考虑不确定性,让机器人在狭窄环境更安全高效避障
U-OBCA: Uncertainty-Aware Optimization-Based Collision Avoidance via Wasserstein Distributionally Robust Chance Constraints
- 用概率约束直接处理多边形障碍物,避免简化几何形状
- 在窄巷和复杂环境中的规划效率提升显著,保守性大幅降低
- 无需假设噪声分布,适合真实场景,可被标准优化器求解
定位误差、障碍物轨迹预测误差及环境扰动带来的不确定性给机器人安全导航带来挑战。现有不确定性感知规划方法常将多边形机器人与障碍物近似为圆或椭圆等简单几何体,虽计算便捷,但显著缩小可行空间,导致过度保守轨迹,甚至在狭小环境中规划失败。此外,许多方法依赖特定噪声分布假设,实际中可能不成立,限制性能保障。为此,本文将基于优化的避障(OBCA)框架拓展为不确定性感知版本,称为U-OBCA。该方法通过构建基于OBCA的概率性机会约束,显式建模多边形机器人与障碍物间的碰撞风险,从而避免几何简化,减少不必要的保守性。这些概率约束在温和分布假设下转化为确定性非线性约束,可由标准数值优化求解器高效处理。理论分析、数值仿真与真实实验验证了该方法的有效性。结果表明,相比现有基线方法,U-OBCA显著降低规划保守性,在窄巷与杂乱环境中实现更高导航效率。
原文摘要 · Abstract (English)
Uncertainties arising from localization error, trajectory prediction errors of the moving obstacles and environmental disturbances pose significant challenges to robot's safe navigation. Existing uncertainty-aware planners often approximate polygon-shaped robots and obstacles using simple geometric primitives such as circles or ellipses. Though computationally convenient, these approximations substantially shrink the feasible space, leading to overly conservative trajectories and even planning failure in narrow environments. In addition, many such methods rely on specific assumptions about noise distributions, which may not hold in practice and thus limit their performance guarantees. To address these limitations, we extend the Optimization-Based Collision Avoidance (OBCA) framework to an uncertainty-aware formulation, termed \emph{U-OBCA}. The proposed method explicitly accounts for the collision risk between polygon-shaped robots and obstacles by formulating OBCA-based chance constraints, and hence avoiding geometric simplifications and reducing unnecessary conservatism. These probabilistic constraints are further tightened into deterministic nonlinear constraints under mild distributional assumptions, which can be solved efficiently by standard numerical optimization solvers. The proposed approach is validated through theoretical analysis, numerical simulations and real-world experiments. The results demonstrate that U-OBCA significantly mitigates the conservatism in trajectory planning and achieves higher navigation efficiency compared to existing baseline methods, particularly in narrow and cluttered environments.
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