Design of Bang-bang Controller Based on a Fuzzy-Neuro Approach: Application to a Heating System

A fuzzy-neuro approach for the design of bang-bang controller is presented in this paper. The approach has been used with success for the time optimal bang-bang control of a heating system. The improved bang-bang controller suppresses the oscillations often observed at the output of an on-off controller. A fuzzy system is used for the implementation of the on-off control. An extension of the fuzzy control is provided by an equivalent neural network of the fuzzy system. A test application, that of a house heating with a two-state furnace, is developed and evaluated with standard hysteresis switching, fuzzy control, and fuzzy-neuro control.     

Fabrication of thick Si resonators with a frontside-releaseetch-diffusion process

A frontside-release etch-diffusion process has been developed to create released single-crystalline Si microstructures without the need for wafer bonding. This frontside-release process is simple and requires only a single mask. A deep dry etch in an electron cyclotron resonance source is used to define the structures, followed by a short boron diffusion to convert them to p⁺⁺ Si. A short etch in ethylenediamine pyrocatechol (EDP) is then used to undercut and release the structures from the frontside of the Si wafer. The structures are isolated from the substrate using a reverse-biased p⁺⁺/n junction. Since the structures have a high aspect ratio, beams longer than 1 mm can be released without sticking to the substrate, and thick resonators are flat with no bending due to stresses. Resonant microstructures with thicknesses ranging from 10 to 55 μm thick have been fabricated using this process and their resonant frequency has been measured. For typical clamped-clamped beam resonators that were 24 μm thick, 5 μm wide, and 400 μm long, with 2-μm comb gaps, a resonant frequency of 90.6 kHz and a quality factor of 362 were measured in air     

A novel integrated silicon capacitive microphone-floating electrode“electret” microphone (FEEM)

A novel principle “electret” microphone, i.e., floating electrode electret microphone, is proposed and implemented in this study. Single-chip fabrication and corrugation technique are used in the design and fabrication of the microphone. The floating electrode is encapsulated by highly insulated materials to ensure that there is no electric-leakage passage between the floating electrode and the electrodes of the microphone. Net-free electronic charges (not “bonded” charges as in traditional electret) in the floating electrode can excite the electric field, which is similar to that of the traditional electret. The floating electrode can be easily charged by use of the “hot” electron technique, available using the avalanche breakdown of the p⁺-n junction. Therefore, the electret microphone is rechargeable, which can greatly increase the lifetime of the device. The preamplifier has been on-chip integrated in a junction-field-effect transistor (JFET) source-follower type with resistors by use of ion implantation. Electret charges are banded in a deep potential trap, thus, this microphone can operate at a high temperature (as high as 300°C) and has high stability and reliability. Experiments show that the prototype has a 3-mV/Pa sensitivity and a larger than 21-kHz frequency bandwidth in a 1 mm ×1-mm diaphragm area. Microphone performance can be further improved by optimized process and design. The fabrication is completely integrated-circuit (IC) compatible, hence, the microphone shows promise in integrated acoustic systems     

一种智能加速度传感器的设计与实现

针对目前加速度传感器智能化程度较低的现状，详细介绍了一种智能加速度传感器的信号调理、串行接口等硬件电路设计和软件实现方案，并采用系统自检和数字滤波技术以增强系统的抗干扰性。试验结果证明，该传感器性能稳定，灵敏度可达到0．28mV/g，具有测量精度高、价格较低、灵活可靠的特点，克服了传统加速度传感器测量精度低、元器件精度要求较高、测试系统复杂昂贵、应用范围具有局限性的缺陷，大大提高了加速度测量的自动化水平，具有重要的应用价值。     

Estimating light vectors in real time

Capturing the appearance of objects under different lighting conditions is useful in texture acquisition, bidirectional reflectance distribution function (BRDF) measurement, and image-based data acquisition. With the acquired data, we can render virtual objects realistically. During the data capture, we must record both the radiance and the light vector. Measuring the light vector is not necessarily easy. We propose a capturing system that estimates the light vector by applying a vision-based technique. It lets the user freely position a handheld light source during capture. The system estimates light-source orientation in real time through a Web cam mounted on the light source. Software running on an ordinary PC analyzes images from the Web cam to recognize the light source direction (the light vector). Our goal is to design a low-cost, portable, and adaptable system. Vision-based approaches offer such characteristics. We use a pose-estimation system to acquire image-based data for relighting.     

在输电网络开放环境下电力市场运行和购电合同的设计

探讨了开展发电企业向大用户直接供电的条件，提出了一种输电网络开放环境下的电力市场运营模式，即中长期金融合的交易和实时平衡市场相结合的电能交易模式。这种模式使市场竞争主体能够有效规避市场风险但又不降低市场竞争力度，而且市场主体之间的合约履行又不制约电网的安全可靠运行，市场运作简单、高效、透明。     

大跨度无粘结预应力梁楼盖结构施工技术

分析、介绍石家庄第二长途电信枢纽工程大跨度无粘结预应力梁楼盖结构的施工方法、张拉工艺及质量控制。     

关于我院学生工作的几点思考

笔者根据学院学生工作实行二级管理的实践,从学生工作职责范畴、培养学生工作者、学生工作者工作成就、学生工作方式方法等方面,以碰到的困惑和自己的思考与大家进行交流,并提出了一些建议.     

基于双输入模糊控制策略的电力系统频率控制

电力系统一般都很复杂且变量又多,实现二阶负载-频率自动控制也相应变得很困难.对此,把误差和误差变化率作为模糊控制器的输入,使得模糊控制器对较小误差具有较强的敏感性,这样有利于消除稳态误差,以适应误差的快速调节和精确调节.仿真结果表明这种模糊控制的策略对于存在扰动且并不是很大的情况是很适用的,提高了系统的稳态性能,减小了响应的超调.     

成型阴极脉冲电化学光整加工在轧辊上的应用

采用成型阴极对冷轧丝杠轧辊进行脉冲电化学光整加工.文章介绍了该方法的基本原理,给出了实验装置,在一定的工艺条件下,对轧辊进行了脉冲电化学光整加工.结果表明,该方法能将轧辊表面粗糙度从0.3μm减小至0.06μm.