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arXiv 2306.07537cs.RO
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面向未知环境下安全任务执行的混合与定向调和势场

Hybrid and Oriented Harmonic Potentials for Safe Task Execution in Unknown Environment

College of Engineering, Peking University(北京大学工学院)

Shuaikang Wang, Meng Guo

AI总结:

本文提出一种基于任务自动机在线增量构建调和势场的方法,结合定向搜索与调和导航控制器,实现未知环境下非完整机器人的安全高效任务执行。

摘要:

调和势场提供了全局收敛且可证明无局部极小值的势场。由于其解析形式,它特别适合生成安全可靠的机器人导航策略。然而,对于由大量重叠的非球形障碍物组成的复杂环境,相关变换函数的计算可能非常繁琐。这在以下情况下尤为明显:(i)工作空间最初未知,且底层势场随着机器人探索而不断更新;(ii)高层任务由多个区域间的顺序导航任务组成,要求机器人在不同势场之间切换。因此,本文提出了一种高效且自动化的方案,根据任务自动机在线增量构建调和势场。引入了一种新颖的两层调和树(HT)结构,该结构促进了用于任务规划的定向搜索算法与用于非完整机器人的基于调和的导航控制器的混合组合。在在线执行过程中,两层结构均被高效且联合地调整,以反映更新后工作空间内导航的实际可行性和成本。全局安全性和收敛性在高层任务规划和低层机器人轨迹中均得到保证。纯势场方法常见的振荡或长绕行问题,以及纯搜索方法常见的急转弯或高计算复杂度问题均得以避免。针对多个强基线进行了广泛的数值仿真和硬件实验。

英文摘要:

Harmonic potentials provide globally convergent potential fields that are provably free of local minima. Due to its analytical format, it is particularly suitable for generating safe and reliable robot navigation policies. However, for complex environments that consist of a large number of overlapping non-sphere obstacles, the computation of associated transformation functions can be tedious. This becomes more apparent when: (i) the workspace is initially unknown and the underlying potential fields are updated constantly as the robot explores it; (ii) the high-level mission consists of sequential navigation tasks among numerous regions, requiring the robot to switch between different potentials. Thus, this work proposes an efficient and automated scheme to construct harmonic potentials incrementally online as guided by the task automaton. A novel two-layer harmonic tree (HT) structure is introduced that facilitates the hybrid combination of oriented search algorithms for task planning and harmonic-based navigation controllers for non-holonomic robots. Both layers are adapted efficiently and jointly during online execution to reflect the actual feasibility and cost of navigation within the updated workspace. Global safety and convergence are ensured both for the high-level task plan and the low-level robot trajectory. Known issues such as oscillation or long-detours for purely potential-based methods and sharp-turns or high computation complexity for purely search-based methods are prevented. Extensive numerical simulation and hardware experiments are conducted against several strong baselines.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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