scholarly journals Robust H∞ Control of Networked System In Microgrid Under Random Packet Loss

Author(s):  
Yiwei Feng ◽  
Jing Ma ◽  
Xin Wang

Abstract The desire for sustainable development has led to the advancement of renewable energy generation through microgrids, and the control and stability of microgrids pose serious challenges to the popularization of microgrids. This article focuses on the stability and performance of the microgrid, and due to its limited channel bandwidth and other factors, may result in the loss of random packets from the sensor to the controller and from the controller to the actuator. To solve the problem, this paper designed a feedback controller based on the observer and robust H∞ control method and has established Bernoulli packet loss model. The proposed controller enables the networked control system robust exponential stability in the sense of mean square. Finally, the correctness and effectiveness of the proposed controller is verified by MATLAB simulation.

2013 ◽  
Vol 572 ◽  
pp. 636-639
Author(s):  
Xi Chen ◽  
Gang Wang

This paper deals with the walking stability analysis of a multi-legged crablike robot over slope using normalized energy stability margin (NESM) method in order to develop a common stabilization description method and achieve robust locomotion for the robot over rough terrains. The robot is simplified with its static stability being described by NESM. The mathematical model of static stability margin is built so as to carry out the simulation of walking stability over slope for the crablike robot that walks in double tetrapod gait. As a consequence, the relationship between stability margin and the height of the robots centroid, as well as its inclination relative to the ground is calculated by the stability criterion. The success and performance of the stability criterion proposed is verified through MATLAB simulation and real-world experiments using multi-legged crablike robot.


2018 ◽  
Vol 7 (2.31) ◽  
pp. 249
Author(s):  
Richa Sharma ◽  
Deepak Nagaria

Networked control system is a closed loop system in which information or data travel through the communication network. The presence of communication network will increase time delay and information losses. Due to these losses and delay the performance of the system decreases. This paper represents an analysis to find the stability of the networked control system with the varying time hindrances present in the network. In this research, it has been assumed that the delay in time is less than the sampling period. The stability conditions for NCS have been procured with the use of the Lyapunov function approach and has been described in terms of LMI(Linear Matrix Inequality).This examination confirm the adequate state of stability through MATLAB simulation and the numerical case demonstrates the outcome.  


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Essam F. Alnatsheh

Congestion control and reduction is paramount in enhancing the performance and speed of communication networks. Despite its efficiency in improving the speed and performance of communication networks, it is imperative to mention that the technique exhibit several issues, such as scheduling algorithms. This paper presents a comparison of different results associated with different scheduling algorithms. Multisource was used to simulate and test different scheduling algorithms, including First In First Out (FIFO), Random Packet Drop, and Last In First Out (LIFO). The comparison was made by analyzing different results, including the average delay vs arrival rate, average buffer utilization vs arrival rate, and packet loss ration vs arrival rate. According to the results, it is evident that the average buffer utilization and average packet delays increased as the rate of data transmitted through the network increased. There was no significant change noticed in the average buffer utilization in all the three algorithms. However, the packet loss ratio was high in Random Packet Loss algorithm than in both FIFO and LIFO for slower arrival rates below 1000. Similarly, FIFO exhibited a significantly high average packet delay than both LIFO and Random Packet Drop algorithms.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Danqing Zhang ◽  
Binbin Xiang ◽  
Aili Yusup ◽  
Na Wang ◽  
Guljaina Kazezkhan

The QiTai Radio Telescope (QTT) will be equipped with the active surface adjustment system (ASAS) to correct the main reflector deformation caused by environmental loading. In order to guarantee the stability and performance of the active surface system under fault conditions, it is necessary to adopt the fault-tolerant method when actuator faults have occurred. In this paper, a fault control method based on actuator faults weighting is proposed to solve the active surface fault control problem. According to the coordinates of the adjustable points of the panels corresponding to the faulty actuators, a new paraboloid is fitted by a weighted health matrix, and the fitting surface is taken as the target to adjust the surface shape.


2021 ◽  
Vol 17 (3) ◽  
pp. 22-28
Author(s):  
Maryam Sadeq Ahmed ◽  
Ali Hussien M Mary ◽  
Hisham Hassan Jasim

This paper presents a robust control method for the trajectory control of the robotic manipulator. The standard Computed Torque Control (CTC) is an important method in the robotic control systems but its not robust to system uncertainty and external disturbance. The proposed method overcome the system uncertainty and external disturbance problems. In this paper, a robustification term has been added to the standard CTC. The stability of the proposed control method is approved by the Lyapunov stability theorem.  The performance of the presented controller is tested by MATLAB-Simulink environment and is compared with different control methods to illustrate its robustness and performance.


2019 ◽  
Vol 14 ◽  
Author(s):  
Tayyab Khan ◽  
Karan Singh ◽  
Kamlesh C. Purohit

Background: With the growing popularity of various group communication applications such as file transfer, multimedia events, distance learning, email distribution, multiparty video conferencing and teleconferencing, multicasting seems to be a useful tool for efficient multipoint data distribution. An efficient communication technique depends on the various parameters like processing speed, buffer storage, and amount of data flow between the nodes. If data exceeds beyond the capacity of a link or node, then it introduces congestion in the network. A series of multicast congestion control algorithms have been developed, but due to the heterogeneous network environment, these approaches do not respond nor reduce congestion quickly whenever network behavior changes. Objective: Multicasting is a robust and efficient one-to-many (1: M) group transmission (communication) technique to reduced communication cost, bandwidth consumption, processing time and delays with similar reliability (dependability) as of regular unicast. This patent presents a novel and comprehensive congestion control method known as integrated multicast congestion control approach (ICMA) to reduce packet loss. Methods: The proposed mechanism is based on leave-join and flow control mechanism along with proportional integrated and derivate (PID) controller to reduce packet loss, depending on the congestion status. In the proposed approach, Proportional integrated and derivate controller computes expected incoming rate at each router and feedback this rate to upstream routers of the multicast network to stabilize their local buffer occupancy. Results: Simulation results on NS-2 exhibit the immense performance of the proposed approach in terms of delay, throughput, bandwidth utilization, and packet loss than other existing methods. Conclusion: The proposed congestion control scheme provides better bandwidth utilization and throughput than other existing approaches. Moreover, we have discussed existing congestion control schemes with their research gaps. In the future, we are planning to explore the fairness and quality of service issue in multicast communication.


Author(s):  
Sunny Katyara ◽  
Lukasz Staszewski ◽  
Faheem Akhtar Chachar

Background: Since the distribution networks are passive until Distributed Generation (DG) is not being installed into them, the stability issues occur in the distribution system after the integration of DG. Methods: In order to assure the simplicity during the calculations, many approximations have been proposed for finding the system’s parameters i.e. Voltage, active and reactive powers and load angle, more efficiently and accurately. This research presents an algorithm for finding the Norton’s equivalent model of distribution system with DG, considering from receiving end. Norton’s model of distribution system can be determined either from its complete configuration or through an algorithm using system’s voltage and current profiles. The algorithm involves the determination of derivative of apparent power against the current (dS/dIL) of the system. Results: This work also verifies the accuracy of proposed algorithm according to the relative variations in the phase angle of system’s impedance. This research also considers the varying states of distribution system due to switching in and out of DG and therefore Norton’s model needs to be updated accordingly. Conclusion: The efficacy of the proposed algorithm is verified through MATLAB simulation results under two scenarios, (i) normal condition and (ii) faulty condition. During normal condition, the stability factor near to 1 and change in dS/dIL was near to 0 while during fault condition, the stability factor was higher than 1 and the value of dS/dIL was away from 0.


Author(s):  
Ahmed Abdalla ◽  
Suhad Mohammed ◽  
Tang Bin ◽  
Jumma Mary Atieno ◽  
Abdelazeim Abdalla

This paper considers the problem of estimating the direction of arrival (DOA) for the both incoherent and coherent signals from narrowband sources, located in the far field in the case of uniform linear array sensors. Three different methods are analyzed. Specifically, these methods are Music, Root-Music and ESPRIT. The pros and cons of these methods are identified and compared in light of different viewpoints. The performance of the three methods is evaluated, analytically, when possible, and by Matlab simulation. This paper can be a roadmap for beginners in understanding the basic concepts of DOA estimation issues, properties and performance.


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