Happy on land and in water: amphibian robots and adaptive morphogenesis
Published On: January 12 2023
OK, we admit this is one geeky blog title, but it’s a great concept. A team of researchers wanted to develop a robot that, like a turtle, could swim and move on land too. And of course, multi-axis load cells played a key role in the development and testing of their Amphibious Robotic Turtle (ART).
“This expanding frontier of applications requires robots to transit multiple environments, a substantial challenge that traditional robot design strategies have not effectively addressed.”
Animals as inspiration
The process of evolution has enabled species to fine-tune their physical characteristics to maximise their effectiveness in their natural environment. If their habitat spans two distinctly different environments, such as land and water, they may not be as efficient in one as the other.
This led the team to reject two existing ways of building their robot:
Biomimetic design, where the robot mimics the “morphology, propulsion mechanism and gait” of a real animal
Adding a unique way of propulsion for each environment to the same robot, which means the robot is inherently energy-inefficient
The team instead opted for:
“‘Adaptive morphogenesis’ – adaptive robot morphology and behaviours realized through unified structural and actuation systems.”
In other word, the best of both worlds, on demand.
Turtle or tortoise?
The team’s Amphibious Robotic Turtle (ART) merged:
“Specialized morphogenic features for aquatic and terrestrial locomotion—the streamlined flipper shape and gaits of sea turtles and the columnar leg shape and gaits of land-faring tortoises… (creating)… Limbs capable of morphing between functional hydro-dynamic and load-bearing shapes.”
This allowed their amphibious robot to swim underwater, move from water to land and vice versa, and travel across various terrains.
The key to this clever transition are the limb joints, which can move through forwards and backwards, up and down, and angle-of-attack axes. The team used a test rig for measuring the force profiles of four gaits (two swimming, one transitional, and one crawling) using a multi-axis load cell on a cantilever bar.
“(The) coordinate system defines positive direction of forces measured via the multi-axis load cell. Adjustable fixtures … tune the robot’s offset from the pool sides and bottom, as well as its submerged depth.”
The multi-axis load cell test rig also enabled them to assess the forces involved in forward and lift motion, to discover the best flapping style for their robotic turtle.
Read all about it
For full details, read their paper online at Nature magazine which includes some great pictures of their turtle-inspired amphibious robot swimming, plus graphs of the forces involved in paddling and flapping.
Load cells for all types of robots
Whatever type of robot you want to create, we have the load cells to help make it happen. We design, manufacture and ship our own brand load cells here in the UK, so delivery times are fast. We are also more than happy to work with you to design a load cell or load cell system that is designed for your specific purpose.