A team from the University of Oxford has developed a new class of soft robots that operate solely on air pressure, without electronics, motors, or computers. These "fluidic robots" can generate complex, rhythmic movements and automatically synchronise their actions.
The study, published in *Advanced Materials*, represents a significant advance in soft robotics. Professor Antonio Forte, lead of RADLab at the Department of Engineering Science, University of Oxford, expressed excitement about "brain-less machines" spontaneously generating complex behaviours. Forte noted this approach decentralises functional tasks, freeing up resources for more intelligent tasks.
Soft robots, made from flexible materials, are well-suited for navigating uneven terrain or handling delicate objects. A primary goal in this field is to embed behaviour and decision-making directly into a robot's physical structure, fostering more adaptive machines.
Replicating automatic behaviour through body-environment interactions is often difficult with traditional electronic circuits, which demand complex sensing, programming, and control systems. Researchers drew inspiration from nature, where body parts often perform multiple roles, and synchronised behaviour can emerge without central control.
Their core innovation is a small, modular component that uses air pressure to execute mechanical tasks, similar to an electronic circuit using electrical current. This single block can actuate (move or deform) in response to air pressure changes, function like a touch sensor by sensing pressure changes or contact, or switch air flow between ON/OFF states like a valve or logic gate.
Multiple identical units, each a few centimetres in size, can be connected to form different robots without altering the basic hardware design. In the study, researchers constructed tabletop robots, approximately the size of a shoebox, capable of hopping, shaking, or crawling.
In one configuration, each individual unit automatically combined all three roles, enabling it to generate rhythmic movement independently once constant pressure was applied. When several responsive units were linked, their movements began to synchronise naturally, without computer control or programming.
These behaviours were demonstrated in a shaker robot, which sorted beads into different containers by tilting a rotating platform, and a crawler robot that detected a table's edge and automatically stopped to prevent a fall. All coordinated movements were achieved mechanically, without external electronic control.
Lead author Dr. Mostafa Mousa, from the Department of Engineering Science, University of Oxford, stated that this spontaneous coordination requires no predetermined instructions, arising purely from how units are coupled and interact with their environment.
Crucially, the synchronised behaviour appears only when the robots are linked and touching the ground. Researchers used the Kuramoto model, a mathematical framework describing how networks of oscillators can synchronise, to explain this phenomenon.
This revealed that complex, coordinated motion can emerge purely from the robots’ physical design when mechanically coupled through the environment. The motion of each robotic leg subtly affects the others via the shared body and ground reaction forces.
A feedback loop is created where forces transmitted through friction, compression, and rebound link the limbs’ motions, leading to spontaneous coordination. Dr. Mousa compared this to fireflies flashing in unison, noting the robots’ air-powered limbs fall into rhythm through physical contact with the ground, not visual cues.
Mousa described this emergent behaviour, previously observed in nature, as a major step towards programmable, self-intelligent robots. Though the soft robots are currently tabletop scale, the design principles are scale-independent.
Researchers aim to investigate these dynamical systems to build energy-efficient untethered locomotors. This would be a step towards large-scale deployment of these robots in extreme environments where energy is scarce and adaptability is vital. Forte added that encoding decision-making and behaviour into a robot's physical structure could lead to adaptive, responsive machines that do not need software to "think," shifting to "robots that are their own brains."
Oxford researchers developed soft robots powered entirely by air pressure.
These "fluidic robots" operate without electronics, motors, or computers.
The robots can generate complex, rhythmic movements and automatically synchronise.
Source: TECHXPLORE
