Design of a Triaxial Piezoelectric Accelerometer

A monolithic MEMS triaxial accelerometer based on piezoelectric lead zirconate titanate (PZT) thin films with highly symmetric quad-beams and a seismic mass, has been designed and simulated. Theoretical and numerical models for this structure are presented. The dynamic response and the trade-off between several design considerations are discussed. Static and modal simulations with FEM (Finite Element Method) simulator have been performed to analyze the mechanical response. It shows that the sensitivities of the three axes (X, Y, Z) are respectively 27, 27, and 29 mv/g, and there is almost no transverse sensitivity for the accelerometer. Also, the device is expected to have good temperature performance.     

Twin-mass accelerometer optimization to reduce the package stresses

The geometry optimization of a piezoresistive Twin-mass accelerometer is presented. The Twin-mass design is the most sensitive design to the stresses of the package compared to the Cantilever beam and the Quad-beam designs. Finite element simulations are carried out to improve the geometry of the Twin-mass design. Substitution of the perpendicular external beams by lateral external beams reduces the effects of the stresses of the package by a factor of more than 40. Moreover, the sensitivity and the figure of merit of the device can be easily increased.     

Non-destructive stiffness detection of utility wooden poles using wireless MEMS sensor

This paper presents the design of a portable wireless measurement system for the non-destructive stiffness detection of wooden poles using MEMS sensor. Low cost capacitive micro-machined accelerometer is mounted on the surface of wooden poles and data collected from the vibrating wooden poles are used for the stiffness analysis of wooden poles. Fast Fourier transform is applied to the collected acceleration data records and the largest spectral peak is identified based on the estimated frequency spectrum. The relationship between the stiffness of a wooden pole and the largest spectral peak is provided. Health conditions of wooden poles are then derived based on the identified spectral peak. Fuzzy logic is also used to solve the problem of small samples. Experimental results and the accuracy of the method are also presented.     

用静电力和SAW滤波器对悬臂梁式SAW加速度计的扩程及其计量标定

提出了用声表面波滤波器测知加速度方向和大小的原理和方法,研究了电容器中的静电吸引力对加速度计敏感质量块的位置稳定作用,以及用它扩大悬臂梁式加速度计量程的原理.还对静电力扩程之后,加速度计测量值的校准、计量标定等问题进行了有益地探讨,针对电容器静电力的非线性扩程特点,提出了查询表式的在线实时测量换算读值方案.     

电容式力平衡加速度计的设计

电容式微机械加速度计是一种将加速度转换成差分电容、通过检测差分电容的变化来检测加速度大小的一类高精度的惯性传感器.利用开关电容电路实现C-V变换,利用反馈静电力实现力平衡闭环控制,设计了一种电容式微机械加速度计.通过构建电容式加速度传感器及外围电路的数学模型,推导了闭环工作的系统函数.并对实际系统进行研制,最后给出了整个系统的测试结果.     

数码手榴弹引信研究与设计

通过引入三轴加速度传感器和单片机,解决现行手榴弹由于延期时间不准确而导致的早爆和迟爆,以及手榴弹未扔出安全范围起爆对操作手引起意外伤亡的问题,提出了一种新型手榴弹引信——数码手榴弹引信的设计方案与研究思路。     

电泵井振动监测及传输系统设计

潜油电泵机组是具有超细长转轴的复杂旋转机械,有复杂的生产及安装工艺,且采用了多级离心泵,在生产过程中会产生强大的振动源,测量并分析机组振动状况,是评估潜油电泵机组的运行状况、提高可靠性的重要手段。本文采用MMA3201振动加速度计监测振动状况,并采用4 mA²0 mA电流环将信号传输到井上MCU进行分析处理,根据监测和处理结果,适时提泵检修,采取合理的减振措施,延长潜油电泵的使用寿命。     

动基座光电平台伺服系统扰动力矩抑制能力仿真与分析

为了提高动基座光电平台视轴稳定精度,必须提高伺服系统对扰动力矩抑制的能力。针对这种情况,提出了在伺服系统中引入加速度反馈闭环来抑制扰动力矩。仿真、分析结果表明,加速度反馈闭环的引入有效增强了动基座光电平台伺服系统的力矩刚度,极大的抑制了扰动力矩,将动基座光电平台视轴稳定精度由177.8 rad提高至8.5 rad。     

基于气体热对流的微机械倾角传感器综述

针对MEMS技术和气体热对流倾角传感器技术的结合,介绍了基于气体热对流的微机械倾角传感器的国内外研究现状和发展趋势;着重分析该种传感器的原理和性能特点,特别是融合了MEMS技术和气体热对流敏感机理的优点:使传感器具有体积小、重量轻、功耗低、成本低、可靠性高、可批量生产、优良的抗振动和抗冲击能力等特性.对基于气体热对流的微机械倾角传感器的进一步研究将有益于提高倾角传感器的性能和扩大其使用范围.     

MEMS加速度计的GPS终端的低功耗系统设计

锂电池供电的便携式GPS定位终端,其待机时间是影响产品实际应用的一个主要因素。采用MEMS加速度计作为运动检测开关,在后台辨别目标体的动静状态,决定系统CPU工作的工作状态,合理配置GPS、GSM各模块的工作模式,优化整个的节电工作状态,可延长终端待机时长。