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91.
飞行模拟器上利用电动伺服加载系统替代传统的电液伺服加载后,需要进一步提高加载系统快速性、扩宽系统频带.建立了电动伺服加载模型,基于不变性原理对多余力矩进行补偿仍不能满足要求的情况下,利用模糊控制的快速响应特性,针对该系统设计出PI和模糊控制相结合的分段复合控制器.通过Matlab仿真结果表明使该系统既保证了控制无静差,静态稳定性好,同时动态性能有了较大提高. 相似文献
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We introduce a quantum key distribution protocol using mean multi-kings’ problem. Using this protocol, a sender can share a bit sequence as a secret key with receivers. We consider a relation between information gain by an eavesdropper and disturbance contained in legitimate users’ information. In BB84 protocol, such relation is known as the so-called information disturbance theorem. We focus on a setting that the sender and two receivers try to share bit sequences and the eavesdropper tries to extract information by interacting legitimate users’ systems and an ancilla system. We derive trade-off inequalities between distinguishability of quantum states corresponding to the bit sequence for the eavesdropper and error probability of the bit sequence shared with the legitimate users. Our inequalities show that eavesdropper’s extracting information regarding the secret keys inevitably induces disturbing the states and increasing the error probability. 相似文献
94.
This study was undertaken to establish one of the most reliable sampling methods and to precisely evaluate the bias involved in the collection of airborne pollutant samples. For the purpose of our study, we investigated the performance of three different types of sampling techniques by measuring major aromatic volatile organic compounds (VOC) in outdoor air; the target analytes specifically include benzene, toluene, ethylbenzene, and xylene (commonly called BTEX). As the first step of our approach, we designed and developed a multi-channel sampling system consisting of a six-port mass flow controller (SJU-MFC) system. Because this system allowed the collection of up to six replicate samples, our measurement results were analyzed and screened statistically for the derivation of high-quality BTEX data. The feasibility of this sampling system was further tested through a comparison with concurrent measurement data sets obtained by two additional, but independent, sampling techniques: (1) automatic continuous sampler (ACS) and (2) on-line GC (O-GC) system. Based on the data sets collected concurrently by three different sampling methods, we attempted to evaluate the compatibility of sampling techniques. Although the results obtained by SJU-MFC system were not statistically different from those of the O-GC system, they were moderately distinguishable from those of ACS. Such patterns were seen consistently, when examined by correlation analysis. The overall results of our study thus generally point out that the compatibility of data sets, when the proper caution is taken, improve significantly among different sampling methodologies. 相似文献
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随着光电跟踪设备的大型化,在系统的惯量增大的同时,机械谐振频率一般会降低,此时控制系统的带宽设计将受到限制,而且大型的光电设备更容易受到风阻、地基振动等各种干扰的影响,从而降低系统的控制精度。由于惯性测量元件——加速度计直接感受被测对象的受力情况,通过引入加速度反馈控制回路,在不增大系统带宽的前提下,中低频段的扰动抑制传递函数幅值下降约25 dB。理论、仿真和实验三方面均验证了该控制方式的有效性。 相似文献
97.
自抗扰控制技术在捷联惯导动基座初始对准中的应用研究 总被引:1,自引:1,他引:1
提出并设计了应用自抗扰控制技术(ADRC)的捷联惯性系统动基座初始对准方案。通过数字仿真,将卡尔曼滤波与自抗扰控制的性能进行了详细的比较,证明该方法具有对准时间快,精度高,抗干扰能力强等特点。 相似文献
98.
Poonam Kumari Kumud Malika Tripathi Lokesh Kumar Jangir Ragini Gupta Kamlendra Awasthi 《Materials Today Chemistry》2021
Graphene is an atomic layer thick carbon-based material with unique two-dimensional architecture and extraordinary physiochemical, optical, electrical, and mechanical properties. Graphene and its derivatives show significant promises for the development of nanoporous ultrathin filtration membranes capable of molecular separation properties. Graphene-based nanofiltration membranes featuring distinct laminar structures can offer various novel mass-transport phenomena for purifying water, energy storage and separation, gas separation, and proton conductors. The latest developments in water purification techniques through graphene-based membranes including engineering, design, and fabrication of diverse graphene, graphene-oxide, and graphene-composite membranes are provided here in relation to their application paradigm for purifying water. The critical views on pollutant removal mechanisms for water purification along with optimization measures are specially highlighted. In addition, the challenges, shortcomings, and future prospects are pointed out. The green and large-scale synthesis technology of graphene coupling with advanced membrane fabrication techniques can promote these state-of-the-art nanofiltration membranes for a wide range of applications. 相似文献
99.
电磁轴承系统的刚度阻尼特性分析 总被引:29,自引:0,他引:29
分析了电磁轴承系统的刚度阻尼特性与系统结构参数及其控制器频响特性之间的关系。给出了系统控制电流的相位对系统稳定性和刚度阻尼特性的影响。提出了电磁轴承系统的复阻尼概念,以及部分刚度阻尼特性指标的实际意义和计算方法。 相似文献
100.
变速恒频风力发电机组的模糊控制 总被引:2,自引:0,他引:2
简要介绍了变速恒频风力发电机组的控制原理,对变速恒频风力发电机组在高于额定风速运行时的变速桨距调节设计了模糊控制器,并用MATLAB对该控制器进行了仿真。 相似文献