New smart artificial muscle could bring human-like feedback to humanoid robot

A team at Seoul National University (SNU) has created an artificial muscle that combines movement and sensing into one system, eliminating the need for separate external sensors. The device uses liquid-metal channels embedded in a liquid-crystal elastomer, allowing it to contract when electrically stimulated while simultaneously measuring internal force and length. The design mimics biological muscle-tendon systems by connecting isotropic and nematic liquid crystal elastomers in series. One liquid metal channel acts as an actuator, generating contraction through heating, while the other functions as a sensor, detecting force and deformation. This dual functionality enables real-time monitoring of the muscle’s state without external input. Researchers demonstrated the muscle’s potential in robotic fingers and grippers, which could identify object stiffness and size while manipulating them. By arranging two muscles to work in opposition—similar to human muscles—the team achieved faster, more precise control over movements, including contraction and relaxation. The system improves robotic feedback by embedding physical intelligence directly into the muscle structure. However, challenges remain, such as heat buildup during repeated movements, which can cause force drift and reduce accuracy. The team proposes solutions like thinner materials, built-in cooling channels, or Peltier-based cooling systems to address these issues. The breakthrough could advance humanoid robotics and assistive technologies by enabling more adaptive, human-like sensing and movement capabilities. Applications may extend to logistics automation, rehabilitation devices, and medical systems where delicate, responsive interactions are critical.