Kinematic Model and Numerical Evaluation of an Origami-Inspired Soft Pneumatic Actuator

In recent years, origami structures have been gradually applied in fields not associated with art, such as robotics, aerospace, electronics, and bio-mechanics by using both, soft and hard materials. Furthermore, origami is a powerful design tool for achieving mechanical intelligence in Soft Robotics. Origami folding in combination with smart materials has been explored for constructing transformable mechanisms while simplifying designing, fabrication, and assembly, to yield compliance and exhibit soft body properties. This paper presents a pneumatic soft actuator with contraction motion actuated by negative pressure, which design is inspired by a variant of Yoshimura’s origami pattern. The main geometrical parameters according to the crease pattern, composed of 4 levels, are described. Moreover, we introduce a kinematic model based on a geometric representation of the i- th level of the actuator, considering that the contraction motion is homogeneous at each level. We derived an equation to describe the total displacement based on the sum of the contraction of the 4 levels. The kinematic model is numerically evaluated through FEM simulations to estimate its performance throughout the actuator’s range of motion. We exhibit a numerical evaluation considering no-homogeneous contraction in each level, finding an error of 2.6 % between both evaluations.