Researchers have developed a new type of McKibben actuator that incorporates a phase-change magnetorheological fluid. This design allows for precise control of stiffness and actuation force through the application of a magnetic field, overcoming the limitations of conventional soft actuators in terms of force and frequency control.

Traditional McKibben actuators, based on the expansion of an elastic tube under pressure, are known for their flexibility but lack the ability to vary their stiffness or maintain a fixed position without constant energy consumption. The integration of the magnetorheological fluid, which can reversibly solidify or liquefy with a magnetic field, endows these actuators with variable stiffness and the ability to lock into a position, thus offering improved frequency control and force output.

This advancement has significant implications for soft robotics, where the need for actuators that can adapt to different tasks and environments is crucial. The ability to dynamically control the stiffness and force of these actuators could lead to the development of more versatile and safer robots for applications such as delicate object manipulation, medical assistance, or exploration in complex environments.