Design of a 3D-printed soft robot with posture and steering control

Both postural maintenance and rhythm generation are keys to generating adaptive behavior in all animals. This is particularly evident in soft animals such as caterpillars, worm and flatworms that are capable of moving freely in all directions and adopting intricate postures. They can also exploit three-dimensional deformations and nonlinear structural properties to move in complex environments and to respond to external forces. These capabilities have inspired a new interest in using soft materials in robotic applications but highly deformable materials create significant design and control problems. In previous work the authors have developed a 3D-printed soft (3D-PS) robot, inspired by caterpillars, as a platform to investigate methods for controlling soft robots. The previous version of the robot is able to reproduce the different gait patterns (inching and crawling motion) of caterpillars by changing temporal difference in the rhythmic deformations of different body parts. In this paper, we have added posture control to the 3D-PS robot together with a steering capability. Experimental results show that although posture and steering are usually related, elastic and continuum properties of the soft body can produce more complex and versatile behaviors.