Light weight design and integrated method for manufacturing hydraulic wheel-legged robots

Design and manufacturing play pivotal roles in hydraulic-driven robotic development. However, previous studies have emphasized mainly results and performance, often overlooking the specifics of the design and manufacturing process. This paper introduces a novel approach known as light weight design and integrated manufacturing (LD&IM) for hydraulic wheel-legged robots. The LD&IM method leverages topology optimization and generative design techniques to achieve a substantial 45% weight reduction, enhancing the robot's dynamic motion capabilities. This innovative design method not only streamlines the design process but also upholds the crucial attributes of light weight construction and high strength essential for hydraulic wheel-legged robots. Furthermore, the integrated manufacturing method, incorporating selective laser melting (SLM) and high-precision subtractive manufacturing (SM) processes, expedites the fabrication of high-quality components. Using the LD&IM approach, a hydraulic-driven single wheel-legged robot, denoted as WLR-IV, has been successfully developed. This robot boasts low mass and inertia, high strength, and a simplified component structure. To assess its dynamic jumping capabilities, the control loop integrates a linear quadratic regulator (LQR) and zero dynamic-based controller, while trajectory planning uses the spring-loaded inverted pendulum (SLIP) model. Experimental jumping results confirm the WLR-IV single-legged robot's exceptional dynamic performance, validating both the effectiveness of the LD&IM method and the rationale behind the control strategy.