Origami Folding Enhances Modularity and Mechanical Efficiency of Soft Actuators

Soft robots have long been attractive to robotic engineers due to their remarkable dexterity; however, reports that standardize soft actuators into modularized off-shelf devices akin to rigid robots are still rare, and the mechanical efficiency of existing designs is still limited. This work identifies origami folding to enable the design of LEGO-like modularized soft actuators with high mechanical efficiency in terms of payload capability and workspace. Herein, three modularized origami actuators that can generate translational, bending, and twisting motion are designed, prototyped, and tested. The translational actuator can contract to 40% of its original length, and the twisting and bending actuators can exert 31 degrees and 52 degrees angular motions, respectively. The translational actuator can exert a blocked force of about 821 times self-weight. The motion of origami soft actuators is accurately modeled using rigid body kinematics, and complex systems built by them are captured by homogeneous transformation. Finally, the modularized design and efficient kinematic model are verified on a manipulator and a reconfigurable letter. Benefiting from the unprecedented modularity and mechanical efficiency, these LEGO-like origami actuators are promising for practical applications like food handling and healthcare.