3D Printed Soft Actuator Evaluation: A Simulation and Experiment Approach

Abstract

The development of bending-type pneumatic soft actuators using fused deposition modelling (FDM) 3D printing has advanced significantly owing to the need for flexible and customizable components in soft robotics. Thermoplastic polyurethane (TPU), a hyperelastic material, is commonly used in this process because of its flexibility and ease of processing. Finite element (FE) simulations were conducted using a third-order Ogden model to predict and evaluate the nonlinear behavior of the TPU. The actuators were designed with three variations of the internal channel configuration: no channel, partial channel, and full channel, and wall thicknesses of 0.8, 1.0, and 1.2 mm, respectively. Each configuration was subjected to input pressures of 100, 200, and 300 kPa, and tested through both FE simulations and physical experiments under identical conditions. A mesh convergence test was performed to optimize the computational accuracy and efficiency. The results showed a close correlation between the simulated and experimental bending angles with an average deviation ranged from 3.70° to 5.83°, and the overall simulation accuracy was 96.93%. The minor discrepancies are attributed to the limitations of the material property measurements, particularly the use of uniaxial tensile data, which may not fully capture the multiaxial deformation behavior of the material. This integrated approach, which combines design variation, computational modelling, material characterization, and experimental validation, demonstrates the reliability of FE in soft actuator development and provides valuable insights for advancing applications in soft robotics and rehabilitation technologies.