Lightweight and Integrated Design of Tubeless Hydraulic Quadruped Robot Based on Additive Manufacturing

ABSTRACT Hydraulic quadruped robots exhibit exceptional terrain adaptability, offering significant potential for environmental exploration and military transportation. However, conventional hydraulic architectures are often plagued by excessive weight, complex pipeline network and mechanical interference, which restrict the improvement of its compactness and flexibility. To address these issues, this paper proposes a tubeless limb leg unit (LLU) featuring an electro‐hydraulic hybrid drive and topologically optimized structural components. By exploring the relationship between motion capability and joint performance parameters, a hybrid drive configuration integrating rotary and linear (RL) actuators is proposed, achieving full integration of actuators and hydraulic flow channels within the LLU. Furthermore, a lightweight reconstruction of critical thigh components is executed using the variable density penalty method combined with a lattice‐filling strategy to mitigate local stress concentrations, which reduces redundant mass by 37% without compromising structural integrity. Subsequently, a compact hydraulic power system is constructed, and an integrated control and simulation platform based on the robot operating system (ROS) framework is designed. Experimental validation demonstrates that the robot exhibits better dynamic stability during standing, trot gait, heavy payload, uneven terrain, and disturbance recovery tests.