Development and applications of an unplugged robotic actuator based on 4D printed hydrogel

摘要

In this study, we propose a new concept of unplugged actuators based on the four-dimensional (4D) printed hydrogel. Unlike traditional robotic actuators that are powered by electrical and pneumatic energy, the natural energy such as water, light, and temperature, is served as the power source of the unplugged actuators. Therefore, the unplugged actuator is energy saving, and complicated drive circuits and external energy storage devices are unnecessary. Based on the concept of the unplugged actuators, we develop an unplugged robotic actuator driven by the 4D printed hydrogel. The power source of the developed unplugged actuator is natural water such as rainwater, and the actuation force is generated due to the expansion of the 4D printed hydrogel. The design and fabrication of the unplugged actuator is introduced, and the relationship between generated forces and time is experimentally calibrated. Furthermore, an origami-based umbrella actuation task was carried out to evaluate the linear actuation ability of the developed unplugged actuator. In addition, to explore the potential in real-world applications, the unplugged actuator was redesigned and then applied to a seed sowing experiment. The selected cactus seeds could be successfully pushed out of the unplugged actuator and fell on the surface of the sowing area, and simultaneously, the seeds were underwent a soak process that was beneficial for germination. • The concept of an unplugged actuator is initially proposed in this study. The unplugged actuator is powered by natural energy such as light, water, and temperature, without using traditional energy sources such as pneumatic and electrical power. • An unplugged actuator is developed based on 4D printed hydrogel. Natural water is used as the power source and the actuation force is generated by the expansion of the 4D printed hydrogel. The developed unplugged actuator is energy-saving, and the design and fabrication are compact and simple. • The proposed unplugged actuator could successfully achieve an origami-based umbrella actuation task and a seed sowing task, which validated the actuation ability and explored the potential in real-world applications.