A nonlinear beam model of photomotile structures

Area of Science:

• Soft Robotics
• Materials Science
• Photomechanics

Background:

• Actuation is a key challenge in soft robotics, limiting functionality and control.
• Light-based actuation offers advantages like remote operation, precise control via distinct frequencies, and efficient power transmission through fiber optics.
• Photochemical processes converting photons to configurational changes are highly desirable for soft robotic actuation.

Purpose of the Study:

• To present a simple modeling framework for light-induced actuation in soft materials.
• To investigate the generation of cyclic or periodic motion under steady illumination.
• To explore the coupling between light absorption and deformation for novel actuation mechanisms.

Main Methods:

• Development of a simplified modeling framework for light-driven soft robotic actuation.
• Study of actuation using liquid crystal elastomers combined with azobenzene photochromes.
• Analysis of the interplay between light absorption, structural deformation, and illumination conditions.

Main Results:

• Demonstrated that cyclic or periodic motion can emerge under steady illumination.
• Identified a crucial coupling between light absorption and deformation as the mechanism for cyclic motion.
• Showcased how changes in illumination conditions, driven by deformation, influence further actuation.

Conclusions:

• The presented modeling framework effectively explains light-induced cyclic motion in soft structures.
• Exploiting the coupling between light absorption and deformation enables the generation of self-sustained oscillations.
• This mechanism can be utilized in closed structures or with structural instabilities for advanced soft robotic applications.