Chinese technologists have successfully developed a robotic dog that is amphibious. This new robot was inspired by the ability of mammals to both move on land and swim in water, and was indeed based on the swimming style of dogs. Previous attempts at developing amphibious robots had been based on insects or reptiles and had often had limitations regarding their dynamics, agility and load capacity.

The project was primarily undertaken at the Shien-Ming Wu School of Intelligent Engineering, at the South China University of Technology, in Guangzhou, in China. Guidance on animal biomechanics and bioinspiration principles was provided by West Chester University, in Pennsylvania in the US. Mechanical design support and conceptual refinement was supplied by the University of Hong Kong in Hong Kong.

“This innovation marks a big step forward in designing nature-inspired robots,” affirmed study corresponding author Yunquan Li. “Our robot dog’s ability to efficiently move through water and on land is due to its bioinspired trajectory planning, which mimics the natural paddling gait of real dogs. The double-joint leg structure and three different paddling gaits address previous limitations such as slow swimming speeds and unrealistic gait planning, making the robotic dog much more effective in the water.”

The technologists developed and tested three different paddling styles for their robot. Two of these were based on the doggy-paddle, and were optimised for propulsion and speed. The third was “trot-like” and was optimised for enhanced stability in the water. In practice, the doggy-paddle style did indeed prove faster, and the robot reached a maximum speed in the water of 0.56 km/h. The trot-like style did provide greater stability. On land, the robot dog achieved a top speed of 1.25 km/h.

These results were obtained by fitting the robot with a unique paddling mechanism, that was based on how dogs swam. The structure was carefully engineered, with precise weight and buoyancy balance, to ensure a performance in the water that was effective and stable.

Future applications for an amphibious robot include rescue missions, military missions and environmental research applications.

The paper reporting this breakthrough was published in the journal Bioinspiration and Biometrics. This is one of the scientific journals published by IOP Publishing, which is the publishing arm of the Institute of Physics, a UK-based global scientific society, founded in 1874.