Wohlhart 6R linkage-based asymmetric deployable structures with generalised contours

Deployable structures based on rigid mechanisms are unconventional structures that can achieve transformations from compact folded states to fully deployed surfaces. The mechanisms are of very low or even single mobility, making the deployment process simpler. Such structures have found significant applications across various fields such as architecture, aerospace engineering, and robotics. Currently, the constituent mechanisms of these structures often come with symmetric geometric conditions, thereby yielding symmetric contours. However, this symmetry requirement makes it less desirable for specific scenarios where more generalised shapes are required. To fill the gap, this paper introduces two novel asymmetric deployable structures whose outlines can be arbitrary triangles based on the Wohlhart 6R linkage. The first structure is made from rod links, capable of transforming between two plane-like states. The second one is a modified version that incorporates rigid panels of uniform thickness as links, which can be folded from a long triangular prism to a shorter one. Their kinematic behaviours are analyzed in detail and validated by physical prototypes. We have also identified viable approaches to tessellating both structures into networks for large-scale applications. This work lays a crucial step towards the construction of asymmetric deployable structures with generalised contours.