Current Issue : January - March Volume : 2019 Issue Number : 1 Articles : 5 Articles
Seafloor observatories enable real-time, continuous and long-term observations that\npromise major breakthroughs in ocean sciences. The effort to dynamically control in situ sensor\nsystems performing individual and cooperative observation tasks is both a challenge and a guarantee\nfor the stable operations of functional observatories. However, current sensor control systems for\nseafloor observatories are application-oriented and focus on specific engineering requirements rather\nthan general model research. In this paper, a sensor control model was proposed to provide a\ntheoretical specification for designing, developing and deploying a sensor control system for cabled\nseafloor observatories. The model abstracted the sensor control as a standardized bidirectional\ninformation flow process and accordingly structured the control system into the application layer,\nthe service layer, the networking layer, and the sensing layer. The layered functions and interactions\nbetween adjacent layers in return realized this information process. A prototype control system\nwas designed and developed, the monitoring architecture of which was derived from one of\nthe deployment scenarios of the sensor control model. The prototype system was tested for its\nplug-and-play enablement through a series of trials such as tank tests and shallow sea trials. It was\nput into service for the operational Xiaoqushan Seafloor Observatory and was consistently functioning\nand presenting satisfactory practical performance in accordance with all the requirements laid for\nthe project....
We address the consensus control problem of time-varying delayed multiagent systems with directed communication topology.\nThe model of each agent includes time-varying nonlinear dynamic and external disturbance, where the time-varying nonlinear\nterm satisfies the global Lipschitz condition and the disturbance term satisfies norm-bounded condition. An improved control\nprotocol, that is, a high-order iterative learning control scheme, is applied to cope with consensus tracking problem, where the\ndesired trajectory is generated by a virtual leader agent. Through theoretical analysis, the improved control protocol guarantees\nthat the tracking errors converge asymptotically to a sufficiently small interval under the given convergence conditions.\nFurthermore, the bounds of initial state difference and disturbances tend to zero; the bound of tracking errors also tends to zero.\nIn the end, some cases are provided to illustrate the effectiveness of the theoretical analysis....
Energy management systems in residential areas have attracted the attention of many\nresearchers along the deployment of smart grids, smart cities, and smart homes. This paper presents\nthe implementation of a Home Energy Management System (HEMS) based on the fuzzy logic\ncontroller. The objective of the proposed HEMS is to minimize electricity cost by managing the energy\nfrom the photovoltaic (PV) to supply home appliances in the grid-connected PV-battery system.\nA fuzzy logic controller is implemented on a low-cost embedded system to achieve the objective.\nThe fuzzy logic controller is developed by the distributed approach where each home appliance has\nits own fuzzy logic controller. An automatic tuning of the fuzzy membership functions using the\nGenetic Algorithm is developed to improve performance. To exchange data between the controllers,\nwireless communication based on WiFi technology is adopted. The proposed configuration provides\na simple effective technology that can be implemented in residential homes. The experimental results\nshow that the proposed system achieves a fast processing time on a ten-second basis, which is fast\nenough for HEMS implementation. When tested under four different scenarios, the proposed fuzzy\nlogic controller yields an average cost reduction of 10.933% compared to the system without a fuzzy\nlogic controller. Furthermore, by tuning the fuzzy membership functions using the genetic algorithm,\nthe average cost reduction increases to 12.493%....
In this paper, we propose a frequency-tunable electromagnetic absorber that uses the mechanical control of substrate thickness. The\nabsorption frequency of the proposed absorber can be changed by varying the substrate thickness. In order to mechanically control\nthe substrate thickness, we introduce a 3D-printed molding with air space. The proposed structure consists of two layers and one\nframe: the FR4 substrate, polylactic acid (PLA) frame, and air substrate. The FR4 and PLA thicknesses are fixed, and the air\nthickness is varied using the PLA frame. Therefore, the effective dielectric constant of the overall substrate can be changed. The\nmetallic rectangular patch and ground are patterned on the top and bottom FR4 substrates, respectively. The performance of the\nproposed tunable absorber is demonstrated from full-wave simulation and measurements. When both of the FR4 substrate\nthicknesses are 0.3mm and the air thickness is changed from 1 to 3.5 mm, the absorption frequency is changed from 8.9 to\n8.0 GHz, respectively. Therefore, the frequency-tuning capability of the proposed absorber is successfully demonstrated....
A new integrated guidance and control (IGC) law is investigated for a homing missile with an impact angle against a ground target.\nFirstly, a control-oriented model with impact angle error of the IGC system in the pitch plane is formulated by linear coordinate\ntransformation according to the motion kinematics and missile dynamics model. Secondly, an IGC law is proposed to satisfy the\nimpact angle constraint and to improve the rapidity of the guidance and control system by combining the sliding mode control\nmethod and nonlinear extended disturbance observer technique. Thirdly, stability of the closed-loop guidance and control\nsystem is proven based on the Lyapunov stability theory, and the relationship between the accuracy of the impact angle and the\nestimate errors of nonlinear disturbances is derived from stability of the sliding mode. Finally, simulation results confirm that\nthe proposed IGC law can improve the performance of the missile guidance and control system against a ground target....
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