脉冲星导航可靠、稳定、精度高,是实现火星探测器自主导航的有效手段之一.针对脉冲星导航中脉冲到达时间的微小误差会引起巨大的位置估计误差这一问题,提出了一种基于扩维Unsented卡尔曼滤波(ASUKF,Augmented State Unscented Kalman Fi...脉冲星导航可靠、稳定、精度高,是实现火星探测器自主导航的有效手段之一.针对脉冲星导航中脉冲到达时间的微小误差会引起巨大的位置估计误差这一问题,提出了一种基于扩维Unsented卡尔曼滤波(ASUKF,Augmented State Unscented Kalman Filter)的火星探测器脉冲星自主导航方法,建立了以位置、速度和脉冲到达时间的常值测量误差作为状态量的导航系统数学模型,可在对探测器位置、速度进行估计的同时有效估计并修正脉冲到达时间的常值测量误差,并降低随机测量误差的影响.仿真结果表明该方法的导航定位精度可达350 m以内,可以满足火星探测自主导航的需要.展开更多
The autonomous exploration and mapping of an unknown environment is useful in a wide range of applications and thus holds great significance. Existing methods mostly use range sensors to generate twodimensional (2D) g...The autonomous exploration and mapping of an unknown environment is useful in a wide range of applications and thus holds great significance. Existing methods mostly use range sensors to generate twodimensional (2D) grid maps. Red/green/blue-depth (RGB-D) sensors provide both color and depth information on the environment, thereby enabling the generation of a three-dimensional (3D) point cloud map that is intuitive for human perception. In this paper, we present a systematic approach with dual RGB-D sensors to achieve the autonomous exploration and mapping of an unknown indoor environment. With the synchronized and processed RGB-D data, location points were generated and a 3D point cloud map and 2D grid map were incrementally built. Next, the exploration was modeled as a partially observable Markov decision process. Partial map simulation and global frontier search methods were combined for autonomous exploration, and dynamic action constraints were utilized in motion control. In this way, the local optimum can be avoided and the exploration efficacy can be ensured. Experiments with single connected and multi-branched regions demonstrated the high robustness, efficiency, and superiority of the developed system and methods.展开更多
为了减少移动机器人在自主探索过程中反复到达已知区域的次数,从而提高自主探索效率,提出一种高效率自主探索算法TMRRT(topological map based rapidly exploring random tree)。首先,将变生长率的局部与全局快速扩展随机树(RRT)作为探...为了减少移动机器人在自主探索过程中反复到达已知区域的次数,从而提高自主探索效率,提出一种高效率自主探索算法TMRRT(topological map based rapidly exploring random tree)。首先,将变生长率的局部与全局快速扩展随机树(RRT)作为探测器来发现地图的边界,并对前沿点进行聚类;同时,将最佳探测点存储下来作为拓扑地图,避免机器人反复到达已探索区域。最后,在不同环境下进行仿真并在实际环境中进行验证。实验结果显示,本文的探索算法相对于RRT算法平均探索时长减小了7.5%以上、平均路径长度减小了19.8%以上,相对于FA(frontier-based approach)自主探索算法平均探索时长减小了15.7%以上、平均路径长度减小了34.3%以上。结果表明,该算法可以有效提高机器人自主探索的效率,在实际环境中具有可行性。展开更多
基金the National Natural Science Foundation of China (61720106012 and 61403215)the Foundation of State Key Laboratory of Robotics (2006-003)the Fundamental Research Funds for the Central Universities for the financial support of this work.
文摘The autonomous exploration and mapping of an unknown environment is useful in a wide range of applications and thus holds great significance. Existing methods mostly use range sensors to generate twodimensional (2D) grid maps. Red/green/blue-depth (RGB-D) sensors provide both color and depth information on the environment, thereby enabling the generation of a three-dimensional (3D) point cloud map that is intuitive for human perception. In this paper, we present a systematic approach with dual RGB-D sensors to achieve the autonomous exploration and mapping of an unknown indoor environment. With the synchronized and processed RGB-D data, location points were generated and a 3D point cloud map and 2D grid map were incrementally built. Next, the exploration was modeled as a partially observable Markov decision process. Partial map simulation and global frontier search methods were combined for autonomous exploration, and dynamic action constraints were utilized in motion control. In this way, the local optimum can be avoided and the exploration efficacy can be ensured. Experiments with single connected and multi-branched regions demonstrated the high robustness, efficiency, and superiority of the developed system and methods.
文摘为了减少移动机器人在自主探索过程中反复到达已知区域的次数,从而提高自主探索效率,提出一种高效率自主探索算法TMRRT(topological map based rapidly exploring random tree)。首先,将变生长率的局部与全局快速扩展随机树(RRT)作为探测器来发现地图的边界,并对前沿点进行聚类;同时,将最佳探测点存储下来作为拓扑地图,避免机器人反复到达已探索区域。最后,在不同环境下进行仿真并在实际环境中进行验证。实验结果显示,本文的探索算法相对于RRT算法平均探索时长减小了7.5%以上、平均路径长度减小了19.8%以上,相对于FA(frontier-based approach)自主探索算法平均探索时长减小了15.7%以上、平均路径长度减小了34.3%以上。结果表明,该算法可以有效提高机器人自主探索的效率,在实际环境中具有可行性。
