Optimal design and experimental validation of 3D printed soft pneumatic actuators

This study develops a novel design of a unit cell-based bending-type soft pneumatic actuator, and formulates the design problem as compliant mechanisms under design-dependent pressure loadings. The proposed design is first optimized by using a topology optimization algorithm, in which the design-dependent loads and fluid-structure interface are tracked and formulated via finite element based approaches. Then, to validate the optimized design, it is modeled numerically using finite element analysis (FEA) and compared with the non-optimized traditional rectangular design. The optimal design can provide 19.5% improvements in bending angle. In addition, the proposed optimal design is prototyped using 3D printing. The prepared single actuator specimens are tested under pneumatic pressure, and the measured deformations are compared with those obtained from FEA. The results reveal that the optimized design can undergo large and compliant deformations under pneumatic pressure and generate a full ( 360 ∘ ) bending. Furthermore, multiple actuator specimens of the proposed design are also assembled and integrated to prototype soft pneumatic grippers, with which several grasping tests are conducted. The adaptability and compatibility of the soft gripper are verified via gripping a wide range of irregular, soft, and fragile objects.