Degeneracy-Aware Factors with Applications to Underwater SLAM
Degeneracy-Aware Factors with Applications to Underwater SLAM
复制标题
简并感知因素及其在水下 SLAM 中的应用
DOI：
10.1109/iros40897.2019.8968577
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
M. Kaess
中科院分区：
文献类型：
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作者：
Akshay Hinduja;Bing;M. Kaess
同步定位与建图 (SLAM) 通常被表述为对图的优化。一种流行的方法是姿势图，它试图解决受姿势间测量（例如里程测量或闭环）约束的机器人姿势。对于距离传感器，这些姿势到姿势的约束可以通过执行扫描匹配技术来实现，例如迭代最近点（ICP）。然而，在几何特征不足或退化的环境中，ICP 解决方案可能不可靠，并导致图优化解决方案的轨迹出现显着漂移。在本文中，我们提出了一种退化感知方法，该方法有两个阶段：（1）退化感知 ICP 算法和（2）部分约束的闭环因子，将（1）的结果合并到 SLAM 位姿图优化中。我们的方法仅在状态空间的良好约束方向上执行更新和优化 ICP 和位姿图。这些方向是根据动态阈值选择的，该阈值在每次迭代时更新。我们将所提出的算法应用于声纳自主水下测绘。为了评估该算法的性能，我们在模拟和现实场景中进行了实验，并展示了该方法对导航漂移的鲁棒性以及在退化环境中拒绝不良闭环的能力，否则会降低轨迹的准确性和生成的地图的质量。
Simultaneous Localization and Mapping (SLAM) is commonly formulated as an optimization over a graph. A popular approach is the pose graph, which seeks to solve for robots poses that are constrained by pose-to-pose measurements, such as odometry measurements or loop closures. For range sensors, these pose-to-pose constraints can be achieved by performing scan matching techniques, such as Iterative Closest Point (ICP). However, in environments with insufficient or degenerate geometric features, the ICP solution can be unreliable and lead to significant drift in the trajectory of the graph optimization solution.In this paper, we propose a degeneracy-aware approach which has two stages: (1) a degeneracy-aware ICP algorithm and (2) a partially constrained loop closure factor to incorporate the results from (1) into the SLAM pose graph optimization. Our approach performs updates and optimizes both ICP and the pose graph in only the well constrained directions of the state space. These directions are selected on the basis of a dynamic threshold, which updates at each iteration. We apply the proposed algorithm to autonomous underwater mapping with sonar. To evaluate the performance of this algorithm, we conduct experiments in both simulation and real world scenarios, and show the method’s robustness to navigational drift and ability to reject poor loop closures in degenerate environments, which would otherwise degrade the accuracy of the trajectory and the quality of the resulting map.