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基于被动行走原理的双足机器人步态规划 被引量:2
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作者 李宏扬 孙中波 田彦涛 《吉林大学学报(信息科学版)》 CAS 2016年第1期79-85,共7页
为解决四连杆双足机器人的平面步态规划问题,提出基于被动行走的平面步态规划。基于3°向下坡面完全被动行走的动力学方程,利用角度不变控制方法施加控制力矩,得到机器人在水平面上的动力学模型。结合常数时间放缩方法对平面参考轨... 为解决四连杆双足机器人的平面步态规划问题,提出基于被动行走的平面步态规划。基于3°向下坡面完全被动行走的动力学方程,利用角度不变控制方法施加控制力矩,得到机器人在水平面上的动力学模型。结合常数时间放缩方法对平面参考轨迹进行时间放缩,得到机器人在水平面上步幅不变,周期可变的行走步态。通过Matlab软件数值仿真结果表明,该研究方法是可行、有效的。 展开更多
关键词 双足机器人 步态规划 角度不变控制 时间放缩 变周期
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City Size Distribution and Its Spatiotemporal Evolution in China 被引量:4
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作者 SHI Lifeng ZHANG Zengxiang +8 位作者 LIU Fang ZHAO Xiaoli WANG Xiao LIU Bin HU Shunguang WEN Qingke ZUO Lijun YI Ling XU Jinyong 《Chinese Geographical Science》 SCIE CSCD 2016年第6期703-714,共12页
Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban... Based on the National Land Use/Cover Database of China(NLUD-C) in the end of the 1980s(the 1980s,hereafter), 1995, 2000, 2005, and 2010, 665 cities were selected to study the size distribution and its changes of urban lands in China. In this study, the spatiotemporal evolutions of urban land size distribution as well as the influence of administrative-level on these cities were explored by combining urban spatial positions and administrative-levels. Results indicate that: 1) City size distribution using urban lands was more practical and reasonable than using non-agricultural population. 2) In the 1980s, cities with ascending urban land rank were centralized in Eastern China, specially the Changjiang(Yangtze) River Delta, the Zhujiang(Pearl) River Delta, and Beijing-Tianjin-Hebei region. Cities in Central, Western, and Northeast China mainly indicated descending urban land rank. 3) The transfer of national development focus resulted in cities with ascending urban land rank becoming evenly distributed nationwide; however, this trend was slightly centralized around Chengdu, Chongqing, and Wuhan in different periods. 4) During the 1980s to 2010, the proportion of cities with ascending urban land rank in provincial capitals, municipalities, and special administrative regions(high-level cities, hereafter) was consistently higher than those in prefecture- and county-level cities except for 2005–2010. The ranks of the majority of the prefecture- and county-level cities were mainly descending, supported by ascending; the proportion of cities with unchanged rank is small. This study breaks through the bottleneck of traditional research in the area of city size distribution by examining urban land replacing the non-agricultural population. The current study also provides scientific explanation for the healthy and reasonable development of urban land as well as the coordinated development of population urbanization and land urbanization. 展开更多
关键词 Chinese city urban land size distribution spatiotemporal evolution remote sensing
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