A Novel Wavy Soft Pneumatic Actuator Combining Variable Thickness and an Unconstrained Base

This letter proposes novel wavy soft pneumatic actuators (WSPAs) that integrates an unconstrained base with an elastic chamber of varying wall thicknesses. The base plate design eliminates bottom constraints, thereby enhancing the bending performance of WSPAs. Wavy elastomer cavities with varying wall thicknesses can minimize radial expansion of the top wall and compress the volume of the cavity, further improving response speed of WSPAs. The effects of varying chamber structures on the bending angle, terminal output force, response velocity, and stress distribution were investigated by finite element simulations and experiment. Key parameters of the actuator were analyzed to acquire their effect on bending characteristics through finite element simulation. Experimental assessments of the functional behavior of WSPAs were conducted, including bending angle tests, spatial pose evaluations, and terminal output force measurements. Under an air pressure of 50 kPa, the WSPAs achieved a bending angle of 294°, while at 40 kPa, the terminal output force reached 3.072 N. Furthermore, a three-claw soft gripper was developed, featuring a working range of D170 mm, capable of handling a weight of 806 g and objects of various shapes.