A soft, bistable valve for autonomous control of soft actuators

Area of Science:

• Robotics
• Materials Science
• Mechanical Engineering

Background:

• Traditional pneumatic and hydraulic actuators rely on rigid valves, limiting flexibility and integration in soft systems.
• Developing soft, self-regulating components is crucial for advancing autonomous soft robotics and mesoscale functions.

Purpose of the Study:

• To introduce a novel soft, elastomeric valve with a bistable membrane for pneumatic control.
• To demonstrate the valve's capability for autonomous functions in soft robotic applications.
• To present a method for integrating simple control and logic into soft actuators.

Main Methods:

• Fabrication of a soft, elastomeric valve utilizing a bistable membrane with snap-through instability.
• Characterization of the valve's distinct snap-upward (ΔP1) and snap-downward (ΔP2) pressures.
• Integration of the valve into pneumatic circuits to create oscillators and enable autonomous robotic actions.

Main Results:

• The soft valve exhibits bistability, maintaining open or closed states without continuous power.
• The valve's snap-through pressures (ΔP1, ΔP2) are designable via membrane geometry and material.
• Integrated circuits demonstrated autonomous grasping and earthworm-like locomotion using a single pressure source.

Conclusions:

• The soft, bistable valve offers a power-free, integrated control solution for soft pneumatic actuators.
• This technology enables autonomous functions in soft robots, simplifying design and control.
• Straightforward fabrication via molding facilitates the adoption of these valves in soft robotics.