Feedback regulated opto-mechanical soft robotic actuators

Natural organisms use sensory feedback to adaptively regulate their behavior, but replicating such feedback mechanisms in synthetic materials remains a major challenge. It is believed that achieving complex feedback mechanisms in responsive materials will pave the way toward autonomous, intelligent structures and actuation without complex electronics. Inspired by biological systems, we present a general strategy for embedding feedback loops into light-responsive materials. We introduce a baffle-actuator system that enables programmed positive or negative feedback by adjusting the baffle's position relative to incident light. This allows self-regulated control of actuation behavior. Using this approach, we transform a light-bending strip into a switchable, multi-stable structure controlled by light intensity. Leveraging negative feedback, we further demonstrate two autonomous soft robots—a walker and a swimmer—with self-regulated motion. Our results highlight the ubiquity and potential of feedback mechanisms in optically responsive materials, opening new avenues for intelligent, electronics-free soft robotics.