Advanced Phototactic Soft Actuators—Model-Informed Control of Liquid Crystal Polymers Using Wide Beam Light

Phototactic soft robotic systems can be effectively controlled without tethering by strategically manipulating light-matter interfaces. In this study, we introduce a novel phototactic soft actuator based on liquid crystal polymers (LCPs), enabling tether-free operation through control of wide beam light illumination. We systematically characterized the bending behaviors of LCPs, revealing tunable photophobic and phototropic responses influenced by the angle, intensity, and design of light shields. To gain deeper insight into these complex deformation dynamics, we developed a predictive computational framework known as the Photo-Thermal-Mechanical (PTM) model, which allows for the programming of sophisticated actuation profiles. By leveraging wide beam light actuation and insights from the PTM model, we designed LCP-based soft robots that exhibit reversible bidirectional motion and precision cargo delivery systems with controlled projectile trajectories. We establish foundational design principles and modeling strategies that utilize a variety of illumination profiles, enabling programmable and predictable phototaxis in soft robotic systems through effective light-matter coupling. Our approach enhances manipulation capabilities and significantly advances the field of phototactic soft robotics, offering safe, versatile, and intuitive solutions.