液浮陀螺仪可靠性技术分析

在可靠性设计与分析的基础上，针对某型液浮陀螺仪技术特点，对影响其可靠性的各种关键因素做了较为详细的分析，同时对陀螺电机这一关键部件提出了可靠性设计方法。通过技术分析提出设计该型高可靠性液浮陀螺仪的关键因素及方法。     

液浮陀螺漂移的试验建模研究

本文采用时间序列分析理论,利用实际测量的数据,建立了液浮陀螺随机漂移的ARMA模型.最终,为便于将模型应用于卡尔曼滤波器中,本文给出了一种实际可行的液浮陀螺漂移模型.     

液浮陀螺电磁场有限元分析

针对液浮陀螺的永磁陀螺电机漏磁场可能造成陀螺噪声大的问题,需首先搞清永磁陀螺电机的漏磁场量值及分布以及与之可能产生耦合力矩的力矩器端部漏磁的量值及分布。用有限元软件ANSYS对其内部主要电磁元件进行了三维有限元数值计算,得出这些元件的气隙磁密分布图和它们的漏磁形式及大小;分析得出陀螺电机的外圆柱面和力矩器端部存在着较大漏磁,两者存在着磁场的耦合作用。在设计中应对陀螺电机的外圆柱面和力矩器的端部施加磁屏蔽。     

长寿命、低功耗、低噪声液浮陀螺仪技术分析

根据我国目前液浮陀螺仪的应用特点，结合已应用于型号的单自由液浮陀螺仪产品，对研究并设计新型长寿命、低噪声、低功耗液浮陀螺仪的各种关键因素做了较为详细的分析，通过分析提出设计该型陀螺仪采取的方法。     

某型液浮陀螺仪定位壳体温度场有限元分析

介绍了某型液浮陀螺仪定位壳体温度场模型,利用有限元分析软件ANSYS对其等效温度场进行分析,得出其温度场分布的精确量化结果,为惯导系统建立起最初的热源,并通过实验验证了分析结果的正确性,为后续的平台热设计研究提供了重要的参考依据。     

液浮陀螺仪浮子组合件动力学分析

基于振动理论建立了液浮陀螺仪浮子组合件的动力学分析模型,用有限元模态分析方法计算了组合件结构的前五阶模态,从机械谐振的角度,将结构的第一阶振型作为浮子伺服系统未建模动特性进行分析,为力反馈伺服系统设计和结构优化提供了重要依据。     

液浮速率积分陀螺温控模型分析和参数设计

本文建立了较完整的液浮速率积分陀螺温控系统模型，并对温控系统的电磁兼容设计、可靠性设计、温度传感器的配置方法、动静态特性设计、以及陀螺电机、环境热传递条件等影响温控性能的工程问题作了具体论述。文中例举了在不同环境条件下达到高稳定精度要求的陀螺温控系统的设计方法。     

惯性组件中两正交陀螺漂移模型的建立与补偿

在双轴位置转台上同时标定两个正交陀螺的漂移系数是在捷联系统测试中遇到的实际问题。本文提出了在双轴转台上采用多位置法来标定两正交陀螺的漂移系数。文中还对陀螺漂移模型及误差补偿作了理论上的探讨，并用实验进行了验证。     

基于有限元分析方法的三浮陀螺用角度传感器优化设计

针对高精度三浮陀螺仪角度传感器要求尺寸约束不变的情况下进一步提升性能的需求,提出一种基于有限元分析的优化设计方法,避免了传统的磁路计算法需要多轮验证、效率低等问题.首先从变压器磁链方程出发推导建立了多级式动圈角度传感器的数学模型,确定了影响传感器灵敏度和激磁电流的主要设计指标:激磁绕组、输出绕组、气隙长度和工作半径,以...     

液浮陀螺仪框架结构刚度特性的研究

本文用有限元数值计算方法对引起液浮陀螺仪 b2 项漂移的陀螺仪框架结构 X、Y方向的刚度特性进行了分析 ,给出了三类框架模型在不同载荷作用下所表现出来的柔度特性 ,并对陀螺仪框架进行了结构优化 ,其结果为陀螺仪的改进设计提供了重要的参考依据     

Effect of regeneration on the thermo-ecological performance analysis and optimization of irreversible air refrigerators

A thermo-ecological performance analysis of an irreversible regenerative air refrigerator cycle exchanging heat with thermal reservoirs is presented. In the analysis, the external irreversibility effects due to heat transfer across finite temperature differences and the heat leak loss between the external heat reservoirs while the internal irreversibilities are due to the non-isentropic compression and expansion processes and the regenerative loss are taken into account. The effects of regeneration and heat sources temperature ratio are given special emphasis and investigated in detail. A comparative performance analysis considering the objective functions of an ecological coefficient of performance, exergetic efficiency and coefficient of performance is also carried out. The maximum of the objective functions and the corresponding optimal conditions have been derived analytically. The obtained results may provide a general theoretical tool for the thermo-ecological design of regenerative air refrigerators.     

基于小波分析与LSSVM的陀螺仪随机漂移建模

为了提高陀螺仪的使用精度,以陀螺仪随机漂移时间序列为研究对象,建立了基于小波分析和最小二乘支持向量机（LSSVM）的陀螺仪随机漂移模型。陀螺仪作为高精度敏感器件,其随机漂移信号具有非线性、弱平稳性等特点,难以补偿。为了提高补偿精度,这里采用小波分析对陀螺仪随机漂移信号进行多尺度分解,利用最小二乘支持向量机方法对重构后的近似序列和细节序列建立非线性子模型,最后将各子模型输出融合作为组合模型输出。最后将该算法用于动调陀螺仪的随机漂移建模,实验结果表明基于该组合算法的非线性模型能够有效地反映陀螺仪的随机漂移特性,建模效果明显优于直接采用LSSVM和ANN建立的模型。     

Effect of air injection method on the performance of an air lift pump

Air lift pump performance was investigated experimentally for different submergence ratios (the ratio between the immersed length of the riser and its total length) using different air injection footpiece designs. For this purpose an air lift pump with a riser 200 cm long and 2.54 cm in diameter, was designed and tested. Nine different air injection footpiece designs were used at four submergence ratios with different air injection pressures (from 0.2 to 0.4 bar). An area of 10 mm² was chosen and divided into nine injection hole arrangements (1, 2, 3, 4, 6, 15, 25, 34 and 48 holes) to cover the whole experimental range. Four submergence ratios were used for this work: 0.75, 0.7, 0.6 and 0.5. The experimental results showed a marked effect on the pump performance when operated with different types of injectors at different submergence ratios. The results indicated that the disk with three holes (D3) gives the highest efficiency at nearly all submergence ratios. Moreover, it is found that there is a suitable disk design for maximum water flow rate at every submergence ratio. Further, the highest efficiency resulted at the largest used submergence ratio, namely 0.75. The pump capacity and efficiency were found to be functions of air flow rate, lift ratio, and injection pressure.     

Effect of inflation pressure on tractive performance of bias-ply tires

This study was to investigate the effect of inflation pressure on the tractive performance of bias-ply tires for agricultural tractors. Traction tests were conducted at velocities of 3, 4, and 5.5 km h⁻¹ under four different surface conditions using a 13.6–28 6PR bias-ply tire as driving the wheel of the test tractor. When the inflation pressure was reduced from 250 to 40 kPa by a decrement of either 30 or 50 kPa depending upon the test surfaces, some of the test results showed that the traction coefficient and tractive efficiency were increased maximally by 14 and 6%, respectively, at 20% slip. However, such improvements in traction were not statistically consistent enough to find any rules regarding the effect of inflation pressure of bias ply tires on the tractive performance of tractors.     

Effect of frequency of air flow on the performance of the Wells turbine

Experimental investigations on the effect of Strouhal number and rotor solidity on the performance of 0.2m diameter Wells self rectifying air turbine with NACA 0021 profile blades are presented. The results show an increase in starting torque with the Strouhal number of airflow and rotor solidity. The effect of Strouhal number on the running performance of the turbine is solidity dependent     

Effect of blade profile on the performance of the Wells self-rectifying air turbine

The effect of blade profile and thickness on the starting and running performance of a 0.2 m diameter Wells turbine is reported. The starting torque can be increased considerably by using thicker NACA aerofoils and modified NACA aerofoil blades and by increasing the turbine solidity. Thicker and modified NACA aerofoil blades also improved the running performance of the turbine. Artificially roughened blades showed degraded performance.     

基于遗传小波神经网络的MEMS陀螺误差建模

研究了一种基于遗传算法改进的小波神经网络.该方法采用小波神经网络为主要逼近手段,并通过遗传算法优化网络的关键参数.由于小波神经网络兼容了神经网络的自学习特性和小波分析的时-频局部性,而遗传算法具有较强的全局搜索能力,二者结合形成的遗传小波神经网络因此具有较高的逼近与容错能力,从而弥补了传统的方差建模方法的不足.将该算法应用到某型MEMS陀螺仪的随机误差建模中,结果表明:遗传小波网络对原始信号的逼近精度误差在以内,较之传统的方差建模方法有了显著的提高,这一精度基本上可以满足MEMS陀螺工程化应用的要求.     

谱分裂对集成光学陀螺灵敏度影响

为寻求谐振式集成光学陀螺可实现灵敏度的优化,基于调频光谱原理,应用双频率组合调制的闭环控制结构,在对通过陀螺核心敏感器件谐振腔的结构参数优化、调制频率选择等措施实现决定于谐振腔谐振特性一阶微分最大值的最佳灵敏度情形的理论分析基础上,研究了谐振峰分裂对陀螺灵敏度的影响。相关实验表明,对于给定结构的谐振式集成光学陀螺,理论上的最佳参数,并不能保证理论最佳灵敏度的实现。通过双频率组合调制下无源环形谐振腔谐振特性的测量,发现了谐振腔谐振峰分裂现象,分裂程度随腔长增加而趋明显;谐振峰的分裂,导致透射谱展宽;透射谱展宽后一阶微分谱最大值的下降,将使陀螺灵敏度随之劣化。为应对这种劣化,需要对系统调制频率进行相应调整,并控制腔长,以抑制峰分裂程度,进而控制对陀螺灵敏度的影响。