Japanese researchers bipedal robot powered by living muscle tissue

Nimble robot design

Previous attempts at building biohybrid robots have shown that these bipedal robots can even turn. However, if a robot must learn to avoid obstacles, these are not necessarily sharp turns. 

A research team led by Shoji Takeuchi at the University of Tokyo worked to demonstrate that a biohybrid robot could be taught to pivot sharply. The team used a nimbler design for its robot to enable finer movements and mimic human gait. 

The robot had a foam bouy top to help it float in water and weighted legs to help it stand straight. The skeleton was made from silicone rubber, making it flexible and easy to bend. The team attached lab-grown skeletal muscle tissue to the silicone rubber on each leg to make a biohybrid robot. 

Making the robot walk and pivot

In this design, the muscle tissue replaces the actuators used in conventional robot designs. Since electric signals make the actuators work, the researchers also used electric signals to put the muscle tissue to work. 

Sending an electric current through the muscle, contracting it, and lifting the leg. The heel then landed forward when the current had dissipated. By alternating the electric current between the two legs every five seconds, the team could get a "walking" movement. 

The bot's speed was still extremely slow, managing only 5.4 millimeters of movement in a minute. That's 0.002 miles an hour. The researchers even got the robot to make a 90-degree turn by zapping only one leg repeatedly every five seconds. In contrast, the other leg served as an anchor. The turn took over a minute to complete but demonstrated that the muscle-driven robot could walk, stop, and make fine-tuned turns. 

"Currently, we are manually moving a pair of electrodes to apply an electric field individually to the legs, which takes time," said Takeuchi in a press release. "In the future, by integrating the electrodes into the robot, we expect to increase the speed more efficiently."

The team plans to add joints and thicker muscle tissues for future experiments, enabling powerful and more sophisticated movements. To upgrade the biological components of the robot, the team will also need to integrate a nutrient supply system that will help sustain and operate the tissues in the air. 

The research findings were published in the journal Matter.