In this paper, we address the problem of enclosing an arbitrarily moving target in three dimensions by a single pursuer while ensuring the pursuer's safety by preventing collisions with the target. The proposed guidance strategy steers the pursuer to a safe region of space surrounding and excluding the target, allowing it to maintain a certain distance from the latter while offering greater flexibility in positioning and converging to any orbit within this safe zone. We leverage the concept of the Lyapunov Barrier Function as a powerful tool to constrain the distance between the pursuer and the target within asymmetric bounds, thereby ensuring the pursuer's safety within the predefined region. Further, we demonstrate the effectiveness of the proposed guidance law in managing arbitrarily maneuvering targets and other uncertainties (such as vehicle/autopilot dynamics and external disturbances) by enabling the pursuer to consistently achieve stable global enclosing behaviors by switching between stable enclosing trajectories within the safe region whenever necessary, even in response to aggressive target maneuvers. To attest to the merits of our work, we conduct experimental tests with various plant models, including a high-fidelity quadrotor model within Software-in-the-loop (SITL) simulations, encompassing various challenging target maneuver scenarios and requiring only relative information for successful execution.

翻译：本文研究在三维空间中由单个追踪器环绕任意运动目标的问题，同时通过防止与目标碰撞来确保追踪器的安全性。所提出的制导策略将追踪器引导至目标周围且排除目标本身的安全空间区域，使其能够与目标保持一定距离，同时在该安全区域内提供更灵活的定位能力，并能收敛至任意轨道。我们利用李雅普诺夫屏障函数的概念作为强大工具，将追踪器与目标之间的距离约束在非对称边界内，从而确保追踪器在预定义区域内的安全性。此外，我们证明了所提制导律在应对任意机动目标及其他不确定性（如飞行器/自动驾驶仪动力学和外部扰动）方面的有效性：通过允许追踪器在必要时切换安全区域内的稳定环绕轨迹，即使面对激进的目标机动，也能持续实现稳定的全局环绕行为。为验证本工作的优势，我们采用多种被控对象模型进行了实验测试，包括软件在环仿真中的高保真四旋翼模型，涵盖了各种具有挑战性的目标机动场景，且仅需相对信息即可成功执行。