A single origami crease pattern can be folded into many different structures from the flat-unfolded state, effectively transforming in shape and function. This makes origami engineering a promising approach to transforming machines, but predicting and controlling this transformation is difficult because the fundamental dynamics of origami systems at the flat-unfolded state are not well understood. Working with Miura-inspired mechanisms, we identify and validate a model to predict configuration switching in mechanical origami systems. The model incorporates a hidden degree of freedom introduced by material compliance in the Miura mechanism. We characterize this pseudojoint statically and dynamically to identify its lumped stiffness and inertia and use it to create a new dynamic model. This model can be used to predict which configuration an origami mechanism will settle in by balancing the kinetic and potential energy of the system. We apply this model to design a branching origami structure with 17 distinct configurations controlled by a single actuator and demonstrate reliable switching between these configurations with tailored dynamic inputs. Given the fact that origami can replicate almost any shape, we expect that this framework will be applicable to transformation in arbitrary structures and mechanisms.

Origami-inspired machines are a promising approach to robotic transformation. In this letter, we present a new method for transformation that uses dynamic response to change the mountain-valley fold pattern. We propose a dynamic model and validate it through experimental characterization of sample mechanisms. We demonstrate that these mechanisms reliably change their dynamic behavior at a discrete switching frequency, and this frequency can be changed by varying the stiffness and mass of the mechanism. This indicates that mechanisms can be designed to respond to different frequencies and selectively transform from a global input. We demonstrate a three-fingered gripping mechanism with a single actuator that can transform between four nontrivial configurations. We believe that this approach can be applied to several types of origami structures.

Origami structures can transform their form and function by changing the direction of their folds. This reconfiguration can enable multifunctional robots, but doing so requires a fast, robust, and repeatable actuation method. In this article, we present an origami gripper that uses dynamic transformation to change its kinematic behavior in less than a second. We characterize individual vertices to show that the transformation is predictable and repeatable for different designs and orientations. We then apply it to a multivertex template that is capable of a wide range of shapes and motion patterns, indicating that transformation can be generalized to complex and functional machines. To demonstrate this, we built a transforming origami gripper on a robotic arm to pick up multiple objects. Demonstrations show that the gripper can quickly reconfigure between three different grasping modes and has sufficient stiffness to engage with and lift multiple objects with distinct geometries.

Origami structures have gained tremendous attention due to their extreme kinematic performance. However, typical origami structures suffer from poor load-bearing capacity due to extreme slenderness of facets. In this letter, we introduce a technique to design an origami-equivalent compliant mechanism which preserves the origami kinetics and kinematics while offering higher load-bearing capacity compared to the original origami structure. In this technique, we offer an energy equivalence principle between the origami and the compliant mechanism. We validate the principle using experimental investigation for a square-twist origami pattern. This principle thus opens up a significant avenue for designing deployable and programmable structures.