A Dexterity and Exploration Enhanced Quadruped Robot With a Multi-Functional Retractable Variable Stiffness Manipulator

Navigating complex environments—ranging from confined spaces to open areas blocked by obstacles or out of reach of traditional robotic arms—remains a major challenge for conventional robotic systems. These challenges include limited dexterity, adaptability, and accessibility. To address these issues, this article proposed a dexterity and exploration enhanced quadruped robot (DEEQR), which was designed with a quadruped base and a multifunctional retractable variable stiffness manipulator (MRVSM). The MRVSM features a compact active-passive composite continuum mechanism with a 12.8 mm diameter, a high-stiffness telescopic mechanism, and a 2.5 mm diameter working channel that supports interchangeable tools such as a 2-DOF grasper or other miniaturized tools. This design enables precise manipulation and exploration in narrow and obstructed environments. Experiments demonstrated that DEEQR can traverse uneven terrain, navigate confined gaps, and perform complex tasks such as a bomb disposal operation inside a backpack with a 5 cm diameter entrance. The robot also successfully explored and delivered water in blocked spaces beyond the direct reach of the quadruped base. These results highlight DEEQR's strong potential for anti-terrorism applications and search and rescue missions in challenging environments.