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A Study of Discrete-Time Optimum Current Controller for the Virtual Synchronous Generator under Constraints 认领
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作者 Atushi Umemura Rion Takahashi Junji Tamura 《智能电网与可再生能源(英文)》 2020年第1期1-20,共20页
In recent years, power generation using renewable energy sources has been increasing as a solution to the global warning problem. Wind power generation can generate electricity day and night, and it is relatively more... In recent years, power generation using renewable energy sources has been increasing as a solution to the global warning problem. Wind power generation can generate electricity day and night, and it is relatively more efficient among the renewable energy sources. The penetration level of variable-speed wind turbines continues to increase. The interconnected wind turbines, however, have no inertia and no synchronous power. Such devices can have a serious impact on the transient stability of the power grid system. One solution to stabilize such grid with renewable energy sources is to provide emulated inertia and synchronizing power. We have proposed an optimal design method of current control for virtual synchronous generators. This paper proposes an optimal control method that can follow the virtual generator model under constrains. As a result, it is shown that the proposed system can suppress the peak of the output of semiconductor device under instantaneous output voltage drop. 展开更多
关键词 Wind Energy Generation Virtual SYNCHRONOUS GENERATOR Electric Current CONTROL Optimal CONTROL Discreate-Time Model Following CONTROL MULTI-OBJECTIVE Genetic Algorithm
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Networked Control Systems:A Survey of Trends and Techniques 认领
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作者 Xian-Ming Zhang Qing-Long Han +4 位作者 Xiaohua Ge Derui Ding Lei Ding Dong Yue Chen Peng 《自动化学报:英文版》 EI CSCD 2020年第1期1-17,共17页
Networked control systems are spatially distributed systems in which the communication between sensors, actuators,and controllers occurs through a shared band-limited digital communication network. Several advantages ... Networked control systems are spatially distributed systems in which the communication between sensors, actuators,and controllers occurs through a shared band-limited digital communication network. Several advantages of the network architectures include reduced system wiring, plug and play devices,increased system agility, and ease of system diagnosis and maintenance. Consequently, networked control is the current trend for industrial automation and has ever-increasing applications in a wide range of areas, such as smart grids, manufacturing systems,process control, automobiles, automated highway systems, and unmanned aerial vehicles. The modelling, analysis, and control of networked control systems have received considerable attention in the last two decades. The ‘control over networks’ is one of the key research directions for networked control systems. This paper aims at presenting a survey of trends and techniques in networked control systems from the perspective of ‘control over networks’, providing a snapshot of five control issues: sampled-data control, quantization control, networked control, event-triggered control, and security control. Some challenging issues are suggested to direct the future research. 展开更多
关键词 Index Terms—Event-triggered CONTROL NETWORKED CONTROL systems QUANTIZATION CONTROL SAMPLED-DATA CONTROL security CONTROL
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Frequency Control of Power System with Renewable Power Sources by HVDC Interconnection Line and Battery Considering Energy Balancing 认领
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作者 Shoyu Onuka Atsushi Umemura +4 位作者 Rion Takahashi Junji Tamura Atsushi Sakahara Fumihito Tosaka Ryosuke Nakamoto 《电力能源(英文)》 2020年第4期11-24,共14页
Recently, introduction of renewable energy sources like wind power generation and photovoltaic power generation has been increasing from the viewpoint of environmental problems. However, renewable energy power supplie... Recently, introduction of renewable energy sources like wind power generation and photovoltaic power generation has been increasing from the viewpoint of environmental problems. However, renewable energy power supplies have unstable output due to the influence of weather conditions such as wind speed variations, which may cause fluctuations of voltage and frequency in the power system. This paper proposes fuzzy PD based virtual inertia control system to decrease frequency fluctuations in power system caused by fluctuating output of renewable energy sources. The proposed new method is based on the coordinated control of HVDC interconnection line and battery, and energy balancing control is also incorporated in it. Finally, it is concluded that the proposed system is very effective for suppressing the frequency fluctuations of the power system due to the large-scale wind power generation and solar power generation and also for keeping the energy balancing in the HVDC transmission line. 展开更多
关键词 High Voltage Direct Current (HVDC) Transmission POWER System Frequency CONTROL COORDINATED CONTROL BATTERY RENEWABLE POWER Energy Balancing
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The Novel Current Control for Virtual Synchronous Generator 认领
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作者 Atsushi Umemura Rion Takahashi Junji Tamura 《电力能源(英文)》 2020年第2期78-89,共12页
In recent years, power generation using renewable energy sources has been developed as a solution to the global warming problem. Among these power generation methods, wind power generation is increasing. However, as t... In recent years, power generation using renewable energy sources has been developed as a solution to the global warming problem. Among these power generation methods, wind power generation is increasing. However, as the penetration level of wind power generation increases, the low inertia and lack of synchronous power characteristics of the penetrated power system can have a significant impact on the transient stability of the grid. The virtual synchronous generator provides the ability of virtual inertia and synchronous power to interconnected inverters. The interconnected inverter with the virtual synchronous generator ability uses, in general, PI control based current controller. This paper proposes a new current-control method and compares it with conventional methods. The proposed current control is a method that follows virtual synchronous generator model that changes every moment by solving the discrete-time linear quadratic optimal control problem for each sampling time interval. The new method follows the conventional method, and therefore the reactive power fluctuation can be suppressed and the interconnected inverter will be downsized. 展开更多
关键词 Wind Energy Generation State FEEDBACK Electric Current CONTROL LINEARIZATION Techniques DISCRETE Time Model Following CONTROL Virtual SYNCHRONOUS GENERATOR
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Tolpyralate + Atrazine Applied Preemergence Provides Residual GR Canada Fleabane [<i>Conyza canadensis</i>(L.) Cronq.] Control Similar to Current Industry Standards 认领
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作者 Nicole M. Langdon Nader Soltani +3 位作者 Alan J. Raedar David C. Hooker Darren E. Robinson Peter H. Sikkema 《农业科学(英文)》 2020年第4期417-424,共8页
Tolpyralate is a benzoylpyrazole, 4-hydroxyphenyl-pyruvate dioxygenase inhibitor, and a herbicide registered for use in corn. The efficacy of tolpyralate plus atrazine to provide full-season residual control of glypho... Tolpyralate is a benzoylpyrazole, 4-hydroxyphenyl-pyruvate dioxygenase inhibitor, and a herbicide registered for use in corn. The efficacy of tolpyralate plus atrazine to provide full-season residual control of glyphosate-resistant (GR) Canada fleabane in corn is not known under Ontario environmental conditions. Five field trials were completed over a two-year period (2018-19) in south-western Ontario on farms with confirmed GR Canada fleabane [Conyza canadensis (L.) Cronq.] populations to determine if tolpyralate + atrazine provides full-season residual control of GR Canada fleabane in corn. Corn injury was less than 10% with all treatments. At 4 weeks after application (WAA), tolpyralate (30 g&middot;ai&middot;ha&minus;1), tolpyralate (40 g&middot;ai&middot;ha&minus;1), and atrazine (560 g&middot;ai&middot;ha&minus;1) controlled GR Canada fleabane 64, 78 and 72%, respectively. A tank mix of tolpyralate + atrazine at both rates improved GR Canada fleabane control to 94%. Saflufenacil/dimethenamid-p, mesotrione + atrazine, and dicamba/atrazine controlled GR Canada fleabane 99, 95 and 92%, respectively. At 8 WAA, tolpyralate (30 g&middot;ai&middot;ha&minus;1), tolpyralate (40 g&middot;ai&middot;ha&minus;1) and atrazine (560 g&middot;ai&middot;ha&minus;1) controlled GR Canada fleabane 83, 88, and 83%, respectively (Table 2). The tank mixes of tolpyralate (30 g&middot;ai&middot;ha&minus;1) + atrazine (560 g&middot;ai&middot;ha&minus;1) and tolpyralate (40 g&middot;ai&middot;ha&minus;1) + atrazine (560 g&middot;ai&middot;ha&minus;1) controlled GR Canada fleabane 94, and 97%, respectively, 8 WAA which was similar to saflufenacil/dimethenamid-p, mesotrione + atrazine and dicamba/atrazine. There was no treatment difference for corn yield. Based on these results, tolpyralate (40 g&middot;ha&minus;1), tolpyralate (30 g&middot;ha&minus;1) + atrazine and tolpyralate (40 g&middot;ha&minus;1) + atrazine, applied PRE, provided similar control of GR Canada fleabane as current industry standards at 8 WAA. 展开更多
关键词 Crop Injury Density Efficacy GLYPHOSATE-RESISTANT Horseweed Marestail RESIDUAL WEED CONTROL Sensitivity WEED CONTROL g·ai·ha-1
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Experimental Evaluation of Parameterized Nonlinear MPC Applied to PEM Fuel Cell 认领
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作者 Cédric Damour Dominique Grondin +2 位作者 Michel Benne Brigitte Grondin-Perez Jean-Pierre Chabriat 《工程(英文)(1947-3931)》 2020年第2期99-116,共18页
This paper proposes a parameterized nonlinear model-based predictive control (NMPC) strategy to tackle the oxygen excess ratio regulation challenge of a proton exchange membrane fuel cell. In practice, the most challe... This paper proposes a parameterized nonlinear model-based predictive control (NMPC) strategy to tackle the oxygen excess ratio regulation challenge of a proton exchange membrane fuel cell. In practice, the most challenging part regarding NMPC strategies remains the on-line implementation. In fact, NMPC strategies, at least in their basic form, involve heavy computation to solve the optimization problem. In this work, a specific parameterization of control actions has been designed to address this limitation and achieve on-line implementation. To assess the effectiveness and relevance of the proposed strategy, the controller has been implemented on-line, experimentally validated on a real fuel cell and compared to the built-in controller. Performance of the parameterized NMPC controller in terms of setpoint tracking accuracy, disturbances rejection and computational cost, have tested under several control scenarios. Experimental results have shown the excellent tracking capability, disturbances rejection ability and low computational cost of the NMPC controller, regardless of the operating conditions. Moreover, compared to the built-in controller the proposed strategy has demonstrated better disturbances rejection capability. Overall, the proposed parameterized NMPC controller appears as an excellent candidate to address the oxygen excess ratio regulation issue. 展开更多
关键词 CONTROL Application Parameterized NONLINEAR Model PREDICTIVE CONTROL PROTON Exchange MEMBRANE Fuel Cell
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W型火焰锅炉分区混合动态喷氨控制系统 认领
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作者 贾晓静 李刚 +4 位作者 武宝会 李明皓 秦昶顺 许博 王小成 《热力发电》 CAS 北大核心 2020年第3期141-147,共7页
针对W型火焰锅炉脱硝系统的还原剂用量偏高以及氨逃逸较高的问题,在分区混合动态喷氨技术的基础上,采用Modbus RTU的485总线通信方式,研究先进的分布式控制系统(DCS)外挂控制系统,提出了“SCR Control+”控制技术与“均衡控制”方法相... 针对W型火焰锅炉脱硝系统的还原剂用量偏高以及氨逃逸较高的问题,在分区混合动态喷氨技术的基础上,采用Modbus RTU的485总线通信方式,研究先进的分布式控制系统(DCS)外挂控制系统,提出了“SCR Control+”控制技术与“均衡控制”方法相结合的控制策略。具体方案为:1)SCR Control+整体排放量优化控制;2)建立一套系统专家数据库,作为分区喷氨量均衡控制模型建立的基础,并通过先进的动态矩阵控制(DMC)优化控制算法,灵活地调整控制规律,适应控制对象特性和机组运行工况的变化,并计算出各分区输出NOx量;3)利用各分区之间反馈值的偏差与偏差的变化速率搭建控制集合,并与目标进行分析比较,修正各分区的阀门开度,达到分区精确均衡控制的目的。该系统应用于湖南某电厂W型火焰锅炉机组,在降低还原剂用量和控制氨逃逸方面取得了良好的效果。 展开更多
关键词 W型火焰锅炉 SCR Control+ 均衡控制 动态矩阵控制 氨逃逸 分区混合 动态喷氨 控制系统
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Aperiodic Sampled-Data Control of Distributed Networked Control Systems Under Stochastic Cyber-Attacks 认领
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作者 Kritika Bansal Pankaj Mukhija 《自动化学报:英文版》 SCIE EI CSCD 2020年第4期1064-1073,共10页
This paper examines the stabilization problem of a distributed networked control system under the effect of cyberattacks by employing a hybrid aperiodic triggering mechanism.The cyber-attack considered in the paper is... This paper examines the stabilization problem of a distributed networked control system under the effect of cyberattacks by employing a hybrid aperiodic triggering mechanism.The cyber-attack considered in the paper is a stochastic deception attack at the sensor-controller end. The probability of the occurrence of attack on a subsystem is represented using a random variable. A decentralized hybrid sampled-data strategy is introduced to save energy consumption and reduce the transmission load of the network. In the proposed decentralized strategy, each subsystem can decide independently whether its state should be transmitted to the controller or not. The scheme of the hybrid triggering mechanism for each subsystem composed of two stages: In the first stage, the next sampling instant is computed using a self-triggering strategy. Subsequently, in the second stage, an event-triggering condition is checked at these sampling instants and the control signal is computed only if the event-triggering condition is violated. The self-triggering condition used in the first stage is dependent on the selection of eventtriggering condition of the second stage. Finally, a comparison of the proposed approach with other triggering mechanisms existing in the literature is presented in terms of the sampling instants,transmission frequency and performance measures through simulation examples. 展开更多
关键词 Cyber-attack distributed networked control system event-triggered control hybrid aperiodic sampled-data control selftriggered control
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Consensus disturbance rejection control of directed multi-agent networks with extended state observer 认领
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作者 Shaopan GUO Zhongkui LI +1 位作者 Yifeng NIU Lizhen WU 《中国航空学报:英文版》 SCIE EI CAS CSCD 2020年第5期1486-1493,共8页
This paper investigates the consensus disturbance rejection problem among multiple high-order agents with directed graphs.Based on disturbance observers,distributed consensus disturbance rejection protocols are constr... This paper investigates the consensus disturbance rejection problem among multiple high-order agents with directed graphs.Based on disturbance observers,distributed consensus disturbance rejection protocols are constructed in leaderless and leader-follower consensus setups.Different from the previous related papers,the consensus protocols in this paper are developed in a fully distributed fashion,relying on only the state information of each agent and its neighbors.Sufficient conditions are provided to guarantee that the asymptotic stability of high-order multi-agent systems can be reached with matched disturbances. 展开更多
关键词 Adaptive control Consensus control Distributed control Disturbance rejection Multi-agent systems
Automatic Generation Control of Multi-area Power System with Network Constraints and Communication Delays 认领
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作者 Ragini Patel Lasantha Meegahapola +2 位作者 Liuping Wang Xinghuo Yu Brendan McGrath 《现代电力系统与清洁能源学报(英文)》 SCIE EI CSCD 2020年第3期454-463,共10页
Newly proposed power system control methodologies combine economic dispatch(ED) and automatic generation control(AGC) to achieve the steady-state cost-optimal solution under stochastic operation conditions. However, a... Newly proposed power system control methodologies combine economic dispatch(ED) and automatic generation control(AGC) to achieve the steady-state cost-optimal solution under stochastic operation conditions. However, a real power system is subjected to continuous demand disturbance and system constraints due to the input saturation, communication delays and unmeasurable feed-forward load disturbances. Therefore, optimizing the dynamic response under practical conditions is equally important. This paper proposes a state constrained distributed model predictive control(SCDMPC)scheme for the optimal frequency regulation of an interconnected power system under actual operation conditions, which exist due to the governor saturation, generation rate constraints(GRCs), communication delays, and unmeasured feed-forward load disturbances. In addition, it proposes an algorithm to handle the solution infeasibility within the SCDMPC scheme, when the input and state constraints are conflicting. The proposed SCDMPC scheme is then tested with numerical studies on a three-area interconnected network. The results show that the proposed scheme gives better control and cost performance for both steady state and dynamic state in comparison to the traditional distributed model predictive control(MPC) schemes. 展开更多
关键词 Automatic generation control CONSTRAINTS distributed control frequency regulation model predictive control(MPC) tie-lines
High AOA decoupling control for aircraft based on ADRC 认领
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作者 LIU Junjie SUN Mingwei +1 位作者 CHEN Zengqiang SUN Qinglin 《系统工程与电子技术:英文版》 SCIE EI CSCD 2020年第2期393-402,共10页
In this paper, a practical decoupling control scheme for fighter aircraft is proposed to achieve high angle of attack(AOA)tracking and super maneuver action by utilizing the thrust vector technology. Firstly, a six de... In this paper, a practical decoupling control scheme for fighter aircraft is proposed to achieve high angle of attack(AOA)tracking and super maneuver action by utilizing the thrust vector technology. Firstly, a six degree-of-freedom(DOF) nonlinear model with 12 variables is given. Due to low sufficiency of the aerodynamic actuators at high AOA, a thrust vector model with rotatable engine nozzles is derived. Secondly, the active disturbance rejection control(ADRC) is used to realize a three-channel decoupling control such that a strong coupling between different channels can be treated as total disturbance, which is estimated by the designed extended state observer. The control surface allocation is implemented by the traditional daisy chain method. Finally,the effectiveness of the presented control strategy is demonstrated by some numerical simulation results. 展开更多
关键词 HIGH angle of attack(AOA) DECOUPLING CONTROL linear extended state observer(LESO) active disturbance REJECTION control(ADRC) thrust vector technology CONTROL allocation
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A novel flow control scheme for reciprocating compressor based on adaptive predictive PID control 认领
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作者 刘雯华 Zhang Jinjie +3 位作者 Zhou Chao Wang Yao Sun Xu Hong Huaibing 《高技术通讯:英文版》 EI CAS 2020年第3期243-252,共10页
In the process of capacity regulation of reciprocating compressor,the frequent change of inlet temperature and pressure makes the control of exhaust flow unstable,resulting in the high pressure ratio of the intermedia... In the process of capacity regulation of reciprocating compressor,the frequent change of inlet temperature and pressure makes the control of exhaust flow unstable,resulting in the high pressure ratio of the intermediate stage.At last the compressor cannot operate safely.To solve the problem,a novel flow control scheme based on inlet temperature and pressure ratio is proposed.In this scheme,the intake model of the cylinder under the capacity regulation condition is established to calculate the load of the first cylinder.Then,the adaptive predictive PID(APPID)controller is designed to control the pressure ratio of other stages,and the grey prediction model is used to predict the pressure output to overcome the system delay.To solve the problem of control parameters tuning,an improved particle swarm optimization(PSO)algorithm is adopted to obtain the optimal control parameters.The effectiveness of the adaptive predictive PID control method is verified by a two-stage compressor model simulation.Finally,the flow control scheme is applied to the actual four-stage air reciprocating compressor flow control system.Although the temperature difference is greater than 15°C,the compressor exhaust flow is maintained at the set value and the pressure ratio is also maintained stable.At the same time,the compressor pressure ratio can be quickly adjusted without overshoot.The application result further verifies the feasibility and effectiveness of the scheme. 展开更多
关键词 reciprocating compressor capacity control predictive PID control internal model control(IMC)
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Control allocation for a class of morphing aircraft with integer constraints based on Lévy flight 认领
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作者 LU Yao SUN You +1 位作者 LIU Xiaodong GAO Bo 《系统工程与电子技术:英文版》 SCIE EI CSCD 2020年第4期826-840,共15页
Aiming at tracking control of a class of innovative control effector(ICE) aircraft with distributed arrays of actuators, this paper proposes a control allocation scheme based on the Lévy flight.Different from the... Aiming at tracking control of a class of innovative control effector(ICE) aircraft with distributed arrays of actuators, this paper proposes a control allocation scheme based on the Lévy flight.Different from the conventional aircraft control allocation problem,the particular characteristic of actuators makes the actuator control command totally subject to integer constraints. In order to tackle this problem, first, the control allocation problem is described as an integer programming problem with two desired objectives. Then considering the requirement of real-time, a metaheuristic algorithm based on the Lévy flight is introduced to tackling this problem. In order to improve the searching efficiency, several targeted and heuristic strategies including variable step length and inherited population initialization according to feedback and so on are designed. Moreover, to prevent the incertitude of the metaheuristic algorithm and ensure the flight stability, a guaranteed control strategy is designed. Finally, a time-varying simulation model is introduced to verifying the effectiveness of the proposed scheme. The contrastive simulation results indicate that the proposed scheme achieves superior tracking performance with appropriate actuator dynamics and computational time, and the improvements for efficiency are active and the parameter settings are reasonable. 展开更多
关键词 flight control control allocation optimization Lévy flight tracking control
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Bioecology of <i>Phonoctonus lutescens</i>(Guérin Meneville and Percheron) Predator of <i>Dysdercus vo&euml;lkeri</i>(Schmidt, 1932), Feeding on Dysdercus voëlkeri in the Laboratory Conditions in Burkina Faso 认领
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作者 Sow Issa Hema S. A. Omer +1 位作者 Sanon Antoine Hema Tiemogo 《农业科学(英文)》 2020年第5期472-486,共15页
The study was conducted at the agricultural experimental station of Farako-B&acirc;, specifically in the Cotton Program. Insects were collected in Farako-B&acirc;?field and raised in the Cotton Program. Dysder... The study was conducted at the agricultural experimental station of Farako-B&acirc;, specifically in the Cotton Program. Insects were collected in Farako-B&acirc;?field and raised in the Cotton Program. Dysdercus vo&euml;keri Schmidt is one of cotton cultivation main pests in Burkina Faso. The control of this devastating cotton bug is based on chemical using. For researching alternative solutions, a part of the biological control method was investigated by using Phonoctonus lutescens which is D. v&ouml;elkeri natural enemy, in order to develop a biological control method. To understand the bioecology of P. lutescens, our study has been carried out on this insect under laboratory conditions when it was feed on its prey which is D. vo&euml;keri. The results have demonstrated that the pre-copulation period is 9.33 ± 2.14 days. The oviposition period is 6.97 ± 1.47 days, after which 366.73 ± 27.43 eggs on average are laid with 92.33% ± 4% hatchability. From hatching to adult stage, P. lutescens larvae development goes through five stages with variable durations according to the stage. The results showed that the development cycle lasted 57.23 ± 5.81 days at a temperature of 27.5&deg;C ± 2&deg;C and a relative humidity of 42% ± 3%. Survival rates ranged from 92% to 97.47%. Males and females lived respectively 87.5 ± 27.99 days and 107.97 ± 24.21 days. These results could permit a better use of P. lutescens through a mass rearing and an optimization of D. vo&euml;keri biological control. 展开更多
关键词 Cotton Biological Control Phonoctonus lutescens Dysdercus vo?lkeri Burkina Faso
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Control performance and energy saving of multi-level pressure switching control system based on independent metering control 认领
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作者 曹晓明 Yao Jing +1 位作者 Sha Tong Wang Pei 《高技术通讯:英文版》 EI CAS 2020年第2期224-234,共11页
Aiming at the problem of large energy consumption in hydraulic control system with large load and variable working conditions,based on the multi-level pressure switching control system(MPSCS),a multi-level pressure sw... Aiming at the problem of large energy consumption in hydraulic control system with large load and variable working conditions,based on the multi-level pressure switching control system(MPSCS),a multi-level pressure switching control system based on independent metering control is proposed combined with the independent metering control technology.The configuration principle of the system is given,the mathematical model of this system is established,and the control strategy of the system under 4 different working quadrants is put forward.Finally,the control performance and energy saving characteristics of the system are tested.The test results show that the switching of high and low pressure power supply has a certain effect on the response of step position and ramp position under impedance working condition.The displacement curves show slow climbing or abrupt change of ramp position,and the position accuracy is less than 1 mm.The multi-level pressure switching control system based on independent metering control can recover and store energy under the transcendence working conditions.The control accuracy is about 1 mm,and the energy recovery rate is about 70%~80%. 展开更多
关键词 MULTI-LEVEL pressure INDEPENDENT METERING CONTROL DISPLACEMENT CONTROL energy SAVING hydraulic switching system
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Robust Stabilization of Non-minimum Phase Switched Nonlinear Systems with Uncertainty 认领
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作者 KHALIL Jouili 《系统科学与复杂性学报:英文版》 SCIE EI CSCD 2020年第2期289-311,共23页
This paper investigates the problem of robust stabilization of a class of switched nonlinear system with uncertain dynamics where each subsystem represents a non-minimum phase.The authors first construct a stabilizing... This paper investigates the problem of robust stabilization of a class of switched nonlinear system with uncertain dynamics where each subsystem represents a non-minimum phase.The authors first construct a stabilizing sliding mode controller for each subsystem to stabilize individually its own unstable internal dynamics.Then,a switching strategy is introduced to select the most appropriate diffeomorphism through an infinity of diffeomorphisms.Sufficient conditions are specifically given for the exponential stability and the exponential upper bound of the trajectory of the switched subsystem,which guarantees the global asymptotical stability of the resulting switched system.Obviously,the proposed control approach can improvemore the transient state,compared to a feedback linearization based on only one diffeomorphism.Simulation studies illustrate the effectiveness of the suggested approach. 展开更多
关键词 Exponential stability sliding mode control switching control uncertain non-minimum phase systems
The Challenges of Diagnosis and Control of Enterotoxaemia Caused by <i>Clostridium perfringens</i>in Small Ruminants 认领
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作者 Rajveer Singh Pawaiya Kumaresan Gururaj +3 位作者 Neeraj Kumar Gangwar Desh Deepak Singh Rahul Kumar Ashok Kumar 《微生物学(英文)》 2020年第5期238-273,共36页
Enterotoxaemia is one of the important pathologies caused by Clostridium perfringens, which produces intestinal and systemic disease in goats, sheep and other animals. These Gram-positive anaerobic bacteria are normal... Enterotoxaemia is one of the important pathologies caused by Clostridium perfringens, which produces intestinal and systemic disease in goats, sheep and other animals. These Gram-positive anaerobic bacteria are normally resident in the intestinal tract of ruminants but during favourable conditions, proliferate uncontrollably and release toxins which produce disease in the host. Different strains of C. perfringens are responsible for several clinical syndromes, including lamb dysentery, pulpy kidney disease and struck. However, the pathology and pathogenesis of caprine enterotoxaemia is not well understood, with limited studies available in goats. Caprine enterotoxaemia can be controlled with the better understanding of its risk factors and pathogenesis. The diagnosis of enterotoxaemia in animals is complex and often requires group of tests than one single test for better specificity and sensitivity. Tentative diagnosis of enterotoxaemia in sheep and goats is based on the history, clinical signs and gross lesions during post-mortem examination of animals;however, confirmatory diagnosis of enterotoxaemia requires different laboratory diagnostic tools. Toxin detection of C. perfringens in case of enterotoxaemia is furthermost accepted benchmark in establishing a definitive diagnosis of enterotoxaemia in intestinal contents. Measuring urine glucose or observing Gram-stained smears of intestinal mucosa can be used as supplementary tests. However, it is also imperative that enterotoxaemia cannot be ruled out in the event of negativity of aforementioned diagnostic tests. Hence, definitive diagnosis of enterotoxaemia in goats can be achieved with the use of molecular techniques (PCR, ELISA and immune-fluorescence) coupled with toxin detection in intestine or biological assays including mouse inoculation test (MIT). In case of goats, vaccine efficacy is poor which may be due to need of high to moderate level of serum antibodies to protect against both systemic and enteric effects because intestinal form of disease is part 展开更多
关键词 CLOSTRIDIUM perfringens Control DIAGNOSIS Enterotoxaemia GOAT Prevention Sheep Small RUMINANTS
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Research on nonlinear model predictive control for turboshaft engines based on double engines torques matching 认领
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作者 Yong WANG Qian’gang ZHENG +1 位作者 Ziyan DU Haibo ZHANG 《中国航空学报:英文版》 SCIE EI CAS CSCD 2020年第2期561-571,共11页
In order to reach a compromise between fast response control and torques matching control in double turboshaft engines,research on nonlinear model predictive control for turboshaft engines based on double engines torq... In order to reach a compromise between fast response control and torques matching control in double turboshaft engines,research on nonlinear model predictive control for turboshaft engines based on double engines torques matching is conducted.Meanwhile,a Nonlinear Model Predictive Control(NMPC)method is proposed,which combines the control index of the power turbine speed with torques matching of double engines creatively.In addition to the control index,the difference of output torques between each engine is also incorporated in the objective function as a penalty term to ensure constant speed control and short torques matching time.Simulation results demonstrate that relative to unilateral torques matching,the settling time of the bidirectional matching method can be reduced by nearly 30.8%.Nevertheless,compared with the bidirectional torques matching method under the cascade PID controller,the NMPC method can decrease the overshoot of the power turbine speed by 65%and reduce the matching time by 15.5%synchronously.Besides fast response control of turboshaft engines,fast torques matching control of double engines is accomplished as well. 展开更多
关键词 DOUBLE turboshaft engines Fast response CONTROL HELICOPTER Nonlinear model PREDICTIVE CONTROL TORQUES MATCHING method
Influence of Adjuvants on the Control of Glyphosate-Resistant Canada Fleabane and Waterhemp in Corn with Tolpyralate 认领
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作者 Nicole M. Langdon Nader Soltani +3 位作者 Alan J. Raedar David C. Hooker Darren E. Robinson Peter H. Sikkema 《美国植物学期刊(英文)》 2020年第3期354-371,共18页
Tolpyralate is a new benzoylpyrazole herbicide for weed management in corn. It is recommended to be co-applied with atrazine along with the adjuvants methylated seed oil concentrate (MSO) plus an ammonium nitrogen fer... Tolpyralate is a new benzoylpyrazole herbicide for weed management in corn. It is recommended to be co-applied with atrazine along with the adjuvants methylated seed oil concentrate (MSO) plus an ammonium nitrogen fertilizer, such as urea ammonium nitrate (UAN). Two studies were conducted on glyphosate-resistant (GR) Canada fleabane and GR waterhemp to determine if an additional adjuvant is still required when tolpyralate plus atrazine are tankmixed with a commercial glyphosate formulation (Roundup WeatherMAX&reg;) in corn. Trials were conducted over a two-year period (2018-19) on farms in south western Ontario with confirmed GR populations. When co-applied with Roundup WeatherMAX&reg;, the addition of MSO to tolpyralate + atrazine increased control of GR waterhemp 9%;however, there was no increase in GR Canada fleabane control from the addition of additional adjuvants. At 8 WAA, all treatments provided > 91% and > 84% control of GR waterhemp and GR Canada fleabane, respectively. This study concludes that the addition of Roundup WeatherMAX&reg;to tolpyralate plus atrazine improves the control of GR waterhemp and GR Canada fleabane in corn. 展开更多
关键词 Biomass Crop Injury Density Sensitivity WEED CONTROL Yield AMARANTHUS tuberculatus Conyza CANADENSIS L. Cronq
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融合VOOK的混合ACO-OFDM可见光通信技术研究 认领
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作者 周颖 李宝龙 李正权 《光电子.激光》 EI CAS CSCD 北大核心 2020年第5期556-562,共7页
调光控制可以实现发光二极管(LED)亮度的变化,满足用户的各种照明需求。可见光通信(VLC)是基于LED照明基础上发展而来的一种通信技术,兼备照明和通信的双重功能,因此,调光控制在VLC领域值得深入研究。本文提出一种全新的兼容调光控制的... 调光控制可以实现发光二极管(LED)亮度的变化,满足用户的各种照明需求。可见光通信(VLC)是基于LED照明基础上发展而来的一种通信技术,兼备照明和通信的双重功能,因此,调光控制在VLC领域值得深入研究。本文提出一种全新的兼容调光控制的VLC系统,该系统将可变单载波开关键控(VOOK)和多载波混合非对称剪裁正交频分复用(HACO-OFDM)融合传输,实现LED调光和高效数据传输的双重功能。同时,针对混合信号引入时间选择性偏置,保证混合信号工作在LED的线性区间,消除非线性失真的影响。更为重要的,引入的时间选择性偏置不会干扰VOOK和HACO-OFDM信号的传输,在接收端,两种信号可以独立地完成检测,不会影响彼此的传输性能,系统误码率不会变差。并且整个系统添加的部分模块未对系统复杂度带来较大的影响。仿真结果验证了提出方案的有效性。 展开更多
关键词 可见光通信(VLC) 可变单载波开关键控(VOOK) 混合非对称剪裁正交频分复用(HACO-OFDM) 调光(Dimming Control)
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