Optimised active disturbance rejection motion control with resonant extended state observer

Tracking sinusoidal references with high precision and rejection of sinusoidal disturbances is a challenging task in the motion control practice. In order to deal with this control problem, a new resonant extended state observer is proposed and introduced in the active disturbance rejection control concept. The frequency analysis shows that an appropriate selection of resonant frequency provides complete rejection of sinusoidal disturbance and ideal reference tracking in the steady state. Further, it is shown that the proposed structure achieves better performances than generalised extended state observer based system in the wide frequency range. Moreover, in order to improve the system performances in transient period, the optimal parameter tuning method is developed. The results demonstrate that the optimally tuned system achieves better performances than the conventionally tuned one by about 25%, with the same robustness and noise sensitivity. The experimental validation of the new controller is carried out on the laboratory model of the didactic three-axis radar platform in fast sinusoidal reference tracking mode.     

基于PSCAD的变速恒频双馈风电系统建模与仿真

为研究变速恒频双馈风电系统的各种高性能控制策略提供有效的动态仿真与分析平台,并克服Matlab仿真环境下所建的模型在动态性能方面存在的不足,采用PSCAD仿真软件建立了变速恒频双馈风电系统的动态仿真模型.基于PSCAD的变速恒频双馈风电系统模型由风机、双馈发电机、功率变换器、控制模块构成, 在建立的模型基础上, 针对电网电压正常情况以及电网电压发生对称、不对称故障时系统的运行特性进行了仿真研究,仿真结果证明了系统模型的正确性.     

一种高速高精度时钟的设计与分析

介绍了一种高性能时钟板的设计思想和电路分析.该时钟板基于频率合成器来产生高精度、高稳定度、低抖动的时钟,用于高速高精度背板测试平台.文中给出了实际时钟的性能分析指标,针对影响时钟性能的相关因素,提出高速时钟电路设计的解决方案,并深入探讨了时钟设计中的相关问题.测试结果表明所得时钟信号性能较好.     

CHV190系列变频器在煤矿皮带输送机上的应用

皮带输送机是保证现代煤矿高产、高效的关键设备。INVT—CHV190系列变频器在煤矿皮带机上的成功应用,体现了其优良的矢量控制和主从同步控制的性能,这对于改善皮带输送机的驱动和调速性能,节约能源以及增加煤矿企业的经济效益都具有非常重要的作用。     

Modal analysis and damage detection by Fiber Bragg grating sensors

Damage detection and localization are critical issues for structural health monitoring. To this aim, many techniques have been proposed relating, the presence of damage to variations of its dynamic features between the undamaged and damaged states. Since a greater information content is localized at higher frequencies, sensing systems with adequate bandwidth and resolution are required. Here, Fiber Bragg grating sensors with an adequate interrogation system are exploited to reveal the presence of damage on a structure. As preliminary step, modal analysis tests in a wide frequency range are performed in order to verify the performances of these optic devices to retrieve high frequency structural dynamic features. As reference sensors, laser Doppler vibrometers and accelerometers, representative of the state of the art for this application field were exploited. Experimental results confirm the excellent performances of Fiber Bragg gratings, not only able to detect damage but also to discriminate between different damage levels.     

Using clustering and dynamic mutual information for topic feature selection

A good feature selection method should take into account both category information and high‐frequency information to select useful features that can effectively display the information of a target. Because basic mutual information (BMI) prefers low‐frequency features and ignores high‐frequency features, clustering mutual information is proposed, which is based on clustering and makes effective high‐frequency features become unique, better integrating category information and useful high‐frequency information. Time is an important factor in topic detection and tracking (TDT). In order to improve the performance of TDT, time difference is integrated into clustering mutual information to dynamically adjust the mutual information, and then another algorithm called the dynamic clustering mutual information (DCMI) is given. In order to obtain the optimal subsets to display topics information, an objective function is proposed, which is based on the idea that a good feature subset should have the smallest distance within‐class and the largest distance across‐class. Experiments on TDT4 corpora using this objective function are performed; then, comparing the performances of BMI, DCMI, and the only existed topic feature selection algorithm Incremental Term Frequency‐Inverted Document Frequency (ITF‐IDF), these performance information will be displayed by four figures. Computation time of DCMI is previously lower than BMI and ITF‐IDF. The optimal normalized‐detection performance (C_det)_norm of DCMI is decreased by 0.3044 and 0.0970 compared with those of BMI and ITF‐IDF, respectively.     

基于ARM的高精度智能流量变送器的设计

介绍了基于 ARM 嵌入式系统的频率流量信号变送器设计,具有智能化、精度高、速度快和功能可扩展的特点。整个系统体积小,结构精简,并有很高的执行效率,很适合在实时性和精度要求高的场合应用。     

X-Q自适应PID及其在多目标满意控制系统中的应用

给出一种新型X-Q自适应控制器,它具有新颖的自适应频率特性对于控制信号而言,它是一个没有任何相位落后的PID,且高频段为一放大倍数为k的放大器,低频段为一积分时间常数为     

A phase‑locked loop using ESO‑based loop flter for grid‑connected converter: performance analysis

An extended state observer (ESO)-based loop flter is designed for the phase-locked loop (PLL) involved in a disturbed gridconnected converter (GcC). This ESO-based design enhances the performances and robustness of the PLL, and, therefore, improves control performances of the disturbed GcCs. Besides, the ESO-based LF can be applied to PLLs with extra flters for abnormal grid conditions. The unbalanced grid is particularly taken into account for the performance analysis. A tuning approach based on the well-designed PI controller is discussed, which results in a fair comparison with conventional PItype PLLs. The frequency domain properties are quantitatively analysed with respect to the control stability and the noises rejection. The frequency domain analysis and simulation results suggest that the performances of the generated ESO-based controllers are comparable to those of the PI control at low frequency, while have better ability to attenuate high-frequency measurement noises. The phase margin decreases slightly, but remains acceptable. Finally, experimental tests are conducted with a hybrid power hardware-in-the-loop benchmark, in which balanced/unbalanced cases are both explored. The obtained results prove the efectiveness of ESO-based PLLs when applied to the disturbed GcC.     

有源电光调制式高功率瞬态电场传感器的研制

瞬态电场防护及应用技术的研究离不开瞬态电场测试系统;文中基于有源电光调制法,研制了一种高功率瞬态电场传感器;通过建立该传感器的等效电路模型,并借助CST仿真建模,分别从频域和时域角度分析了传感器的接收特性,并得到了一致的结果;最后利用脉冲噪声模拟器和吉赫兹横电磁波小室对研制的传感器性能进行了测试;结果表明:接收天线为单极子天线,天线负载采用高阻时响应电压与被测电场场强成正比;研制的传感器带宽为10kHz～314MHz,可用于纳秒级高功率瞬态电场的时域测试。     

一种改进引导式宽带数字接收机设计

提出一种引导式宽带数字接收机的改进设计,它采用信道化接收多同时到达窄信号,并采用非相干能量累积和加权数字瞬时频率测量联合检测(估计)信道化输出信号,然后,通过跨信道信号判决生成宽带信号的带宽和中频等信息,以此引导对宽带信号的变带宽数字下变频接收。理论分析与实验表明:上述措施明显提高了信号检测灵敏度和引导信息的可靠性,同时,使接收机具有较高的信号截获概率。     

基于Hilbert曲线和位置自调节法的图像版权保护算法

以小波的相关理论为基础,先把水印图像预置乱处理,对宿主图像直接进行小波包分解,之后将水印的低频部分和中高频部分分别采用Hilbert曲线扫描和位置自调节法嵌入到宿主图像中,嵌入强度可根据图像的内容自适应调节。通过实验观察,新算法在抗压缩和抗剪切性能有所提升,同时隐蔽性和抗噪能力也得到了较大改观,结果充分说明该算法是一种性能较为优良的图像版权保护算法。     

两变频调速电机系统的神经网络逆同步控制

针对以恒压频比工作方式的两台变频器+感应电机系统的特点,导出了两变频调速电机系统的统一数学模型,并证明该系统可逆.进一步采用静态神经网络加积分器构成的动态神经网络来构造该逆系统,并将神经网络逆系统与两变频调速电机系统相串联复合成由速度和张力子系统组成的伪线性系统,实现速度和张力的解耦.然后分别对速度和张力子系统设计线性闭环控制器从而实现对两变频调速电机系统的高性能控制.实验结果表明系统具有较好的动、静态性能和较强的抗负载扰动的能力,提出的神经网络逆同步控制方法为解决交流多电机系统解耦控制的难题提供了新思路.     

High quality factor copper inductors integrated in deep dry-etched quartz substrates

This paper reports on an inductor fabrication method capable to deliver high quality factor (Q) and high self-resonance frequency (SRF) devices using quartz insulating substrates and thick high-conductivity copper lines. Inductors are key devices in RF circuits that, when fabricated on traditional semiconductor substrates, suffer from poor RF performances due to thin metallization and substrate related losses. Many previous works revealed that RF performances are strongly dependent on the limited metallization thickness and on the conductivity of the substrate. In this paper we demonstrate a new fabrication process to improve the Q factor of spiral inductors by patterning thick high conductive metal layers directly in a dielectric substrate. Moreover, we develop and validate accurate equivalent circuit modeling and parameter extraction for the characterization of the fabricated devices.     

基于MR的船用减振抗冲隔离器试验研究

提出了一种新型的船用减振抗冲隔离器系统。此隔离器由钢丝绳弹簧和磁流变(MR)阻尼器并联组成,应用MR阻尼器的高阻尼和阻尼可控性使该隔离器的力学性质可控,进而实现协调解决船舶设备的低频减振和高频抗冲击问题。在对隔离器抗冲减振性能的研究中,分别采用了数值试验和模型试验方法,并进行了对比分析。研究结果表明:隔离器系统对振动和冲击响应有较好的控制作用,尤其体现在抑制系统共振和控制系统的低频振动上。     

基于小波阈值消噪的陀螺信号的抗差估计

为了削弱陀螺漂移对光纤陀螺寻北精度的影响,在小波阈值消噪的基础上,采用抗差估计处理陀螺信号.首先进行频谱分析,确定相应的多分辨分析尺度及对不同尺度下的高频系数采取的措施.对噪声占主要成份的尺度层其高频系数置零,对噪声与有用信号都存在的尺度层进行小波阈值消噪处理.然后将抗差估计应用于陀螺数据的处理,利用一次抗差估计求得的观测残差再用中位数法求得均方差因子,采用高崩溃污染率的初值辅以IGGⅢ方案迭代解算的混合算法.计算结果表明这种方法能够有效地抵制异常扰动的影响,提高了寻北精(密)度.     

Oxide‐TFT technologies for next‐generation AMOLED displays

Abstract— High‐mobility high‐reliability low‐RC‐delay oxide TFTs have been developed. Their performances are good enough for AMOLED displays even for the large‐sized super‐high‐resolution, or high‐frame‐rate displays. In this paper, the status of oxide‐TFT development and the issues for the mass‐production of next‐generation AMOLED displays will be discussed, and three types of AMOLED displays using different oxide materials and TFT structures will be demonstrated.     

Classification of motor imagery electroencephalography signals using spiking neurons with different input encoding strategies

Motor imagery-based brain–computer interfaces decode users’ intentions from the electroencephalogram; however, poor spatial resolution makes automatic recognition of these intentions a challenging task. New classification approaches with low computational costs and high classification performances need to be developed in order to increase the number of users benefitted by these systems. On the other hand, spiking neuron models, which are mathematical abstractions of real neurons, have shown good performances in several classification tasks, making these models suitable for motor imagery classification. In this work, two different encoding strategies for spiking neuron models, applied to the classification of motor imagery time–frequency features of stroke patients and healthy subjects, were evaluated. Classification performances and computational costs of spiking neuron models were compared against those of linear discriminant analysis, support vector machines and artificial neural networks. Results showed that a time-varying encoding strategy is more suitable for motor imagery classification, and its implementation computational cost is low. Therefore, a spiking neuron model with a time-varying encoding strategy could increase the number of potential users of brain–computer interfaces.

     

基于隶属度函数的决策层融合算法

虹膜识别对所采集的样本图像较为苛刻的要求所造成的高采集失败率和注册失败率是阻碍它推向大规模应用的重要原因,也是目前虹膜识别研究的难点问题之一。在适当降低虹膜图像采集质量要求的条件下,能够大幅降低采集失败率和注册失败率,但同时也降低了识别的性能。采用数据融合的方法,在识别的决策层引入对应的脸像特征模板的相似度判据,根据所提出的基于隶属度函数的决策层融合算法实现融合决策。实验结果表明,这种多生物特征融合决策的方法既可以使得虹膜的采集失败率和注册失败率保持在实际应用可以接受的程度,又能够使得整体的识别性能达到目前虹膜识别技术的水平。