Fused Deposition Modelling for 3D Printing of Soft Anthropomorphic Actuators

Abstract

Soft actuators are increasingly gaining attention in the robotics community due to several favourable properties rooted mainly in their inherent compliance. They are safe, can easily grasp different objects, and cheap to manufacture. However, particularly in the case of FDM (Fused Deposition Modelling) printed actuators, their design is usually an iterative process that relies on intuition due to complex material models, nonlinearities, large deformations, and residual stresses caused by imperfect interlayer structure. This makes such actuators difficult to model and control and limits their implementation despite some comparative advantages over the other 3D printing technologies. In this study, to characterize the properties of FDM printed soft actuators, we compare a simple but computationally effective linear model with a realistic experimentally generated hyperelastic material model of a soft actuator. Based on these insights, we 3D print a fully operational soft anthropomorphic hand and use it in a set of experiments to evaluate the limitations of the models and suggest design and printing parameters to improve soft actuators' performance.