Structural design of soft robotics using a joint structure of photoresponsive polymers

Abstract

Photoresponsive polymers (PRPs) have a non-contact bending behavior based on their position when they are irradiated by a specific wavelength of light. In this paper, the behavior of self-deforming PRPs is discussed through multiscale simulations and structural designs. In repeated bending, it is difficult to return to the initial state through different paths because the PRP moves periodically in the same path. We designed an anti-obstructing motion of a PRP operator based on a nonlinear co-rotational finite element model, which could not be designed for the existing bending behavior. The PRP operator can move independently in specified directions by attaching an opaque part to the PRP operator as a joint structure. The device can be divided into two separate regions. One region can be bent to move the desired object, and then the PRP operator can move away, avoiding the object by bending in the other region. The PRP operators can take actions whether to move an object or to avoid an obstacle and adjust the friction force of robot feet based on bio-inspiration. In our experiments, the production process of PRPs is presented, and operations implemented in soft robot applications of gear rotation and walking.