基于MMA7455的施工升降机安全控制系统的设计

针对当前施工升降机自动化程度低、安全管理弱的问题,设计了一种施工升降机自动化的远程安全控制系统。该系统由重量传感器采集重量信号,经加速度传感器校正后监测吊笼负载情况并报警。同时通过无线模块接收各楼层分机发送的呼叫信号,系统根据同向优先、就近优先的原则及吊笼载荷情况综合判断施工升降机起升运行,并利用GPRS模块进行远程监测报警。通过现场试验可知,该远程安全控制系统能有效提高运输效率和避免误报警情况,具有稳定性好、管理方便等特点。     

Experimental study on the package of high-g accelerometer

In this paper, the effect of the package die adhesive and package shell on the performances of silicon based MEMS high-g accelerometers was reported. Using Raman spectroscopy, the residual stress caused by different package die adhesive thickness and different package shell material was characterized. It can be concluded from the testing results that: with thicker die adhesive, the residual stress increment was much smaller; the piezoresistance variation caused by this residual stress was much smaller; and the temperature shift of the output voltage was much smaller. Comparing with the ceramic package, the stainless steel package has bigger sensitivity and bigger anti-overload ability.     

Estimation of energy expenditure in a work environment: Comparison of accelerometry and oxygen consumption/heart rate regression

The aim of this study was to compare estimation of energy expenditure (EE) in working environments, either from accelerometry or from an individual oxygen consumption/heart rate ([Vdot]O₂/HR) regression curve. The study participants were 46 volunteer workers aged 27±6 years old. A significant correlation between EE predicted by the [Vdot]O₂/HR curve and the accelerometer was observed (r=0.78, p <0.01). However, more disparities were observed between the two methods when the mean job intensity was not within 16% and 23% higher than resting HR. The accelerometer overestimated by a mean of 34.4% the prediction by [Vdot]O₂/HR regression if the intensity of the task was lower than a total of 1000 kcal/shift and underestimated the prediction by a mean of –24.9% if EE estimation of the work shift was higher than a total of 1500 kcal/shift. Despite a high correlation between both methods in the whole group, EE evaluated by accelerometry does not correspond to EE predicted by the [Vdot]O₂/HR regression curves when evaluated individually.     

光纤陀螺仪测试系统设计与软件实现

介绍了一套光纤陀螺仪自动化测试系统,测试系统可以完成光纤陀螺静态测试、速率测试和环境试验测试等。测试系统硬件主要包括测试工控机、数据采集卡及环境测试设备,测试软件基于MicrosoftWindows系统和Microsoft Visual C++6.0软件开发平台。测试系统可以实现多通道光纤陀螺数据采集、分析与处理、动态显示,并控制速率转台和高低温试验箱等环境试验设备完成光纤陀螺多种性能测试。实际应用表明,自动化测试系统可以大大提高光纤陀螺的测试效率,满足批量化生产的需求,实现了测试过程的标准化。     

Bulk micromachining of silicon in TMAH-based etchants for aluminum passivation and smooth surface

The fabrication of silicon based micromechanical sensors often requires bulk silicon etching after aluminum metallization. All wet silicon etchants including ordinary undoped tetramethyl ammonium hydroxide (TMAH)-water solution attack the overlaying aluminum metal interconnect during the anisotropic etching of (100) silicon. This paper presents a TMAH-water based etching recipe to achieve high silicon etch rate, a smooth etched surface and almost total protection of the exposed aluminum metallization. The etch rate measurements of (100) silicon, silicon dioxide and aluminum along with the morphology studies of etched surfaces are performed on both n-type and p-type silicon wafers at different concentrations (2, 5, 10 and 15%) for undoped TMAH treated at various temperatures as well as for TMAH solution doped separately and simultaneously with silicic acid and ammonium peroxodisulphate (AP). It is established through a detailed study that 5% TMAH-water solution dual doped with 38 gm/l silicic acid and 7 gm/l AP yields a reasonably high (100) silicon etch rate of 70 μm/h at 80 °C, very small etch rates of SiO₂ and pure aluminum (around 80 Å/h and 50 Å/h, respectively), and a smooth surface (±7 nm) at a bath temperature of 80 °C. The etchant has been successfully used for fabricating several MEMS structures like piezoresistive accelerometer, vaporizing liquid micro-thruster and flow sensor. In all cases, the bulk micromachining is carried out after the formation of aluminum interconnects which is found to remain unaffected during the prolonged etching process at 80 °C. The TMAH based etchant may be attractive in industry due to its compatibility with standard CMOS process.     

谐振式光纤陀螺全数字闭环方案

谐振式光纤陀螺是一种新型的惯性传感仪器,与传统机械陀螺和其他光学陀螺相比具有很多理论上的优势.数字信号处理电路的谐振式光纤陀螺全数字闭环是采用双频率数字锯齿波相位调制技术对光路进行了相应的调制和解调.对光信号中夹杂的大量白噪声以及数字信号处理中由于有限位数的A/D引入的量化噪声进行综合考虑,提出了用比信号带宽高很多的采样率对含有噪声的信号进行过采样,加上后续的数字信号处理,低位数A/D和高位数A/D的检测效果几乎一样.数字调制的精度影响了系统的精度,使用平均法用低位的D/A可以实现很大的调制动态范围.经过基于文中设计的数字系统的实验,得到了和理论仿真类似的解调曲线,证明了文中提出的数字闭环方案的可行性.     

采用神经网络补偿压电陀螺的零位温漂

针对中低精度的压电陀螺静态零位输出随温度漂移严重的问题，分析了产生的原因，做了相应的实验，提出了用BP神经网络进行补偿的方法。该方法具有很强的非线性映射能力，减少压电陀螺的零位输出误差，并且将实验结果与传统的方法的结果进行比较，实验证明，在不改变陀螺结构的情况下，该方法能有效地将陀螺的静态零位温漂误差减小一个数量级以上，从而使该类型陀螺能够应用于中高精度系统中。     

基于微加速度传感器的无线鼠标的设计

研究基于微加速度传感器的无线鼠标的设计,讨论了MEMS无线鼠标的软件、硬件设计和系统组成,给出了M atlab环境下系统的模型和算法。模拟结果说明:无线鼠标的设计是合理可行的,提出的二次积分近似算法是简捷有效的。     

一种三维加速度计弹性体的分析与设计

介绍了一种可用于振动测量的三维加速度计弹性体结构,其采用3个相互垂直的双平行应变梁组合的形式,每个平行梁敏感一个分量的加速度.经分析和试验结果表明:该加速度计具有灵敏度较高、交叉干扰小,完全满足预期设计要求.     

一种扭摆式硅微机械加速度传感器

介绍了一种基于体硅微机电系统(MEMS)工艺制作的扭摆式硅微机械加速度传感器,对制作过程的一些工艺问题进行探讨,并提出相应的解决办法,主要涉及到硅-玻璃阳极键合、结构释放等关键工艺。对测试结果进行了初步分析,分辨力可以达到1mgn,测试±1gn范围内线性度可以达到99.99%。