In context
By late 2023, underwater robotics had advanced beyond propeller-driven vehicles to address challenges in complex seabed environments. Hexapod robots, with redundant limbs and discrete ground support, emerged as promising platforms for tasks like exploration and maintenance where traditional ROVs and tracked vehicles struggle with stability and terrain adaptability.
What was reported
The review, published in the Chinese journal Robot, systematically surveys underwater hexapod robot platforms and their motion planning technologies. Notable platforms include the US 'Antelope' (Ursula and Ariel) for mine clearance, Canada's AQUA for coral reef monitoring, Korea's CR200 and CR6000 for seabed operations, and China's deep-sea CSV for scientific exploration. These robots vary in size, depth rating, and actuation, with some integrating manipulators for tasks like cutting and sampling.
Key technical areas are analyzed: stability criteria (static and dynamic), path planning adapted from terrestrial hexapods, and adaptive walking methods, including traditional adjustments and deep reinforcement learning approaches. The review notes that underwater conditions—such as buoyancy, currents, and soft seabeds—require specialized solutions beyond land-based methods.
Challenges remain, including limited depth ratings, slow walking speeds, and control complexity. The review calls for further development in autonomous navigation and adaptive gait generation to enhance operational capability in unstructured underwater environments.
Why it mattered
This review underscored the growing role of legged robots in underwater industrial applications, where stable positioning and terrain adaptability are critical. For manufacturers and system integrators, it highlighted a shift toward more versatile robotic platforms capable of inspection and intervention in challenging subsea settings, potentially reducing reliance on human divers and improving safety and efficiency.
"The underwater hexapod robot has redundant limbs, and can walk in various gaits. It has a broad application prospect for its discrete supporting way and excellent adaptability to the complex and special terrains."
Source: 《机器人》期刊 (robot.sia.cn) · Published 2023-11-10 · “水下六足机器人及其运动规划研究现状”