Event-triggered sampling and fault-tolerant control co-design based on fault diagnosis observer

A co-design scheme of event-triggered sampling mechanism and active fault tolerant control(FTC) is developed. Firstly,a fault diagnosis observer is designed to estimate both the fault and the state simultaneously by using the event-triggered sampled output. Some H∞constraints between the estimation errors and the event-triggered sampling mechanism are established to ensure the estimation accuracy. Then, based on the constraints and the obtained fault information, an event-triggered detector and a static fault tolerant controller are co-designed to guarantee the stability of the faulty system and to reduce the sensor communication cost.Furthermore, the problem of the event detector and dynamic FTC co-design is also investigated. Simulation results of an unstable batch reactor are finally provided to illustrate the effectiveness of the proposed method.

Earthquake triggering and delaying caused by fault interaction on Xianshuihe fault belt, southwestern China

The coseismic Coulomb stress change caused by fault interaction and its influences on the triggering and delaying of earthquake are briefly discussed. The Xianshuihe fault belt consists of Luhuo, Daofu, Kangding, Qianning and Ganzi fault. Luohuo (MS=7.6, 1973)-Kangding (MS=6.2, 1975)-Daofu (MS=6.9, 1981)-Ganzi (MS=6.0, 1982) earthquake is a seismic sequence continuous on the time axis with magnitude greater than 6.0. They occurred on the Luhuo, Kangding, Daofu and Ganzi fault, respectively. The coseismic Coulomb stress changes caused by each earthquake on its surrounding major faults and microcracks are calculated, and their effects on the triggering and delaying of the next earthquake and aftershocks are analyzed. It is shown that each earthquake of the sequence occurred on the fault segment with coseismic Coulomb stress increases caused by its predecessors, and most after-shocks are distributed along the microcracks with relatively larger coseismic Coulomb stress increases resulted from the main shock. With the fault interaction considered, the seismic potential of each segment along Xianshuihe fault belt is reassessed, and contrasted with those predicted results ignoring coseismic Coulomb stress change, the significance of fault interaction and its effect on triggering and delaying of earthquake are emphasized. It is con-cluded that fault interaction plays a very important role on seismic potential of Xianshuihe fault belt, and the maximal change of future earthquake probability on fault segment is up to 30.5%.

Stress triggering of the Lushan M7. 0 earthquake by the Wenchuan Ms8. 0 earthquake

The Wenchuan Ms8.0 earthquake and the Lushan M7.0 earthquake occurred in the north and south segments of the Longmenshan nappe tectonic belt, respectively. Based on the focal mechanism and finite fault model of the Wenchuan Ms8.0 earthquake, we calculated the coulomb failure stress change. The inverted coulomb stress changes based on the Nishimura and Chenji models both show that the Lushan MT. 0 earth- quake occurred in the increased area of coulomb failure stress induced by the Wenchuan Ms8. 0 earthquake. The coulomb failure stress increased by approximately 0. 135 - 0. 152 bar in the source of the Lushan M7.0 earthquake, which is far more than the stress triggering threshold. Therefore, the Lushan M7.0 earthquake was most likely triggered by the coulomb failure stress change.

The stress field variation caused by faulting and the prediction for seismic risk

The stress field caused by faulting has an effect on the stability of the neighboring faults, and the study on the fault interaction has a close relation with the prediction of seismic risk. Stress field caused by the rectangle fault in the semi-infinite elastic medium is calculated on the basis of the elastic dislocation theory. The result shows that most of the successive large earthquakes, in the southwestern part of China and North China, occurred in the increasing area of shear stress S(xy) and the decreasing area of normal stress S(yy) The increasing of earthquake occurrence probability has a function relation with the increasing of stress. Earthquake triggering is resulted from the increasing of shear stress and the decreasing of normal stress. An activation coefficient A, of the earthquake is defined to express the change of seismic activity. The concrete risk region can be obtained through space scanning of At value. Finally, the fault interaction in a large scope is discussed in this paper.

An evidence for earthquake ocurence time related with geologic structure──Relations between local mean lunar times of earthquake ocurence and their fault trends

The relation between the local mean lunar time τ of earthquake occurrence and their fault trends is studied in this paper. The local mean lunar times τ of 53 earthquakes in 24 groups are calculated. Because the tidal generation force arisen by the moon is a cyclic function of about 12 hours 25 minutes in the main, the two tidal generation forces anywhere in the earth arising by the moon are equal in general when the moon lies to the two sites of 180° interval of local mean lunar time. Based on this phenomenon the values Δ τ of τ 1- τ 2 or τ 1-τ 2±180° of two earthquakes occurring repetitiously in the same place are also calculated. The calculated results show that if the fault trends of the two earthquakes in the same place is near, the Δ τ is usually smaller and if the fault trends of the two ones is not near, the Δ τ is usually larger and the distribution of the local mean lunar time τ of earthquakes in different places is dispersive even if fault trends of these earthquakes are near, and the τ does not concentrate on the lower and upper transit of the moon. The above phenomena clear up that the triggering earthquake of earth solid tide arisen by the moon is relative with the fault trends of earthquakes and we ought to think over the difference of environmental conditions of earthquake preparation of each seismogenic zone and can not make statistics to earthquakes in different places when we study the relation between the solid earth tide arisen by the moon and earthquakes.

青藏高原东缘及邻区强震构造研究新进展:专辑序言

青藏高原东缘作为调节高原物质向东挤出的构造转换带,发育了高密度活动断裂和具有高频强震活动,而且地质地貌复杂,人口相对密集,因而成为我国地震灾害问题最突出的地区之一。近年来,伴随地震灾害风险普查和活断层探测等工作的深入,对青藏高原东缘及邻区强震构造及相关地震灾害的调查研究程度得到不断提升。为了及时交流相关的研究成果,支撑区域防震减灾和地质安全评价等工作,《地震科学进展》编辑部组织了“青藏高原东缘及邻区强震构造”成果专辑2期。此期专辑共征集优选了强震构造、地震与灾害和构造地貌相关领域的代表性学术论文11篇,希望这些成果可进一步提升对区域强震构造特征、地震活动风险及触发地质灾害规律等的认识,从而为防范强震灾害风险提供科学依据或参考。

自适应事件触发机制下分布时滞Markov跳变网络化系统H_(∞)故障检测

传统事件触发机制中阈值的选择会对信号传输效率产生很大影响。针对此问题,研究了自适应事件触发机制下具有分布时滞的Markov网络化系统的故障检测问题。设计了一种模态相关的自适应事件触发机制,通过动态调整阈值,提高了网络资源利用率。考虑网络时延和数据丢包现象,同步设计触发器和故障检测滤波器。构造模态相关的Lyapunov泛数,根据积分不等式技术推导出使系统随机稳定且具有H_(∞)性能的充分条件。利用解耦方法和LMI技术求解出了故障检测滤波器参数。最后通过数值仿真验证了方案在节省网络资源上的优势。

基于动态事件触发通信协议的多智能体系统自适应可靠控制

针对多智能体系统中邻居节点间通信资源受限的情况,研究基于动态事件触发通信协议的多智能体系统自适应可靠一致性控制问题.首先,设计一种基于自适应参数估计技术的容错控制策略,来应对未知执行器故障.其次,提出一种新型动态事件触发函数,通过增加具有自适应调节能力的动态变量来延长事件触发间隔.在此基础上,证明在智能体之间非连续通信的情况下,所提方法仅依靠智能体与邻居在触发时刻的交互信息就可以确保一致性误差的收敛.此外,从理论上说明智能体间的事件触发通信不存在芝诺现象.最后,针对无人船编队系统开展仿真,结果能够说明所提自适应事件触发可靠控制方法的有效性.

基于事件触发采样的无尾翼飞机自适应容错姿态控制

针对具有通信带宽受限的无尾翼飞机姿态跟踪控制问题,考虑模型不确定、外部扰动及执行器故障的影响,提出一种基于事件触发采样与自适应的容错姿态控制方法。首先,在无尾翼飞机六自由度动力学与运动学模型基础上建立了面向控制的姿态控制模型。通过引入事件触发机制成功降低了控制器与执行器通道之间通信频率,缓解了总线的通信压力同时避免了Zeno现象的发生。然后,通过自适应的有界估计成功补偿了执行器故障及事件触发引起的采样误差的影响。最后,基于Lyapunov稳定性分析证明了所提出的控制方法能够保证系统所有信号一致最终有界。数值仿真结果表明,所提出的控制方法能够有效降低控制器的更新频率,同时实现无尾翼飞机姿态对于控制指令的跟踪。

新型电磁感应式无源触发器分析与设计

针对混合型限流熔断器中电子触发器存在的有源触发和不能全范围分断问题,该文提出了一种能够实现无源供电且具备全范围分断能力的新型电磁感应式无源触发器方案。首先介绍了新型触发器的工作原理,开展了自感应供电、幅值整定两个内容的分析设计;然后利用有限元仿真软件将电磁场和电路进行耦合建模,基于该模型分析了铁芯线圈磁感应强度随位置的变化特性;提出了采用单霍尔芯片进行短路电流幅值判断的方法,减小了芯片的功耗,从而解决了新型触发器在低上升率工况下感应供电不足的问题;同时为了提高触发器的可靠性,设计了延时控制电路;最后根据设计参数制造样机,在短路判断幅值10 kA的限流条件下分别对混合型限流熔断器进行了8 A/μs最小短路电流上升率和33 A/μs最大短路电流上升率的检测试验,试验结果验证了分析设计方法的可行性和有效性。

基于改进事件触发与1-D CNN的MMC冗余子模块开路故障实时诊断策略

在模块化多电平换流器(MMC)中存在大量的子模块(SM),其可靠性直接影响整个系统的安全稳定运行。本文引入了具有容错能力的新型冗余SM,并在此基础上提出了一种基于改进事件触发与一维卷积神经网络(1-D CNN)的MMC冗余SM开路故障实时诊断策略。首先,选定MMC中特定SM构成的集成单元的电容电压作为事件触发对象,大大减少了传统诊断策略中需要观测的电容数量;其次,从有效地减少计算负担角度出发,改进事件触发流程,并结合1-D CNN算法有条件地对集成单元电容电压和桥臂电流波动情况分别进行检测,构建出MMC故障实时诊断系统;最后,综合考虑故障集成单元与故障桥臂位置定位出开路SM,进而完成新型冗余SM条件下MMC的容错运行。利用Matlab/Simulink搭建的19电平MMC模型,验证了所提实时诊断策略的有效性。

混合型限流熔断器触发装置用电流互感器铁芯结构设计

针对短路电流保护装置的电流测控单元因电子元器件失效或电源掉电而导致保护装置拒动的问题,提出了一种无源电磁式电流互感器,分析了触发装置的工作原理,根据铁芯材料的磁化特性曲线,确定了互感器有效工作区间内铁芯的最大磁感应强度。针对铁芯在大电流条件下磁通容易饱和的问题,通过仿真分析了气隙分布对互感器内磁感应强度的影响。设计出在短路电流峰值为15 kA时仍可有效工作的电磁式电流互感器铁芯结构,三维瞬态电磁场仿真显示短路电流上升率为20 A/μs、二次绕组匝数为30匝时,铁芯二次绕组侧输出电压不小于14 V。最后设计制作了采用无源电磁式电流互感器作为触发装置的混合型限流熔断器工程样机,并进行了短路电流检测实验,实验结果与仿真基本一致,证明了铁芯设计的准确性和有效性。

基于事件触发的水面无人艇无模型容错饱和控制

针对外界未知扰动、无人艇模型动态参数无法获取、推进器饱和及故障水面无人艇轨迹跟踪控制问题,本文提出一种基于事件触发的水面无人艇无模型饱和容错控制方法。利用无模型参数滑模控制结构,使参数误差收敛至残差集。该方法对参数变化具有良好的鲁棒性能。控制器中引入饱和函数及容错方法来补偿由于执行机构故障和饱和所产生的推力损失。为节约有限的通信资源和系统能量,在执行机构和控制器之间部署事件触发机制,采用事件触发通讯机制产生分段控制信号,降低执行机构的更新频率。仿真结果表明所提出基于事件触发的饱和容错方法能够使跟踪误差和速度误差收敛至可容许范围内,证明所提算法的优越性和可靠性。

以2022年马尔康震群为例研究震群发震机制

地震是人类所面临的危害最严重的自然灾害之一,了解地震的孕震、发震机理对防震减灾、国家地震安全等具有重要的科学和社会价值.相较于前震-主震-余震型、主震-余震型地震,震群型地震更易造成较大的灾害,因此对震群孕育发生机理的研究刻不容缓.2022年6月10日四川省阿坝州马尔康市发生震群事件,其中包括MS5.8、MS6.0、MS5.2等三次较大震级的地震,此次地震序列的精定位结果、可靠的震源参数为开展震群孕震机制的研究提供了良好的数据基础.本文基于数值模拟的方法,利用断层的运动学参数建立黏弹模型,根据弹性位错、孔隙流体扩散等理论,从发震断层的能量积累、释放两个角度探讨马尔康震群可能的发震机理.对发震断层系统应力加载的模拟结果表明,震区的应力加载较均匀的分配到两条近平行发震断层上,使其在相同的时期内积累了相近的震间构造应力,进而发生相似震级的震群事件.考虑震群序列之间可能存在的应力触发作用,同震库仑应力计算的结果显示马尔康震群序列中各主要地震未受到同震静态应力触发作用.而对发震断层等效摩擦系数的判断及其附近流体扩散的研究认为马尔康震群发震断层震前受流体活动的影响,等效摩擦系数下降从而导致断层破裂,震后流体调整导致的孔隙压力变化进一步促进后续地震的发生.

一种宽输入范围高侧保护控制器电路设计

为满足复杂应用环境下对负载提出的严苛要求,设计一种具有宽输入范围的高侧保护控制器电路,可在正常开/关转换和故障条件下实现对高侧NMOSFET的智能控制。电路采用0.18μm 120 V BCD工艺设计,输入电压工作范围为5.5 V至65 V。在电路芯片中加入保护电路,对上电复位、过压、欠压等进行保护;以振荡器、电荷泵、故障比较器等构成控制电路;为防止芯片误触发关断外部NMOSFET,设计加入故障触发延迟时间电路。仿真结果表明,该电路芯片能够在标准输入电压范围内正常工作,栅源电压大于10.5 V,达到预期设计要求。

一起励磁涌流闭锁导致的配电自动化开关异常动作案例分析

立足于当前云南电网配电自动化实用化背景,结合系统内一起配电自动化开关异常动作案例,针对配电自动化开关励磁涌流闭锁功能错误触发开展分析并给出优化建议。首先,介绍了线路参数及保护配置情况,奠定后续分析基础。之后,基于SOE信息复现开关动作过程,明确开关异常动作情况。最后,结合故障录波信息阐述配电自动化开关异动原因,并给出优化建议。

高压电容柜的改造

针对高压电容柜因运行时间长而频出故障的问题,对其进行了升级改造。对改造后电容柜采用的强触发技术、阀组故障检测技术和阀组过零检测技术进行了分析。

基于改进PR控制器的电网单相接地装置故障消弧方法

为快速触发消弧控制动作,迅速消除接地故障,减少故障持续时间,研究改进PR控制器的电网单相接地装置故障消弧方法。此方法主要利用消弧的模式,在单相接地消弧装置中,设计PI+重复控制器为内环控制装置,改进后的PR控制器为外环控制装置;在电流内环控制中,PI+重复控制器确保电流内环能够快速、准确地跟踪参考电流,实现对故障电流的精确注入补偿;在外环控制中,改进后PR控制器在电流内环注入补偿电流的基础上,进一步控制中性点电压,使得配电网故障所在相的电压值为零,实现电网单相接地的可靠消弧控制。实验结果显示,此方法具备快速且精确的消弧控制能力。