A digital oscillation-amplitude stabilizer

The design of a stabilizer of the oscillation amplitude of a mechanical oscillator is described. The stabilizer is characterized by digital tracking control of the feedback-circuit gain. The value of the digital code directly proportional to the oscillator damping factor is directly read out with an automated system. The digital-feedback linearity simplifies the calibration—only one reference point is necessary. Original Russian Text ? V.L. Tsymbalenko, 2009, published in Pribory i Tekhnika Eksperimenta, 2009, No. 3, pp. 129–131.     

数字磁罗盘的全姿态罗差补偿

针对现有磁罗盘罗差补偿方法成本高、效率低和全姿态补偿能力不足的问题,提出了一种基于几何变换的全姿态罗差补偿方法.首先,根据外磁干扰对磁传感器采样值的影响,建立了几何变换罗差补偿模型,将罗差补偿参数由12个减少到9个.其次,将牛顿法算子引入到粒子群算法中建立了混合粒子群优化算法,采用粒子群算法选取优化参数初始值,以牛顿法...     

A voltage stabilizer on a storage capacitor

A voltage stabilizer on a storage capacitor is intended for converting constant unstabilized voltages into pulsed voltages with stabilized amplitudes in power supply circuits for lasers. The principle of operation of this stabilizer is based on preliminarily charging of the storage capacitor to a voltage intended for compensating for an alternating component of the input voltage. The proposed technical decision significantly increases the laser emission stability. A voltage U _out = 1000 ± 1 V was obtained across the storage capacior, and the stabilization coefficient was ～100.     

组合航向系统中数字磁罗盘的罗差补偿研究

研制了一种由数字磁罗盘和角速度陀螺组成的组合航向系统.为了提高系统的航向精度,本文提出了两种有效的误差补偿方法八位置最小二乘法和椭圆假设补偿法.通过将两种算法应用在HMR3300型数字磁罗盘进行航向测量,分析并比较了两种算法的可行性和有效性.实验结果表明椭圆假设补偿法是一种更为智能的误差补偿算法,它能够实现数字磁罗盘的自动误差补偿和自动校准,误差补偿效果良好.     

A digital nanovoltmeter

The dynamic cancellation algorithm of the temperature error of the chopped-stabilized amplifier (modulation-demodulation (MDM) amplifier) is described. The digital voltmeter, which is based on this algorithm, features a sensitivity threshold of 0.1 nV, when the time constant is 850 s, and the temperature drift of the bias voltage is 40 pV/°C in a 400-μV dynamic range.     

磁悬浮轴承数字控制器的设计

以数字信号处理器TMS320F2812和复杂可编程器件EPM7128为控制核心,设计了四自由度磁悬浮轴承系统的控制硬件电路。在CCS环境中用C语言编写了系统的程序,采用抗积分饱和的增量式积分分离PID系统控制算法实现系统的控制。针对实验室的四自由度轴承进行了悬浮试验,试验结果表明系统悬浮动态性能良好,达到了控制性能的要求。     

大客车横向稳定杆的虚拟疲劳分析

根据大客车横向稳定杆的几何参数、载荷及约束情况,建立了横向稳定杆的有限元分析模型。基于疲劳寿命预测的相关理论,结合Abaqus有限元分析软件和nSoft疲劳分析软件进行虚拟疲劳分析,在较短的时间内获得了横向稳定杆的疲劳寿命分布、寿命薄弱位置等信息。结果表明,虚拟疲劳分析能大大缩短产品的开发周期,减少试验的工作量,降低开发成本。     

A digital phase shifter

A digital phase shifter with linear phase-shift variations with a π/N step, where N is the overall division factor of used frequency dividers, is described. The device is easy to realize and intended to easily set and change a phase-shift step, carrying out the reverse (manual and automatic) phase change with a preset rate. The device is good for use in phase and ultrasonic measurement techniques.     

基于ARM7的磁悬浮轴承数字控制系统设计

以ARM7TDMI-S CPU为内核的LPC2131微处理器为核心,设计了同极型四自由度径向主动磁悬浮轴承控制器硬件电路及控制软件,采用变速积分-抗积分饱和增量式数字PID实现了对系统转轴位置及线圈电流的双闭环控制。试验结果表明:磁悬浮轴承具有良好的控制精度及静态刚度,满足了磁悬浮轴承控制性能的初步要求。     

Performance of a fast digital integrator in on-field magnetic measurements for particle accelerators

The fast digital integrator has been conceived to face most demanding magnet test requirements with a resolution of 10 ppm, a signal-to-noise ratio of 105 dB at 20 kHz, a time resolution of 50?ns, an offset of 10 ppm, and on-line processing. In this paper, the on-field achievements of the fast digital integrator are assessed by a specific measurement campaign at the European Organization for Nuclear Research (CERN). At first, the architecture and the metrological specifications of the instrument are reported. Then, the recent on-field achievements of (i) ±10 ppm of uncertainty in the measurement of the main field for superconducting magnets characterization, (ii) ±0.02 % of field uncertainty in quality assessment of small-aperture permanent magnets, and (iii) ±0.15 % of drift, in an excitation current measurement of 600 s under cryogenic conditions, are presented and discussed.     

A robust nonlinear stabilizer as a controller for improving transient stability in micro-grids

This paper proposes a parametric-Lyapunov approach to the design of a stabilizer aimed at improving the transient stability of micro-grids (MGs). This strategy is applied to electronically-interfaced distributed resources (EI-DRs) operating with a unified control configuration applicable to all operational modes (i.e. grid-connected mode, islanded mode, and mode transitions). The proposed approach employs a simple structure compared with other nonlinear controllers, allowing ready implementation of the stabilizer. A new parametric-Lyapunov function is proposed rendering the proposed stabilizer more effective in damping system transition transients. The robustness of the proposed stabilizer is also verified based on both time-domain simulations and mathematical proofs, and an ultimate bound has been derived for the frequency transition transients. The proposed stabilizer operates by deploying solely local information and there are no needs for communication links. The deteriorating effects of the primary resource delays on the transient stability are also treated analytically. Finally, the effectiveness of the proposed stabilizer is evaluated through time-domain simulations and compared with the recently-developed stabilizers performed on a multi-resource MG.     

独立悬架前横向稳定杆改进设计方法

独立悬架前横向稳定杆的改进设计,可采用经典的计算方法,但存在需已知受力大小等问题。采用计算自振频率的方法能直接根据结构参数得出加长后的前横向稳定杆的直径的改变量。以原型件和改动件的第一阶自振频率相等为标准,分别用理论计算和Ansys模态分析两种方法得出了一致性很好的结论。     

某车型横向稳定杆的疲劳可靠性分析

横向稳定杆能有效预防车辆的侧翻,对保证汽车安全行驶起着重要作用,因此估算稳定杆的疲劳寿命尤为必要.目前有限元分析已成为一种获得零部件力学特性的有效且可靠的方法,所以借助有限元软件,为横向稳定杆的疲劳寿命估算及寿命值的分布提供了技术支持.为此首先建立该种车型稳定杆的参数化模型,并对其进行疲劳寿命的估算并在此基础上进行疲劳可靠性分析,得到疲劳寿命的分布及累积概率密度函数曲线等.最后对照稳定杆疲劳试验的寿命要求对疲劳可靠性分析结果进行了分析.     

一种基于移动水印代理技术的数字版权检测系统

本文提出了一种基于移动代理技术的网络多媒体数据防拷贝和版权跟踪与检测模型,非常适合于大型分布式网络中的多媒体数据版权保护与跟踪检测.分析了移动水印代理的创建与派遣以及基于移动水印代理的版权跟踪和检测过程.在水印实时检侧过程,该系统设计了水印代理中心完成移动水印代理的创建、派遣、任务执行和终止行为.该系统的各个工作模块相对独立,易于系统的扩充.     

A method for evaluation of an optical image stabilizer in an image sensor module

A figure of merit called the image clarity index is proposed for quantifying the performance of an optical image stabilizer (OIS) subjected to hand jitter. The image clarity index is defined as the slope angle of the normalized edge spread intensity of a captured image. A two-dimensional map of the index can offer clues as to the design limit on shake angle and frequency. Because of its relative simplicity over the existing metrics such as the modulation transfer function, the proposed index is especially suitable for summary evaluation of OISs and rapid benchmarking of OIS-equipped image sensor modules.     

A digital dynamic amplitude-frequency spectrum analyzer

A new method for recurrent calculations of spectral coefficients is used in the analyzer. A spectrum analyzer developed in accordance with up-to-date digital processing conceptions is based on very-large-scale-integration components, such as a high-speed field programmable gate array (FPGA) and a specialized signal microprocessor. The analyzer is based on a personal computer PCI card and operates on the Windows platform.     

A digital arbitrarily shaped signal synthesizer

A principle of designing a tabular signal synthesizer, which simplifies its design, is proposed. A functional diagram of the synthesizer module allowing one to easily reproduce it in the microprocessor system is given. For this synthesizer version, the maximal size of the signal table is 8192 14-bit words.     

A high-resolution digital time-interval measurement instrument

A new method for time-interval measurements is described and the results of measurements on a prototype are given. This method uses a virtually periodic exponential signal as the reference clock and consists of measuring both the phase deviation and the number of cycles of this clock signal between the beginning and the end of the unknown time-interval. The use of two auxiliary sinusoidal signals in order to measure the phase of the corresponding periodic exponential signal is discussed, also considering the main causes of error. The functional block diagram of the prototype is described in detail and the measurement results show that a resolution improvement of two orders of magnitude with respect to the period of the clock signal can easily be obtained.