With the rapid development of robotics swarm technology, there are more tasks that require the swarm to pass through complicated environments safely and efficiently. Virtual tube technology is a novel way to achieve this goal. Virtual tubes are free spaces connecting two places that provide safety boundaries and direction of motion for swarm robotics. How to determine the design quality of a virtual tube is a fundamental problem. For such a purpose, this paper presents a degree of flowability (DOF) for two-dimensional virtual tubes according to a minimum energy principle. After that, methods to calculate DOF are proposed with a feasibility analysis. Simulations of swarm robotics in different kinds of two-dimensional virtual tubes are performed to demonstrate the effectiveness of the proposed method of calculating DOF.

翻译：随着机器人集群技术的快速发展，越来越多的任务要求集群能够安全高效地穿越复杂环境。虚拟管道技术是实现这一目标的新颖方法。虚拟管道是连接两处空间的自由区域，为集群机器人提供安全边界和运动方向。如何评估虚拟管道的设计质量是一个基础性问题。为此，本文基于最小能量原理，为二维虚拟管道提出了一种可流通度指标。随后，提出了计算可流通度的方法并进行了可行性分析。通过对集群机器人在不同类型二维虚拟管道中的仿真实验，验证了所提可流通度计算方法的有效性。