skip to main content

Search for: All records

Award ID contains: 1933124

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Han, Jae-Hung ; Shahab, Shima ; Yang, Jinkyu (Ed.)
  2. null (Ed.)
    Abstract A new paradigm called physical reservoir computing has recently emerged, where the nonlinear dynamics of high-dimensional and fixed physical systems are harnessed as a computational resource to achieve complex tasks. Via extensive simulations based on a dynamic truss-frame model, this study shows that an origami structure can perform as a dynamic reservoir with sufficient computing power to emulate high-order nonlinear systems, generate stable limit cycles, and modulate outputs according to dynamic inputs. This study also uncovers the linkages between the origami reservoir’s physical designs and its computing power, offering a guideline to optimize the computing performance. Comprehensive parametric studies show that selecting optimal feedback crease distribution and fine-tuning the underlying origami folding designs are the most effective approach to improve computing performance. Furthermore, this study shows how origami’s physical reservoir computing power can apply to soft robotic control problems by a case study of earthworm-like peristaltic crawling without traditional controllers. These results can pave the way for origami-based robots with embodied mechanical intelligence . 
    more » « less
  3. Soft pneumatic actuators have become indispensable for many robotic applications due to their reliability, safety, and design flexibility. However, the currently available actuator designs can be challenging to fabricate, requiring labor-intensive and time-consuming processes like reinforcing fiber wrapping and elastomer curing. To address this issue, we propose to use simple-to-fabricate kirigami skins—plastic sleeves with carefully arranged slit cuts—to construct pneumatic actuators with pre-programmable motion capabilities. Such kirigami skin, wrapped outside a cylindrical balloon, can transform the volumetric expansion from pneumatic pressure into anisotropic stretching and shearing, creating a combination of axial extension and twisting in the actuator. Moreover, the kirigami skin exhibits out-of-plane buckling near the slit cut, which enables high stretchability. To capture such complex deformations, we formulate and experimentally validates a new kinematics model to uncover the linkage between the kirigami cutting pattern design and the actuator’s motion characteristics. This model uses a virtual fold and rigid-facet assumption to simplify the motion analysis without sacrificing accuracy. Moreover, we tested the pressure-stroke performance and elastoplastic behaviors of the kirigami-skinned actuator to establish an operation protocol for repeatable performance. Analytical and experimental parametric analysis shows that one can effectively pre-program the actuator’s motion performance, with considerable freedom, simply by adjusting the angle and length of the slit cuts. The results of this study can establish the design and analysis framework for a new family of kirigami-skinned pneumatic actuators for many robotic applications. 
    more » « less
  4. null (Ed.)
  5. null (Ed.)
    In the field of soft robotics, harnessing the nonlinear dynamics of soft and compliant bodies as a computational resource to enable embodied intelligence and control is known as morphological computation. Physical reservoir computing (PRC) is a true instance of morphological computation wherein; a physical nonlinear dynamic system is used as a fixed reservoir to perform complex computational tasks. These dynamic reservoirs can be used to approximate nonlinear dynamical systems and even perform machine learning tasks. By numerical simulation, this study illustrates that an origami meta-material can also be used as a dynamic reservoir for pattern generation, output modulation, and input sensing. These results could pave the way for intelligently designed origami-based robots that interact with the environment through a distributed network of sensors and actuators. This embodied intelligence will enable the next generations of soft robots to autonomously coordinate and modulate their activities, such as locomotion gait generation and limb manipulation while resisting external disturbances. 
    more » « less
  6. null (Ed.)
    Via analytical modeling and experimental validation, this study examines the bending stiffness adaptation of bistable origami modules based on generalized Kresling pattern. These modules, which are the building blocks of an octopus-inspired robotic manipulator, can create a reconfigurable articulation via switching between their stable states. In this way, the manipulator can exhibit pseudo-linkage kinematics with lower control requirements and improved motion accuracy compared to completely soft manipulators. A key to achieving this reconfigurable articulation is that the underlying Kresling modules must show a sufficient difference in bending stiffness between their stable states. Therefore, this study aims to use both a nonlinear bar-hinge model and experimental testing to uncover the correlation between the module bending stiffness and the corresponding origami designs. The results show that the Kresling origami module can indeed exhibit a significant change in bending stiffness because of the reorientation of its triangular facets. That is, at one stable state, these facets align close to parallel to the longitudinal axis of the cylindrical-shaped module, so the module bending stiffness is relatively high and dominated by the facet stretching. However, at the other stable states, the triangular facets are orientated close to perpendicular to the longitudinal axis, so the bending stiffness is low and dominated by crease folding. The results of this study will provide the necessary design insights for constructing a fully functional manipulator with the desired articulation behavior. 
    more » « less
  7. null (Ed.)
    Soft pneumatic actuators have found many applications in robotics and adaptive structures. Traditionally, these actuators are constructed by wrapping layers of reinforcing helical fibers around an elastomeric tube. This approach is versatile and robust, but it suffers from a critical disadvantage: cumbersome fabrication procedures. Wrapping long helical filaments around a cylindrical tube requires expensive equipment or excessive manual labor. To address this issue, we propose a new approach towards designing and constructing pneumatic actuators by exploiting the principle of kirigami, the ancient art of paper cutting. More specifically, we use “kirigami skins” — plastic sleeves with carefully arranged slit cuts — to replace the reinforcing helical fibers. This paper presents an initial investigation on a set of linear extension actuators featuring kirigami skins with a uniform array of cross-shaped, orthogonal cuts. When under internal pressurization, the rectangular-shaped facets defined by these cuts can rotate and induce the desired extension motion. Through extensive experiments, we analyze the elastic and plastic deformations of these kirigami skins alone under tension. The results show strongly nonlinear behaviors involving both in-plane facet rotation the out-of-plane buckling. Such a deformation pattern offers valuable insights into the actuator’s performance under pressure. Moreover, both the deformation characteristics and actuation performance are “programmable” by tailoring the cut geometry. This study lays down the foundation for constructing more capable Kirigami-skinned soft actuators that can achieve sophisticated motions. 
    more » « less