Origami is an ancient art, transforming a paper sheet into a three-dimensional structure. Due to the superiorly foldable properties, it has great potential for various engineering fields, such as deployable structures, robotics, architectures and materials. Rigid origami is a special type of origami, where its creases and facets can be regarded as hinges and rigid links, respectively. Hence, a single-vertex rigid origami consisting of at least four creases meeting at one point can be considered as a spherical linkage. A rigid origami pattern with a lot of vertices forms a mobile assembly of spherical linkages. According to the mobility of the assembly, rigid origami can be classified into two groups, one-DOF origami and multi-DOF origami. The multi-DOF origami generally consists of the six-crease origami vertex and the five-crease origami vertex. As multi-DOF origami patterns can be deployed to variable configurations, they have been widely used in morphing robots. However, sometimes one motion characteristic is needed, it is a challenge to accurately control a multi-DOF origami system. Reducing the DOF of multi-DOF origami patterns and obtaining one-DOF origami patterns with the equivalently and symmetrically kinematic property are the main objectives.
        Dr. Xiao Zhang and Prof. Yan Chen of the Department of Mechanical Engineering, Tianjin University, proposed a vertex-splitting technique to reduce the DOF based on a six-crease origami vertex. This technique is applied to the multi-vertex diamond origami pattern to produce six types of one-DOF basic assemblies. Then, forty-two types of one-DOF origami patterns are obtained, one of which mixed with four-, five-, and six-crease vertices. This technique can be applied to other multi-DOF origami patterns and help to realize single drive control. The six types of one-DOF basic assemblies form a new rule in the one-DOF determination in complex origami patterns and the design of large-scale one-DOF origami patterns.

(a) The one-DOF origami pattern with four- and six-crease vertices, (b) the one-DOF origami pattern with four-, five-, and six-crease vertices, (c) the multi-DOF diamond origami pattern.

        The research result was accepted by Journal of Mechanisms and Robotics of ASME on 4th March 2019 and published in volume 11, issue 3 in June 2019. (DOI: 10.1115/1.4043214)

Xiao Zhang, Yan Chen, 2019, Vertex-Splitting on a Diamond Origami Pattern, ASME J. Mech. Rob., 11(3): 031014. (https://doi.org/10.1115/1.4043214)