Muscle-driven bipedal robot that can mimic human gait and make sharp turns

Compared with robots, human limbs are extremely flexible, capable of fine movements, and can efficiently convert energy into motion. Inspired by human gait, Japanese researchers combined muscle tissue and artificial materials to create a bipedal biohybrid robot that can walk and rotate. The relevant paper was published in the journal Matter on the 26th.

Bipedal biohybrid robot.
Image credit: Takeuchi Laboratory, University of Tokyo

The corresponding author of the paper, Professor Masaharu Takeuchi of the University of Tokyo, said that biohybrid robots are a fusion of biology and mechanics, a new field of robots characterized by biological functions. Using muscles as actuators, researchers can build a compact robot and achieve efficient and silent movement through a soft touch.

The robot has an innovative bipedal design that builds on previous biohybrid robots that used muscle. Currently, muscle tissue can drive biohybrid robots to crawl forward, swim in a straight line, and turn, but not to make sharp turns. However, being able to rotate and make sharp turns are essential features that robots need to avoid obstacles.

To build a robot with more flexible and delicate movements, researchers designed a biohybrid robot that mimics human gait and operates in water. The robot has a foam buoy top and weighted legs that help it stand upright underwater. The robot's skeleton is made mainly of silicone rubber, which can bend to accommodate muscle movement. The researchers then attached strips of skeletal muscle tissue grown in the laboratory to the silicone rubber and two legs.

When the researchers stimulated the muscle tissue with electricity, the muscle contracted and lifted the leg; when the current was removed, the heel landed forward. By alternating electrical stimulation between the left and right legs every 5 seconds, the biohybrid robot was able to walk at a speed of 5.4 mm/minute.

To turn, the researchers repeatedly tapped the right leg every five seconds, using the left leg as an anchor. The robot completed a 90-degree left turn in 62 seconds.

Before upgrading the robot with more biological components, the team must integrate a nutrient supply system to maintain living tissue and the device structure, allowing the robot to operate in air, the researchers said.

In recent years, many scientists have been committed to making robots "evolve" to be more like humans: not only to train them to chat and think like humans, but also to make them look more like humans. This is very useful. For example, if the food delivery robots in hotels, the guide robots in hospitals, and the accompanying robots in nursing homes are stiff and cold in appearance and speech, the user experience will inevitably be greatly reduced. On the other hand, if the appearance and chat style of these service robots can be made more like humans, users can experience the "warmth" of robots, thereby greatly enhancing the value of service robots.