论文标题

机器人导航的无奇异指导矢量场

Singularity-free Guiding Vector Field for Robot Navigation

论文作者

Yao, Weijia, de Marina, Hector Garcia, Lin, Bohuan, Cao, Ming

论文摘要

大多数现有的路径遵循导航算法无法保证全局收敛到所需的路径,也不能保证由于存在导航算法返回不可靠甚至没有解决方案的单数点而启用自我交织所需的路径。一个典型的示例是在矢量场引导路径跟踪(VF-PF)导航算法中产生的。这些算法基于向量场,而单数点正是向量场减小的位置。在本文中,我们表明,传统的VF-PF算法在数学上不可能实现全球收敛到所需的自我交织或什至简单闭合的所需路径(确切地说是单位圆的同构)。在这种新的不可能结果的激励下,我们提出了一种新颖的方法,可以将自我交织或简单的封闭期望路径转变为在较高维度的空间中的非自我交织和无界(准确地说是对真实线的同构)的方法。与这一新的期望路径相对应,我们在较高维度的空间上构建了一个无奇异的引导矢量场。因此,利用了该新的引导矢量场的整体曲线,以使全局收敛到较高的所需路径,因此,在较低维的子空间上积分曲线的投影将其收敛到物理(较低维)所需路径。严格的理论分析是使用动态系统理论进行理论结果进行的。此外,通过理论分析和数值模拟,我们提出的方法是结合常规VF-PF算法和轨迹跟踪算法的扩展方法。最后,为了显示我们提出的复杂工程系统方法的实际价值,我们在大风环境中使用固定翼飞机进行室外实验,以遵循2D和3D所需的路径。

Most of the existing path-following navigation algorithms cannot guarantee global convergence to desired paths or enable following self-intersected desired paths due to the existence of singular points where navigation algorithms return unreliable or even no solutions. One typical example arises in vector-field guided path-following (VF-PF) navigation algorithms. These algorithms are based on a vector field, and the singular points are exactly where the vector field diminishes. In this paper, we show that it is mathematically impossible for conventional VF-PF algorithms to achieve global convergence to desired paths that are self-intersected or even just simple closed (precisely, homeomorphic to the unit circle). Motivated by this new impossibility result, we propose a novel method to transform self-intersected or simple closed desired paths to non-self-intersected and unbounded (precisely, homeomorphic to the real line) counterparts in a higher-dimensional space. Corresponding to this new desired path, we construct a singularity-free guiding vector field on a higher-dimensional space. The integral curves of this new guiding vector field is thus exploited to enable global convergence to the higher-dimensional desired path, and therefore the projection of the integral curves on a lower-dimensional subspace converge to the physical (lower-dimensional) desired path. Rigorous theoretical analysis is carried out for the theoretical results using dynamical systems theory. In addition, we show both by theoretical analysis and numerical simulations that our proposed method is an extension combining conventional VF-PF algorithms and trajectory tracking algorithms. Finally, to show the practical value of our proposed approach for complex engineering systems, we conduct outdoor experiments with a fixed-wing airplane in windy environment to follow both 2D and 3D desired paths.

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