Several ground-based robots have been developed to support dangerous fire extinguishing activities; however, in such cases, it is difficult to access the fire sources directly. The concept of a hose-type robot called ‘dragon firefighter’ (DFF) is proposed herein; it emits high-pressure water from a fire hose and floats it for direct transmission to the fire point. A stable levitation with 2 m length was realized; however, for practical use, we must extend the floating length of the robot. This study was aimed at extending the floating length of a hose-like body. Two primary issues need to be addressed for achieving this aim: lack of a sufficient reaction force for flying and torsion along the longitudinal direction of the body. Therefore, our robot was first extended using a middle nozzle. A flow channel model was constructed, and an injection hole was designed to achieve a cross-sectional area that could generate a sufficient reaction force. An adjustable jet direction nozzle was designed with four degrees of freedom to control the net force and torsion torque. Finally, a simple proportional-derivative control was incorporated to adjust the twist angle, float the DFF (3.6 m length), surmount a wall, and subsequently, extinguish the fire. GRAPHICAL ABSTRACT

中文翻译：

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使用多喷水喷嘴的 4 m 长飞软管式机器人灭火

已经开发了几种地面机器人来支持危险的灭火活动；然而，在这种情况下，很难直接接近火源。本文提出了一种称为“龙消防员”（DFF）的软管式机器人的概念；它从消防水带中喷出高压水并将其漂浮起来，直接输送到着火点。实现了 2 m 长的稳定悬浮；然而，为了实际使用，我们必须延长机器人的浮动长度。这项研究旨在延长软管状主体的浮动长度。实现这一目标需要解决两个主要问题：缺乏足够的飞行反作用力和沿车身纵向的扭转。因此，我们的机器人首先使用中间喷嘴进行了扩展。构建了流道模型，并设计了一个注射孔，以达到能够产生足够反作用力的横截面积。一个可调节的喷射方向喷嘴被设计成具有四个自由度来控制净力和扭矩。最后，采用一个简单的比例微分控制来调整扭转角、浮动 DFF（3.6 m 长）、越过墙壁，随后灭火。图形概要