An Inchworm-Like Climbing Robot Based on Cable-Driven Grippers

In climbing robots, weak grasping, large size, and a lack of self-perception capability are critical problems that urgently need to be solved. Inspired by the excellent grasping ability of primate hands and the simple locomotion method of inchworms, this study proposes an inchworm-like climbing robot based on synergistic cable-driven grippers and a telescopic torso. First, the overall structure of the climbing robot was designed by analyzing the characteristic movements of primate hands and inchworms. Next, a cable-driven soft gripper was designed based on geometric, modulus, and motion similarity with primate hands using dimensionless analysis. Then, a telescopic climbing robot torso was designed to mimic the peristalsis motion of inchworms by using double flexible thin-shelled rods that bend easily in the forward direction and resist movement in the reverse direction. Subsequently, flexible tensile strain sensors were designed based on carbon nanotubes and iron nanowires and then integrated into the soft grippers and torso for self-perception of the motion state. Subsequently, flexible sensors, soft grippers, and a telescopic torso were fabricated using casting and dipping-pulling technology. Finally, the climbing performance of the robot was experimentally tested. The results indicate that the robot can stably climb pipes with different roughness and diameters, and the embedded sensors can capture the motion of the gripper and torso. The climbing speed of the robot was 3.3 mm/s for horizontal pipes and 1.0 mm/s for vertical pipes.