Electro-Hydraulic Muscles Help Robot Legs on Uneven Terrain

Scientists at ETH Zürich are very good at making robots stand up straight

In 2022, the school’s robotics team taught the ANYmal robot, which walks on all fours, how to climb mountains without falling. A new study from the school, published with help from the Max Planck Institute for Intelligent Systems in Stuttgart, takes a unique method to the problem of getting across rough terrain.

A hybrid electro-hydraulic system powers the artificial arms that the schools show off. The legs can automatically adapt to the surface they’re walking on. They also move faster and jump higher than most electric legs, and they don’t need any extra sensors or tools to do these things.

Thomas Buchner says, “As soon as we apply a voltage to the electrodes, they are drawn to each other because of static electricity.” “The same static electricity makes my hair stick to a balloon when I rub it against my head.”

Based on the energy, the bags then either get bigger or smaller. The method doesn’t make a lot of heat like most electric actuators.

In other words, the actuators help the machine move over rough ground and jump high. However, the method is still not ready to be used in the real world.

“Our system is still not as good as walking robots with electric motors.” “Right now, the leg is attached to a rod, jumps around, and can’t move freely,” says Max Planck Institute professor Christoph Keplinger. “If we add the robotic leg to a four-legged robot or a humanoid robot with two legs, we might be able to use it as a rescue robot one day when batteries power it.”

The actuators for the legs are pretty easy to use. The teams say they look like “oil-filled plastic bags like those used to make ice cubes.” After that, electrodes are put on top of those bags. It sounds a bit like a school science project, to be honest.