4D printing of pneumatic soft robots sensors and actuators

The unique behaviors exhibited by mollusks such as the octopus or paramecium in nature have inspired the development of soft robotics and actuators. As a novel type of bionic continuum robot, its safety, compliance and high flexibility make it more suitable for interacting with humans and the environment. Apart from low cost, light weight and strong functionality, soft robotics and actuators take advantage of the simple types of drive systems to generate complex motion, which has great potential for development in the fields of industry, medical treatment, complex environment exploration, and military affairs. Among numerous soft actuators, the pneumatic ones based on volume expansion and contraction have great command in good compliance, high power-to-weight ratio and low manufacturing cost, making them a research hotspot. Due to the increasingly complex structure of the demand, conventional manufacturing methods (including mold casting, and hand-made) have been unable to meet its manufacturing requirements. The rapid development of 4D printing technology and its equipment evolved from 3D printing has laid the foundation for this generation of soft pneumatic robots and actuators. Highly flexible materials compatible with 4D printing preparation requirements provide a variety of additive manufacturing methods in fabrication. The introduction of functional materials into specific desired locations helps to tailor the functionality of soft actuators by engineering the structure and deformation modes. Through discussing the current state of 4D printable soft pneumatic robotics and actuators, a feasible predictive analysis of future further developments and developments is provided. With aided by 4D printing, soft pneumatic robots and actuators incorporating functional materials enable a top-down approach to shorten the path between materials science and applications.