Structure design and parameter optimization of a new vacuum-powered soft bending actuator

Abstract

Abstract Vacuum-powered actuators possessing inherent safety, reliability, and durability demonstrate promising prospects in soft robotics. Herein, we develop a new type of vacuum-powered soft bending actuator (VSBA) based on the coordinated collapse of chambers. Theoretical analysis and finite element modeling are conducted to investigate the bending performance and chamber deformation. Results indicate that the relationships between the bending angle, output force, and negative pressure are nonlinear. The bending angle reaches its maximum when the chamber volume approaches zero. The maximum bending angle and output force based the experimental measurement are 119.7° and 114.51 mN, respectively. Furthermore, the effect of key parameters on the bending performance is systematically investigated. It is found that the maximum bending angle increases, while the maximum output force decreases, with the rise of the bottom wall thickness. The bending performance initially improves and then declines as the upper wall thickness increases. The inner angles of the chamber can be further optimized to enhance the bending performance of the VSBA. Consequently, a multi-objective optimization is performed based on the established metamodel. Compared to the initial design, the optimized parameters resulted in a 30.98% increase in the bending angle. Finally, a soft three-finger gripper incorporating the VSBAs is developed, demonstrating its ability to grasp various objects and highlighting the potential applications of the VSBA. The research contributes significantly to advancing the field of soft actuators and provides a reliable solution for soft robotic applications.