Air-powered leopard robot doesn’t need a complex brain to walk

Most of the quadruped robots that have previously wowed and terrified us on video have relied on powerful computational engines and substantial processing power to move their mechanized limbs. This approach has provided some incredibly lifelike, efficient movements in robots like Boston Dynamics’ WildCat, but their complicated nature has slowed the deployment of walking robots outside of the lab. A team from Osaka University in Japan is working on a more natural approach to walking robots that sacrifices power in the name of simplicity.

The robot is called Pneupard, a regrettable contraction of “leopard” and “pneumatic.” Knowing that, you should have a basic idea of what makes this system of locomotion different. Rather than using actuators and motors to move, Pneupard has a series of artificial muscles that run on compressed air. Each muscle is made from a rubber tube sheathed in nylon and contracts as air is pumped in. The air-powered limbs of a so-called “biometric” robot have the potential to be more realistic than one based on electric motors. They actually deform and flex without breaking, which allows for a wider range of movement.

This design is much more analogous to a real muscle, so the researchers believe it will be easier to create lifelike locomotion of the sort seen in WildCat. Basically, the Osaka University team wants to see how locomotion can be offloaded from a centralized robotic brain to the rest of the body. Their approach takes into account the way a real animal works it’s not all higher brain functions controlling your gait and posture. The feedback of peripheral nerves, the brainstem, spine, and muscles all figure into the way we move.

Pneupard doesn’t even have a complex brain right now in the video above it is relying entirely on a type of rhythmic controller called a central pattern generator, or CPG. That means there are no external signals telling the limbs how to move, instead everything is based on the interaction of the pneumatic muscles and skeletal frame, which rhythmically cycle back to their starting positions after each step. A CPG like this is essentially a biological system, so it could make future robots more lifelike.

The current design is intentionally simple (and loud). The clicking sound in the video is from the on-board valves flicking on and off to control airflow, but it was even louder before researchers cut down the number of muscles. With fewer muscles, the team is able to study its CPG system and improve future versions. They have already installed force sensors on the robot’s feet which should be able to give Pneupard a more natural gait. More muscles could be re-added later to smooth out the motion.

Just because Pneupard doesn’t have a brain right now doesn’t mean it never will. Integrating a CPG with the more traditional pre-programmed movements of robots like BigDog and WildCat could be the thing that makes walking robots easier and cheaper to develop in the future.

courtesy extremetech