KAIST Develops Rapid, Two-Way Hybrid Smart Actuator for Robotics and Space Structures
A research team at the Korea Advanced Institute of Science and Technology (KAIST), led by Professor Seong Su Kim, has developed a two-way shape memory material-based hybrid smart actuator. This technology offers rapid operation, under one second, without a motor, addressing limitations in lightweight actuation devices for applications like space structures and robotic arms.
Technology Overview
This hybrid actuator combines Shape Memory Alloys (SMA) and Shape Memory Polymers (SMP) to enable reversible self-shape change. SMAs are metallic materials that revert to their original shape upon heating, while SMPs are polymer materials that alter their shape in response to thermal or other external stimuli.
Addressing Previous Limitations
Conventional shape memory materials faced significant limitations, including one-way deformation, slow recovery speeds, or issues with accurate shape restoration during repetitive use due to differing stiffness between metal alloys and polymer materials.
Design Improvements and Performance
To overcome these challenges, the KAIST team made two key improvements:
- Material enhancement: The chemical composition of the SMP was adjusted and reinforced with carbon fibers to increase rigidity.
- Structural design: A 'tape spring' structure was incorporated, which utilizes a 'snap-through' phenomenon to store and instantaneously release energy, improving movement speed and accuracy.
The developed actuator achieves full two-way actuation, demonstrating an increased range of deformation, a nearly 100% recovery rate, and significantly improved recovery speed.
This allows for repetitive operation without complex control systems, a crucial advance for practical applications.
Potential Applications and Publication
This actuator's ability to achieve two-way deformation, sub-second actuation speed, and high deployment accuracy represents a significant advance in the practical application of shape memory material-based actuation technology. Professor Kim stated that the technology could be applied in fields such as robotic grippers requiring repetitive motions and deployable structures for space applications.
The research, with Ph.D. student Dajeong Kang as lead author, was published online on January 19, 2026, in Advanced Functional Materials and was featured as the Front Cover of its March 2026 issue. The study received support from the Ministry of Science and ICT and the National Research Foundation of Korea.