Calibration of robotic drilling systems with a moving rail

Industrial robots are widely used in aircraft assembly systems such as robotic drilling systems. It is necessary to expand a robot＇s working range with a moving rail. A method for improving the position accuracy of an automated assembly system with an industrial robot mounted on a moving rail is proposed. A multi-station method is used to control the robot in this study. The robot only works at stations which are certain positions defined on the moving rail. The calibration of the robot system is composed by the calibration of the robot and the calibration of the stations.The calibration of the robot is based on error similarity and inverse distance weighted interpolation.The calibration of the stations is based on a magnetic strip and a magnetic sensor. Validation tests were performed in this study, which showed that the accuracy of the robot system gained significant improvement using the proposed method. The absolute position errors were reduced by about 85%to less than 0.3 mm compared with the maximum nearly 2 mm before calibration.     

抑制飞控系统舵机间隙影响的非线性补偿器设计

通过对舵机间隙非线性特性的分析和极限环的定义及产生条件的讨论,在飞控系统中采用非线性补偿的方法,设计了间隙补偿器,并介绍了其工程实现方法,进行了相应的数字仿真和半物理仿真试验以及试验结果的对比分析。结果表明,此方法有效地解决了飞控系统由于舵机间隙引起的超调与极限环振荡现象,使飞控系统对舵机的频率特性以及间隙各方面要求大大降低,其工程实现方法简单实用、普遍性较强,具有较高的工程应用价值。     

1700℃热校准风洞

１７００℃热本单位风洞是一台高温、高速的稳态与动态温度校准装置。本文介绍了１７００℃热校准风洞的主要性能和特点，以及为此而采取的保温与冷却相结合的结构设计、高温内壳设计和其它的一些技术方法。     

温度冲击试验箱的参数测量

简介了温度冲击试验原理，提供了一种测量温度冲击试验设备参数的方法，并分析了一个实例。     

Meteor radar temperatures over Collm (51.3°N, 13°E)

The method of obtaining absolute temperature estimates by measuring the ambipolar diffusion coefficient with meteor radars in the mesopause region is basically well known. However, there is still a need to refine and adjust the background temperature gradient model which is necessary to calculate the temperature values. Therefore, a detailed comparison with independent temperature measurements is necessary to evaluate the performance of the method and to obtain more information about the temperature gradient. Recent studies provide some evidence that the impact of the gradient model on temperature estimates affects the absolute temperatures, but that it is of minor importance for wave analysis. This paper focuses on a detailed evaluation of the meteor radar temperatures by comparing them with SABER satellite and OH-emission mesopause region temperatures. The seasonal variation of the observed temperatures is well reproduced by the COMMA general circulation model.     

卫星摄影系统象移补偿速高比计算

本文研究了卫星摄影系统象移补偿速高比计算。从飞机上拍摄地面景物时,象移补偿速高此中的速度为地面相对飞机的速度,通常称为地速。但是,从卫星上拍摄地面照片时,如果把速高比中的速度取为地面相对于卫星的速度,则会导出谬误。为此,作者对速高比的定义进行了推广,对于这种拓广的速高比定义,也能适用于从飞机上拍摄地面景物的速高比计算。本文在推导公式过程中,把地球视为旋转椭球体,卫星轨道为椭圆轨道,导出了计算星下点速度和速高比的公式。最后与把地球视为正球体,忽略轨道偏心率的计算结果相比较,速高比的相对误差不超过0.5%。     

航空自动控制系统中的延时及其补偿

总结了作者40年来在各种不同的航空自动控制系统研制过程中，所出现的各类延时，给出了造成各种延时的原因，综述了延时对自动系统的控制精度、稳定性及操纵性的严重影响，并提出对延时所致后果的补偿方法。     

热电偶温度与电势互换公式

本文对铜—铜镍(康铜)(T)、镍铬—铜镍(康铜)(E)、铁—铜镍(康铜)(T)和铂铑13—铂(R)四种热电偶,根据温度 T→电势 E 的分度公式,采用多项式回归的方法,得出了电势 E→温度 T 的拟合公式,与分度公式比较,最大偏差在0.04℃以下,0℃以上的回归公式最大偏差小于0.02℃。     

Evidence of change after 2001 in the seasonal behaviour of the mesopause region from airglow data at El Leoncito

Airglow intensities and rotational temperatures of the OH(6-2) and O₂b(0-1) bands acquired at El Leoncito (32°S, 69°W) provide good annual coverage in 1998–2002, 2006, and 2007, with between 192 and 311 nights of observation per year. These data can therefore be used to derive the seasonal variations during each of these seven years, in airglow brightness and temperatures at altitudes of 87 and 95 km. From 1998 to 2001, seasonal variations are similar enough so that they can be well represented by a mean climatology, for each parameter. On the other hand, these climatologies do not agree with what is usually observed at other sites, maybe due to the particular orographic conditions at El Leoncito. With respect to the last three fully documented years (2002, 2006, and 2007), the similarity from year to year deteriorates, and there are greater differences in the seasonal behaviour, more or less in all the parameters. The differences include, e.g., maxima occurring earlier or later than “normal”, by one or two months. All this may suggest the build-up of a new regime of intraseasonal variability, with a possible relationship to corresponding changes in wave activity.     

太阳风中的Alfven波耗散与电子和质子温度分布问题

根据动力论Alfven波耗散机制,详细计算了动力论Alfven波衰减的能量分配给质子和电子的比率.初步解释了高速太阳风中质子温度比电子温度高的事实,定性说明了r＜10R_s时电子快速冷却的原因.