Autonomous soft robot with earthwork-like locomotion using an air source of constant pressure. Autonomous soft robot with earthwork-like locomotion using an air source of constant pressure. (A) The earthworm consists of a linear bellows actuator with cylindrical sleeve as a restoring spring and a soft, bistable valve, integrated into the rear of the actuator. The design of the valve is the same as that for the pneumatic oscillator, with the bottom chamber of the valve connected to the bellows actuator. The bellows actuator bends upward during inflation and downward during deflation, which causes asymmetric contact between the feet and the ground, leading to asymmetric friction and directional movement. (B) Photographs of the moving earthworm at three points in time (movie S7). (C) Pressure inside the robot and positions of front end, rear end, and center as a function of time for PS = 17 kPa. The red dots indicate the times when the photographs in (B) were taken. Philipp Rothemund et al. Sci. Robotics 2018;3:eaar7986 Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works