Wireless Networked Control Research Articles

Control-Aware Resource Scheduling Method for Wireless Networked Control Systems

Control-Aware Resource Scheduling Method for Wireless Networked Control Systems

High traffic communication congestion control for wireless sensor networks based on harmony search optimization

In wireless sensor networks (WSNs), communication between the wireless nodes requires minimum response delay, minimum congestion and communication reliability. A wide variety of sensors produces a mixture of heterogeneous traffics with different reliability requirements. The article focuses on high traffic congestion which affects communication and produces latency. In the existing approaches, the congestion was controlled and the optimization was done during the time of node deployment. In the proposed method, high traffic congestion was controlled by a hop-by-hop approach which was applied in the statically deployed sensor nodes, the optimization was performed at the time of communication. To provide a uninterrupted communication to the WSNs the proposed approach analyses the occupancy ratio of the buffer and evaluates the downstream node congestion level. Here, the Harmony Search Algorithm is considered for design the optimal sensor network with Support Vector Machine (SVM). The experimental result shows the effectiveness and feasibility of the HSA-SVM environment. Also, it significantly enhances communication in diverse traffic conditions, specifically in heavy traffic areas with limited data.

Real-time optimized wireless networked control system with cooperative network protocols

In this paper, we present a real-time optimized fuzzy fuzzy proportional integral derivative (FPID)-controlled wireless networked system for a high-torque direct current (DC) motor. The main challenge faced by such systems is the delay in the wireless networked control system (WNCS). We employed a powerful FPID controller tuned using particle swarm optimization (PSO) technique to compensate for the delay. The system is tested on a network using the TrueTime simulator with different parameters. The results show that the system exhibits a very stable response, with the FPID controller compensating for the delay effectively. Increasing the number of nodes negatively impacts the system's performance, resulting in higher overshoot, longer settling time, and longer rise time. Moreover, the choice of bandwidth share and sampling time significantly affects the system's stability and real-time response. The use of transmission control protocol/internet protocol (TCP/IP) or user datagram protocol (UDP) protocols with Node MCU is necessary to transfer data from the Arduino Microcontroller to MATLAB, as MATLAB TrueTime simulator does not support direct serial communication. In conclusion, this study highlights valuable insights into the performance of the proposed system, demonstrating the need for further improvements in the system's design and control algorithms to achieve stable operation.

Retracted: Connection Quality Prediction and Nonlinear Control of Power Grid Communication Wireless Network

Retracted: Connection Quality Prediction and Nonlinear Control of Power Grid Communication Wireless Network

A game-theoretical paradigm for collaborative and distributed power control in wireless networks

A game-theoretical paradigm for collaborative and distributed power control in wireless networks

Enhanced Congestion Control in Wireless Networks: A Joint Random Early Detection and Drop Tail Mechanism

Enhanced Congestion Control in Wireless Networks: A Joint Random Early Detection and Drop Tail Mechanism

Age of Loop for Wireless Networked Control System in the Finite Blocklength Regime: Average, Variance and Outage Probability

Age of information (AoI) is an effective measure of the information freshness for wireless networked control systems (WNCSs). However, the AoI performance for a closed loop of WNCS with two-way delays has remained unexplored, especially in the finite blocklength (FBL) regime. In this paper, we investigate the peak age of loop (PAoL) performances, including the average, variance and outage probability of PAoL, for WNCSs with FBL over fading channels. Their closed-form expressions are respectively derived regarding the blocklength and the maximum number of allowable transmissions. We prove that the average PAoL is less than the sum of the average peak AoI in uplink (UL) and downlink (DL) due to the coupling between UL and DL. We also show that there is a tradeoff between the average PAoL and the variance/outage probability of PAoL. Based on the comprehensive performance analysis, we study a PAoL-oriented communication and control co-design with an adaptation scheme for transmission power, blocklength and the maximum number of allowable transmissions. Simulation results verify the correctness of the analytical results and show that the proposed PAoL-oriented scheme significantly outperforms the UL only and DL only optimization schemes, with an up to 8-fold reduction in the average control cost.

Edge-Computing-Enabled Low-Latency Communication for a Wireless Networked Control System

This study proposes a novel strategy for enhancing low-latency control performance in Wireless Networked Control Systems (WNCSs) through the integration of edge computing. Traditional networked control systems require the receipt of raw data from remote sensors to enable the controller to generate an appropriate control command, a process that can result in substantial periodic communication traffic and consequent performance degradation in some applications. To counteract this, we suggest the use of edge computing to preprocess the raw data, extract the essential features, and subsequently transmit them. Additionally, we introduce an adaptive scheme designed to curtail frequent data traffic by adaptively modifying periodic data transmission based on necessity. This scheme is achieved by refraining from data transmission when a comparative analysis of the previously transmitted and newly generated data shows no significant change. The effectiveness of our proposed strategy is empirically validated through experiments conducted on a remote control system testbed using a mobile robot that navigates the road by utilizing camera information. Through leveraging edge computing, only 3.42% of the raw data was transmitted. Our adaptive scheme reduced the transmission frequency by 20%, while maintaining an acceptable control performance. Moreover, we conducted a comparative analysis between our proposed solution and the state-of-the-art communication framework, WebRTC technology. The results demonstrate that our method effectively reduces the latency by 58.16% compared to utilizing the WebRTC alone in a 5G environment. The experimental results confirm that our proposed strategy significantly improves the latency performance of a WNCS.

Development of a wireless sensor network simulator using energy-efficient traffic routing methods

This document represents possible algorithms and methods for the analysis, optimization, and control of wireless sensor networks. The main goal of the work is to find the optimal implementation of the particle swarm optimization method for solving the problem of improving the energy consumption of such networks. The result of the work is a software package for simulating WSN (Wireless sensor network) networks using all the methods of routing and optimization of WSN networks presented in the work. The usage of a combination of routing schemes and different systems of device state management raises the wireless sensor network lifetime and reduces the power consumption of the network. The developed and presented in the work network simulator allows any developer to design and test different network topologies with various network parameters. Such software will make it easy to design such networks both for large enterprises and independent developers.

Transmission Power Policies for Energy-Efficient Wireless Control of Nonlinear Systems

We present an emulation-based controller and transmission policy design procedure for nonlinear wireless networked control systems. The objective is to ensure the stability of the closed-loop system, in a stochastic sense, together with given control performance, while minimizing the average power used for communications. The controller is designed by emulation, i.e., ignoring the network, and the transmission power is given by threshold policies. These policies involve waiting a given amount of time since the last successful transmission instant, as well as requiring that the measured wireless channel gain is above a given threshold, before attempting a new transmission. Two power control laws are investigated: i) a constant power and ii) a power level inversely proportional to the channel gain. We explain how to select the waiting time, the channel threshold and the power level to minimize the induced average communication power, while ensuring the desired control objectives.

Time delay effect reduction on the wireless networked control system using an optimized FOPI-FOPD controller

Wireless Networked Control System (WNCS) is made up of an actuator, sensor, and controller that communicates through a wireless network rather than typical point-to-point cable connections. Lower maintenance costs, greater flexibility, and increased safety are the main WNCS advantages, so as a result, it has attracted a lot of researchers. Nevertheless, time delays and packet losses in wireless data transmission are classified as complicated problems, which impair WNCS output accuracy and may influence the overall system stability. Integer-Order PI-PD (PI-PD) and Fractional-Order PI-PD (FOPI-FOPD) controllers are proposed to reduce the impact of the control signal transmission's time delay and improve system performance. Matlab Simulink and True-time simulator are used to simulate the WNCS, and ZigBee protocol is used in transceiving the control signal between the controller and the system. Rotary Inverted Pendulum (RIP) acted as the controller's objective. The Grey Wolf Optimization (GWO) technique is utilized to evaluate the best controller parameters. Xbee S2 modules are used to implement the signal transmission process over ZigBee protocol. The FOPI-FOPD controller outperforms the PI-PD controller in the simulation and experimental results in decreasing the influence of time delay on system stability

A Compensation Model for Packet Loss Using Kalman Filter in Wireless Network Control Systems

In Wireless Network Control System (WNCS), a study approach is relevant for the development and analysis of control strategies that provide the operation of dynamic systems. Among the real characteristics of the communication channels, a packet loss is one of the main deficiencies present in the transmission of data in a wireless network. For a dynamic system in the presence of losses, a filtering technique makes it possible to estimate system states using process output measurements and to mitigate a performance drop. It is important to study packet losses in Wireless Network Control Systems because packet loss can severely degrade the network performance. Wireless networks are particularly vulnerable to packet loss due to factors such as interference, fading and signal attenuation. The present work analyzed the behavior of a real WNCS plant at different levels of packet loss using the IEEE 802.15.4 protocol. Also, we propose a compensation model for packet loss using the Kalman filter. The packet loss process is based on a Gilbert-Elliot model and is compared with a Proportional-Integral-Derivative (PID) controller. The results show that by applying Kalman filters it is possible to improve the operation of the process in case of losses during data transmission. It was observed through the simulation that it is possible to reduce the error of the system output in relation to the reference in the presence of packet loss. For a loss ratio of 30%, the observed improvement in the system behavior with the use of the Kalman filter was 26.1%.

Goal-Oriented Wireless Communication for a Remotely Controlled Autonomous Guided Vehicle

This letter considers a remote control Autonomous Guided Vehicle (AGV), where packets carrying sensory data and control information are sent through a time-correlated wireless fading channel. We illustrate there is an inherent dependency between the data rate and the resulting control accuracy for such a system. We propose a goal-oriented wireless solution, in which data transmission rate is continuously adapted according to Age-of-Loop metric to achieve precise remote trajectory control of an AGV. The numerical analysis shows that the proposed solution provides higher control accuracy at the AGV trajectory compared to straightforward fixed-rate transmission policies, and to a reference solution based on Age-of-Information metric, more commonly used in research of wireless networked control systems.

Inference and performance aware multi-channel scheduling and routing scheme with call admission control in wireless mesh networks

As wireless mesh networks have been deployed in the urban area, dynamic channel allocation is more challengeable because co-located wireless mediums are likely to be tuned to the same channels and may interfere with communication. Further, existing model doesn’t consider reutilizing routing resource. This paper presents an efficient scheduling and routing model considering an external interference and routing resource reutilization for multi-channel wireless mesh networks. Each mesh node uses a novel technique to estimate the usage status of all the channels within its interference range and assigns channels dynamically to radios to minimize interference within the mesh network and between the mesh network and collocated wireless networks. Simulation results demonstrate that our proposed algorithm can improve the network throughput, reduce packet failure rate and consume more energy while transmission substantially compared to other algorithms by removing the interference overestimation problem and assigning channels aggressively with priority.

Effects of Jamming Attacks on Wireless Networked Control Systems Under Disturbance

Jamming attacks on wireless networked control systems are investigated for the scenarios where the system dynamics face exogenous disturbance. In particular, the control input packets are assumed to be transmitted from a controller to a remotely located linear plant over an insecure wireless communication channel that is subject to jamming attacks. The time-varying likelihood of transmission failures on this channel depends on the power of the jamming interference signal emitted by an attacker. We show that jamming attacks can prevent stability when the system faces disturbance, even if the attacked system without disturbance is stable. We also show that stability under jamming and disturbance can be achieved if the average jamming interference power is restricted in a certain way that we characterize in this article. We illustrate our results on an example networked control system with a fading wireless channel, where the outage probability is affected by jamming attacks.

Event‐driven fault‐tolerant attitude control of spacecraft with finite‐time disturbance observer under input saturation

AbstractThis paper investigates the attitude stabilization problem for a bandwidth‐constrained spacecraft subjected to model uncertainty, external disturbances, actuator faults, and saturated input. The proposed attitude controller is developed by combining the disturbance observer with an event‐trigger technique to provide disturbance attenuation meanwhile respecting the constraint on the wireless control network. The proposed disturbance observer estimates the lumped disturbance within a finite time, and its output is then fed to the composite control law. The presented control scheme relaxes the use of a priori upper bound knowledge of disturbance and resolves the unwinding problem in the quaternion‐based attitude representation. The closed‐loop stability analysis under the proposed algorithm shows the uniformly ultimately bounded convergence of state trajectories. Moreover, the designed event trigger approach avoids the Zeno behavior. The numerical simulation with comparative analysis illustrates the efficacy of the proposed controller in terms of convergence time, steady‐state bound, rate of control update, and energy consumption.

Wireless networked control over lossy uplinks abstracted by finite-state Markov channels

Networked control systems using wireless links to convey information among sensors, controllers, and actuators greatly benefit from having an accurate estimate of the communication channel condition. To this end, the finite-state Markov channel abstraction allows for reliable channel state estimation. This paper develops a Markov jump linear system representation for wireless networked control with intermittent channel state observation, message losses, and generalized hold-input dropout compensation. Furthermore, it exploits the emerging structural properties of the system to solve the finite-horizon linear quadratic regulation problem efficiently.

Energy efficient congestion control in wireless sensor networks using meta-heuristic algorithms

Energy efficient congestion control in wireless sensor networks using meta-heuristic algorithms

Link Analysis for Solving Multiple-Access MDPs With Large State Spaces

Wireless communication networks can be well-modeled by Markov Decision Processes (MDPs). While traditional dynamic programming algorithms such as value and policy iteration have lower complexity than brute force strategies, they still suffer from complexity issues for large state spaces. In this paper, the development of moderate complexity algorithms with high performance is sought for wireless network control. To this end, the approximate value function can be computed by projecting the original value function into a lower-dimensional subspace with the careful choice of basis vectors using tools from graph signal processing (GSP). Although GSP theory mainly focuses on undirected graphs, the transition graphs of MDPs for wireless networks are generally directed. For this reason, graph symmetrization based on the co-link method is considered due to its ability to preserve multi-hop dependencies in the graph. Given the multiple-access model under consideration, key properties of the transition probability matrix are exploited to determine the optimal subspace for the approximate value function with low complexity. The numerical results for a multiple-access channel show that the proposed algorithm can find the optimal basis vectors with high accuracy, and furthermore, the approach is robust to changes in system parameters. It is also shown that the projected equation method outperforms the state aggregation technique in producing higher accuracy with a lower runtime complexity.

Transmission Power Control in Wireless Sensor Networks Using Fuzzy Adaptive Data Rate.

As the technology of Internet of Things (IoT) becomes popular, the number of sensor nodes also increases. The network coverage, extensibility, and reliability are also the key points of technical development. To address the challenge of environmental restriction and deployment cost, most sensor nodes are powered by batteries. Therefore, the low-power consumption becomes an important issue because of the finite value of battery capacity. In addition, significant interference occurs in the environment, thereby complicating reliable wireless communication. This study proposes a fuzzy-based adaptive data rate for the transmission power control in wireless sensor networks to balance the communication quality and power consumption. The error count and error interval perform the inputs of a fuzzy system and the corresponding fuzzy system output is guard that is utilized for limiting the upper bounds of data rate and transmission power. The long-term experimental results are introduced to demonstrate that the control algorithm can overcome environmental interference and obtain low-power performance. The sensor nodes have reliable communication under an ultra-low-power consumption. The experimental results show that the total power consumption of the proposed approach has been improved 73% compared with the system without executing the algorithm and also indicate the Packet Error Rate (PER) is close to 1%. Therefore, the proposed method is suitable for the battery supply IoT system.