key management. Then, we propose a new scalable key management (SKM) scheme characterized by combining identity-based cryptosystem and efficient key tree technique. The scheme SKM possesses advantages of efficiency and flexibility in key management. In particular, the cost of SKM is $O(\log n)$ in either aspect of computation and communication ( $n$ is the number of smart meters), which is significantly reduced from the cost of $O(n)$ in the scheme of Liu et al. We analyze security and performance of SKM in detail to show that SKM is efficient in computation and communication cost. [ABSTRACT FROM PUBLISHER]

This paper addresses the problem of cluster formation control for a networked multi-agent system (MAS) in the simultaneous presence of aperiodic sampling and communication delays. First, to fulfill multiple formation tasks, a group of agents are decomposed into $M$ distinct and nonoverlapping clusters. The agents in each cluster are then driven to achieve a desired formation, whereas the MAS as a whole accomplishes $ M $ cluster formations. Second, by a proper modeling of aperiodic sampling and communication delays, an aperiodic sampled-data cluster formation protocol (CFP) is delicately constructed such that the information exchanges among neighboring agents only occur intermittently at discrete instants of time. Third, a detailed theoretical analysis of cluster formability is carried out and a sufficient and necessary condition is provided such that the system is $M$-cluster formable. Furthermore, a discontinuous Lyapunov functional approach is developed to derive a design criterion on the existence of an admissible sampled-data CFP. Finally, numerical simulations on a team of nonholonomic mobile robots are given to illustrate the effectiveness of the obtained theoretical result. [ABSTRACT FROM AUTHOR]

This paper addresses the distributed formation control problem of a networked multi-agent system (MAS) subject to limited communication resources. First, a dynamic event-triggered communication mechanism (DECM) is developed to schedule inter-agent communication such that some unnecessary data exchanges among agents can be reduced so as to achieve better resource efficiency. Different from most of the existing event-triggered communication mechanisms, wherein threshold parameters are fixed all the time, the threshold parameter in the developed event triggering condition is dynamically adjustable in accordance with a dynamic rule. It is numerically shown that the proposed DECM can achieve a better tradeoff between reducing inter-agent communication frequency and preserving an expected formation than some existing ones. Second, an event-triggered formation protocol is delicately proposed by using only locally triggered sampled data in a distributed manner. Based on the formation protocol, it is shown that the state formation control problem is cast into an asymptotic stability problem of a reduced-order closed-loop system. Then, criteria for designing desired formation protocol and communication mechanism are derived. Finally, the effectiveness and advantages of the proposed approach are demonstrated through a comparative study in multirobot formation control. [ABSTRACT FROM PUBLISHER]

User authentication in wireless sensor networks (WSN) is a critical security issue due to their unattended and hostile deployment in the field. Since the sensor nodes are equipped with limited computing power, storage, and communication modules, authenticating remote users in such resource-constrained environment is a paramount security concern. Until now, impressive efforts have been made for designing authentication schemes with user anonymity by using only the lightweight cryptographic primitives, such as symmetric key encryption/decryption and hash functions. However, to the best of our knowledge, none has succeeded so far. In this paper, we take an initial step to shed light on the rationale underlying this prominent issue. In order to do that here at first, we demonstrate that the existing solutions for anonymous user authentication in WSN are impractical. Subsequently, we propose a realistic authentication protocol for WSN, which can ensure various imperative security properties like user anonymity, untraceability, forward/backward secrecy, perfect forward secrecy, etc. [ABSTRACT FROM AUTHOR]

This paper analyzes the exponential stability of a discrete-time linear plant in feedback control over a communication network with $N$ sensor nodes, dynamic quantization, large communication delays, variable sampling intervals, and round-robin scheduling. The closed-loop system is modeled as a switched system with multiple-ordered time-varying delays and bounded disturbances. We propose a time-triggered zooming algorithm implemented at the sensors that preserves exponential stability of the closed-loop system. A direct Lyapunov approach is presented for initialization of the zoom variable. The proposed framework can be applied to the plants with polytopic type uncertainties. The effectiveness of the method is illustrated on cart-pendulum and quadruple-tank processes. [ABSTRACT FROM PUBLISHER]

A controller area network (CAN)-based distributed system may develop faults at run-time. These faults need to be detected and diagnosed. This paper proposes a new algorithm named adaptive fault diagnosis algorithm for CAN (AFDCAN). It is designed for low-cost resource-constrained distributed embedded systems. The proposed algorithm detects all faulty nodes on the CAN. It allows new node entry and reentry of repaired faulty nodes during a diagnostic cycle. AFDCAN is found to provide high fault tolerance and to ensure reliable communication. It uses single-channel communication deploying the bus-based standard CAN protocol. A hardware implementation of the proposed algorithm has been used to obtain the results. The results show that the proposed algorithm diagnoses all faults in the system. Analysis of the proposed algorithm proves that the algorithm uses a definite and bounded number of testing rounds and messages to complete one diagnostic cycle. [ABSTRACT FROM PUBLISHER]

This article concentrates on designing a strictly stealthy attack strategy from the adversarial perspective against the multisensor cyber-physical systems (CPSs) under the round-robin protocol (RRP). The aim is to maximize the attack performance and remain strictly stealthy at the same time. Different from the existing attacks against the single-sensor application scenario, we propose a stealthy attack strategy for multisensor networked systems. In addition, due to the scheduling effects of the RRP, only incomplete transmitted data can be corrupted at each time step. Thus, a novel protocol-based attack model is developed, and then the corrupted error covariance at the remote side is derived to quantify the attack performance. Next, a convex optimization problem is formulated to solve the optimal attack parameters, which leads to the worst filtering performance. Moreover, the analytical expression of the optimal attack parameters is presented and proved. Finally, the experiments on a permanent magnet synchronous machine monitoring system are conducted to verify our results. [ABSTRACT FROM AUTHOR]

This article proposes a flexible formation tracking control protocol (FFTC) for multiple unmanned surface vessels (USVs) to pass through narrow water channels with unknown curvatures. An observer is developed to estimate the curvatures of channels. A flexible formation tracking control protocol is, thereby designed to steer USV fleets to pass through narrow channels in a flexible serial formation. Furthermore, the asymptotically stable conditions of the closed-loop multi-USV systems are theoretically derived. Finally, both numerical simulation and experimental results with a fleet of three HUSTER-0.3 USVs are reported to substantiate the effectiveness of the proposed FFTC protocol for navigating through narrow channel in a laboratory context. [ABSTRACT FROM AUTHOR]

In this article, to estimate the battery state of health (SOH) under realistic electric vehicle (EV) conditions, a robust and efficient data-driven algorithm is developed and validated through comprehensive battery life testing. More than 50 state-of-the-art EV battery cells have been tested under a variety of cycling conditions with different charging protocols, dynamic driving cycles, voltage ranges, pulse rates, and temperatures. Some of the cells have also been tested under a combination of cycling and storage conditions, constant current and multistep charging, and a periodic temperature variation that mimics real life conditions. Only partial data (voltage, current, and temperature) within a narrow state-of-charge range under a dynamic driving condition are required to extract the health indicators. A neural network is trained to find the mapping between the health features and the battery SOH. The life test data are divided into three groups. The first dataset (55% of data) is used for training and initial validation and testing, whereas the second and third datasets (45% of data) are entirely used for the final validation and testing to minimize the network overfitting. The results show that the SOH estimation root-mean-squared error for all datasets is less than 0.9%, signifying the fidelity and reliability of the proposed method. [ABSTRACT FROM AUTHOR]

This article presents the $\epsilon$ -stealthy attack against cyber-physical systems under the stochastic communication protocol (SCP), which is used to avoid data collisions. The aim is to develop an optimal attack strategy to degrade the estimation performance maximally, while remaining a certain level of stealthiness characterized by the Kullback–Leibler divergence. Taking the SCP-introduced effects into account, a novel attack model is proposed, where only a part of the transmitted data is utilized to construct the attack signal at each time instant. Subsequently, the optimization problem is formulated. Different from the existing results, where only the numerical solution is given, the analytical expression of the optimal attack parameters is presented, where the analytical solution has more advantage in analyzing how the parameters affect the attack performance. Finally, the numerical simulations on a three-tank system and the experiments performed on a networked permanent magnet synchronous machine prototype system are provided to validate our results. [ABSTRACT FROM AUTHOR]

The security of data propagation is a critical challengefor the widespread use of networked control systems (NCSs), while the conventional strategies based on estimation techniques cannot solve this issue well. Furthermore, the contradiction between the security and the real-time nature of the control method has not been settled yet. The aim of this article is to propose a novel real-time control method empowered by blockchain technologies to resolve the security problems of NCSs under potential cyberattacks. To facilitate the analysis of blockchain-assisted NCSs, a cyber-authentic-physical system (CAPS) framework is proposed. One of the significant features of the CAPS is that the defense of NCSs against attacks is built by introducing a blockchain protocol. Theoretical analysis reveals the relationship among the scale of the peer-to-peer network, the security of the CAPS, and the latency of NCSs, as well as clarifies the impact of the introduction of the blockchain mechanism on the performance of NCSs. With the networked secure control mechanism designed in this article, the security and stability of NCSs can be achieved simultaneously, and their sufficient conditions are also given. Finally, simulations and practical experiments are presented to show the efficacy of the suggested secure control strategy. [ABSTRACT FROM AUTHOR]

Phasor measurement units (PMUs) are widely used to monitor the operating conditions of a smart grid. The PMU communication network is, generally, a public wide area network, hence it is vulnerable to cyberattacks. At present, IEEE C37.118.2 is widely used as the communication standard for PMU communication. However, the IEEE C37.118.2 standard does not specify any security mechanism to protect the PMU data from cyberattacks. Deviation in the transmitted data of PMUs may lead to devastating consequences, such as blackouts in the grid. To mitigate cyberattacks on a PMU, this article proposes a security mechanism based on key distribution scheme that ensures integrity along with confidentiality. This mechanism involves addition of new security fields to IEEE C37.118.2 message structure. The introduction of security mechanism imposes additional computational complexity on resource constraint PMU devices and addition of new security fields in PMU message structure increases overall message size which in turn increases communication delays. In order to assess the additional computational complexity and increased communication delays, an experimental set up consisting of PMU simulators and network emulator is developed in this article. The developed PMU simulator generates IEEE C37.118.2 messages with proposed security mechanisms. Results validate the applicability of the proposed security mechanism in PMU networks without any repercussions. [ABSTRACT FROM AUTHOR]

This article proposes an equal-distance surrounding control method for second-order nonlinear multiagent systems (MASs) to encircle multiple moving targets with guaranteed collision avoidance. First, a distributed estimator is developed to approximate the center of moving targets. Then, an adaptive distributed control law is designed for the MASs to accomplish equal-distance surrounding collaboratively. In particular, conditions for assuring asymptotical stability for the closed-loop MAS are derived. Finally, experimental results with unmanned surface vessels are reported to substantiate the effectiveness of the proposed coordinated surrounding control method. [ABSTRACT FROM AUTHOR]

The constant-current constant-voltage (CC–CV) charging method is a common approach to charge batteries with a single charger. Recently, with the emergence of high power-density batteries, e.g., supercapacitors, several chargers are typically connected in parallel to provide the required charging power in many applications. However, the classical decentralized control scheme for the multicharger system leads to the current imbalance, which deteriorates the reliability of the charging system. In this article, we extend the CC–CV charging protocol to multicharger systems using a cooperative control method, which can alleviate the current imbalance among chargers effectively. First, the motivation and charging system modeling of this work are provided. Then, a cooperative CC charging protocol and a cooperative CV charging protocol are presented, respectively, and a switching logic is designed to achieve the switching between them based on the supercapacitor voltage. The closed-loop model of the proposed charging system is developed using the block diagram. A laboratory testbed is built to verify the effectiveness of the proposed method. Experiment results show that the proposed method provides a better current balancing and voltage regulation performance when compared with existing decentralized control methods. [ABSTRACT FROM AUTHOR]

A method called “adaptive channel diversity” (ACD), which improves wireless performance in terms of reliability and latency, is proposed. With ACD, the optimum frequency channels are selected on the basis of the amount of dynamic radio interference. ACD was implemented in two prototype systems operating in the 2.4-GHz industry–science–medical band based on the ISA100.11a standard, namely, time-division multiple access and frequency channel hopping. According to an evaluation of the prototype systems, a 10−4 packet error rate was achieved within a 1.3-s latency for a 30-terminal star topology and within a 0.85-s latency for a 5-terminal multihop topology. These evaluation results are consistent with the results of simulations based on probabilistic analysis. [ABSTRACT FROM PUBLISHER]

Process-level communication network brings digital technology to the high-voltage switchyard, a major stage in the evolution to ensure the protection control and data acquisition of smart substation. This network requires a mission-critical protocol such as high-availability seamless redundancy (HSR). Two main drawbacks of HSR, however, are the transmission latency introduced by each hop in the single ring (SR) topology and the unnecessary traffic due to the duplicated copies of sending frames. This study presents two enhanced solutions and fully implements quick removing (QR) approach to HSR for improving the latency and reducing the traffic volume in process-level network. The main idea of these two enhanced solutions is to reduce the minimum number of hops required for delivery messages to destinations for reducing the maximum end-to-end latency (ML). To achieve traffic reduction, the QR approach is concretized in HSR nodes for fully applying to any closed-loop HSR networks. Performance of IEC 61850-based process bus networks are analyzed theoretically and demonstratively by Network Simulator-2 (NS-2) and OPNET Modeler®. The combination of enhanced solutions and the QR algorithm solves both main drawbacks of HSR, improving the network performance optimally. These enhancements of HSR are applicable to not only on substation automation networks, but also to any real-time industrial networks. [ABSTRACT FROM AUTHOR]