车载导航系统陀螺的自适应校正方法

分析了低成本压电振动陀螺误差及其影响因素,在实验的基础上得出采用温度补偿陀螺误差的可行性。建立了联合卡尔曼滤波方程融合GPS和INS信息,估计定位信息和陀螺误差。提出车载GPS/INS组合导航系统中陀螺零漂误差和标度因子误差的校正过程启动条件,当条件满足时,以估计的陀螺误差为输入,采用温度误差校正表学习算法对陀螺误差模型进行训练。用道路实验数据对提出的陀螺校正算法进行验证,结果表明该算法精度高、收敛快、可操作性好。     

内燃机瞬时转速测量及其误差研究

论述了测量内燃机瞬时转速的PC仪器的工作原理 ,构成及其应用实例 ,并对磁电式转速测量系统固有的测量误差进行了详细分析研究。     

人的失误模型在船舶溢油事故应急中的应用分析

船舶交通事故问题的预测一直是业内研究人员十分重视的研究课题。分别采用回归预测法、时间序列预测法、灰色理论预测法和贝叶斯统计预测法等不同方法,结合国内某港引航站近十多年来船舶引航总量和事故的实际情况,进行了比较分析和对未来情况予以预测。着重就贝叶斯方法在港口船舶引航风险预测中的运用进行了探讨。结论证明贝叶斯估计方法得到的结果具有良好的预测效果。     

船舶机损事故人误原因因素的层次分析法

基于认知系统工程分类方法，应用层次分析法构建了船舶机损事故人误原因因素结构模型，将成对比较矩阵的特征向量作为因素的权重，确定相关因素的影响力排序。给出了一种识别船舶机损事故中人误原因主要影响因素的实用方法，并针对性地提出相应预防措施，减少船舶机损事故提供可靠的理论依据。     

A combined use of phase plane and handling diagram method to study the influence of tyre and vehicle characteristics on stability

This paper deals with in-curve vehicle lateral behaviour and is aimed to find out which vehicle physical characteristics affect significantly its stability. Two different analytical methods, one numerical (phase plane) and the other graphical (handling diagram) are discussed. The numerical model refers to the complete quadricycle, while the graphical one refers to a bicycle model. Both models take into account lateral load transfers and nonlinear Pacejka tyre–road interactions. The influence of centre of mass longitudinal position, tyre cornering stiffness and front/rear roll stiffness ratio on vehicle stability are analysed. The presented results are in good agreement with theoretical expectations about the above parameters influence, and show how some physical characteristics behave as saddle-node bifurcation parameters.     

离焦对光测影响的初步研究

分析离焦产生机理,并通过实验的方法,定量地分析离焦对光测的影响.有助于解决在进行大视场测量时,特别是对大视场内的运动目标位置进行测昔时,在什么位置标定既方便又不影响测量精度的难题.     

发动机振动信号不对称现象分析

某柴油机振动信号出现不对称现象,其最大值与最小值差异较大。该信号的频谱特性表明:在0-100 Hz频段内,存在发动机转速的2阶、4阶、6阶分量,其中2、4阶分量之间存在某种微妙的相位关系,导致其在时域叠加后出现不对称现象。本文进一步研究了2阶、4阶分量在800~3 000 r/min整个转速范围内的振动位移,发现低转速时比高转速时大87.5%以上。根据发动机力学模型认为这是由发动机倾覆力矩引起的,指明了改进方向,为该发动机的改进方案提供了检验依据。     

电磁环境船模预测技术的误差分析研究

基于缩比船模原理,从模型限制误差、方法误差和问题本身的误差等方面分析电磁环境船模预测技术的主要误差源,并在此基础上分别论述上述误差源对电磁环境预测精度产生的影响.可以有针对性地采取相应措施控制误差,以更好地获取逼近于实船的电磁环境分布特性.     

Flexural gravity wave generation by initial disturbances in the presence of current

The effect of uniform current on the generation of flexural gravity waves resulting from initial disturbances at a point was analyzed in two dimensions. The problem was formulated as an initial boundary value problem under the assumptions of the linearized theory of water waves. By direct application of the Laplace transform and then the Fourier transform, explicit expressions for the velocity potential and free surface elevation were obtained in integral forms; these were evaluated asymptotically for large distances and times by the application of the method of the stationary phase to obtain the far field behavior of the surface elevations in specific cases. Simple numerical computations were performed to illustrate the effect of uniform current on the surface elevation, wavelength, phase velocity, and group velocity of the flexural gravity waves and on the far field behavior of the progressive waves in two different cases, namely, when there is an initial depression concentrated at the origin and an initial impulse concentrated at the origin.