含高比例新能源的异步互联送端系统直流FLC的阶跃死区控制策略及优化

针对含高比例新能源的异步送端系统直流频率限制控制器(FLC)死区控制及参数优化问题,提出了一种直流FLC阶跃死区控制策略。基于考虑含高比例新能源的多机系统频率响应模型,分析了直流FLC死区参数以及高比例新能源装机容量对送端系统频率响应的影响。加入阶跃决策系统,构建改进型直流FLC阶跃死区控制策略。搭建兼顾直流FLC动作特性以及对送端系统频率偏差抑制效果的改进型直流FLC阶跃死区控制策略参数优化模型。使用群智能算法求解出改进型直流FLC阶跃死区控制器最优参数。仿真结果表明优化后的直流FLC死区控制方法可以显著改善送端系统的频率稳定支撑能力。

甘蓝BoFLCs基因标记开发及优异单倍型聚合

开花抑制因子FLOWERING LOCUS C(FLC)编码MADS-box家族蛋白,在拟南芥的春化途径中起关键作用。为了探究甘蓝BoFLCs在春化过程中的作用,利用CRISPR/Cas9技术对甘蓝自交系GL的BoFLCs基因进行编辑,显著提早了其开花时间,明确了BoFLCs的基因功能。以晚花甘蓝自交系20-2221(P_(1),BoFLCs-w)和中早花甘蓝自交系20-2229(P_(2),BoFLCs-z)为亲本,构建BC_(1-2)P_(2)和BC_(2)F_(1)分离群体。通过序列比对分析,发现BoFLC_(1)、BoFLC3和BoFLC5在双亲间均存在序列差异,并根据这些差异序列开发了其特异性分子标记。利用BoFLCs特异性分子标记对BC_(2)F_(1)群体进行筛选,最终获得1个包含BoFLC_(1)-w/w、BoFLC5-w/w纯合单倍型以及BoFLC3-w/z杂合单倍型的植株(BC_(2)F_(1)-29),其抽薹时间和开花时间分别比回交亲本20-2229晚8.00 d和13.00 d;4个包含BoFLC_(1)-w/w、BoFLC3-w/w纯合单倍型以及BoFLC5-w/z杂合单倍型的植株(BC_(2)F_(1)-55、BC_(2)F_(1)-119、BC_(2)F_(1)-121和BC_(2)F_(1)-163),平均抽薹时间和开花时间比20-2229分别晚9.75 d和(13.50 d;3个包含BoFLC_(1)-w/w、BoFLC3-w/w)和BoFLC5-w/w纯合单倍型的植株(BC_(2)F_(1)-82、BC_(2)F_(1)-106和BC_(2)F_(1)-192),平均抽薹时间和开花时间分别比20-2229晚11.33 d和15.67 d。本研究开发了BoFLCs特异性分子标记,并实现了BoFLCs优异基因型的高效聚合,改良了亲本20-2229的抽薹性。

基于预测模糊FLC控制下农业生产过程监控与优化

该文以温室监控系统为案例,针对传统PLC控制在复杂环境下的局限性,提出了一种基于预测模糊FLC控制的优化技术,该技术利用模糊逻辑对环境变量进行模糊化处理,并结合预测算法对未来状态进行预测,从而实现对温室环境的精准控制和优化调节。通过试验验证,该优化技术能够提高温室生产效率、降低能耗成本,并保障农作物的生长质量和产量稳定性。研究结果可以为农业生产过程的智能化监控与优化提供新的思路和方法。

Robust fixed-time flight controller for a dual-system convertible UAV in the cruise mode

This paper investigates the attitude tracking control problem for the cruise mode of a dual-system convertible unmanned aerial vehicle(UAV)in the presence of parameter uncertainties,unmodeled uncertainties and wind disturbances.First,a fixed-time disturbance observer(FXDO)based on the bi-limit homogeneity theory is designed to estimate the lumped disturbance of the convertible UAV model.Then,a fixed-time integral sliding mode control(FXISMC)is combined with the FXDO to achieve strong robustness and chattering reduction.Bi-limit homogeneity theory and Lyapunov theory are applied to provide detailed proof of the fixed-time stability.Finally,numerical simulation experimental results verify the robustness of the proposed algorithm to model parameter uncertainties and wind disturbances.In addition,the proposed algorithm is deployed in a open-source UAV autopilot and its effectiveness is further demonstrated by hardware-in-the-loop experimental results.

Precision Motion Control of Hydraulic Actuator Using Adaptive Back-Stepping Sliding Mode Controller

Hydraulic actuators are highly nonlinear when they are subjected to different types of model uncertainties and dynamic disturbances.These unfavorable factors adversely affect the control performance of the hydraulic actuator.Although various control methods have been employed to improve the tracking precision of the dynamic system,optimizing and adjusting control gain to mitigate the hydraulic actuator model uncertainties remains elusive.This study presents an adaptive back-stepping sliding mode controller(ABSMC)to enhance the trajectory tracking precision,where the virtual control law is constructed to replace the position error.The adaptive control theory is introduced in back-stepping controller design to compensate for the model uncertainties and time-varying disturbances.Based on Lyapunov theory,the finite-time convergence of the position tracking errors is proved.Furthermore,the effectiveness of the developed control scheme is conducted via extensive comparative experiments.

Path Tracking Controller Design of Automated Parking Systems via NMPC with an Instructible Solution

Parking difficulties have become a social issue that people have to solve.Automated parking system is practicable for quick par operations without a driver which can also greatly reduces the probability of parking accidents.The paper proposes a Lyapunov-based nonlinear model predictive controller embedding an instructable solution which is generated by the modified rear-wheel feedback method(RF-LNMPC)in order to improve the overall path tracking accuracy in parking conditions.Firstly,A discrete-time RF-LNMPC considering the position and attitude of the parking vehicle is proposed to increase the success rate of automated parking effectively.Secondly,the RF-LNMPC problem with a multi-objective cost function is solved by the Interior-Point Optimization,of which the iterative initial values are described as the instructable solutions calculated by combining modified rear-wheel feedback to improve the performance of local optimal solution.Thirdly,the details on the computation of the terminal constraint and terminal cost for the linear time-varying case is presented.The closed-loop stability is verified via Lyapunov techniques by considering the terminal constraint and terminal cost theoretically.Finally,the proposed RF-LNMPC is implemented on a selfdriving Lincoln MKZ platform and the experiment results have shown improved performance in parallel and vertical parking conditions.The Monte Carlo analysis also demonstrates good stability and repeatability of the proposed method which can be applied in practical use in the near future.

On-Chip Micro Temperature Controllers Based on Freestanding Thermoelectric Nano Films for Low-Power Electronics

Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.

Laboratory Implementation of Direct Torque Controller based Speed Loop Pseudo Derivative Feedforward Controller for PMSM Drive

This paper,evaluate the effectiveness of a proposed speed loop pseudo derivative feedforward(PDFF)controller-based direct torque controller(DTC)for a PMSM drive against the performance of existing PI speed controller-based DTC and hysteresis current controller(HCC).The proposed PDFF-based speed regulator effectively reduces oscillation and overshoot associated with rotor angular speed,electromagnetic torque,and stator current.Two case studies,one using forward-to-reverse motoring operation and the other involving reverse-to-forward braking operation,has been validated to show the effectiveness of the proposed control strategy.The proposed controller's superior performance is demonstrated through experimental verification utilizing an FPGA controller for a 1.5 kW PMSM drive laboratory prototype.

Contact detumbling toward a nutating target through deformable effectors and prescribed performance controller

Detumbling operation toward a rotating target with nutation is meaningful for debris removal but challenging. In this study, a deformable end-effector is first designed based on the requirements for contacting the nutating target. A dual-arm robotic system installed with the deformable end-effectors is modeled and the movement of the end-tips is analyzed. The complex operation of the contact toward a nutating target places strict requirements on control accuracy and controller robustness. Thus, an improvement of the tracking error transformation is proposed and an adaptive sliding mode controller with prescribed performance is designed to guarantee the fast and precise motion of the effector during the contact detumbling.Finally, by employing the proposed effector and the controller,numerical simulations are carried out to verify the effectiveness and efficiency of the contact detumbling toward a nutating target.

Hierarchical Controller Synthesis Under Linear Temporal Logic Specifications Using Dynamic Quantization

Linear temporal logic(LTL)is an intuitive and expressive language to specify complex control tasks,and how to design an efficient control strategy for LTL specification is still a challenge.In this paper,we implement the dynamic quantization technique to propose a novel hierarchical control strategy for nonlinear control systems under LTL specifications.Based on the regions of interest involved in the LTL formula,an accepting path is derived first to provide a high-level solution for the controller synthesis problem.Second,we develop a dynamic quantization based approach to verify the realization of the accepting path.The realization verification results in the necessity of the controller design and a sequence of quantization regions for the controller design.Third,the techniques of dynamic quantization and abstraction-based control are combined together to establish the local-to-global control strategy.Both abstraction construction and controller design are local and dynamic,thereby resulting in the potential reduction of the computational complexity.Since each quantization region can be considered locally and individually,the proposed hierarchical mechanism is more efficient and can solve much larger problems than many existing methods.Finally,the proposed control strategy is illustrated via two examples from the path planning and tracking problems of mobile robots.

Intelligent Fractional-Order Controller for SMES Systems in Renewable Energy-Based Microgrid

An autonomous microgrid that runs on renewable energy sources is presented in this article.It has a supercon-ducting magnetic energy storage(SMES)device,wind energy-producing devices,and an energy storage battery.However,because such microgrids are nonlinear and the energy they create varies with time,controlling and managing the energy inside them is a difficult issue.Fractional-order proportional integral(FOPI)controller is recommended for the current research to enhance a standalone microgrid’s energy management and performance.The suggested dedicated control for the SMES comprises two loops:the outer loop,which uses the FOPI to regulate the DC-link voltage,and the inner loop,responsible for regulating the SMES current,is constructed using the intelligent FOPI(iFOPI).The FOPI+iFOPI parameters are best developed using the dandelion optimizer(DO)approach to achieve the optimum performance.The suggested FOPI+iFOPI controller’s performance is contrasted with a conventional PI controller for variations in wind speed and microgrid load.The optimal FOPI+iFOPI controller manages the voltage and frequency of the load.The behavior of the microgrid as a reaction to step changes in load and wind speed was measured using the proposed controller.MATLAB simulations were used to evaluate the recommended system’s performance.The results of the simulations showed that throughout all interruptions,the recommended microgrid provided the load with AC power with a constant amplitude and frequency.In addition,the required load demand was accurately reduced.Furthermore,the microgrid functioned incredibly well despite SMES and varying wind speeds.Results obtained under identical conditions were compared with and without the best FOPI+iFOPI controller.When utilizing the optimal FOPI+iFOPI controller with SMES,it was found that the microgrid performed better than the microgrid without SMES.

基于矩阵解耦的精馏塔VOFFLC温控系统

针对复杂的精馏塔MIMO温控系统的多变量、非线性、强耦合的特点和自适应需求,设计了基于矩阵解耦精馏塔的VOFFLC系统。首先,对温控系统的多变量控制模型进行改进,利用矩阵解耦理论实现对角解耦,以此改变控制通道的特性;然后,设计基于矩阵解耦的精馏塔VOFFLC温控系统,实现精馏塔的塔顶和塔底的自适应温控;最后,采用仿真实验,对所设计的多种温控系统进行性能比较。实验结果表明,VOFFLC系统可以实现控制参数的自适应,具有更强的论域容错性和鲁棒性。

硫化氢信号对大白菜FLCs时空表达模式的调控作用

硫化氢(H_(2)S)是一种气体信号分子,可以促进植物的开花,且这一过程与开花的关键因子FLOWERING LOCUS C(FLC)有关。大白菜中已报道的FLC同源基因有4种。本研究对这4种FLC同源基因进行了时空表达模式和功能分化研究,以及H_(2)S对BrFLCs的表达模式的调控作用进行了探讨。结果表明:4种BrFLCs同源基因的表达表现出不同的时空特异性。其中,BrFLC 1、2和3的发育时期表达模式与拟南芥AtFLC相似,而BrFLC 5未表现出发育时期特异性。BrFLC 1只在叶中表达,而BrFLC 2在不同组织中均有表达,BrFLC 3在各组织中的表达量最高,但组织特异性差异不明显,BrFLC 5表达量不高且不具有组织特异性。经外源H_(2)S处理,BrFLCs表达略有下调,叶片中的BrFLC 2表达量最低。H_(2)S还能够不同程度地调节BrFLCs下游基因的表达,这可能和BrFLCs的表达模式改变有关。综上所述,H_(2)S可能通过调节大白菜中4个BrFLCs基因的表达模式影响其植株的开花时间。

北方白菜型冬油菜BrFLC家族的全基因组鉴定、克隆及表达分析

春化过程是冬性植物抽薹开花前的主要阶段。FLC(FLOWERING LOCUS C)基因在春化过程中可以整合上游信号调控植物开花。为了解白菜型冬油菜中FLC基因的特征及其春化功能,以6个拟南芥FLC基因为索引从白菜型冬油菜基因组中鉴定得到10个BrFLC基因,其中8个均含有7个外显子。10个BrFLC分布于4条染色体上,存在明显的基因复制现象。进化及保守结构分析显示聚为一类的成员蛋白质保守Motif分布相似。基因上游1500bp的启动子区域均含有光应答元件,其中BrFLC4、BrFLC5和BrFLC6含低温响应元件,BrFLC3、BrFLC4、BrFLC7、BrFLC9含激素响应元件。比对发现,位于A02上的BrFLC6基因序列与大白菜中已注释的Bra031886差异性较大。克隆到陇油6号、陇油17、天油2号和天祝小油菜中的BrFLC6基因,序列相似性达99.5%。分析其中序列差异最大的BrFLC6基因,qRT-PCR检测发现它可在根、茎、叶、花蕾及花中表达;春化处理后则表达下调,不同品种间下调幅度有差异。结合春化率的观察,认为春化过程抑制了BrFLC6的表达,且基因表达水平与白菜型冬油菜通过春化所需的时间有关。

Observer-Based Path Tracking Controller Design for Autonomous Ground Vehicles With Input Saturation

This paper investigates the problem of path tracking control for autonomous ground vehicles(AGVs),where the input saturation,system nonlinearities and uncertainties are considered.Firstly,the nonlinear path tracking system is formulated as a linear parameter varying(LPV)model where the variation of vehicle velocity is taken into account.Secondly,considering the noise effects on the measurement of lateral offset and heading angle,an observer-based control strategy is proposed,and by analyzing the frequency domain characteristics of the derivative of desired heading angle,a finite frequency H_∞index is proposed to attenuate the effects of the derivative of desired heading angle on path tracking error.Thirdly,sufficient conditions are derived to guarantee robust H_∞performance of the path tracking system,and the calculation of observer and controller gains is converted into solving a convex optimization problem.Finally,simulation examples verify the advantages of the control method proposed in this paper.

In-situ pressure-preserved coring for deep exploration:Insight into the rotation behavior of the valve cover of a pressure controller

In-situ pressure-preserved coring(IPP-Coring)is considered to be the most reliable and efficient method for the identification of the scale of oil and gas resources.During IPP-Coring,because the rotation behavior of the pressure controller valve cover in different medium environments is unclear,interference between the valve cover and inner pipe may occur and negatively affect the IPP-Coring success rate.To address this issue,we conducted a series of indoor experiments employing a high-speed camera to gain greater insights into the valve cover rotation behavior in different medium environments,e.g.,air,water,and simulated drilling fluids.The results indicated that the variation in the valve cover rotation angle in the air and fluid environments can be described by a one-phase exponential decay function with a constant time parameter and by biphasic dose response function,respectively.The rotation behavior in the fluid environments exhibited distinct elastic and gravitational acceleration zones.In the fluid environments,the density clearly impacted the valve cover closing time and rotation behavior,whereas the effect of viscosity was very slight.This can be attributed to the negligible influence of the fluid viscosity on the drag coefficient found in this study;meanwhile,the density can increase the buoyancy and the time period during which the valve cover experienced a high drag coefficient.Considering these results,control schemes for the valve cover rotation behavior during IPP-Coring were proposed for different layers and geological conditions in which the different drilling fluids should be used,e.g.,the use of a high-density valve cover in high-pore pressure layers.

A fuzzy control and neural network based rotor speed controller for maximum power point tracking in permanent magnet synchronous wind power generation system

When the wind speed changes significantly in a permanent magnet synchronous wind power generation system,the maximum power point cannot be easily determined in a timely manner.This study proposes a maximum power reference signal search method based on fuzzy control,which is an improvement to the climbing search method.A neural network-based parameter regulator is proposed to address external wind speed fluctuations,where the parameters of a proportional-integral controller is adjusted to accurately monitor the maximum power point under different wind speed conditions.Finally,the effectiveness of this method is verified via Simulink simulation.

Hybrid Optimization Based PID Controller Design for Unstable System

PID controllers play an important function in determining tuning para-meters in any process sector to deliver optimal and resilient performance for non-linear,stable and unstable processes.The effectiveness of the presented hybrid metaheuristic algorithms for a class of time-delayed unstable systems is described in this study when applicable to the problems of PID controller and Smith PID controller.The Direct Multi Search(DMS)algorithm is utilised in this research to combine the local search ability of global heuristic algorithms to tune a PID controller for a time-delayed unstable process model.A Metaheuristics Algorithm such as,SA(Simulated Annealing),MBBO(Modified Biogeography Based Opti-mization),BBO(Biogeography Based Optimization),PBIL(Population Based Incremental Learning),ES(Evolution Strategy),StudGA(Stud Genetic Algo-rithms),PSO(Particle Swarm Optimization),StudGA(Stud Genetic Algorithms),ES(Evolution Strategy),PSO(Particle Swarm Optimization)and ACO(Ant Col-ony Optimization)are used to tune the PID controller and Smith predictor design.The effectiveness of the suggested algorithms DMS-SA,DMS-BBO,DMS-MBBO,DMS-PBIL,DMS-StudGA,DMS-ES,DMS-ACO,and DMS-PSO for a class of dead-time structures employing PID controller and Smith predictor design controllers is illustrated using unit step set point response.When compared to other optimizations,the suggested hybrid metaheuristics approach improves the time response analysis when extended to the problem of smith predictor and PID controller designed tuning.

PD-like finite time controller with simple structure for satellite attitude control

A finite time controller with PD-like structure for satellite attitude control is proposed in this paper.The controller is constructed with simple structure based on standard PD controller.The fractional order term is designed hence system could both have strong robustness and finite time convergence rate,and the advantage of finite time control and PD control is combined in this paper.System convergence rate is discussed by Lyapunov method,and the constraint on control parameters is given by implementing the coupled term of angular velocity and attitude quaternion.Moreover,the accuracy at steady stage depending on control parameters is given hence system could converge to this field within finite time.System stability and performance is demonstrated by numerical simulation results.

Programmable Logic Controller Block Monitoring System for Memory Attack Defense in Industrial Control Systems

Cyberattacks targeting industrial control systems(ICS)are becoming more sophisticated and advanced than in the past.A programmable logic controller(PLC),a core component of ICS,controls and monitors sensors and actuators in the field.However,PLC has memory attack threats such as program injection and manipulation,which has long been a major target for attackers,and it is important to detect these attacks for ICS security.To detect PLC memory attacks,a security system is required to acquire and monitor PLC memory directly.In addition,the performance impact of the security system on the PLC makes it difficult to apply to the ICS.To address these challenges,this paper proposes a system to detect PLC memory attacks by continuously acquiring and monitoring PLC memory.The proposed system detects PLC memory attacks by acquiring the program blocks and block information directly from the same layer as the PLC and then comparing them in bytes with previous data.Experiments with Siemens S7-300 and S7-400 PLC were conducted to evaluate the PLC memory detection performance and performance impact on PLC.The experimental results demonstrate that the proposed system detects all malicious organization block(OB)injection and data block(DB)manipulation,and the increment of PLC cycle time,the impact on PLC performance,was less than 1 ms.The proposed system detects PLC memory attacks with a simpler detection method than earlier studies.Furthermore,the proposed system can be applied to ICS with a small performance impact on PLC.