电压补偿型高温超导限流-储能系统仿真及实验研究

电压补偿型高温超导限流-储能系统是一种新型的超导电力装置，它具有暂态时限制短路电流、稳态时储存能量同时补偿电压不平衡和改善系统谐波的功能．本文介绍了电压补偿型高温超导限流—储能系统的原理和拓扑结构，利用MatLab仿真工具对其改善电力系统电能质量的功能进行了仿真，并通过DSP芯片TMS240实现了该功能的实验研究，验证了仿真结果的可行性．     

使用多线程技术提高VR应用的性能

VR系统十分复杂，计算机的处理任务十分繁重，处理器的处理速度跟不上应用提出的新要求。以常用的VR工具软件WorldToolKits为例，在建立好场景图并且进入仿真循环后，除了完成一般的操作系统的任务之外，计算机在每一个仿真步中的任务有：读入VR设备传感器的数据；调用仿真任务；根据输入更新场景中的仿真对象；调用仿真事件、虚拟物体执行仿真任务；虚拟物体沿路径前进一步；进行物体的渲染。如果使用虚拟装配系统进行复杂机械产品的虚拟装配，系统一方面要进行复杂零部件的渲染；另一方面在装配过程中还需要进行碰撞检测和干涉检查；另外，通常在VR系统中包含有数据手套、头盔和跟踪定位装置等硬件设备，而系统在每一帧都需要采集这些设备传感器的数据，这些操作都需要消耗大量的处理器资源。     

可见光光学目标模拟器的研制

介绍一种能够建立逼真的可见光目标———背景环境的可见光光学目标模拟器。整个装置由计算机图像生成系统、胶片图像源系统、光学耦合系统、主控计算机、控制系统及二轴转台等部分组成。该装置实现了图像源系统与导引头光学系统的完善耦合 ,成像质量高 ,且结构紧凑 ,重量轻 ,是一种理想的可见光目标———背景图像仿真设备     

针对系统暂态稳定性的超导磁储能装置容量研究

电力系统中所需超导磁储能装置（SMES）的容量是其应用中一个重要研究内容．文章运用暂态能量函数法（TEF）分析含超导磁储能装置的单机无穷大系统的故障过程，对超导磁储能装置向系统注入有功，提高系统阻尼和改善系统暂态稳定性进行仿真分析．仿真结果验证了超导磁储能装置对系统的作用效果，在此基础上利用暂态能量初步分析了超导磁储能装置向系统注入能量和系统的暂态能量函数的关系，进一步探讨系统暂态稳定性对超导磁储能装置容量的要求．     

实时数据驱动的交会对接仿真平台设计与实现

航天器地面综合测试时,为了在测试数据显示基础上,动态展示航天器交会对接过程,验证交会对接飞行方案的正确性,为航天员手控交会对接训练提供支持,设计航天器交会对接仿真系统,给出交会对接仿真平台设计架构。通过对航天器建模、虚拟场景装配、模型驱动方法、阳照区/阴影区绘制、姿态和星下点轨迹计算方法研究,开发实现航天器交会对接仿真平台。平台由实时测试数据驱动,在航天器地面静态测试下,可以实时显示航天器三维飞行状态及星下点轨迹。目前,仿真平台已经应用于航天器地面综合测试过程中,同时,平台可以扩展支持航天器在轨飞行动态展示,丰富了航天器测试和监视手段,具有较高工程应用价值。     

电压补偿型高温超导限流-储能系统仿真及实验研究

电压补偿型高温超导限流-储能系统是一种新型的超导电力装置,它具有暂态时限制短路电流、稳态时储存能量同时补偿电压不平衡和改善系统谐波的功能.本文介绍了电压补偿型高温超导限流-储能系统的原理和拓扑结构,利用MatLab仿真工具对其改善电力系统电能质量的功能进行了仿真,并通过DSP芯片TMS240实现了该功能的实验研究,验证了仿真结果的可行性.     

一种红外搜索系统的分布式多传感器航迹融合算法

红外搜索系统作为被动式搜索系统，一般只能获得目标所处位置的方位角和俯仰角信息，缺乏距离信息，在无测距装置的条件下，只能依靠角度信息进行数据融合。依据角度值的三角函数关系，提出了一种新的分布式多传感器航迹加权融合算法，算法经仿真验证有效，降低了融合航迹的误差。在对量测数据进行误差修正的基础上，算法效果更加显著。     

基于嵌入式系统的农产品智能出库设备的设计

农产品出库是连接仓储与物流的重要环节,目前农产品出库操作粗放、信息无法跟踪、智能程度不高。结合嵌入式ARM系统与Windows系统的优势,对出入库中小包装条码扫描,大包装与小包装之间的信息核查,将大小包装信息不符的剔除出去,大小包装吻合的通过升降皮带的传输运送到转载车上等的研究,设计具备传输装置、出库产品条码扫描装置、剔除装置、显示控制装置的农产品出库设备,提出核心部件控制流程,实现了订单核查、产品剔除、传输控制等上位机软件功能。测试表明该设备精确实现移动装卸货与货车的无缝对接,能很好检查出错订单,提高出库过程的智能化程度。     

基于OpenCV的水下机器人单目定位技术研究与仿真

针对水下机器人自主回收对接时的定位问题,提出了一种基于OpenCV的单目定位技术研究与仿真方法。首先确定回收装置回收侧的光源标记点信息;借助OpenCV算法库,通过对水下机器人自带摄像机的标定,得出反应摄像机固有信息的内参数;通过摄像机对回收装置光源标记点的识别,得出光源标记点在图像上的像素坐标,结合其世界坐标,得出反映回收装置在摄像机坐标系下位置和姿态关系的平移和旋转向量,进而确定水下机器人在回收装置坐标系下的位置和姿态信息。最后运用CATIA软件对摄像机拍摄模型进行建模和仿真,结果表明,本文所提方法不仅能快速地获得水下机器人的位置和姿态信息,而且定位精度高,满足水下机器人在自主回收对接时的设计要求。     

多脉冲叠加高压系统及测量技术

 介绍了多脉冲叠加高压系统的核心部件：一个双次级绕组高压脉冲变压器，它能形成多路脉冲并叠加合成为梯形脉冲波，从而改善了波形的上升下降沿。该系统输出电压由3个衰减正弦波叠加而成，脉冲幅度大于100kV，脉冲宽度2～5μs。同时，在双次级绕组高压脉冲变压器上设计一个小型结构型电容分压装置，解决了变压器与其它装置对接装配后高压的监测和测量。     

THE WAVE NUMBER ANALYSIS AND OPTIMAL CONTROL OF ACOUSTIC RADIATION OF A FLEXIBLE COUPLER LINK OF A LINKAGE MECHANISM

A method for suppressing the acoustic radiation of flexible coupler link with piezoelectric elements is developed. According to the result of wave number analysis of the coupler link, it is found that not all of the components contribute to the acoustic radiation. Based on this fact, a new equation of motion the configuration of which vector directly reflect the performance of structural acoustic radiation is obtained by taking a set of transformation on the equation describing the vibration of the structure. Thus, the problem of acoustic control is successfully transformed to the problem of vibration control. Subsequently, a quadratic optimal sound radiation control method is developed, and the validity of the method is shown by some simulation results.     

光纤水听器解调技术研究进展

光纤水听器是水声研究领域的关键技术,在实际应用中具有显著优势,广泛应用于AUV导航定位、资源勘探、海水警戒等场景.光纤水听器将声信号转化为光信号传播,在接收信号时就需要对光信号进行解调提取出声压信号.总结了几种常用的信号解调算法及关键技术,包括PGC解调法、3×3耦合器解调法和外差解调法;介绍了各种解调算法的基本原理和...     

Acoustic method for calibration of audiometric bone vibrators

The standard method for the calibration of audiometric bone vibrators requires the use of an artificial mastoid, a device that converts vibratory energy to an electrical analog. The mechanical input impedance of the device is designed to represent the average mechanical impedance of the human head. For calibration purposes, it is not necessary that the coupling device represent the impedance of the head. It is only necessary that it provides a repeatable measurement of the output of the vibrator that can be related to the normal threshold of hearing at each test frequency. In addition to the mechanical output that serves as the stimulus for the hearing test, bone vibrators produce an acoustic signal that is proportional to the mechanical force delivered to the head. By determining the transfer function relating the acoustic sound pressure to the mechanical force, the acoustic signal can serve as a proxy for the vibratory stimulus. This article describes the design and validation of an acoustic coupler for the calibration of audiometric bone vibrators.     

Q-switching an all-fiber laser using acousto-optic null coupler

A new method for Q-switching an all-fiber laser is presented. It is based on induced acoustic long period grating operating on a null coupler, which acts as acoustically controlled tunable output coupler. Q-switching is achieved by switching on and off the acoustic wave in a burst mode, thereby generating laser pulses that are ~400 times shorter than the acoustically controlled coupler’s rise time. Output pulse energy of 22 μJ and temporal width of ~100 ns were measured at a wavelength of 1.54 μm.     

未知耦合腔体积活塞发声器声压级的检测

本文简要介绍了活塞发声器的工作原理及其声压级的测量原理，着重分析了未知耦合腔体积活塞发声器的有效体积与声压级的测量方法。     

A Novel Acoustic Emission Fiber Optic Sensor Based on a Single Mode Optical Fiber Coupler

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A Novel Acoustic Emission Fiber Optic Sensor Based on a Single Mode Optical Fiber Coupler

This paper reports, for the first time, on the use of a fused-taper single mode optical fiber coupler as a sensing element for the detection of acoustic emission (AE) and ultrasound. When an acoustic wave impinges on the mode-coupling region of a coupler, the coupling coefficient is modulated via the photo-elastic effect. Therefore, the transfer function of the coupler is modulated by an acoustic wave. The sensitivity of the sensor at 140 kHz was approximately 5.2 mV/Pa and the noise floor was 1 Pa. The bandwidth of the sensor was up to several hundred kHz. This AE sensor exhibits significant advantage compared with interferometer-based AE sensors.     

Optical fiber coupler array for multi-point sound field measurements

A pressure-sensitive device using an optical fiber coupler is proposed, and is integrated into an array system to measure sound field distributions. The optical coupling between two optical fibers is modulated by the applied sound field with the use of a membrane mechanically connected to the coupler. In the array system, a large number of the optical coupler sensors are connected two-dimensionally, and sound pressure at each sensor can be read out by switching the input light sources in turn. A prototype of the basic array system based on this principle was made, and its performance was demonstrated. The signal discrimination between each element was confirmed in a 2x2 array; then, using a four-element linear array, we demonstrated the steering of beam based on the phased array method.     

A time-selective technique for free-field reciprocity calibration of condenser microphones

In normal practice, microphones are calibrated in a closed coupler where the sound pressure is uniformly distributed over the diaphragm. Alternatively, microphones can be placed in a free field, although in that case the distribution of sound pressure over the diaphragm will change as a result of the diffraction of the body of the microphone, and thus, its sensitivity will change. In the two cases, a technique based on the reciprocity theorem can be applied for obtaining the absolute sensitivity either under uniform pressure or free-field conditions. In this paper, signal-processing techniques are considered that improve the accuracy of the free-field calibration method. In particular, a fast Fourier transform (FFT)-based time-selective technique for removing undesired reflections from the walls of the measurement chamber has been developed and applied to the electric transfer impedance function between two microphones. The acoustic centers of the microphones have been determined from the "cleaned" transfer impedance values. Then, the complex free-field sensitivities of the microphones have been calculated. The resulting complex sensitivities and acoustic centers have proved to be in good agreement with previously published data, and this confirms the reliability of the time-selective technique, even in nonanechoic environments. Furthermore, the obtained results give a new reference for further comparisons, because they cover a frequency range with an accuracy that has not been obtained by previously published data.     

Transverse pressure distributions in a simple model ear canal occluded by a hearing aid test fixture

The sound field in a model ear canal with a hearing aid test fixture has been investigated experimentally and theoretically. Large transverse variations of sound pressure level, as much as 20 dB at 8 kHz, were found across the inner face of the hearing aid. Variations are greatest near the outlet port of the receiver and the vent port. Deeper into the canal, the transverse variations are less significant and, at depths greater than 4 mm, only a longitudinal variation remains. The model canal was cylindrical, 7.5 mm diameter, and terminated with a Zwislocki coupler to represent absorption by the human middle ear. The outer end of the canal was driven by the receiver in the hearing aid test fixture, with the acoustic output entering the canal through a 1 mm port. The hearing aid was provided with a 20-mm-long vent, either 1 or 2 mm in diameter. The sound field inside the canal was measured using a specially designed 0.2-mm-diam probe microphone [Daigle and Stinson, J. Acoust. Soc. Am. 116, 2618 (2004)]. In parallel, calculations of the interior sound field were performed using a boundary element technique and found to agree well with measurements.