Another lesson from plants: the forward osmosis-based actuator.

Area of Science:

• Biomimetics and Bioinspired Engineering
• Materials Science
• Robotics

Background:

• Osmotic actuation, a plant-inspired strategy, offers low power consumption and effective movement across diverse conditions.
• Existing osmotic actuators lack the speed required for certain applications, limiting their bioinspired potential.

Purpose of the Study:

• To develop a novel, low-power-consumption actuator with rapid actuation time (minutes).
• To design and fabricate a forward osmosis-based actuator mimicking plant movement timescales.
• To achieve forces comparable to existing technologies while maintaining minimal power usage.

Main Methods:

• Analysis of plant movements and osmotic actuation modeling informed the actuator design.
• Fabrication of a forward osmosis-based actuator with a characteristic size of 10 mm.
• Integrated strategy addressing design and material challenges for enhanced performance.

Main Results:

• Developed the fastest osmotic actuator to date, with a characteristic actuation time of 2-5 minutes.
• The actuator generates forces exceeding 20 N with power consumption on the order of 1 mW.
• Model predictions closely align with experimental observations, validating performance.

Conclusions:

• The developed osmotic actuator achieves a plant cell-like timescale, demonstrating a successful bioinspired approach.
• Its high force output and low power consumption make it a promising candidate for bioinspired robotics.
• This work represents a significant advancement in osmotic actuation technology for practical applications.