Modeling and Analyzing Dynamic Response for An Offshore Bottom-Fixed Wind Turbine with Individual Pitch Control

The asymmetric or periodically varying blade loads resulted by wind shear become more significant as the blade length is increased to capture more wind power.Additionally,compared with the onshore wind turbines,their offshore counterparts are subjected to additional wave loadings in addition to wind loadings within their lifetime.Therefore,vibration control and fatigue load mitigation are crucial for safe operation of large-scale offshore wind turbines.In view of this,a multi-body model of an offshore bottom-fixed wind turbine including a detailed drivetrain is established in this paper.Then,an individual pitch controller(IPC)is designed using disturbance accommodating control.State feedback is used to add damping in flexible modes of concern,and a state estimator is designed to predict unmeasured signals.Continued,a coupled aero-hydro-servo-elastic model is constructed.Based on this coupled model,the load reduction effect of IPC and the dynamic responses of the drivetrain are investigated.The results showed that the designed IPC can effectively reduce the structural loads of the wind turbine while stabilizing the turbine power out-put.Moreover,it is found that the drivetrain dynamic responses are improved under IPC.

A Feasibility Study of an Individualized Voiding Program in Japan to Improve the Sense of Control in Older People with Functional Urinary Incontinence

Purpose: This study intended to assess the feasibility of an individualized voiding program in Japan aimed at improving the sense of micturition control in older people with functional urinary incontinence. Method: Following the interview guide, FGIs were conducted in two groups (4 - 6 participants) consisting of nurses and care workers with more than 5 years of experience as practitioners of urination care. Data were analyzed using a qualitative descriptive approach. Results: We determined that the program purpose is to “enable caregivers to work as a well-coordinated team to humanely facilitate excretion independence in older people, which is essential for living with dignity”, as this confirmed the importance of maintaining the sense of micturition control in older people for their well-being. In the program outline, we extracted the following five categories: 1) setting selection criteria for recipients considering the status of micturition induction, 2) careful collection of information and assessment of lower urinary tract symptoms in older people in case of environmental changes, 3) examination of methods used for assessing lower urinary tract symptoms according to the facility environment, 4) confirmation of the recipient’s micturition habits and request for assistance, and 5) conducting necessary examination for setting the intervention period and evaluation period according to the target condition. The feedback on the program guide was summarized in the statement—specific successful cases help frame and implement the micturition induction plan. Conclusion: We confirmed the feasibility of the micturition induction plan for improving the sense of control in older people with functional urinary incontinence. Upon evaluating the program guide, we deemed that referring to specific successful cases helps frame and implement the micturition induction plan. It is extremely important to verify the effectiveness of the program going forward.

Interaction and Its Solution in Individual Matching Case-control Study

Objective To indicate the deficiency of the classical method for analyzing data on individual matching case-control study in consideration of the interaction between the study factor (exposure) and the matching factor, and to find out a proper method for handling this deficiency. Method First, experimental data with 50 pairs of cases and controls were used for strata analysis according to the values of a matching factor to illustrate the possible interaction between a risk factor (exposure) and the matching factor. Second, a detailed procedure was proposed for analyzing such data. Results Interaction between the study factor and matching factor was demonstrated by using strata analysis and unconditional logistic regression analysis. Therefore the results from the classical analysis for such data might be incorrect. Conclusion Data from individual matching case-control study design should be dealt with strata analysis or multivariate analysis to explore and evaluate the possible interaction between the s

Robust Variable-Pitch Control Design of PMSG Via Perturbation Observer

Wind turbine employs pitch angle control to maintain captured power at its rated value when the wind speed is higher than rated value.This work adopts a perturbation observer based sliding-mode control(POSMC)strategy to realize robust variable-pitch control of permanent magnet synchronous generator(PMSG).POSMC combines system nonlinearities,parametric uncertainties,unmodelled dynamics,and time-varying external disturbances into a perturbation,which aims to estimate the perturbation via a perturbation observer without an accurate system model.Subsequently,sliding mode control(SMC)is designed to completely compensate perturbation estimation in real-time for the sake of achieving a global consistent control performance and improving system robustness under complicated environments.Simulation results indicate that,compared with vector control(VC),feedback linearization control(FLC),and nonlinear adaptive control(NAC),POSMC has the best control performance in ramp wind and random wind and the highest robustness in terms of parameter uncertainty.Specially,the integral absolute error index of!m of POSMC is only 11.69%,12.10%and 15.14%of that of VC,FLC and NAC in random wind speed.

Blade pitch control of straight-bladed vertical axis wind turbine

Collective pitch control and individual pitch control algorithms were present for straight-bladed vertical axis wind turbine to improve the self-starting capacity.Comparative analysis of straight-bladed vertical axis wind turbine(SB-VAWT) with or without pitch control was conducted from the aspects of aerodynamic force,flow structure and power coefficient.The computational fluid dynamics(CFD) prediction results show a significant increase in power coefficient for SB-VAWT with pitch control.According to the aerodynamic forces and total torque coefficient obtained at various tip speed ratios(TSRs),the results indicate that the blade pitch method can increase the power output and decrease the deformation of blade;especially,the total torque coefficient of blade pitch control at TSR 1.5 is about 2.5 times larger than that of fixed pitch case.Furthermore,experiment was carried out to verify the feasibility of pitch control methods.The results show that the present collective pitch control and individual pitch control methods can improve the self-starting capacity of SB-VAWT,and the former is much better and its proper operating TSRs ranges from 0.4 to 0.6.

Two Different Role Division Control Strategies for Torque and Axial Force of Conical Bearingless Switched Reluctance Motor

Although the five-degree-of-freedom magnetic levitation system composed of two conical bearingless switched reluctance motors(CBSRMs)owns the simplest structure,the torque and levitation forces are coupled greatly.Therefore,it is difficult to make the rotor rotate and be fully levitated simultaneously.To solve this problem,two different role division control strategies are proposed in this paper,i.e.individual role division and mutual role division control strategies.The difference between them is the selection of motor which controls the torque or the axial force.In order to understand the characteristics of control variables,the principle and mathematical model of CBSRM are introduced.After that,two control strategies are explained in detail.To verify the demonstrated performance,the simulations are completed with MATLAB/Simulink.

Orthokeratology for myopia control: an optometrist’s view

Orthokeratology(OK)is a clinical technique that uses reverse geometry design rigid contact lenses to reshape the corneal profile and modify its refractive power during overnight lens wear in order to correct refractive error temporarily.OK achieves its reshaping effect through thinning of the central corneal epithelium.This raises concerns about the safety of this modality particularly in terms of microbial keratitis(MK).Since the mid 2000’s,with our increasing understanding of modifiable risk factors for MK in OK the prevalence of MK appears to have reduced significantly.It is now clear that the relative risk of MK in overnight OK is equivalent to other modalities of contact lens wear,provided that safe practice is followed in terms of lens fitting,wear and care.Although OK was originally used predominantly for correction of low to moderate myopic refractive error,its use for myopia control have become more common in recent years.This follows on from published clinical trials demonstrating an average of approximately 45%reduction in axial eye elongation when overnight OK is used in progressive myopic children.But there is significant individual variability in efficacy,and one of the current challenges for OK in myopia control is to identify those children who will benefit most from this particular intervention.Modifying OK lens parameters to customise corneal reshaping for enhanced myopia control efficacy also remains a significant challenge for the future of this modality.

Observer-Based Disturbance Accommodation Control Strategy for Useful Lifetime Control and Structural Load Mitigation of Wind Turbines

Wind turbines undergo degradation due to various factors which induce stress, thereby leading to fatigue damage to various wind turbine components. In addition, the current increase in demand for electrical power has led to the development of large wind turbines, which result in increased structural loads, therefore, increasing the possibility of early failure due to fatigue load. This paper proposes a proportional integral observer (PI-Observer) based disturbance accommodation controller (DAC) with individual pitch control (IPC) for load mitigation to reduce components’ damage and ensure the wind turbine is operational for the expected lifetime. The results indicate a reduction in blades’ bending moments with a standard deviation of 15.9%, which positively impacts several other wind turbine subsystems. Therefore, the lifetime control strategy demonstrates effective structural load mitigation without compromise on power generation, thus, achieving a nominal lifetime control to inhibit premature failure.

含静止无功发生器的直驱风电并网系统稳定性分析及振荡抑制策略

风电并网系统稳定性分析及振荡抑制策略大多集中于风电场本身,针对含静止无功发生器(SVG)的直驱风电并网系统研究较少。基于特征值灵敏度筛选出对含SVG的直驱风电并网系统稳定性较显著的控制通道,然后基于独立通道分析设计理论将并网系统由多输入多输出耦合系统等效拆分为多个单输入单输出控制通道,在定性分析并网系统稳定性的同时定量评估不同控制通道间的交互作用程度。为抑制控制通道间的交互作用,提出了基于H∞鲁棒控制的次同步振荡抑制策略。通过电磁暂态仿真,验证了基于独立通道分析设计理论分析并网系统稳定性的正确性以及基于H∞鲁棒控制的次同步振荡抑制策略的有效性。

管制员个体工作负荷多维量化研究

为提高空管系统高效运行,聚焦管制员个体工作负荷建立量化模型;首先设计试验采集一线16名区域管制员的岗前与岗后各项指标数据,根据测试数据变化,选择出敏感变量,描述个体工作负荷;其次建立包含心理感知负荷、生理反应负荷与脑力工作负荷3个维度的综合评估指标体系,构建管制员个体工作负荷指数模型;然后通过熵权-客观组合法求解个体工作负荷指数最优权重,最终得出管制员个体工作负荷量化模型;最后进一步根据管制员个体工作负荷综合指数进行K-Means聚类分析,结果表明:管制员因个体不同岗后工作负荷存在差异。依据个体工作负荷指数大小,管制员可分为3类,A类管制员数量占总人数50%,岗后个体工作负荷增长最小;B类管制员数量占总人数43.75%,岗后负荷增长居中;C类管制员数量占总人数6.25%,岗后负荷增长最大,与教员对管制员能力的评分结果一致。

深井矿山热害防治及制冷降温技术应用

随着金属矿山开采深度的增加,高地温越加显现,而矿山在热害控制方面经验不足、个体防护及培训缺失、有效的机械制冷技术应用较少等,亟待加强深井金属矿山热害防治安全技术相关研究。本文分析了深井矿山热环境对作业人员、生产效率的影响,总结了热害防治的综合措施,包括通风系统优化、热源控制、个体防护、压缩空气制冷、机械制冷等方面,列举了南非、澳大利亚两座典型深井矿山机械制冷降温技术的典型应用,供其他深井矿山借鉴。

奶牛智慧养殖关键技术研究与应用

奶牛养殖业是我国农业产业的重要组成部分,也是支撑我国乳制品加工企业发展的关键产业。然而,传统的粗放式养殖模式下,需要大量的人力和物力投入,导致奶牛生产效率低下,牛奶质量也无法保证。随着物联网、人工智能等新一代信息技术的快速发展,中国的奶牛养殖业正逐步从过去的粗放型养殖模式向规模化、集约化、智能化的养殖模式发展。本文通过查阅文献,结合生产实际,综述了智能环境控制、个体识别、精准饲喂、生理和行为监测等智慧养殖关键技术的研究进展及其在奶牛生产中的应用,并为本文提到的关键技术绘制了一幅智慧养殖模式图,以期为我国奶牛养殖业提高生产效益和转型升级提供理论和技术支持。

某住宅建筑空气源热泵采暖系统能耗优化分析

针对青岛某户式空气源热泵系统冬季供暖测试中存在的问题,如房间温度超标、无人时房间也开启供暖等,进一步对系统的运行控制进行了优化模拟。通过调整室内温度设定值及考虑房间使用时间等,分析了不同控制方式下的系统能耗情况。结合房间实际使用情况,建筑2层房间仅在周末时使用,对此进行了房间供暖末端的启停设置。在采暖设定温度与实测温度相同时,通过关闭2层不使用的房间供暖末端进行系统控制,单位建筑面积能耗和电耗分别下降21.1%和20.9%。当供暖季所有房间供暖末端开启时,室内温度均按照集中供热室内设计采暖温度18℃设定,单位面积能耗和电耗分别为81.7 kW·h/m^(2)、22.1 kW·h/m^(2),较实际系统下降了23.7%、21.4%;当房间2层供暖末端仅周末开启时,室内温度设定为18℃,单位建筑面积能耗和电耗分别降低为58.4 kW·h/m^(2)、15.5 kW·h/m^(2)。与实测能耗相比,通过运行优化控制,单位建筑面积供热量最大可降低45.4%,耗电量降低44.9%。相关分析结果为空气源热泵户式独立供暖系统的节能运行提供了参考。

漂浮式海上风电机组无模型自适应容错控制策略

漂浮平台运动和海上恶劣条件使得漂浮式海上风电机组(FOWT)建模难度大且故障率较高,为此,提出一种无需对FOWT进行数学建模的无模型自适应主动容错控制策略。该策略主要包括故障智能诊断和故障自适应补偿系统:故障智能诊断系统利用卷积神经网络模型对时序信号进行空间特征挖掘完成故障智能诊断;故障补偿系统采用无模型自适应控制策略实现,将动态补偿过程转化为非线性系统实时控制问题,通过实时求解补偿因子来应对和恢复多种故障,有效降低了控制器开发成本且避免了建模产生的误差。在多种故障场景下进行仿真实验,结果验证了提出控制策略的容错能力,不仅可使叶轮载荷保持平衡,且可降低塔筒载荷。

考虑个体习惯的轮椅机器人人机共享避障方法

为了避免个体操作习惯对智能轮椅机器人(WR)人机共享运动控制的影响,引入动态强化学习策略,基于三重奖励系统建立个体操作习惯与碰撞风险的关联特性,提出能够自适应用户行为及保证安全性的模糊强化学习状态融合式共享控制策略.为了实现机器人的智能操控,采用距离型模糊推理算法建立基于座椅压力的方向意图识别模型和机器人人机共享控制框架.面向用户意图方向与机器人实际方向的偏差度,分别基于高斯函数与偏差率建立当前奖励函数与预测奖励函数,以估计用户操作习惯.基于边界距离建立任务奖励函数,以估计人机安全性.基于模糊强化学习策略,利用三重奖励函数构建用户操作习惯与安全性的关联性,以动态调整共享控制中的用户控制权重,适应个体习惯,提高人机共享的操控精度和安全性.在实验室搭建试验环境,验证了所提算法的有效性.

个体化健康教育在传染病防控工作中的应用效果分析

目的探究在传染病防控工作中的运用个体化健康教育的效果和价值。方法选择2021年6月至2023年6月北京市中青年社会人员500名作为研究对象,采用随机数字表法将选取的研究对象平均分成对照组250名与试验组250名,对比两组研究人员的健康教育指导满意度、传染病防控知识掌握度评分以及传染病发生情况。结果对照组的健康教育指导满意度低于试验组(P<0.05);试验组的传染病防控知识掌握度评分高于对照组(P<0.05);试验组发生流行性感冒、甲肝或乙肝、肺结核、艾滋病等传染性疾病低于对照组(P<0.05)。结论个体化健康教育在传染病防控工作中的效果有目共睹,重视和加强个体化健康教育能有效减少传染病发病情况,改善社会人员对传染病防治的意识和水平,提升传染病防控工作满意度,进一步推进传染病防治工作,有利于健康卫生事业稳定发展。

肺动态顺应性指导个体化呼气末正压通气对老年患者腹腔镜结直肠癌术中肺功能的影响

目的观察肺动态顺应性(Cdyn)指导个体化呼气末正压通气(PEEP)对老年患者腹腔镜结直肠癌术中肺功能的影响。方法选择择期行腹腔镜结直肠癌根治术的老年患者68例,男37例,女31例,年龄65~79岁,BMI<30 kg/m^(2),ASAⅡ或Ⅲ级。采用随机数字表法将患者分为两组:个体化PEEP组(P组)和对照组(C组),每组34例。P组在插管完成即刻、气腹-屈氏体位建立即刻、气腹结束即刻行肺复张及PEEP滴定试验,C组设置固定PEEP 5 cmH_(2)O。记录P组3次滴定时最佳PEEP和实际VT。记录气管插管完成后10 min(T_(1))、气腹-屈氏体位建立后10 min(T_(2))、60 min(T_(3))、手术结束拔管前(T_(4))PaO_(2)、PaCO_(2)、PETCO_(2),计算氧合指数(OI)、死腔/潮气量比值(Vd/VT)、肺泡-动脉血氧分压差(A-aDO_(2))、驱动压和Cdyn。采用ELISA法测定麻醉诱导前(T0)、拔管后10 min(T5)的白细胞介素-8(IL-8)、肿瘤坏死因子-α(TNF-α)、肺Clara细胞分泌蛋白(CC16)及肺泡表面活性物质-D(SP-D)的浓度。记录术后肺部并发症(PPCs)的发生情况。结果P组滴定最佳PEEP的中位数为4 cmH_(2)O。与C组比较,P组T_(4)时PaO_(2)、OI明显升高,T_(1)、T_(3)、T_(4)时Cdyn明显升高,T_(1)—T_(4)时驱动压明显降低,T5时CC16血清浓度明显降低(P<0.05)。两组T_(1)—T_(4)时PaCO_(2)、PETCO_(2)、A-aDO_(2)、Vd/VT差异无统计学意义。两组术后3 d均未发生严重PPCs。结论在老年患者腹腔镜结直肠癌根治术中,采用压力控制通气下肺动态顺应性指导个体化PEEP的肺保护通气策略,可提高患者术中肺动态顺应性,降低驱动压,改善手术结束时氧合,降低术后CC16血清浓度,改善术中肺功能。

Evaluation of individualized treatment of nonproliferative diabetic retinopathy:a multicenter,randomized,parallel-controlled study

OBJECTIVE:To evaluate the differences in the efficacy of stationary treatment and individualized treatment for patients with nonproliferative diabetic retinopathy(NPDR).METHODS:This study was a randomized,controlled,multicenter clinical trial.Participants with NPDR were randomized into the stationary treatment group or the individualized treatment group.The stationary treatment group was given the basic treatment and Qiming granules,and the individualized treatment group was given the basic treatment,Qiming granules,and individualized Chinese herbal medicines over a 12-week period.The individualized therapeutic formula was also changed over time to adjust to the changes in the clinical presentation of the patient.We conducted observations of fundus retinal exudation and hemorrhage,visual acuity,Traditional Chinese Medicine symptom scores and other indicators.RESULTS:A total of 140 participants with NPDR were randomized into the stationary treatment group or the individualized treatment group,and 132 participants completed this study.Following the 12-week treatment,significant improvements in both primary and secondary outcomes were observed in the stationary and individualized treatment groups.No remarkable difference in the primary outcomes between the two groups was observed.However,there was a significant difference in the Traditional Chinese Medicine symptom scores(18±7 vs 15±6;P<0.05).There were no severe adverse effects.CONCLUSION:Compared with stationary treatment,individualized treatment is more effective at relieving the Traditional Chinese Medicine symptoms and improving vision and fundus lesions at 12 weeks post treatment.

风机独立变桨减载模型预测控制研究

针对风力发电机组在额定风速以上运行时承受的不平衡载荷波动问题,提出了一种基于状态空间模型的独立变桨模型预测控制策略。首先基于风机仿真软件FAST对风电机组非线性系统线性化;然后将建立的线性时不变(LTI)模型与非线性风机系统对比验证预测模型的拟合度;最后建立FAST-MATLAB联合仿真的NREL5MW风机模型,在湍流风模式下进行仿真。所提出的控制策略与传统PI控制策略相比,在稳定功率的前提下有效地减少了不平衡载荷,提高了风电机组运行稳定性。

基于尿流动力学和膀胱安全容量的脊髓损伤后神经源性膀胱个体化综合尿控管理效果观察

目的探讨基于尿流动力学和膀胱安全容量的个体化综合尿控管理在脊髓损伤后神经源性膀胱患者中的应用效果。方法选取2021年7月至2023年7月广东省工伤康复医院收治的60例脊髓损伤后神经源性膀胱患者作为研究对象,采用随机数字表法分为观察组和对照组,每组30例。对照组采取基于尿流动力学的尿控管理,观察组在对照组基础上采取以膀胱容量扫描仪为指导的个体化综合尿控管理,两组均持续干预观察4周。比较两组患者神经源性膀胱症状变化、不良事件发生情况、尿路感染情况以及生活质量。结果观察组干预后神经源性膀胱症状评分均低于对照组,差异有统计学意义(P<0.05);观察组不良事件总发生率、尿路感染发生率均低于对照组,差异有统计学意义(P<0.05);观察组干预后健康调查简表(SF-36)各项评分均高于对照组,差异有统计学意义(P<0.05)。结论基于尿流动力学和膀胱安全容量的个体化尿控管理方案可改善脊髓损伤后神经源性膀胱患者神经源性膀胱症状,降低不良事件及尿路感染的发生率,促进患者生活质量提升。