NEPTUNE: Nonentangling Trajectory Planning for Multiple Tethered Unmanned Vehicles

Abstract--Despite recent progress in trajectory planning for multiple robots and a single tethered robot, trajectory planning for multiple tethered robots to reach their individual targets without entanglements remains a challenging problem. In this paper, a complete approach is presented to address this problem. First, a multi-robot tether-aware representation of homotopy is proposed to efficiently evaluate the feasibility and safety of a potential path in terms of (1) the cable length required to reach a target following the path, and (2) the risk of entanglements with the cables of other robots. Top-down view of a workspace to illustrate an entanglement situation. The efficiency of the proposed homotopy representation is compared against the existing single and multiple tethered robot planning approaches. While there exists abundant literature on multi-robot path I. NMANNED vehicles such as unmanned aerial vehicles (UAVs), unmanned ground vehicles (UGVs) and unmanned robot planning problem focus on the single robot case and surface vehicles (USVs) have been widely adopted use a representation of homotopy to identify the path or cable in industrial applications due to reduced safety hazards for configuration [8]-[11]. Feasible paths are found by searching humans and potential cost saving [1], [2]. For autonomous tethered robots, it is robots efficiently. Moreover, slow graph expansion requires important to consider the risk of the tether being entangled offline construction of the graph prior to online planning. Each robot is attached to one end of a slack and online trajectory generation framework for non-entangling flexible cable that is allowed to lie on the ground.