Flexible soft robot arm moves with light — no wires or chips inside

Engineers at Rice University have developed a flexible, octopus-inspired soft robotic arm that operates entirely through light beams, eliminating the need for wires or internal electronics. This innovative arm is powered by a light-responsive polymer called azobenzene liquid crystal elastomer, which contracts when exposed to blue laser light and relaxes in the dark, enabling precise bending motions. The arm’s movement mimics natural behaviors, such as a flower stem bending toward sunlight, allowing it to perform complex tasks like obstacle navigation and hitting a ball with accuracy. The control system uses a spatial light modulator to split a laser into multiple adjustable beamlets, each targeting different parts of the arm to flex or contract as needed. Machine learning, specifically a convolutional neural network trained on various light patterns and corresponding arm movements, enables real-time, automated control of the arm’s fluid motions. Although the current prototype operates in two dimensions, the researchers aim to develop three-dimensional versions with additional sensors, potentially benefiting applications ranging from implantable surgical devices to industrial robots handling soft materials. This approach promises robots with far greater flexibility and degrees of freedom than traditional rigid-jointed machines.