多自由度机器人位姿稳定性控制方法研究

对于多自由度机器人位姿控制方法来说,机器人位姿稳定性受到各种因素的干扰,容易发生位姿失稳现象,为此,提出一种新的方法来解决此问题.采用扩展卡尔曼滤波算法实现多自由度机器人各个传感器数据的有效融合,获取多方位机器人位姿数据;通过传感器信号处理去除机器人位姿测量噪声,使用自适应扩展技术实现机器人参量与姿态角校正信息融合,通过反演积分项自适应调节姿态参量并弥补稳态误差,实现机器人的位姿稳定控制.仿真实验结果表明,该控制方法能够准确实现多自由度机器人位姿稳定性控制,即使引入扰动机制仍然不会出现控制失衡,具有较好的稳态控制效果.     

Arctic microorganisms respond more to elevated UV-B radiation than CO2

Surface ultraviolet-B radiation and atmospheric CO2 concentrations have increased as a result of ozone depletion and burning of fossil fuels. The effects are likely to be most apparent in polar regions where ozone holes have developed and ecosystems are particularly sensitive to disturbance. Polar plant communities are dependent on nutrient cycling by soil microorganisms, which represent a significant and highly labile portion of soil carbon (C) and nitrogen (N). It was thought that the soil microbial biomass was unlikely to be affected by exposure of their associated plant communities to increased UV-B. In contrast, increasing atmospheric CO2 concentrations were thought to have a strong effect as a result of greater below-ground C allocation. In addition, there is a growing belief that ozone depletion is of only minor environmental concern because the impacts of UV-B radiation on plant communities are often very subtle. Here we show that 5 years of exposure of a subarctic heath to enhanced UV-B radiation both alone and in combination with elevated CO2 resulted in significant changes in the C:N ratio and in the bacterial community structure of the soil microbial biomass.     

Wet and dry deposition of Chernobyl releases

The passage of the Chernobyl plume over the United Kingdom in May 1986 led to the deposition of radionuclides on the ground by wet and dry deposition processes. Here we analyse rainfall during the passage of the plume and the published monitoring data obtained afterwards, and show that levels of deposited 137Cs can be closely related to rainfall intercepting the plume. 137Cs was present in the atmosphere mostly as particulate species with wet deposition mechanisms dominating. In contrast, 131I was present as particulate and vapour phase material, and reported levels on grass and in cow's milk show that both wet and dry deposition mechanisms were important. 131I on grass and in cow's milk therefore shows a different geographic pattern to 137Cs, and is not so closely related to rainfall. We have calculated washout factors for locations where there are data on deposition, rainfall and air concentrations during the passage of the Chernobyl plume. From these factors and interpolated concentrations in the atmosphere, the total deposition of 137Cs has been estimated at each of 4,000 rain gauge stations in the United Kingdom. The results are presented as deposition contours and have been compared with measurements in parts of the country. Estimates of the total deposition of 131I and 137Cs show that less than or equal to 1% of the estimated total releases from Chernobyl were deposited on the United Kingdom.     

基于卷积神经网络的目标识别及姿态检测

基于深度学习方法,运用Faster R-CNN目标检测架构和ZFNet卷积神经网络,针对微装配系统目标的特点对网络进行训练,在此基础上设计了一个网络对识别目标进行姿态检测.实验结果表明:采用深度学习方法可以有效地对部分遮挡的目标进行识别并检测其姿态,相比于传统方法,该方法对环境适应性更强且速度更快,具有实际应用价值.     

移动机器人车载摄像机位姿的高精度快速求解

在分析移动机器人车载摄像机位姿的特殊性质的基础上,根据摄像机的等效转轴构造辅助旋转矩阵,利用该旋转矩阵将原始待分解本质矩阵和单应矩阵转换为一类简单的、可通过初等数学运算进行分解的本质矩阵和单应矩阵。仿真实验的结果表明,该车载摄像机位姿估计算法较传统方法具有更高的精度和更快的运算速度,对摄像机等效转轴的扰动也具有很好的鲁棒性。此外,分解出的可能解的数目较传统算法减少了一半,且在除诱导单应阵的空间景物平面与地面垂直的情况下,均能直接得到移动机器人的唯一转角,为移动机器人姿态控制提供了极大的便利。     

浅谈生育观念与贫困落后

人口增长过快、质量不高是贫困落后地区的一个显著特点。文中论述了影响生育观念的因素－－促进生育观念的转变,控制人口增长、提高人口质量对加快经济发展,提高人们生活水平的重要意义。     

高校贫困生的心理问题及其成因与对策

高校贫困生心理问题呈逐年上升趋势.我们应把握他们心理问题的表现及特点,在成因分析的基础上,通过建立健全心理健康教育和咨询体系、关注贫困生心理健康、强化育人环境、助困与育人有机结合等措施,不断增强他们的心理调适能力和社会生活适应能力,从根本上解决高校贫困生的心理危机,使他们成为人格健全、富于理想、勇于创新的人才.     

怒江州致贫因素分析及对策探讨

怒江州是云南和全国最贫困的少数民族自治州之一.山高坡陡,耕地量少质差;80%人口居于海拔大于1 400 m山地,长期处于种粮为主的原始农业状态;人地矛盾加剧,轮歇种植和陡坡垦殖严重,生态环境恶化;经济基础薄弱,贫困程度深;交通不便,社会、经济、文化发展长期滞后.本文以翔实的资料、案例对怒江州的贫困原因进行深层次分析,并提出以下脱贫对策思路:修建山地干线公路,改善山区生产、生活条件;山地停止种粮,全面退耕还林还牧;调整产业结构,重建生态环境;建设山区新农村,拓展生存空间.