Design and Analysis of a Soft Bidirectional Bending Actuator for Human-Robot Interaction Applications

The design of a novel, soft bidirectional actuator which can improve the human-robot interactions in collaborative applications is proposed in this paper. This actuator is advantageous over the existing designs due to the additional degree of freedom for the same number of pressure inputs as found in the conventional designs. This improves the workspace of the bidirectional actuator significantly and is able to achieve higher angles of bidirectional bending at much lower values of input pressure. This is achieved by eliminating the passive impedance offered by one side of the bending chamber in compression when the other side of the chamber is inflated. A simple kinematic model of the actuator is presented and theoretical and finite element analysis is carried out to predict the fundamental behavior of the actuator. The results are validated through experiments using a fabricated model of the soft bidirectional bending actuator.