Fabrication of internally driven micro centrifugal force pumps based on synchronous micro motors

In this paper, the fabrication process and mounting of a micro centrifugal force pump based on a synchronous motor is presented. The pump unit as well as the electromagnetic drive unit is fully integrated and mainly realized by means of micro fabrication technologies including UV-depth lithography and electroplating. Furthermore, one specialty is the application of polymer magnets which allow a miniaturization of the toothed rotor down to 2 mm. The presented pump reveals a promising basic concept for other micro rotary pumps like spiral, impeller, or gear pumps.     

基于无线传感网的风机应力监测系统

本文介绍了监测风机应力的无线传感器网络体系结构.研究了风机结构,在此基础上对关键点进行了应变片的粘贴.应变传感器主要由前端的应变桥路和后端数据采集系统组成,应变桥路由应变片组成,根据实际工程要求可以将桥路搭配成全桥或半桥等不同桥路.本文阐述了测量桥路原理、应变片粘贴方法及组桥线路连接方式,同时,设计了上微机数据采集软件...     

直驱式风电机组发电机转子支架强度分析

为实现某直驱式风电机组发电机转子支架的强度设计要求,应用有限元软件和疲劳分析软件,研究有限元方法在极限强度和疲劳强度分析中的应用.基于HyperMesh建立直驱式发电机有限元模型,采用MSC Nastran计算分析转子支架的极限强度.在极限强度不满足强度设计要求的情况下,对转子支架的结构进行优化.基于疲劳分析软件,计算分析转子支架的疲劳损伤.最终得到优化后的转子支架设计满足强度设计要求.     

A real-time optimal energy-saving walking pattern generator based on gradient descent method and linear quadratic control

Many recent approaches have successfully generated a stable walking pattern for biped robots, but discussions about its optimization are relatively few. In this paper, a Center of Gravity (COG) trajectory optimization method is proposed to minimize the cost function of joint torque, joint limit, and joint speed limit. The linear quadratic control-based inverted pendulum controller optimizes the COG trajectories in sagittal and lateral directions with the COG height trajectory. The COG height trajectory is optimized by finding the derivative of the cost function with respect to the COG height offline. Then the proposed walking pattern generator builds the COG height trajectory database of different walking steps for online connection of a walking pattern. The walking pattern generator is verified by experiments and simulations of different step cycles with our humanoid robot, NINO, and it can clearly reduce the required joint torque of the robot while walking. In addition, compared with the fixed COG height trajectory, the energy consumption is reduced by 14% from the experimental results. Thus, the method succeeds in generating a more energy-saving walking pattern.     

A generative image fusion approach based on supervised deep convolution network driven by weighted gradient flow

In recent times, convolution neural networks (CNNs) have been utilized to generate desired images benefiting from the layered features. However, few studies have focused on integrating these features gained from multiple sources to obtain a high-quality image. In this paper, we propose a generative fusion approach using a supervised CNN framework with analysis and synthesis modules. According to it, the salient feature maps obtained from the analysis module are integrated to yield output generation by iteratively back-propagating gradients. Furthermore, a differential fusion strategy based on weighted gradient flow is embedded into the end-to-end fusion procedure. To transfer previous network configurations to current fusion tasks, the proposed network is fine-tuned according to the pretrained network such as VGG16, VGG19 and ResNet50. The experimental results indicate superior evaluations of the proposed approach compared with other state-of-the-art schemes in various fusion scenes, and also verify that the CNN features are adaptable and expressive to be aligned to generate fused images.     

Extracting facial features by an inhibitory mechanism based on gradient distributions

The extraction of facial features is a fundamental and crucial step in most face detection and recognition systems. Here a set of approaches are proposed for extracting internal and external facial features in a gray-level images containing single or multiple faces of various sizes, at different locations without any restriction on the background. These approaches are distinctive in several aspects: the use of some rarely exploited photometric properties as the basis of facial features extraction, a novel metrics on radial symmetry of gradient orientations, and an inhibitory mechanism for extracting internal facial features and a simple mechanism for external ones.     

基于FPGA的高精度信号发生器

在当代许多电子信息系统中,信号源的性能参数往往对系统的功能起着决定性作用。采用直接数字频率合成技术(Direct Digital Synthesize,DDS),基于现场可编程门阵列(Field-Programmable Gate Array,FPGA)设计了能同时输出4路信号的高精度信号发生器。同时依靠串口通信的方式,通过PC端的控制界面实时调节系统输出信号的频率、相位和死区时间。     

滞环细胞神经网络实现多涡卷混沌发生器

提出利用2个具有滞环输出的CNN细胞实现了多涡卷混沌发生器．首先用标准CNN细胞的状态方程来表示多涡卷混沌发生器的状态方程，通过对比来确定CNN模板的参数，用运算放大器来实现CNN细胞的状态方程及不同形式的滞环输出方程，分别采用不同形式的滞环输出函数实现双涡卷和三涡卷混沌吸引子．本系统由运算放大器，电阻及电容构成，易于实现集成．最后，应用Orcad Pspice进行了电路仿真，验证了结论的正确性．     

基于MFE-GASVM的机载燃油泵故障诊断

机载燃油泵的健康状态是保障飞行任务完成的先决条件,实现机载燃油泵故障诊断的关键是敏感故障特征的提取。由于机械系统的复杂性,机载燃油泵振动信号的随机性表现在不同尺度上,因此需要对振动信号进行多尺度分析。基于此,在模糊熵的基础上引入尺度因子,对振动信号在不同尺度下进行复杂性度量。然后将多尺度模糊熵特征量作为支持向量机的输入参数以识别故障状态,并采用遗传算法对支持向量机的核函数参数及惩罚参数进行优化。实验结果分析表明,该方法可有效提取故障特征,实现机载燃油泵的故障诊断。     

Optimization and development of a universal flow-based microfluidic gradient generator

Generation of concentration gradients of reactive molecules is of fundamental importance for many applications including biology, pharmaceutical and chemical engineering. By numerically simulating the flow behaviour, we reveal the possible factors that cause significant error in the gradients generated by the conventional universal microfluidic gradient generator (MGG) device reported previously. Based on these computational analyses, we optimize the geometrical design of the conventional 2-inlet MGG devices and improve the accuracy of the generated gradients. Moreover, we innovatively propose a 3-inlet MGG design showing desirable accuracy and versatility on creating various gradient profiles using the one single device. We further demonstrate our numerical simulation by fabricating the MGG devices by soft lithography and experimentally produce concentration gradients of diverse power functions. In general, the current study substantially improves the performance of universal MGG devices, which can serve as powerful tools for widespread applications in biology and chemistry.     

Simulation and experimental investigation on tree concentration gradient generator with U-shape microchannel

Microsystem Technologies - This paper describes a novel design and a simple, low cost fabrication method of concentration gradient generator which can generate the approximate linear and quadratic...     

基于梯度的纹理合成

为避免纹理映射引起的接缝和扭曲,近几年人们提出了一些基于样图的纹理合成方法,但大多数算法仅考虑两个匹配块之间对应元素的颜色差别作为评价相似性的量度,对于一些纹理图像,找到的不是最佳的匹配块,因此合成后,没有得到令人满意的效果.为此,提出一个新的纹理合成算法.不仅考虑了颜色的相似性,还加入了梯度,把颜色和梯度作为衡量两个匹配块之间的相似性量度,使得找到的匹配块与样本中待匹配的块之间的相似性程度有所提高.经实验验证,获得比较理想的效果.     

模型驱动的自动化测试架构

如何在确保软件质量的前提下有效缩短上市周期的问题日益显得重要。在实际工作中基于MDT的思路研究出了一种基于模型驱动的自动化测试架构。该架构通过算法直接将UML系统设计模型转换成U2TP测试设计模型,然后由测试设计模型根据测试策略和测试工程方法自动生成测试用例,实现了测试资源重利用和测试活动的前移从而有效缩短了测试周期。     

基于FPGA的SVPWM发生器的实现

在工业与民用的电力传动控制系统中,常采用电动机驱动机械运动,空间矢量脉宽调制SVPWM是一种驱动电动机旋转的高效脉宽调制方式。本论文详细介绍了空间矢量脉宽调制系统的工作原理及其功能架构,提出了一种基于现场可编程门阵列FPGA的SVPWM发生器的硬件设计方案,并在一片FPGA中得到了具体验证和实现,该方案结合了SVPWM与FPGA的优点,在高性能运动控制系统中有重要的应用价值,为设计高性能的电机控制专用芯片奠定了基础。     

Optofluidic DNA computation based on optically manipulated microdroplets

DNA computing is a promising approach for dealing with biomolecular information. Although several DNA logic circuits which can evaluate biomolecular inputs have been proposed, they have serious drawbacks in the processing speed and the amount of molecules used in implementation. Here, we present optofluidic DNA computation as an effective method for constructing a DNA computing system. By confining the reaction space of DNA computation to the inside of a microdroplet and manipulating a group of droplets with external light signals, we improve usability of DNA computation as well as the processing performance. Optical manipulation is applied to transport the droplets and to initiate DNA computation by forced merging of the droplets. The proposed method has advantages over conventional DNA computation schemes in flexible operations, simultaneous multiplexed evaluation, and processing acceleration. As the first demonstration of optofluidic DNA computation, logical AND and OR operations are performed by optical manipulation of microdroplets which contain either DNA logic gates or input molecules. Also, considerable reduction in the processing time is confirmed on the optofluidic DNA computation owing to reduction of the reaction space to the microdroplet.     

梯度与曲率变形力相结合的图像配准方法

针对Demons算法将形变配准视作扩散问题,仅靠梯度信息确定浮动图像的位移,在梯度非常小时图像形变方向不能确定,会导致错误的配准变换这一弊病,将等照度线曲率作为一个控制形变的驱动力因素引入Demons扩散方程,建立了一个具有梯度与曲率双重驱动力的非线性扩散模型,将其应用于图像配准。实验结果表明,这一模型较经典Demons算法具有更好的配准性能。     

自组装纳米金内毒素压电传感器的研究

利用纳米金颗粒自组装于金片表面上,用于固定多粘菌素B(PMB),研制了一种内毒素压电传感器。先在石英晶体电极表面自组装1,6—己二硫醇,再通过纳米金与巯基的共价键合作用,在巯基自组装膜的另一端的巯基表面形成一均匀的纳米金单层膜,实现PMB在传感器表面的固定。实验探讨了影响纳米金自组装和PMB固定等主要实验参数和条件;考核了采用此固定化方法传感器的响应性能。结果表明:与单纯采用自组装方法比,传感器在灵敏度和分辨力方面均有较大的改善。     

基于形式化描述测试用例生成的研究与实现

根据高安全系统实现和评估的需要,提出基于形式化Z描述的测试用例生成方法,并据此实现了测试用例自动生成工具,可进行符合更改条件/判定覆盖准则的测试用例生成,以解决生成测试用例数量与质量间的取舍问题。与相关工作相比,可以降低形式化描述的要求,减少人工参与的成分,提高测试用例生成的有效性和效率。     

基于DDS技术的任意波发生器

本文给出了基于DDS技术的VXI系统平台上任意波形发生器功能电路的一种设计方法。介绍了DDS技术在波形产生功能电路中的应用,推出了利用DAC实现高精度线性程控的一种方法。最后简要说明了仪器软件的实现方式及主要功能。