Most birds can navigate seamlessly between aerial and terrestrial environments. Whereas the forelimbs evolved into wings primarily for flight, the hindlimbs serve diverse functions such as walking, hopping and leaping, and jumping take-off for transitions into flight¹. These capabilities have inspired engineers to aim for similar multimodality in aerial robots, expanding their range of applications across diverse environments. However, challenges remain in reproducing multimodal locomotion, across gaits with distinct kinematics and propulsive characteristics, such as walking and jumping, while preserving lightweight mass for flight. This trade-off between mechanical complexity and versatility² limits most existing aerial robots to only one additional locomotor mode^3,4,5. Here we overcome the complexity–versatility trade-off with RAVEN (Robotic Avian-inspired Vehicle for multiple ENvironments), which uses its bird-inspired multifunctional legs to jump rapidly into flight, walk on the ground, and hop over obstacles and gaps similar to the multimodal locomotion of birds. We show that jumping for take-off contributes substantially to the initial flight take-off speed^6,7,8,9 and, remarkably, that it is more energy efficient than taking off without the jump. Our analysis suggests an important trade-off in mass distribution between legs and body among birds adapted for different locomotor strategies, with greater investment in leg mass among terrestrial birds with multimodal gait demands. Multifunctional robot legs expand the opportunities to deploy traditional fixed-wing aircraft in complex terrains through autonomous take-offs and multimodal gaits.

大多数鸟类可以在空中和陆地环境之间无缝导航。前肢进化成翅膀主要用于飞行，而后肢则具有多种功能，例如行走、跳跃和跳跃，以及用于过渡到飞行¹ 的跳跃起飞。这些功能激发了工程师在空中机器人中实现类似的多模态，从而在不同环境中扩展了其应用范围。然而，在具有不同运动学和推进特性的步态（例如行走和跳跃）中再现多模态运动，同时保留飞行的轻质质量，仍然存在挑战。这种机械复杂性和多功能性之间的权衡² 限制了大多数现有的空中机器人只能使用一种额外的运动模式^3,4,5。在这里，我们用 RAVEN（受多 EN 环境启发的机器人鸟类车辆）克服了复杂性与多功能性的权衡，它使用其受鸟类启发的多功能腿快速跳跃飞行，在地面上行走，并跳过障碍物和缝隙，类似于鸟类的多模式运动。我们表明，起飞时跳跃对初始飞行起飞速度^6,7,8,9 有很大贡献，并且值得注意的是，它比不跳跃的起飞更节能。我们的分析表明，在适应不同运动策略的鸟类之间，腿部和身体之间的质量分布存在重要的权衡，在具有多模式步态需求的陆生鸟类中，对腿部质量的投资更大。多功能机器人腿通过自主起飞和多模式步态，扩大了在复杂地形中部署传统固定翼飞机的机会。