Northwestern University soft robot moves without hardware or electricity

Researchers at Northwestern University have developed a new material that acts as a soft robot. The material can walk at human speed, pick up and transport cargo to a new location, climb up hills, and spin to release cargo. The first of its kind material is nearly 90 percent water by weight and is sized in centimeters.

It's able to move without complex hardware, hydraulics, or electricity. Instead, it's activated by light and walks in the direction of an external rotating magnetic field. The robot is designed to resemble a four-legged octopus and is fully functional in aquatic environments. Possible uses for the robots include using them to help catalyze different chemical reactions.

The soft robots could also be molecularly designed to recognize and actively remove particles in a specific environment that are unwanted. Researchers also believe there are medical applications, including using the robots to deliver bio-therapeutics or cells to specific tissues with precision. The robotic material makes the new robot much faster than previous work that was done in the same lab on soft robots.

In the previous study, the robotic materials could bend over timescales of minutes and crawl at a slow pace of one step every 12 hours. The new materials can take about one step per second in response to a magnetic field, allowing for steering. Scientists coupled responses to light and magnetic fields to design a robot able to pick up cargo and deliver it to the destination by walking or rolling.

Once at the destination, the soft robot can unload the cargo by inverting its shape, so smooth payloads slide off the robot or performing a spinning move to dislodge and release stickier objects. The water-field structure and embedded skeleton of aligned nickel filaments that are ferromagnetic are responsible for the robot's precise movement and agility.

The robot's soft component is a molecularly designed network with parts allowing it to respond to light and hold or expel water in its interior. With exposure to a magnetic field, the embedded skeleton in the bent robot exerts cyclic forces on the soft components activating the legs to move along a pre-determined path. Researchers on the project see a future with armies of microrobots that can perform tasks in a coordinated way.