Biomimetic fiber reinforced dual-mode actuator for soft robots

Abstract

In robotics, bioinspiration brings scenarios where soft robots acquire life-like abilities and better integrate themselves into the natural world. Because of their visual and functional similarity to biological organisms, soft robots are commonly presumed to be more “natural” and therefore more appealing than traditional rigid robots. The bio-inspired soft bending actuators play a crucial role in soft robotics and have been extensively investigated at present. The existing bending actuators are mainly achieved by the bladder’s asymmetric deformation, such as pneumatic network (Pneu-Nets) bending actuators, fiber reinforcement actuators, and braid sleeve actuators. To improve the bending efficiency and strength, a bio-inspired dual-mode actuator (DMA) with a build-in angle sensor was proposed. It couples asymmetric deformation and tendon-driven through a novel fiber winding method. A soft resistive sensor was designed and prepared for easy deployment. We then fabricate three types of bending actuators and experimentally validate the bending efficiency of the DMAs. A theoretical model for the relationship between actuation pressure and bending angle is established. To evaluate its performance, the curvature, bending angle, output force, and the bending angle of the sensor feedback were measured. The results show that DMA has good bending efficiency and output force, and the tendon has an obvious reinforcing effect on the actuator. In addition, the embedded sensor has excellent embeddable deployment performance and compatibility. Finally, demonstrates the grabbing and holding of various objects using grippers composed of different lengths and numbers of DMAs. And showed the underwater flexible manipulator operation with the three-finger gripper with bending feedback as it can estimate the size of the objected like human hand.