无人机的自主飞行是无人机相关研究的重点方向,如何在复杂环境中快速分析环境,并规划一条安全可行的路径,是该方向的研究目标。针对传统路径搜索算法存在的路径不平滑问题,采用三阶B样条曲线进行预规划航迹。在欧式有符号距离函数(Eucli...无人机的自主飞行是无人机相关研究的重点方向,如何在复杂环境中快速分析环境,并规划一条安全可行的路径,是该方向的研究目标。针对传统路径搜索算法存在的路径不平滑问题,采用三阶B样条曲线进行预规划航迹。在欧式有符号距离函数(Euclidean Signed Distance Functions, ESDF)地图提供的梯度信息的基础上,分别在平滑、碰撞和可行性上设计约束方程,实现轨迹动态重规划。针对路径动态更新中,时间间隔变化产生的控制点不再符合约束的问题,采用各向异性曲线拟合方法,实现时间再分配,保障在动态更新路径的过程中,新产生的路径与原路径相似且具有同样的可行性。实验证明,该算法实现了无人机的自主路径规划与优化,能够进行动态避障,面对复杂环境具有鲁棒性。展开更多
Environmental factors affect animal behavior in a variety of ways. Compared to animals in the wild, captive animals are kept in narrow enclosures, suffer higher densities and are more intensely affected by human activ...Environmental factors affect animal behavior in a variety of ways. Compared to animals in the wild, captive animals are kept in narrow enclosures, suffer higher densities and are more intensely affected by human activities. Therefore, behavioral elasticity is likely modified to some extent in captive animals, which may negatively affect the possibility of successful release of endangered species in the wild. In our study we investigated the behaviors of the Oriental White Stork (Ciconia boyciana) in a semi-natural enclosure from 15 October 2005 to 8 September 2006 in Hefei Wildlife Park, China. The behavioral data were collected by instantaneous and scan sampling methods, and we analyzed the relationships between environmental factors and their behaviors. The amounts of time spent on maintenance behavior (foraging and moving) were at similar levels for birds reproducing multibroods (Group 1), birds reproducing one brood (Group 2) and birds without reproduction (Group 3). On the other hand, the amount of time spent on elastic behavior (defensive, breeding and preening) for Group 3 was lower than that for Groups 1 and 2. The behavioral pattern of the storks exhibited marked seasonal changes, which may be a function of ambient temperature, human disturbanc, and the length of daylight, but not of wind intensity. Our results provide basic data for future conser- vation measures of this endangered species.展开更多
文摘无人机的自主飞行是无人机相关研究的重点方向,如何在复杂环境中快速分析环境,并规划一条安全可行的路径,是该方向的研究目标。针对传统路径搜索算法存在的路径不平滑问题,采用三阶B样条曲线进行预规划航迹。在欧式有符号距离函数(Euclidean Signed Distance Functions, ESDF)地图提供的梯度信息的基础上,分别在平滑、碰撞和可行性上设计约束方程,实现轨迹动态重规划。针对路径动态更新中,时间间隔变化产生的控制点不再符合约束的问题,采用各向异性曲线拟合方法,实现时间再分配,保障在动态更新路径的过程中,新产生的路径与原路径相似且具有同样的可行性。实验证明,该算法实现了无人机的自主路径规划与优化,能够进行动态避障,面对复杂环境具有鲁棒性。
基金supported by the National Natural Science Foundation of China (Grant No. 3087317, 30470257)the Anhui Academic and Technical Leaders Fund
文摘Environmental factors affect animal behavior in a variety of ways. Compared to animals in the wild, captive animals are kept in narrow enclosures, suffer higher densities and are more intensely affected by human activities. Therefore, behavioral elasticity is likely modified to some extent in captive animals, which may negatively affect the possibility of successful release of endangered species in the wild. In our study we investigated the behaviors of the Oriental White Stork (Ciconia boyciana) in a semi-natural enclosure from 15 October 2005 to 8 September 2006 in Hefei Wildlife Park, China. The behavioral data were collected by instantaneous and scan sampling methods, and we analyzed the relationships between environmental factors and their behaviors. The amounts of time spent on maintenance behavior (foraging and moving) were at similar levels for birds reproducing multibroods (Group 1), birds reproducing one brood (Group 2) and birds without reproduction (Group 3). On the other hand, the amount of time spent on elastic behavior (defensive, breeding and preening) for Group 3 was lower than that for Groups 1 and 2. The behavioral pattern of the storks exhibited marked seasonal changes, which may be a function of ambient temperature, human disturbanc, and the length of daylight, but not of wind intensity. Our results provide basic data for future conser- vation measures of this endangered species.
