A Humidity-Powered Soft Robot with Fast Rolling Locomotion

A range of soft robotic systems have recently been developed that use soft, flexible materials and respond to environmental stimulus. The greatest challenge in their design is the integration of the actuator, energy sources, and body of robots while achieving fast locomotion and well-defined programmable trajectories. This work presents such a design that operates under constant conditions without the need for an externally modulated stimulus. By using a humidity-sensitive agarose film and overcoming the isotropic and random bending of the film, the robot, which we call the Hydrollbot, harnesses energy from evaporation for spontaneous and continuous fast self-rolling locomotion with a programmable trajectory in a constant-humidity environment. Moreover, the geometric parameters of the film were fine-tuned to maximize the rolling speed, and the optimised hydrollbot is capable of carrying a payload up to 100% of its own weight. The ability to self-propel fast under constant conditions with programmable trajectories will confer practical advantages to this robot in the applications for sensors, medical robots, actuation, etc.

Automated summary

A range of soft robotic systems have been developed recently, which utilize soft materials and respond to environmental stimuli. This research presents a design that achieves fast self-rolling locomotion with programmable trajectories under constant-humidity conditions, without the need for external modulation. By using a humidity-sensitive agarose film, this robot, called the Hydrollbot, harnesses energy from evaporation to propel itself. The optimized Hydrollbot is capable of carrying a payload up to 100% of its own weight. This robot's ability to self-propel with programmable trajectories under constant conditions offers practical advantages in applications such as sensors, medical robots, and actuation.