Muscle-inspired sheet-like robot navigates the tightest spaces

A POSTECH research team has developed a thin, flexible robotic actuator inspired by human muscle proteins. As thin as paper, yet capable of generating strong forces, this robot can maneuver through tight spaces and manipulate objects, making it suitable for a wide range of applications—from surgical robots to industrial equipment. The study has been published in Nature Communications.

Most conventional robots are built with rigid metal components, giving them strength but limiting their ability to perform delicate motions or operate in confined environments.

In the medical field, there is a growing need for robots that can assist with surgeries inside the human body. In industrial settings, flexible robots are needed for tasks like inspecting complex machinery or cleaning narrow pipelines. However, technologies that combine both flexibility and strength have been lacking—until now.

The team, including Dr. Hyung Gon Shin from Samsung Electronics’ Future Robotics Division (formerly a Ph.D. researcher at POSTECH), and Professors Keehoon Kim and Wan Kyun Chung from the Department of Mechanical Engineering at POSTECH (Pohang University of Science and Technology), turned to human muscle movements for inspiration.

They mimicked the function of myosin, a protein in muscles that generates large movements through repeated small contractions. Using this concept, they developed a thin, sheet-shaped pneumatic actuator.

At first glance, the actuator appears to be a simple sheet, but inside it contains dozens of small air chambers and multi-layered, multi-channel air pathways.

When air is injected sequentially into the sheet, the surface protrusions move in multiple directions, gradually accumulating small forces to produce larger movements. Even when bent, the actuator can crawl like a caterpillar using only its protrusions. The surface can move in six directions—up, down, left, right, and rotation—and allows flexible control over speed and distance.

The research team validated the performance of their technology through a series of experiments. In object manipulation tests, the robot moved with delicate precision akin to human fingers, and it also successfully completed tasks involving moving objects underwater.

Notably, it can handle tasks like cleaning narrow pipelines, which are difficult for conventional robots. Additionally, the team developed a mathematical model to predict the robot’s movements, laying the foundation for diverse future designs and applications.

This research is expected to bring innovative changes to both everyday life and industry. In medical settings, robots can assist with precision surgeries by navigating through small openings.

In industrial environments, they can perform various tasks such as inspections in confined spaces. Additionally, when applied to home cleaning and caregiving robots, they are expected to interact with people in a more delicate and responsive manner.

Professor Keehoon Kim explained the significance of this research as “successfully integrating a complex three-dimensional pneumatic network within a thin and flexible structure, enabling multi-directional movements through a bio-inspired approach.”

He added, “We hope this technology will be applied in various fields, including surgical robots, collaborative robots in industrial settings, and exploration environments.”