A Stretchable Fiber with Tunable Stiffness for Programmable Shape Change of Soft Robots

Area of Science:

• Robotics
• Materials Science
• Biomimetics

Background:

• Soft robots require precise shape control, often achieved with complex pneumatic actuators.
• Existing methods struggle with drastic stiffness changes needed for advanced manipulation.
• Nature, like in worms, utilizes programmable stiffness for complex shape evolution.

Purpose of the Study:

• To develop a new method for controlling soft robot shape using tunable stiffness.
• To overcome limitations of existing shape control technologies in soft robotics.
• To mimic biological mechanisms for advanced soft robot actuation.

Main Methods:

• Fabrication of a hybrid fiber with series-connected stiff and soft components.
• Utilizing a locking/unlocking mechanism in the soft component to alter overall fiber stiffness.
• Creating a network of these hybrid fibers for distributed stiffness control.

Main Results:

• Achieved a membrane stiffness contrast exceeding 100x in under 6 seconds.
• Demonstrated efficient actuation with low input power (3 W).
• Successfully manipulated a single-chambered soft body in multiple directions.

Conclusions:

• The hybrid fiber offers a promising new approach for soft robot shape control.
• This technology enables complex shape transformations in soft robots.
• It provides a biomimetic alternative to complex pneumatic systems in soft robotics.