Modular Soft Robotic Actuators from Flexible Perforated Sheets

• Published in: Advanced engineering materials 2023-10, Vol.25 (19), p.n/a
• Main Authors: Pagliocca, Nicholas, Trkov, Mitja, Koohbor, Behrad
• Format: Article
• Language: English
• Subjects: actuators; architected structures; mechanical metamaterials; modular robots; soft robotics
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.202300583

Soft robotic actuators can be designed to achieve complex and tailored motions while simultaneously leveraging their compliance to interact with complex and often delicate environments. Mechanical metamaterials reveal a route to customizable deformations, force exertion, and mechanical energy efficiency attainable by careful arrangement of local geometric features. Herein, modular soft robotic actuators are developed from soft elastomers and flexible thermoplastic sheets of various unit cell designs. The efforts are focused on center‐symmetric perforated sheets, which are formed into flexible cylindrical skins that surround the soft inflatable actuators. The results demonstrate the influence of perforation geometry on the spatial stiffness of the reinforcement structure and the proposed actuators’ response through several investigations. It is demonstrated that the free‐boundary displacement, maximal force exertion, and mechanical energy efficiency of extensile actuators are dependent on a change of deformation mode in the mesostructure. The spatial stiffness concept is extended to develop soft robotic actuators that can bend, twist, and perform hybrid motions, such as simultaneous bending and twisting. Multisegment soft robotic arms are also developed from the aforementioned actuators. Investigations in this study provide a step toward the development of highly customizable and programmable soft robotic actuators for various applications. Modular soft robotic actuators are designed by carefully tuning the spatial stiffness of a flexible reinforcement structure at the mesoscale. The utility of the proposed methodology is first demonstrated by controlling the deformations, force exertion, and quantifying the energy efficiency of extensile actuators. The design concepts are extended to the development of actuators with programmable complex motions.