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Origami shape transformation is dictated by predefined folding patterns and their folding sequence. The working principle of robotic origami is based on the same principle: we design quasi-2D tiles and connecting hinges and define and program their folding sequences. Since the tiles are often of uniform shape and size, their final configuration is governed by the kinematic relationship. Mathematicians, computer scientists and even architects have studied a wide range of origami algorithms. However, for multiple shape transformations, the origami design parameters and consequently sequence planning become more challenging. In this work, we present a reconfigurable interactive interface, a physicsbased modeling control interface to explore the design space of origami robots. We developed two interactive modes for proof of concept of a bidirectional communication interface between virtual and physical environments. The first interaction mode is origami-inspired, foldable surfaces with distributed sensors that can recreate folding sequences and shape transformations in a virtual environment via hardware-in-loop simulation. Its complementary digital transcription lays the foundation for a robotic origami design tool that provides visual representation of various design formulations as well as an intuitive controller for robotic origami. In the second interaction mode, we construct a physics-based modeling interface for intuitive user manipulation of robotic origami in a virtual environment. Algorithms for graphical representation and command transformation were developed for robotic interaction. Lastly, we tested the efficacy of the algorithms on prototypes to discover the applications and capacities of the reconfigurable interactive interface.

Understanding the external environment depends heavily on vision, audition, and touch. Like vision and audition, the human sense of touch is complex. Tactile perception is composed of multiple fundamental and physical experiences felt as changes in stiffness, texture, shape, size, temperature, and weight by the skin. While researchers and industries have made continuous efforts to abstract and recreate these haptic experiences, haptic devices are still limited in invoking intricate and rich sensations. Herein, the design, model, and experimental validation of a wearable skin-like interface, able to recreate the roughness, shape, and size of a perceived object is presented; a platform for an interactive "physical" experience. The cogency of immersion through tactile feedback on moldable clay by the user response from the active haptic feedback, is examined. For the experimental test, a soft pneumatic actuator (SPA)-skin interface (90 Hz bandwidth) with a complex actuation pattern is prototyped. The SPA-skin's performance using three sets of simulated textures (<300 μm) and for reconstructing simulated contours (of a rectangle, circle, or trapezoid) in the virtual reality (VR) platform is investigated. The experimental results demonstrated for the first time how artificially created tactile feedback can indeed simulate physical interaction, with 83% average accuracy for contour reconstruction.

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This paper presents the proof-of-concept for a 4D printed active compliant hinge with a selectively variable stiffness for the deployment and reorientation of satellite appendages. We use 4D printing to create an active compliant hinge capable of bending to a given angular position, holding the position without consuming energy and reorienting itself multiple times in a slow and controlled manner without using rigid mechanisms and, therefore, requiring no lubrication. The deployment and the reorientation of the hinge are achieved by exploiting thermally induced stiffness modulation of one of the constituting materials and two antagonistic shape memory alloy actuators. The hinge is specifically designed for the case study of a 6U CubeSat with two orientable solar panels. In this work, we first explain the working principle of the hinge and propose three different actuation strategies to increase the energy collection of the considered CubeSat. Second, we describe the specific functional and geometric requirements of the hinge, the resulting design and the fabricated functional prototype. The latter is tested in a standard laboratory environment to measure the range of motion, the energy consumption and the actuation time. Finally, the feasibility of the three proposed actuation strategies is evaluated considering the corresponding net increase in collected energy. The results show that the hinge is compatible with the stowing requirements and capable of achieving maximum angular positions larger than 90 • in both directions and holding any intermediate position with an accuracy of less than 3 • . The three actuation strategies considered lead, in a standard laboratory environment, to an increase in energy generation between 54% and 72%.

A dual‐band terahertz metamaterial absorber using one‐layer periodically patterned hexagon graphene structure is proposed. By periodically loading six graphene stubs to the honeycomb hexagon graphene structure without increase of the overall size, a new high‐frequency absorption peak will be obtained to realize a dual‐band frequency response. By tuning the structural parameters or Fermi energy levels of the presented terahertz metamaterial absorber, both of the two absorption bands will be changed to the required working frequencies for design specifications. Moreover, the proposed terahertz metamaterial absorber has the properties of polarization independence and incident angle insensitivity, which are of great significance in the applications of some detecting and sensing systems. This work will be a good candidate for the design guidance of various metamaterial absorbers using graphene with single or dual absorption bands.

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