Humanoid Robots Gain Artificial Tendons for Greater Strength and Mobility
Researchers at the Massachusetts Institute of Technology (MIT) have taken a major step toward more lifelike robots by developing synthetic tendons that work in tandem with lab-grown muscles. The innovation promises to significantly enhance the strength and agility of humanoid and biohybrid robots.
From artificial muscles to tendon-driven motion
MIT scientists have previously created artificial muscles that mimic natural ones. The new synthetic tendons are designed to transfer the force of these muscles to robotic systems such as grippers. By combining lab-grown muscles with synthetic skeletons, researchers have already built robots capable of crawling, running, swimming, and gripping. However, until now, these robots have struggled to match the power and flexibility of biological organisms.
Hydrogel tendons boost performance
The artificial tendons are made of a durable, flexible hydrogel. Researchers connected the rubber band–like tendons to lab-grown muscles, forming a “muscle-tendon unit.” The other end of the tendon was attached to the fingers of a robotic gripper. When the muscle contracted, the tendons pulled the gripper’s fingers together—three times faster than without the tendons—and with 30 times more force.
“This muscle-tendon unit can be integrated into a wide range of biohybrid robot designs as a universal component,” says MIT researcher Ritu Raman. “We are introducing artificial tendons as interchangeable connectors between muscle actuators and robot skeletons. Such modularity could accelerate the development of everything from microscopic surgical instruments to autonomous exploration machines.”
Overcoming miniaturization limits
Traditional actuators are difficult to shrink without losing efficiency. “Most actuators that engineers work with are very hard to miniaturize. Beyond a certain size, the basic physics no longer work,” explains Raman. “Muscles are different: each cell is an independent actuator that generates both force and movement. In principle, this allows us to build extremely small robots.”
The advantages of living actuators
Lab-grown muscles offer additional benefits. They can strengthen through training and heal naturally when damaged. For this reason, researchers envision muscular robots exploring environments that are too remote or hazardous for humans, from deep-sea trenches to extraterrestrial terrains.
With artificial tendons, MIT’s biohybrid robots take a significant step closer to matching the versatility and resilience of living creatures, opening new possibilities for robotics in medicine, industry, and exploration.
