Control Channel Research Articles

Design of Proton Exchange Membrane Hydrogen Fuel Cell Control System Based on Response Speed and Uncertainty Characteristics

In an effort to settle the issue of poor control accuracy caused by external interference (such as environment and load changes) in the control process of hostage switch film fuel cell, a PEMFC control channel design method based on response speed and uncertainty characteristics was proposed in this study. The channel structure model and parameter model of PEMFC operate channel are established, and its response speed and uncertainty characteristics are analyzed. The proportional integral-differential (PID) operate method is used to obtain the signal model of the current vector data under the optimal operate state, and the AC coupling of the capacitor is used to suppress the loss. The simulation results show that this method can improve the stability and convergence of PEMFC, effectively correct the error, and the operate accuracy reaches 99%.

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.

Online State Estimation for Supervisor Synthesis in Discrete-Event Systems With Communication Delays and Losses

In the context of networked discrete-event systems (DESs), communication delays and losses exist between the plant and the supervisor for observation and between the supervisor and the actuator for control. In this paper, we first introduce a new framework for supervisory control of networked DESs. Under the introduced framework, we address the state estimation problem for supervisor synthesis of networked DESs with both communication delays and losses. The estimation algorithm considers the effect of the controls imposed on the system. Additionally, the estimation algorithm is based on the control decisions available up to the moment, and all the future control decisions are assumed to be unknowable. Two notions, called “observation channel configuration” for tracking observation delays and losses and “control channel configuration” for tracking control delays and losses, are defined. Then, we introduce an online approach for state estimation of the controlled system. Compared with the existing approach, the proposed approach under the introduced framework can estimate the states of the controlled system more accurately. As an application of the proposed approach, we finally show that the existing methods can be applied to synthesize maximally permissible and safe networked supervisors.

New bell plate controlled multi-inertia channel magnetorheological fluid mount wide frequency vibration isolation control study

This paper introduces a novel type of magnetorheological fluid (MRF) mount designed to achieve wide-frequency vibration isolation for engines. While previous studies have explored vibration isolation using hydraulic mounts, there has been limited research on achieving wideband isolation with MRF mounts. Consequently, this paper presents an innovative MRF mount structure and investigates wideband vibration isolation control for engines. Initially, experiments with a multi-channel MRF damper validate the switchable operation of controllable channels. A novel controllable multi-inertia channel MRF mount system is proposed, aligning the working mode of controllable inertia channels with that of the MRF damper. The lumped parameter method is employed to derive the mathematical model of the MRF mount, and its high and low-frequency dynamic characteristics are thoroughly examined. Subsequently, a real-time multi-island genetic algorithm-optimized controller is developed to investigate wideband vibration isolation within the MRF mount system. The findings indicate that: (1) The MRF mount demonstrates adjustable low-frequency dynamic stiffness and loss angle within the frequency range of f = 0–50 Hz. In the frequency range of f = 50–100 Hz, the mount achieves its lowest dynamic stiffness value, effectively addressing the issue of high-frequency stiffening. (2) The real-time multi-island genetic optimized controller exhibits superior vibration isolation performance compared to traditional sky-hook control and hybrid sky-hook control methods, achieving optimal vibration isolation for the mount.

Enhanced PON and AMCC Joint Transmission with GMM-Based Probability Shaping Techniques

In ITU-T standards, auxiliary management and control channels (AMCCs), as defined, facilitate the rapid deployment and efficient management of wavelength division multiplexing passive optical network (WDM-PON) systems. The super-imposition of an AMCC introduces additional interference to a PON signal, resulting in the degradation of the performance of the overall transmission. In prior research, we proposed employing a Gaussian mixture model (GMM) to fit a baseband-modulated AMCC signal. Following the analysis of the interference model and the distribution characteristics of received signal errors, we propose a combined optimization method for a transmitter and receiver in this paper. This method, grounded in probabilistic shaping (PS) techniques, optimizes the probability distribution of the transmitted signal based on the AMCC interference model, with the objective of reducing the error rate in PON signal transmission. We have validated this approach within a 50G-PON experimental system by utilizing PAM4 modulation. The experimental results demonstrate the effectiveness of this method for mitigating the impact of baseband-modulated AMCC, thereby reducing the error rate in PON signal transmission. The approach presented in this paper can further minimize the performance degradation introduced by baseband-modulated AMCC in WDM-PON systems, enhancing the efficiency of WDM-PON deployment.

Charging modulation of the pyridine nitrogen of covalent organic frameworks for promoting oxygen reduction reaction

Covalent organic frameworks (COFs) are ideal templates for constructing metal-free catalysts for the oxygen reduction reaction due to their highly tuneable skeletons and controllable porous channels. However, the development of highly active sites within COFs remains challenging due to their limited electron-transfer capabilities and weak binding affinities for reaction intermediates. Herein, we constructed highly active catalytic centres by modulating the electronic states of the pyridine nitrogen atoms incorporated into the frameworks of COFs. By incorporating different pyridine units (such as pyridine, ionic pyridine, and ionic imidazole units), we tuned various properties including dipole moments, reductive ability, hydrophilicity, and binding affinities towards reaction intermediates. Notably, the ionic imidazole COF (im-PY-BPY-COF) exhibited greater activity than the neutral COF (PY-BPY-COF) and ionic pyridine COF (ion-PY-BPY-COF). Specifically, im-PY-BPY-COF demonstrated a half-wave potential of 0.80 V in 0.1 M KOH, outperforming other metal-free COFs. Theoretical calculations and in situ synchrotron radiation Fourier transform infrared spectroscopy confirmed that the carbon atoms in the ionic imidazole rings improved the activity by facilitating binding of the intermediate OOH* and promoting the desorption of OH*. This study provides new insights into the design of highly active metal-like COF catalysts.

Синтез робастной системы управления манипуляционным роботом с полиномиальными регуляторами на основе грамианного метода

Since manipulation robots can have several control channels, and their nonlinear coordinate relationships lead to internal parametric disturbances, along with variations in mechanical parameters, the use of Gramian methods for the synthesis of robust automatic control systems seems to be an effective way to improve the quality of control of such objects. When developing a robust control system for a manipulative robot, the method of polynomial modal control is used, local regulators are synthesized for both parts of the manipulator and a centralized controller is synthesized using an object model adjusted by the Gramian method. The calculations of the regulator based on the linear model of a two-link robot manipulator and the analysis of the transient characteristics of the movement of its links are carried out in the MATLAB software package. A method to synthesize a robust control system for a manipulation robot is proposed. It is based on a linearized mathematical model of a control object with a dynamic (polynomial) controller, aimed at changing the singular number of controllability and observability Gramians and subsequent calculation of a centralized controller to control the original nonlinear object. The use of a modified object model makes it possible to improve the robust properties and increase the speed of the control system for a nonlinear robotic object while maintaining the aperiodic nature of the processes under conditions of mutual influence of links and parameter variations. The proposed method makes it possible to improve the quality of control of manipulative robots and their productivity in conditions of intensification of technological production.

Minimization of sensor activation in discrete-event systems with control delays and observation delays

In discrete-event systems, to save sensor resources, the agent continuously adjusts sensor activation decisions according to a sensor activation policy based on the changing observations. However, new challenges arise for sensor activation in networked discrete-event systems, where observation delays and control delays exist between the sensor systems and the agent. In this paper, a new framework for activating sensors in networked discrete-event systems is established. In this framework, we construct a communication automaton that explicitly expresses the interaction process between the agent and the sensor systems over the observation channel and the control channel. Based on the communication automaton, we can define dynamic observations of a communicated string. To guarantee that a sensor activation policy is physically implementable and insensitive to non-deterministic control delays and observation delays, we further introduce the definition of delay feasibility. We show that a delay feasible sensor activation policy can be used to dynamically activate sensors even if control delays and observation delays exist. A set of algorithms are developed to minimise sensor activation in a transition-based domain while ensuring a given specification condition is satisfied. A practical example is also provided to show the application of the proposed framework. Finally, we briefly discuss how to extend the proposed framework to a decentralised observation setting.

WHICH POWER DECIDES ON THE BASIC HUMAN GOODS OF JOHN FINNIS' NATURAL LAW THEORY IN BRAZILIAN DEMOCRACY?

The work presents a description of the basic human goods in Finnis' theory (2007), which are: knowledge, life, play, aesthetic experience, friendship, practical reasonableness and religion. To then question which power has the basis to decide on basic human goods in a democracy. The article brings jurisprudence from the Federal Supreme Court in which the court ruled on basic human values, that is, basic human goods shaped outside the political arena, configuring a possible obstruction of the channels of democratic alternation and popular control. To explain the strengthened judiciary power, the text repeatedly uses Hirschl's theory (2020), which asserts that one of the causes of the strength of the judiciary is the avoidance of politicians in making difficult moral or political decisions, which, once decided, rarely present absolute numbers. of winners, therefore, with political spoils that are difficult to manage. This movement between powers causes a transfer of the locus of political debate, which migrates from the powers constituted by direct representatives of the people to the courts, reaching the doctrine about the separation of powers and democracy, otherwise let's see: basic human goods being designed by judges in to the detriment of powers that reveal popular sovereignty. The tension between democracy and judicial control of pure politics, apparently, is revealed when we analyze that a counter-majority court would have the last word in democratic processes for delineating the major political issues of a country.

Development of embedded fuzzy control using reconfigurable FPGA technology

The purpose of this work is to investigate the construction of fuzzy embedded control systems combining fast execution and parallel processing capabilities provided by Field Programmable Gate Arrays (FPGAs) and Reconfigurable Inputs/Outputs (RIO) chips. A fixed-point fuzzy controller is developed and implemented on a fast mechatronic system with high-speed control and high channel count on an FPGA target. This paper provides a brief introduction to deploying Fuzzy Logic Control (FLC) methods using RIO-FPGA technology. It suggests a technique for implementing the three stages that constitute the FLC and the PD-like FLC and PID-like FLC structures into practice. Controllers with 1 and 2 degrees of freedom are developed and tested experimentally. Parallel loops, key challenging advantage of LabVIEW programming, are utilized for decoding feedback signals, generating pulse trains for actuator's drivers and for calculation of control gains. An NI-SbRIO board that combines deployable devices with a real-time processor, a re-configurable FPGA, and analogue and digital input–output ports is used. The experimental work demonstrates the significant enhancement of implementing reconfigurable embedded fuzzy control upon such mechatronic systems.

Vortex random lasing with tunable wavelength and orbital angular momentum

Random lasing with special structured light field has broad application prospects in various fields. However, the complex spatial modes of random lasing increase the difficulty of light field regulation and limit its practical application. Here, a vortex random lasing with dynamically tunable wavelength and orbital angular momentum is proposed based on the microfluidic channel. Different color random lasers are integrated into the same microfluidic channel for coarse control of the emission wavelengths from 462 to 685 nm by dynamically controlling the liquid flow. A special-shape cavity with a variable size of a gain region is further constructed to finely manipulate the emission wavelengths. Moreover, the vortex random lasing with tunable orbital angular momentum mode from −50 to 50 is realized. The results provide an outstanding strategy for generating the partially coherent vortex beams and may promote the practical applications of random lasers in the fields of sensing, imaging, and communication.

Optically biased and controlled signal processing in silicon photonics.

Optically biased and controlled signal processing is demonstrated in a commercial foundry silicon photonics integrated circuit process. Data and control signals are carried by different wavelengths in a WDM format. Optical signals on bias and control channels are converted to electrical voltages using series stacked photodiodes operating in photoconductive mode. Two examples of this scheme, namely, an amplitude modulator and a two-tap sequence detector capable of supporting different modulation formats, are experimentally demonstrated. The amplitude modulator requires 0.25 mW of optical control signal power to tune its optical output power by 15 dB. The two-tap sequence detector maps the consecutive symbols of a modulated signal such as OOK, PAM-3, and PAM-4, to distinct levels. A maximum control signal power of 5 mW is needed to calibrate and bias the sequence detector. This latter scheme may be extended to detect longer sequences and other modulation formats.

The model of a discrete communication channel in the control channel of satellite communication systems

The control channels used in modern satellite communication systems (CCC) for multiplexers used in modern satellite communication systems are designed to transmit control messages regarding changes in the frame structures of organized compressed digital streams. Increased requirements are placed on the reliability of messages transmitted in these channels compared to messages transmitted in sealed channels. In the presence of phase flickering, as well as with a decrease in the signal-to-noise ratio (SNR) in communication channels formed on the basis of convolutional codes, the effect of grouping errors occurs at the input of decoders of noise-resistant codes in control channels. Therefore, information about the statistical properties of messages received at the input of a decoder designed to ensure the reliability of control channel messages is important in the synthesis of decoding algorithms capable of taking into account these statistical properties.

Explainable Learning-Based Timeout Optimization for Accurate and Efficient Elephant Flow Prediction in SDNs

Accurately and efficiently predicting elephant flows (elephants) is crucial for optimizing network performance and resource utilization. Current prediction approaches for software-defined networks (SDNs) typically rely on complete traffic and statistics moving from switches to controllers. This leads to an extra control channel bandwidth occupation and network delay. To address this issue, this paper proposes a prediction strategy based on incomplete traffic that is sampled by the timeouts for the installation or reactivation of flow entries. The strategy involves assigning a very short hard timeout (Tinitial) to flow entries and then increasing it at a rate of r until flows are identified as elephants or out of their lifespans. Predicted elephants are switched to an idle timeout of 5 s. Logistic regression is used to model elephants based on a complete dataset. Bayesian optimization is then used to tune the trained model Tinitial and r over the incomplete dataset. The process of feature selection, model learning, and optimization is explained. An extensive evaluation shows that the proposed approach can achieve over 90% generalization accuracy over 7 different datasets, including campus, backbone, and the Internet of Things (IoT). Elephants can be correctly predicted for about half of their lifetime. The proposed approach can significantly reduce the controller–switch interaction in campus and IoT networks, although packet completion approaches may need to be applied in networks with a short mean packet inter-arrival time.

Research of microprocessor device and software for remote control of a robotic system

The modern stage of the development of intelligent robotic systems is characterized by the expansion of fields of application, which is due to autonomous work and decision-making in conditions of uncertainty. The object of research is the system of remote control of robotic systems. During the remote control of robotic systems, problems arise that are associated with the use of wireless communication in real time. The article analyzes software and hardware implementations of various remote control systems suitable for use as part of autonomous robotic systems and analyzes promising microcontroller platforms for implementing a remote control device for a robotic system. A brief review of existing protocols for transmitting control signals using radio communication equipment and microprocessor platforms for the development of embedded systems is performed, among which a solution is selected for research. Several approaches to the control of a robotic system are highlighted – control using a wired connection and corresponding protocols, control via wireless communication or via the Internet, control via general-purpose network protocols. The target platform is chosen and justified, and the S.BUS protocol is analyzed with the provision of an algorithm for obtaining the values of the control channels from the S.BUS package. The structure and algorithm of functioning of the microprocessor remote control system based on the ESP32 microcontroller and the FreeRTOS OS are given. A study of the operation process of the proposed remote control system is carried out, for which it is placed on the chassis of a ground autonomous robotic system with four-wheel drive, and the delay time of the control signal from the receiver to the engine control modules is determined. According to the conducted analysis, the expediency of using specialized radio communication equipment with the S.BUS protocol for controlling executive devices as part of a robotic system, for precise movement control in real time, is shown.

Increasing the accuracy of the vessel’s course orientation

The object of the study is the process of increasing the accuracy of measuring the vessel's course and course orientation by using the mathematical model of the gyrocompass in the on-board computer. On modern vessels, the gyrocompass is the main course measuring device. Its advantages lie in measuring the current course relative to the geographic meridian, its readings are not affected by magnetic anomalies, as was the case when using magnetic compasses, which led to a partial or complete loss of orientation of control objects. At the same time, gyrocompasses also have their drawbacks. The most significant of them is the inertial deviation of the sensitive element caused by the curvature of the Earth's surface, a change in course, acceleration or deceleration of the vessel. With the appearance of the moments of these forces, the axis of the gyrocompass leaves the equilibrium position and begins to make precessional movements. To reduce the inertial deviation, constructive solutions and recommendations to shipmasters regarding the consideration of deviational errors are used. Structural solutions lead to an increase in weight, complexity of the design, a decrease in reliability, and an increase in cost. The recommendations of regulatory documents regarding the consideration of the inertial deviation of the sensitive element of the gyrocompass are difficult to implement in practice, but they can be implemented in the on-board computer of the vessel control system by using a mathematical model of the sensitive element. The paper developed a method of increasing the accuracy of gyrocompass course measurement and the accuracy of course orientation by using an observation device built on the basis of a mathematical model of the gyrocompass in the on-board computer of the course control system. This makes it possible to estimate the useful component of course measurement and deviational errors from changes in speed and course, the curvature of the earth's surface. The useful component, without deviational errors, is used in the vessel's course control channel. The developed method can be used on vessels, provided it is integrated into the existing automated system of the on-board computer to solve the problem of monitoring the components of the gyrocompass measurement.

Experimentally ruling out joint reality based on operational completeness

Whether the observables of a physical system admit real values is of fundamental importance to a deep understanding of nature. In this work, we report a device-independent experiment to confirm that the joint reality of two observables on a single two-level system is incompatible with the assumption of operational completeness, which is strictly weaker than that of preparation noncontextuality. We implement two observables on a trapped 171Yb+ ion to test this incompatibility via violation of certain inequalities derived from both linear and nonlinear criteria. Moreover, by introducing a highly controllable dephasing channel, we show that the nonlinear criterion is more robust against noise. Our results push the fundamental limit to delineate the quantum–classical boundary and pave the way for exploring relevant problems in other scenarios.

TPAAD: Two‐phase authentication system for denial of service attack detection and mitigation using machine learning in software‐defined network

AbstractSoftware‐defined networking (SDN) has received considerable attention and adoption owing to its inherent advantages, such as enhanced scalability, increased adaptability, and the ability to exercise centralized control. However, the control plane of the system is vulnerable to denial‐of‐service (DoS) attacks, which are a primary focus for attackers. These attacks have the potential to result in substantial delays and packet loss. In this study, we present a novel system called Two‐Phase Authentication for Attack Detection that aims to enhance the security of SDN by mitigating DoS attacks. The methodology utilized in our study involves the implementation of packet filtration and machine learning classification techniques, which are subsequently followed by the targeted restriction of malevolent network traffic. Instead of completely deactivating the host, the emphasis lies on preventing harmful communication. Support vector machine and K‐nearest neighbours algorithms were utilized for efficient detection on the CICDoS 2017 dataset. The deployed model was utilized within an environment designed for the identification of threats in SDN. Based on the observations of the banned queue, our system allows a host to reconnect when it is no longer contributing to malicious traffic. The experiments were run on a VMware Ubuntu, and an SDN environment was created using Mininet and the RYU controller. The results of the tests demonstrated enhanced performance in various aspects, including the reduction of false positives, the minimization of central processing unit utilization and control channel bandwidth consumption, the improvement of packet delivery ratio, and the decrease in the number of flow requests submitted to the controller. These results confirm that our Two‐Phase Authentication for Attack Detection architecture identifies and mitigates SDN DoS attacks with low overhead.

A modified modular multilevel converter to reduce the second order ripples in the submodule capacitor voltage: Design and analysis

SummaryThe modular‐multilevel converter (MMC) faces the problem of second order ripples in the sub‐module DC capacitor voltage during the low frequency operation at the load side. To sort out this problem, this paper demonstrates a three‐phase modified MMC that includes a novel circuit placed between upper and lower arms of each phase, where load is connected through proposed circuit. The aim of the proposed circuit is to reduce the magnitude of the ripples in each sub‐module's DC capacitor voltage; moreover, it also uses a less number of components compared with the conventional circuits. In order to keep the capacitor voltage at its rated value and to prevent the development of common mode voltage, the proposed circuit uses the high frequency‐based power transfer control channel for balancing power between the upper or top and lower or bottom arms. Furthermore, the mathematical analysis, operating principle, and proposed control is explained in detail for the conventional MMC and modified MMC. The simulation results have been obtained for the modified MMC with resistive load by using MATLAB and Simulink. An experimental test results have been verified with simulation results for the modified MMC topology.

Methodology for the Synthesis of a Multicopter Controller Acting as a Swarm Agent using the Thermal Motion Equivalent Method

The paper is dedicated to the development of a method for the synthesis of the control system of a swarm multicopter. The motion of the agents in the swarm is organised by the thermal motion equivalent method. The idea of the method is the behavioral similarity of the thermal motion of the atoms by the agents. In the practical implementation of the thermal motion equivalent method, it is important to ensure constancy of velocity and isotropy of agent dynamics. Violating these properties will cause the swarm to fail a mission, such as an area exploration, by reducing the RMS speed of the agents to zero. The proposed solution to these problems is to synthesize a modal controller for the agent-boundaries test system for the slowest control channel, thereby ensuring RMS velocity constancy of the agent. The synthesized controller is used as a filter in the fast-acting channels, the second horizontal channel and the vertical channel. In the fast-acting channels, an additional filter is proposed to bring their dynamics to the slowest channel, thereby ensuring isotropy. The inclusion of a limit on the maximum length of the equivalent field vector ensures isotropy. The synthesis was carried out using a simplified multicopter dynamics mathematical model, obtained with small UAV deviations from the vertical and without considering the Coriolis force. The methodology for the synthesis of a multicopter control system for functioning as part of a swarm is developed using the obtained results. Numerical simulation results of both a single vehicle in closed space and a swarm using a more complete nonlinear dynamic quadcopter model are presented. The proposed method has the advantage of simple synthesis using a linear model. Numerical simulation results confirm the operability of the developed methodology.