振动式微机械陀螺的电学模拟

根据振动式微机械陀螺的动力学模型导出其等效的电学模型，并利用电路模拟工具对其进行了模拟。利用电路模拟结果，分析了陀螺的运动特性。利用这个电学模型，可以与接口电路混合模拟，优化检测电路的设计。     

单片三轴硅微机械振动陀螺仪研究

设计、制造了一种单片集成三轴硅微机械振动陀螺仪.该器件由两个结构完全相同的单轴水平陀螺仪和一个单轴垂直陀螺仪组合而成,三只单轴陀螺仪均采用静电驱动、电容检测的结构形式.采用体硅溶解薄片法制造了该三轴陀螺仪芯片,并对其在空气中的驱动性能进行了初步测试.测试结果表明,该单片三轴硅微机械振动陀螺仪驱动模态的实际谐振频率与理论值之间的最大误差小于5%,满足设计要求.     

载体加速度对静电驱动微机械陀螺响应的影响分析

载体的运动会导致微机械陀螺的响应发生变化,因而引起测量误差,甚至导致系统故障。针对载体运动对微机械陀螺响应的影响开展研究。考虑载体运动以及微陀螺的非线性支承刚度和非线性静电力,基于拉格朗日方程建立了系统的动力学方程。利用谐波平衡法结合留数定理求解了含分式非线性项的系统的周期响应,研究了载体加速度对系统响应特性的影响,发现驱动方向的载体加速度主要导致系统的灵敏度降低。检测方向的载体加速度除使得系统灵敏度降低,还会导致零偏,且零偏和加速度的大小成正比,但比例系数与驱动电压无关。驱动电压较小时,载体在检测方向较小的加速度对灵敏度和非线性度影响很小;而在驱动电压或者检测方向加速度较大时,系统的灵敏度急剧下降,且非线性度也发生了剧烈变化。     

基础简谐激励下匀速旋转运动电流变夹层梁的振动稳定性

摘 要：建立了基础激励和定轴转动联合作用时电流变夹层梁的运动微分方程,着重研究了基础简谐激励和匀速旋转运动作用时电流变夹层梁的振动稳定性。采用多尺度法获得了梁的一次近似解析解和参激振动失稳的条件。通过对电流变夹层梁在不同激励参数、控制电场和旋转角速度时的振动响应时间历程曲线和对应相图的数值分析,探讨了电场作用下电流变夹层梁的参激振动稳定性。仿真结果表明,在一定的条件下,可以通过控制作用于电流变夹层梁的电场强度来改变系统出现运动不稳定的临界激励幅值,提高结构的动力稳定性。     

基于单轴气浮台的角动量输出测量方法

星载转动部件的角动量输出测量是卫星姿态控制系统设计的必要环节,该文介绍了一种利用单轴气浮平台测量转动部件角动量输出的系统和方法。通过对系统转动惯量和角速度的测量,得到转动部件输出角动量的大小及变化,最后以实例形式给出测试步骤、数据处理方法、测试结果及精度分析。与直接测量法相比,该方法测试设备简单,测量精度高,测量误差小于5%,尤其对具有多转动单元、多自由度转动部件的耦合测量优势明显,具有较高的工程应用价值。     

微机械陀螺信号处理方法的比较研究

介绍了谱消除法、小波变换和数学形态学滤波三种信号处理方法进行消噪的基本原理,并分别采用这三种方法对微机械陀螺的静态漂移信号和动态仿真信号进行了去噪声处理,对处理前后的信号误差大小及其分布情况以及处理过程的运算量和实时性进行了比较.结果表明,对于静态漂移信号的处理,三种方法的滤波效果大致相当.对于动态信号,数学形态学滤波器的滤波效果比其它两种滤波器的滤波效果要好,并且,数学形态学滤波器具有运算量小,实时性较好的优点,十分易于硬件实现.     

无陀螺捷联惯导系统综述

结合国内外的文献资料,对无陀螺捷联惯导系统的研究进行了总结,重点讨论了无陀螺捷联惯导系统中的两个重要问题．即加速度配置方式和角速度解算方法,简要分析了无陀螺捷联惯导系统的误差和精度问题．最后对无陀螺捷联惯导系统的未来研究方向进行了展望．     

栅结构微陀螺大角速度信号输入下分辨率的研究

主要研究了大角速度信号输入对栅结构振动式微陀螺及其检测电路分辨率的影响。在0.01-200°/s的动态范围内,按照设计值,陀螺器件与检测电路组成的系统能够分辨0.01°/s的输入角速度变化。考虑到驱动电压和积分电容与敏感电容的特性差异的影响后,当输入角速度大于10°/s时,整个系统即无法分辨0.01°/s的输入角速度变化。针对这种情况,提出了在传感器件上集成关键元件的方法来解决大角速度信号输入下整个系统分辨率降低的问题。     

基于锁相技术的微机械陀螺闭环驱动电路

传统的闭环驱动电路其输出信号的频率与微机械陀螺驱动方向的固有频率存在一定偏差,且频率抖动较大,系统的建立时间较长．基于上述不足,在分析微机械陀螺闭环驱动方式工作原理的基础上,提出一种基于锁相技术的闭环驱动电路方案,电路进入稳定工作状态时,交流驱动电压与驱动方向敏感电流的相位及频率一致．微机械陀螺在驱动方向谐振,显著改善了输出信号的频率特性．仿真结果表明,这种闭环驱动电路输出信号频率与微机械陀螺驱动模态固有频率完全一致,频率抖动及系统建立时间分别是传统闭环驱动电路的38％和50％．通过实验验证了该方法的可行性     

等径道角挤压对Mg-6Al合金性能的影响

为了优化铸态Mg-6Al合金等径道角挤压的工艺参数,通过等径道角挤压实验研究了工艺参数对其性能的影响.研究表明:等径道角挤压可大幅度提高Mg-6Al合金坯料的力学性能.当Mg-6Al合金挤压1道次至4道次后,其力学性能提高较大,微观组织明显细化.随挤压温度从260℃升高至300℃,被挤压坯料的力学性能先提高后降低.当挤压路径为路径B,挤压道次为4道次,挤压温度为300℃时,Mg-6Al合金的力学性能最高,其抗拉强度为308.2 MPa,延伸率达到30.6%.     

Influence of impact velocity on fragmentation and the energy efficiency of comminution

Comminution processes such as crushing and grinding are essential stages in mining and mineral processing operations to reduce the size of ore and rock, and to liberate the valuable mineral for beneficiation. Comminution is energy-intensive and responsible for most of the energy used during mineral recovery. Energy efficiency is very low since almost all the energy is dissipated as heat instead of generating new surface area. This paper reports on studies conducted on strain rates achieved by various velocities of impacts that enhance energy efficiency and mineral liberation. The research focuses on understanding comminution fracture mechanics and on quantifying the distribution of energy with respect to generating new surface area. In interpreting breakage energy phenomena, accurate measurements of surface roughness and surface area are essential. A novel approach to measure surface roughness and surface area based on a fractal analysis procedure has been developed. Changes in surface roughness of broken specimens under variable loading rates were studied using a laser probe to generate 3D topographical maps of the fracture surfaces. The results indicate that surface roughness and hence, specific surface area, increase with increasing loading rate by several orders of magnitude as particle size decreases to 1 μm. Below this limit, surface roughness begins to diminish from particle–particle attrition. An apparatus to measure the quantitative parameters of impact at different velocities on aggregated rock samples is proposed. Experiments are being carried out at projectile velocities up to 500 m s⁻¹ utilizing a compressed-air device. The results suggest possible efficiency improvements in breakage under the velocity of impact.     

The effect of coplanar sensor spacing on determining the angular acceleration of vehicles

Vehicle vibration presents challenges to a packaged product that is inevitable in any distribution environment. Typically products are tested in only a single, vertical axis; researchers have shown that there is energy in all six axes of motion. In this work, we study the recording methods of the six degrees of freedom (6DOF) motion of a transport vehicle. Using a co-planar sensor array, three tri-axial linear accelerometers and three angular rate sensors mounted in a L shape are used to calculate the rotational accelerations that occur in the back of a vehicle. Missing from prior work is a scientific study designed to determine the minimum sensor spacing necessary to accurately capture the yaw, pitch, and roll of transport vehicles. A sensitivity study is conducted to determine the effect of the misplacement and misorientation of sensors on the angular acceleration calculation. A laboratory study is used to determine the distance error begins to accumulate in the angular acceleration calculation in response to a sinusoidal input. A field study is conducted to calculate the rotational motions of a vehicle on a rough road. It is found that a mounting fixture is valuable in assuring the necessary sensor placement accuracy needed to accurately determine angular accelerations of a truck. Additionally, laboratory and field analysis show that as the sensor spacing location approaches the origin sensor, angular acceleration calculation error increases due to a loss in distinctiveness. It is desired for a close sensor mounting array, but there is a trade off between measurement accuracy and compactness of the recording array. A limit exists where the sensors can not be mounted in close proximity.     

无控旋转弹的外弹道转速仿真与分析

针对目前存在的无控旋转弹外弹道转速测试成本高和测试精度较低等问题,提出FLUENT仿真软件和ADAMS仿真软件结合的仿真测试方法。该方法以无控旋转弹为研究主体,借助FLUENT软件进行模型的建立,计算域的建立和网格的划分,得到模型在不同马赫数下受到的空气阻力图以及模型在不同马赫数和不同攻角下的力矩图。然后在ADAMS仿真软件中,通过对弹丸建立合适的三维模型和施加合适的载荷之后,得到弹丸的外弹道角速度曲线,并与实际测得的曲线进行对比,结果显示仿真的角速度曲线和实测曲线基本一致。     

Penetration response of silicon carbide as a function of impact velocity

Reverse ballistic experiments were used to investigate confinement, pre-damaged and intact, and rod size effects on penetration of long, gold rods into silicon carbide (SiC-N). Rod diameters were 1.0 mm and 0.75 mm, and lengths were 70 mm and 50 mm, respectively. Within data scatter, penetration velocity was the same for intact (bare or sleeved), pre-damaged (thermally shocked with non-contiguous cracks), and in situ comminuted SiC-N. Penetration velocity was independent of rod diameter within the data scatter. An expression for the penetration velocity versus impact velocity is found using linear regression. It is proposed that the reason there is no difference in the penetration rate between intact and pre-damaged (failed) SiC is because, after the first few microseconds following impact, the rod penetrates failed material in both cases.     

一种新型激光陀螺的检测方法

本文通过对新型四频差动激光陀螺输出信号的分析,给出了一种适应新型四频差动激光陀螺输出信号的检测方法。通过APD和高频低噪声前置放大器实现光电接收,通过集中选频放大电路进行滤波和放大,然后采用模拟乘法器实现自乘检波,并根据该方法设计了实际的检测电路。采用直管四频激光器的背向输出来模拟新型四频差动激光陀螺的输出,对电路进行了实际测试。通过测试,验证了检测电路方法的可行性。     

星载空间目标光电跟踪角速度伺服系统设计

设计了星载空间目标光电跟踪角速度伺服系统,它包括补偿校正环节、驱动功放环节、以光学望远镜和跟踪架为被控制对象的机械操作环节以及视轴稳定回路。选择直流力矩电机作为跟踪架驱动元件,以提高系统的跟踪精度。利用 Matlab 进行系统特性仿真的结果表明,设计的系统相角裕度为 69°,幅值裕度为 35.8dB,截止频率为 10rad/s,调节时间为 0.7s,具有良好的跟踪性能,达到了预期的要求。     

A power series for vibration of a rotating nanobeam with considering thermal effect

In this article, the equation of motion for a rotating nanocantilever has been developed based on the Euler–Bernoulli beam model, which includes the effect of temperature, small scale effect, and centrifugal force. A power series method has been employed to obtain the exact solution of the natural frequencies. The results also compared with other solutions of exact and approximate differential quadrature method. The effects of temperature, angular velocity, and small scale in the vibration characteristics of a rotating nanocantilever beam are investigated. It is shown that the effect of temperature plays a significant role in the behavior of the vibration of a rotating nanocantilever. Nondimensional frequency increases in the first mode with increasing the nonlocal parameter while it is inverse for the second and third modes of vibration.